Battery

Abstract

The utility model 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] This application relates to the field of battery technology, and more particularly to a battery. Background Technology

[0002] Metal-packaged batteries are a type of battery that uses a metal casing as the encapsulation material. The metal casing includes a bottom case and a sealing cap, which are typically made of aluminum or steel and provide a robust protective structure for the battery.

[0003] In related technologies, laser welding is used to weld the sealing cap to the bottom shell; however, laser welding is expensive to manufacture and often results in incomplete or incomplete welding, leading to poor sealing of the metal shell. Utility Model Content

[0004] In view of the above problems, this application provides a battery to solve the problems of high manufacturing cost and poor sealing performance of metal casing in related technologies.

[0005] To achieve the above objectives, the embodiments of this application provide the following technical solutions:

[0006] This application provides a battery comprising: a cell including a cell body and a tab assembly extending from one side of the cell body; a bottom shell having an opening; a sealing cap covering the opening to form a sealed cavity within the bottom shell, the cell being located in the sealed cavity; the sealing cap including a body and a sidewall extending from the side of the body near the bottom shell, the sidewall surrounding the opening; a bending structure provided at the opening, the bending structure including: a connected bending portion and a flange, the bending portion being connected to the edge of the opening, the bending portion and / or the flange being connected to the sidewall via a sealant layer; at least one end of the sealant layer extending beyond the overlapping area of ​​the bending structure and the sidewall.

[0007] In one embodiment of this application, the bent portion includes an arc-shaped protrusion with its apex facing the body. One end of the arc-shaped protrusion is connected to the edge of the opening, and the other end of the arc-shaped protrusion is connected to the first end of the flange. The tail end of the flange extends away from the body. The intersection of the sidewall and the body has a first arc-shaped corner. One end of the sealant layer overflows between the arc-shaped protrusion and the first arc-shaped corner, and / or, the other end of the sealant layer overflows between the tail end of the flange and the sidewall.

[0008] In one embodiment of this application, the bent portion includes a first horizontal connecting section and a second arc-shaped corner and a third arc-shaped corner disposed at both ends of the first horizontal connecting section. The second arc-shaped corner is connected to the edge of the opening, and the third arc-shaped corner is connected to the first end of the flange. The tail end of the flange extends close to the body. The flange surrounds the outer periphery of the sidewall, and one end of the sealant layer overflows from between the tail end of the flange and the sidewall.

[0009] In one embodiment of this application, the bent portion includes a first horizontal connecting segment and a second arc-shaped corner and a third arc-shaped corner disposed at both ends of the first horizontal connecting segment. The second arc-shaped corner is connected to the edge of the opening, and the third arc-shaped corner is connected to the first end of the flange. The tail end of the flange extends close to the body. The sidewall surrounds the outer periphery of the flange. The intersection of the sidewall and the body has a first arc-shaped corner. 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 sidewall.

[0010] In one embodiment of this application, the tail end of the flange is further connected to a second horizontal connecting segment disposed opposite to the first horizontal connecting segment. The second horizontal connecting segment is connected to the body through the sealant layer, and one end of the sealant layer overflows from between the second horizontal connecting segment and the body.

[0011] In one embodiment of this application, the end of the sidewall away from the body includes a fastening flange bent toward the sealing cavity, and the fastening flange abuts against a portion of the first horizontal connecting segment.

[0012] In one embodiment of this application, the bottom shell includes a bottom surface opposite to the body. A boss protruding towards the body is provided on the bottom surface, the boss being close to the edge of the bottom surface. The sealing cavity formed between the bottom surface and the body is a first receiving cavity. The sealing cavity formed between the boss and the body is a second receiving cavity, and the second receiving cavity communicates with the first receiving cavity. The electrode assembly includes a positive electrode and a negative electrode, the positive electrode being located within the second receiving cavity. A post hole is also provided on the boss, a positive electrode post passing through the post hole and connected to the positive electrode. The negative electrode is connected to the sealing cavity.

[0013] In one embodiment of this 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 element, the content of the cadmium metal element is greater than 3000PPM.

