Battery

Abstract

The utility model provides a battery, which comprises a battery cell, a battery cover and a battery cover, the packaging body is used for packaging the battery cell and comprises a first side part and a second side part, a first main body part of the first side part and a second main body part of the second side part are respectively positioned on two opposite sides of the battery cell, a first connecting part of the first side part is connected with a second connecting part of the second side part, and the electric conductor extends out from a connecting part of the first connecting part and the second connecting part; the distance between the first connecting part and the first main body part in the first direction is greater than the distance between the second connecting part and the second main body part in the first direction; the first insulating glue comprises a first glue layer connected with the electric conductor and a third glue layer connected with the first connecting part; the second insulating glue comprises a fourth glue layer connected with the electric conductor and a sixth glue layer connected with the second connecting part; the melting point of the third adhesive layer is greater than that of at least one of the first adhesive layer, the fourth adhesive layer and the sixth adhesive layer. According to the utility model, the packaging reliability, high-temperature safety and other performances of the battery can be improved.

Description

Technical Field

[0001] The utility model relates to the field of electrochemical energy storage devices, in particular to a battery. Background Art

[0002] Batteries are common electrochemical energy storage devices, widely used in consumer electronics, electric vehicles, power tools and other products. However, in related technologies, the performance of battery packaging reliability and high temperature safety needs to be further improved.

[0003] Specifically, a battery usually includes a battery cell and a package that encapsulates the battery cell. The battery cell is provided with a pole ear extending from a sealing portion of the package. The sealing portion from which the pole ear extends is connected by a package, a pole ear glue bonded between the package and the pole ear, and a multi-layer structure such as the pole ear. The package has a deep pit side and a shallow pit side. At the sealing portion, an extension range of the deep pit side toward the shallow pit side is greater than an extension range of the shallow pit side toward the deep pit side, that is, a depression depth of the deep pit side is greater than a depression depth of the shallow pit side. Therefore, the center of the battery cell is more inclined toward the deep pit side. When the battery is subjected to mechanical abuse such as falling or impact, tearing, breakage, and resulting battery leakage are likely to occur between the deep pit side and the pole ear at the sealing portion from which the pole ear extends. Utility Model Content

[0004] The utility model provides a battery, which can improve the bonding strength between the package body on the deep pit side and the conductors such as the pole ears extending out of the package body, avoid tearing and damage between the package body and the conductor on the deep pit side and the battery leakage caused by the tearing and damage, thereby improving the falling safety of the battery on the deep pit side, while taking into account the high temperature safety and other performances of the battery.

[0005] In one aspect of the utility model, a battery is provided, comprising: a battery cell provided with a conductor; a package encapsulating the battery cell, comprising a first side portion and a second side portion, the first side portion comprising a first main body portion and a first connecting portion connected to each other, the second side portion comprising a second main body portion and a second connecting portion connected to each other, the first main body portion and the second main body portion are respectively located on opposite sides of the battery cell, the first connecting portion is connected to the second connecting portion, and the conductor extends from a connecting portion between the first connecting portion and the second connecting portion; a distance between the first connecting portion and the first main body portion in a first direction is greater than a distance between the second connecting portion and the second main body portion in the first direction, and the first direction is parallel to a direction from the first main body portion to the second main body portion; a first insulating glue is provided between the conductor and the first connecting portion; the first insulating glue comprises a first glue layer connected to the conductor, and a third glue layer connected to the first connecting portion; a second insulating glue is provided between the conductor and the second connecting portion; the second insulating glue comprises a fourth glue layer connected to the conductor, and a sixth glue layer connected to the second connecting portion; the melting point of the third glue layer is greater than the melting point of at least one of the first glue layer, the fourth glue layer, and the sixth glue layer.

[0006] According to one embodiment of the utility model, the packaging body includes a first adhesive layer, the first adhesive layer of the first connecting part is connected to the third adhesive layer, and the first adhesive layer of the second connecting part is connected to the sixth adhesive layer; preferably, the difference between the melting point of the first adhesive layer and the melting point of the third adhesive layer is 0 to 40°C.

[0007] According to one embodiment of the utility model, the melting point of the first adhesive layer is 95-130°C; and / or, the melting point of the third adhesive layer is 120-165°C; and / or, the first adhesive layer includes one or more of a propylene-ethylene copolymer layer, a butene-modified polypropylene layer, a polyethylene layer, a maleic anhydride grafted modified polypropylene layer, a metallocene-modified polypropylene layer, and a maleic anhydride grafted modified polyethylene layer; and / or, the third adhesive layer includes one or more of a polypropylene layer, an anhydride grafted modified polypropylene layer, and an ethylene-modified polypropylene layer; and / or, the fourth adhesive layer The melting point is 95 to 130°C; and / or, the melting point of the sixth adhesive layer is 95 to 130°C; and / or, the fourth adhesive layer includes one or more of a propylene-ethylene copolymer layer, a butene-modified polypropylene layer, a polyethylene layer, a maleic anhydride grafted modified polypropylene layer, a metallocene-modified polypropylene layer, and a maleic anhydride grafted modified polyethylene layer; and / or, the sixth adhesive layer includes one or more of a propylene-ethylene copolymer layer, a butene-modified polypropylene layer, a polyethylene layer, a maleic anhydride grafted modified polypropylene layer, a metallocene-modified polypropylene layer, and a maleic anhydride grafted modified polyethylene layer.

[0008] According to one embodiment of the utility model, the first insulating adhesive further includes a second adhesive layer located between the first adhesive layer and the third adhesive layer; preferably, the melting point of the second adhesive layer is greater than the melting point of the first adhesive layer; preferably, the melting point of the second adhesive layer is greater than or equal to the melting point of the third adhesive layer; preferably, the melting point of the second adhesive layer is 140 to 170°C; preferably, the second adhesive layer includes one or more of a polypropylene layer and an anhydride grafted modified polypropylene layer.

[0009] According to one embodiment of the utility model, the second insulating adhesive further includes a fifth adhesive layer located between the fourth adhesive layer and the sixth adhesive layer; preferably, the melting point of the fifth adhesive layer is greater than the melting point of the fourth adhesive layer and / or the sixth adhesive layer; preferably, the difference between the melting points of the fifth adhesive layer and the fourth adhesive layer is 10 to 75°C; preferably, the difference between the melting points of the fifth adhesive layer and the sixth adhesive layer is 10 to 75°C; preferably, the melting point of the fifth adhesive layer is 140 to 170°C; preferably, the fifth adhesive layer includes one or more of a polypropylene layer and an anhydride grafted modified polypropylene layer.

[0010] According to an embodiment of the present invention, the sixth adhesive layer includes a fluorescent adhesive layer.

[0011] According to one embodiment of the present utility model, the thickness of the first insulating glue is 40 to 200 μm; and / or, the width of the first insulating glue along the length direction of the conductor is 3.5 to 6 mm; and / or, the first insulating glue includes a first covering portion covering the conductor, and a first extension portion extending beyond the conductor in the width direction of the conductor, the first extension portions are respectively present on opposite sides of the first covering portion in the width direction of the conductor, and the width of each of the first extension portions in the width direction of the conductor is 1.2 to 3.5 mm; and / or, the thickness of the second insulating glue is 40 to 200 μm; and / or, the width of the second insulating glue along the length direction of the conductor is 3.5 to 6 mm; and / or, the second insulating glue includes a second covering portion covering the conductor, and a second extension portion extending beyond the conductor in the width direction of the conductor, the second extension portions are respectively present on opposite sides of the second covering portion in