[0014] In one embodiment of this application, the sealant layer includes a first adhesive layer, a second adhesive layer, and a third adhesive layer stacked sequentially, wherein 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 this application, the battery cell body includes a plurality of positive electrode plates and a plurality of negative electrode plates, as well as positive flexible tabs and negative flexible tabs extending from the edges of the plurality of positive electrode plates. The positive flexible tabs and positive rigid tabs are welded together, and the negative flexible tabs are welded together with the bottom shell. The battery cell also includes protective adhesive paper covering the solder marks of the positive flexible tabs and positive rigid tabs. In the battery thickness direction, the projection of the sealing adhesive layer beyond the overlapping area of ​​the bending structure and the sidewall partially overlaps with the projection of the positive flexible tab; and / or, the projection of the sealing adhesive layer beyond the overlapping area of ​​the bending structure and the sidewall does not overlap with the projection of the positive electrode plate.

[0016] In one embodiment of this application, the sealant layer covers the entire sealing cap; and / or, the width of the sealant layer beyond the overlapping area of ​​the bent structure and the sidewall is <2mm; and / or, in the battery thickness direction, the height of the sidewall is >0.5mm; and / or, the cell body includes a plurality of positive electrode plates and a plurality of negative electrode plates, the negative electrode plate 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.

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

[0018] By incorporating a bent structure at the opening of the bottom shell, when the sealing cap is placed over the opening, the bent structure connects with the side wall of the sealing cap, increasing the contact area at the junction of the bottom shell and the sealing cap, thereby enhancing the connection strength between the bottom shell and the sealing cap. Simultaneously, a sealing layer is provided between the bent structure and the side wall of the sealing cap, thus fixing the bottom shell and the sealing cap together, improving the connection stability and sealing effect, and enhancing battery reliability. Furthermore, the sealing layer has low manufacturing cost and a simple manufacturing process. Moreover, the bent structure, without affecting the battery's width dimension, further increases the overlap area of ​​the bottom shell, sealing layer, and side wall of the sealing cap, preventing external moisture from entering the casing through the space between the sealing layer and the bottom shell or the sealing layer and the side wall of the sealing cap, extending the possible path length for moisture entry, and further ensuring the airtightness of the casing.

[0019] Furthermore, the overflow of the sealant layer also prevents external moisture from entering the sealed cavity through the gaps between the bent structure and the sidewalls, while also ensuring complete insulation between the bottom shell and the sealing cap. Additionally, the bottom shell and sealing cap are bonded together by the sealant layer. When thermal runaway occurs inside the cell, the heat generated by the cell is conducted to the shell, causing the sealant layer to melt. This creates a pressure relief channel between the sealant layer and the bottom shell, allowing air inside the battery to be released promptly through the sealant layer and the bottom shell. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A schematic diagram of the battery casing provided in the embodiments of this application. Figure 1 ;

[0022] Figure 2 Cross-section of the battery casing in its thickness direction as provided in the embodiments of this application Figure 1 ;

[0023] Figure 3 for Figure 2 Enlarged view of section A;

[0024] Figure 4 Cross-section of the battery casing in its thickness direction as provided in the embodiments of this application Figure 2 ;

[0025] Figure 5 for Figure 4 Enlarged view of section B;

[0026] Figure 6 Cross-section of the battery casing in its thickness direction as provided in the embodiments of this application Figure 3 ;

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

[0028] Figure 8 Cross-section of the battery casing in its thickness direction as provided in the embodiments of this application Figure 4 ;

[0029] Figure 9 for Figure 8 Enlarged view of section D;

[0030] Figure 10Cross-section of the battery casing in its thickness direction as provided in the embodiments of this application Figure 5 ;

[0031] Figure 11 Cross-section of the battery casing in its thickness direction as provided in the embodiments of this application Figure 6 ;

[0032] Figure 12 A schematic diagram of the battery casing provided in the embodiments of this application. Figure 2 ;

[0033] Figure 13 A cross-sectional view of the battery in the thickness direction provided in an embodiment of this application.

[0034] Figure label:

[0035] 100 - Bottom shell;

[0036] 101-Injection hole; 102-Pole post hole; 103-Bottom surface; 104-Boss;

[0037] 200 - Sealing cap;

[0038] 201-Body; 202-Side wall; 203-First arc-shaped corner; 204-Fastening flange;

[0039] 300 - Sealant layer;

[0040] 301 - First extension segment; 302 - Second extension segment; 303 - Third extension segment; 304 - Fourth extension segment; 305 - Fifth extension segment;

[0041] 400 - Bending section;

[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 terminal;

[0044] 600 - Cell body;

[0045] 601 - Positive electrode tab; 602 - Positive soft electrode tab; 603 - Protective adhesive paper. Detailed Implementation

[0046] To make the above-mentioned objectives, features, and advantages of the embodiments of this application more apparent and understandable, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0047] In this embodiment of the 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 casing provided in this application embodiment includes: a battery cell, a bottom shell 100, and a sealing cap 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 shell 100 has an opening.

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

[0052] A sealing cover 200 is provided over the opening of the bottom shell 100 to form a sealed cavity inside the bottom shell 100 for installing the battery cell.

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

[0054] Or, refer to Figure 4 The side wall 202 is arranged around the opening, and the opening of the bottom shell 100 is provided with a bent structure. When the sealing cover 200 is placed over the opening of the bottom shell 100, the bent structure is arranged around the outer periphery of the side wall 202; that is, at this time the bent structure surrounds the outer wall surface of the side wall 202.

[0055] The connection between the bent structure and the side wall 202 can increase the contact area at the junction 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.

[0056] The bending structure includes: a bent portion 400 and a flange 402 connected together, the bent portion 400 being connected to the edge of the opening, and the bent portion 400 and / or the flange 402 being connected to the sidewall 202 through a sealant layer 300.

[0057] In other words, a sealant layer 300 is provided between the side wall 202 and the bent 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 bent portion 400, or to bond the side wall 202 and the flange 402, thereby fixing the bottom shell 100 and the sealing cover 200 together.

[0058] Meanwhile, at least one end of the sealant layer 300 extends beyond the overlapping area of ​​the bent structure and the sidewall 202.

[0059] In other words, at least one end of the sealant layer 300 may overflow between the bend 400 and the sidewall 202, or at least one end of the sealant layer 300 may overflow between the flange 402 and the sidewall 202.

[0060] By incorporating 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, thereby enhancing the reliability of the battery. Furthermore, the sealing layer 300 has low manufacturing cost and a simple manufacturing process. Moreover, the bending structure, without affecting the battery's width dimension, further increases the overlap area of ​​the bottom shell, sealing layer, and sealing cover sidewalls, preventing external moisture from entering the casing through the space between the sealing layer and the bottom shell or between the sealing layer and the sealing cover sidewalls, thus extending the possible path length for moisture entry and further ensuring the airtightness of the casing.

[0061] Furthermore, the overflow of the sealant layer 300 also prevents external moisture from entering the sealed cavity through the gap between the bent structure and the side wall 202, while ensuring complete insulation between the bottom shell 100 and the sealing cover 200. When thermal runaway occurs inside the cell, the heat generated by the cell is conducted to the shell, causing the sealant layer to melt. This creates a pressure relief channel between the sealant layer and the bottom shell, allowing air inside the battery to be released in a timely manner through the space between the sealant layer and the bottom shell.

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

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

[0064] In this embodiment of the application, the first threshold can be 100 degrees.

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

[0066] In this embodiment, the width of the sealant layer 300 extending beyond the overlapping area of ​​the bent structure and the sidewall 202 is less than 2mm. That is, the distance between the edge of the overflow portion of the sealant layer 300 and the edge of the overlapping area is less than 2mm. This ensures complete insulation between the bottom shell 100 and the sealing cover 200, saves costs, maintains the aesthetics of the battery, and prevents the sealant layer from extending excessively into the bottom shell, thus affecting the energy density inside the cell.

[0067] In this embodiment, the height of the sidewall 202 in the battery thickness direction is greater than 0.5mm, thereby ensuring the sealing width and sealing effect.

[0068] refer to Figure 2 and Figure 3 In the first embodiment, the bent portion 400 includes an arcuate 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, and the other end of the arc-shaped protrusion 401 is connected to the head end of the flange 402. The tail end of the flange 402 extends away from the body 201.

[0070] In other words, the bent structure extends out from the edge of the opening, avoiding 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 cap 200 covers 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; the intersection of the side wall 202 and the body 201 has a first arc-shaped corner 203 to make the side wall 202 and the body 201 transition smoothly; 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] In other words, in this embodiment, the sealant layer 300 is located in the vertical and bent portions of the bent structure, which can effectively improve the bonding strength and sealing performance of the sealing cap 200 and the bottom shell 100, thereby improving the reliability of the battery casing.

[0075] In this embodiment, both the first arc-shaped corner 203 and the arc-shaped protrusion 401 are arc-shaped bends, and the arc angles of the first arc-shaped corner 203 and the arc-shaped protrusion 401 are the same. The arc-shaped bends do not have sharp right-angle edges, which can more evenly distribute stress, making the battery casing more robust and stable.

[0076] In this embodiment, 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 to Figure 3 In this embodiment of the 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, the end of the sealant layer 300 located between the first arc-shaped corner 203 and the arc-shaped protrusion 401 has a first extension 301, which is attached to the body 201 and extends into the sealed cavity; the end of the sealant layer 300 located between the inner wall surface of the side wall 202 and the flange 402 has a second extension 302, which is exposed outside the battery casing from the end of the side wall 202; wherein the end of the side wall 202 is away from the body 201.

[0079] In this embodiment, in the direction of the body 201 toward the bottom shell 100 (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 302 exposed outside the battery shell from the end of the side wall 202 can be tightly attached to the flange 402.

[0080] The first extension 301 and the second extension 302 are both overflow portions of the sealant layer 300. The first extension 301 is the portion of the sealant layer 300 that overflows into the sealing cavity, and the second extension 302 is the portion of the sealant layer 300 that overflows outside the sealing cavity and at the bonding point between the bottom shell 100 and the sealing cover 200.

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

[0082] The second extension section 302 can prevent external moisture from entering the sealing cavity through the gaps in the bending structure and the side wall 202, while further improving 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 segment 403 and a second arc-shaped corner and a third arc-shaped corner disposed at both ends of the first horizontal connecting segment 403.

[0084] On 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 spaced apart, the second arc-shaped corner is connected to the edge of the opening, the third arc-shaped corner is connected to the first end of the flange 402, and the tail end of the flange 402 extends close to the main body 201.

[0085] In other words, the bending structure extends from the edge of the opening toward the sealing cover 200. When the sealing cover 200 covers 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 sealing cavity formed after the sealing cover 200 is connected to the bottom shell 100 increases, so as to be suitable for various types of battery cells.

[0086] In this embodiment, when the sealing cap 200 covers 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 sealing cavity; and the flange 402 surrounds the outer periphery of the outer wall surface of the side wall 202.

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

[0088] The end of the side wall 202 abuts against the first horizontal connecting section 403 to form a sealed cavity, serving as the first layer of seal; the sealing adhesive layer 300 provided in the vertical part of the bent structure serves as the second layer of seal, which can effectively improve the bonding strength and sealing performance of the sealing cover 200 and the bottom shell 100, thereby improving the reliability of the battery casing.

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

[0090] In other words, the end of the sealant layer 300 located between the outer wall surface of the side wall 202 and the flange 402 also includes a third extension 303, which protrudes from the tail end of the flange 402 outside the battery casing.

[0091] The third extension 303 is the portion of the sealant layer 300 that overflows outside the sealing cavity and at the bonding joint between the bottom shell 100 and the sealing cover 200. The third extension 303 can prevent external moisture from entering the sealing cavity through the gaps in 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 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 segment 403 and a second arc-shaped corner and a third arc-shaped corner disposed at both ends of the first horizontal connecting segment 403.

[0094] On 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 spaced apart, the second arc-shaped corner is connected to the edge of the opening, the third arc-shaped corner is connected to the first end of the flange 402, and the tail end of the flange 402 extends close to the main body 201.

[0095] In other words, the bending structure extends from the edge of the opening toward the sealing cover 200. When the sealing cover 200 covers 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 sealing cavity formed after the sealing cover 200 is connected to the bottom shell 100 increases, so as to be suitable for various types of battery cells.

[0096] In this embodiment, when the sealing cap 200 covers 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] The side wall 202 of the sealing cover 200 intersects with the body 201 and has a first arc-shaped corner 203. There is a gap between the tail end of the flange 402 and the first arc-shaped corner 203.

[0098] A sealant layer 300 is provided between the inner wall surface of the side wall 202 and the flange 402. One end of the sealant layer 300 overflows from the tail end of the flange 402 and the first arc-shaped corner 203 and extends to the 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 body 201 through the gap between the tail end of the flange 402 and the first arc-shaped corner 203, and extends into the sealing cavity while adhering tightly to the body 201.

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

[0100] Meanwhile, the fourth extension 304 of the sealant layer 300, as the overflow portion of the sealant layer 300 within the sealing cavity, extends beyond the first arc-shaped corner 203 and into the sealing cavity, thereby contacting and reacting with the electrolyte, extending the cycle performance and service life of the battery cell; preventing gaps from forming after the sealant layer 300 in the overlapping area of ​​the bent structure and side wall 202 reacts with the electrolyte, thus affecting the overall sealing performance; at the same time, the sealant layer 300 extends inward, thereby fixing the bottom shell 100 and the sealing cover 200 in the battery thickness direction and battery width direction, preventing them from shifting in the battery thickness direction and battery width direction, improving the bonding strength of the bottom shell 100 and the sealing cover 200, and also ensuring complete insulation between the bottom shell 100 and the sealing cover 200.

[0101] Continue to refer to Figure 7 In this embodiment of the application, the end of the sidewall 202 is far away from the body 201. The end of the sidewall 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 around the bent structure, so that the end of the side wall 202 is engaged with the bent structure. At the same time, it is also bonded by the sealant layer 300, which further improves the connection strength between the bottom shell 100 and the sealing cover 200.

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

[0104] On 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 spaced apart, the second arc-shaped corner is connected to the edge of the opening, the third arc-shaped corner is connected to the first end of the flange 402, and the tail end of the flange 402 extends close to the main body 201.

[0105] In other words, the bending structure extends from the edge of the opening toward the sealing cover 200. When the sealing cover 200 covers 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 sealing cavity formed after the sealing cover 200 is connected to the bottom shell 100 increases, so as to be suitable for various types of battery cells.

[0106] In this embodiment, when the sealing cap 200 covers 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 of the body 201 toward 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 body 201 through a sealing layer 300. One end of the sealing layer 300 overflows from between the second horizontal connecting section 405 and the body 201.

[0108] The intersection of the side wall 202 of the sealing cap 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 disposed between the first arc-shaped corner 203 and the fourth arc-shaped corner 406, and also between the second horizontal connecting section 405 and the body 201.

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

[0111] In this embodiment, the sealant layer 300 is located in the vertical and bent portions of the bent structure, which can effectively improve the bonding strength and sealing performance of the sealing cap 200 and the bottom shell 100, thereby improving the reliability of the battery casing.

[0112] Compared to the third embodiment, the fourth embodiment adds a second horizontal connecting section 405 extending into the sealed cavity. At the same time, the sealing adhesive layer 300 also extends into the sealed cavity along with the second horizontal connecting section 405, thereby simultaneously 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), preventing the sealing cover 200 from shifting.

[0113] Continue to refer to Figure 9 In this embodiment, the other end of the sealant layer 300 overflows from between the first 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 305, which protrudes from the end of the side wall 202 outside the battery casing; wherein, the end of the side wall 202 is away from the body 201 of the sealing cover 200.

[0114] The fifth extension 305 is the portion of the sealant layer 300 that overflows outside the sealing cavity and at the bonding joint between the bottom shell 100 and the sealing cover 200. The fifth extension 305 can further improve the bonding strength between the bottom shell 100 and the sealing cover 200, and can also prevent external moisture from entering the sealing cavity.

[0115] Continue to refer to Figure 9 In this embodiment of the application, the second horizontal connecting segment 405 is parallel to and spaced apart from the body 201 of the sealing cover 200 to ensure the connection stability of the sealing adhesive layer 300 between the second horizontal connecting segment 405 and the body 201.

[0116] In this embodiment, in the direction of the main body 201 toward the bottom shell 100 (Z-axis shown in the figure), the lengths of the ends of the first extension segment 301, the second extension segment 302, the third extension segment 303, the fourth extension segment 304, and the fifth extension segment 305 are all less than 2 mm. This saves costs while ensuring complete insulation between the bottom shell 100 and the sealing cover 200.

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

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

[0119] The boss 104 is also provided with a pole hole 102, and a positive pole 500 is inserted into the pole hole 102. The positive pole 500 is connected to the positive tab 601.

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

[0121] By placing the positive electrode tab 601 inside the second receiving cavity, the space used by the cell 600 is saved, thereby improving the energy density of the battery.

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

[0123] In this embodiment, the surface of the sealant layer 300 has a nickel plating layer, which is used to improve the corrosion resistance of the sealant layer 300.

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

[0125] The nickel plating layer contains cadmium, with a cadmium content greater than 3000 PPM.

[0126] In this embodiment, the sealant layer 300 includes a first adhesive layer, a second adhesive layer, and a third adhesive layer stacked sequentially. The first adhesive layer, the second adhesive layer, and the third adhesive layer have different melting points, and 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, so as to improve the stability of the sealant layer 300.

[0127] In this embodiment, the sealant layer 300 includes a first adhesive layer, a second adhesive layer, and a third adhesive layer stacked sequentially. The first adhesive layer, the second adhesive layer, and the third adhesive layer have different melting points. The melting point of the second adhesive layer is higher than that of the first adhesive layer and the third adhesive layer. This characteristic of being higher in the middle and lower on both sides can ensure the stability of the sealant layer 300.

[0128] In this embodiment of the application, the battery cell body 600 includes a plurality of positive electrode plates and a plurality of negative electrode plates, as well as positive electrode soft tabs 602 extending from the edges of the plurality of positive electrode plates and negative electrode soft tabs extending from the edges of the plurality of negative electrode plates. The positive electrode soft tabs 602 and the positive electrode hard tabs are welded together, and the negative electrode soft tabs are welded together with the sealing cavity of the bottom shell 100.

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

[0130] Along the battery thickness direction (Z-axis shown in the figure), the projection of the sealant layer 300, which extends beyond the overlapping area of ​​the bent structure and sidewall 202, partially overlaps with the projection of the positive electrode tab 602. In other words, the sealant layer 300 within the sealed cavity can separate the positive electrode tab 601 from the bottom shell 100 or the sealing cover, preventing the positive electrode tab 601 from wobbling back and forth during a battery drop, which could easily lead to contact and short circuits with the bottom shell 100 or the sealing cover.

[0131] Alternatively, in the battery thickness direction (Z-axis shown in the figure), the projection of the sealant layer 300 beyond the overlapping area of ​​the bent structure and the sidewall 202 does not overlap with the projection of the positive electrode sheet. That is, the sealant layer 300 and the cell body do not overlap in the thickness direction, thereby avoiding the impact on the energy density of the cell.

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

[0133] In another embodiment, a heat-sealing layer is also formed between the cell body and the sealing cap. The heat-sealing layer is used to bond the cell body and the sealing cap and prevent the cell body from shifting 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 cell and affecting the energy density.

[0134] In summary, this application provides a battery comprising: a battery cell, a bottom shell 100, a sealing cap 200, and a sealing layer 300. The battery cell includes a battery cell body 600 and a tab assembly extending from one side of the battery cell body 600. The bottom shell 100 has an opening. The sealing cap 200 covers the opening to form a sealed cavity within the bottom shell 100, the sealed cavity being used to install the battery cell. The sealing cap 200 includes a body 201 and a sidewall 202 extending from the side of the body 201 near the bottom shell 100, the sidewall 202 surrounding the opening. A bending structure is provided at the opening. The bending structure includes: a bent portion 400 and a flange 402 connected together, the bent portion 400 being connected to the edge of the opening, and the bent portion 400 and / or the flange 402 being connected to the sidewall 202 via the sealing layer 300. At least one end of the sealing layer 300 extends beyond the overlapping area of ​​the bending structure and the sidewall 202.

[0135] By incorporating a bending structure at the opening of the bottom shell 100, when the sealing cover 200 is placed over the opening, the bending structure connects with the side wall 202 of the sealing cover 200, increasing the contact area at the junction of the bottom shell 100 and the sealing cover 200, thereby enhancing the connection strength between the bottom shell 100 and the sealing cover 200. Simultaneously, a sealing adhesive layer 300 is provided between the bending structure and the side wall 202 of the sealing cover, thus fixing the bottom shell 100 and the sealing cover 200 together, improving the connection stability and sealing performance, and enhancing the reliability of the battery. Furthermore, the sealing adhesive layer 300 has low manufacturing cost and a simple manufacturing process.

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

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

[0138] The various embodiments or embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other.

[0139] It should be noted that the terms "one embodiment," "embodiment," "exemplary embodiment," "some embodiments," etc., mentioned in the specification indicate that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not, is within the knowledge scope of those skilled in the art.

[0140] Generally speaking, terms should be understood at least in part by their use in context. For example, at least in part by context, the term "one or more" as used in the text can be used to describe any feature, structure, or characteristic of the singular meaning, or a combination of features, structures, or characteristics of the plural meaning. Similarly, at least in part by context, terms such as "a" or "the" can also be understood to convey either singular or plural usage.

[0141] It should be readily understood that the terms “on,” “above,” and “on top of” in this disclosure should be interpreted in the broadest possible sense, such that “on” means not only “directly on something” but also “on something” with an intermediate feature or layer therebetween, and that “above” or “on top of” means not only “on top of something” but also “on top of something” without an intermediate feature or layer therebetween (i.e., directly on something).

[0142] Furthermore, for ease of explanation, spatially relative terms such as "below," "below," "under," "above," and "above" may be used 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 other than those shown in the figures. The device may have other orientations (rotated 90 degrees or in other orientations), and the spatially relative descriptive terms used herein may be interpreted accordingly.

[0143] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this 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 having an opening; A sealing cap is provided over the opening to form a sealed cavity within the bottom housing, and the battery cell is located in the sealed cavity; The sealing cap includes a body and a sidewall extending from the side of the body near the bottom shell, the sidewall being disposed around the opening; The opening is provided with a bending structure, which includes a bent part and a flange connected together. The bent part is connected to the edge of the opening, and the bent part and / or the flange are connected to the side wall through a sealant layer. At least one end of the sealant layer extends beyond the overlapping area of ​​the bent structure and the sidewall.

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

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

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

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

6. The battery according to claim 4, characterized in that, The end of the sidewall away from the 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 includes a bottom surface, which is opposite to the body. A protrusion protruding towards the body is provided on the bottom surface, and the protrusion is close to the edge of the bottom surface. The sealed cavity formed between the bottom surface and the body is a first receiving cavity; The sealing cavity formed between the boss and the body is a second receiving cavity, and the second receiving cavity is connected to the first receiving cavity; The electrode assembly includes a positive electrode and a negative electrode, with the positive electrode located within the second receiving cavity; The protrusion is also provided with a pole hole, and a positive pole is inserted into the pole hole and connected to the positive electrode tab; The negative electrode tab 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 plating layer; The thickness of the nickel plating layer is 0.5um-5um.

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 stacked sequentially, wherein 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 main body of the battery cell includes multiple positive electrode plates and multiple negative electrode plates, as well as positive soft electrode tabs extending from the edges of the multiple positive electrode plates and negative soft electrode tabs extending from the edges of the multiple negative electrode plates. The positive soft electrode tabs and positive hard electrode tabs are welded together, and the negative soft electrode tabs are welded together with the bottom shell. The battery cell also includes protective adhesive paper covering the solder marks of the positive soft tab and the positive hard tab; In the battery thickness direction, the projection of the sealant layer beyond the overlapping area of ​​the bent structure and the sidewall partially overlaps with the projection of the positive electrode tab; / or, The projection of the sealant layer beyond the overlapping area of ​​the bent structure and the sidewall 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 cap; and / or, The width of the sealant layer extending beyond the overlapping area of ​​the bent structure and the sidewall is <2 mm, and / or, In the battery thickness direction, the height of the sidewall is >0.5mm, and / or The main body of the battery cell includes multiple positive electrode plates and multiple negative electrode plates. The negative electrode plate includes a negative current collector and a negative active layer located on the negative current collector.

Images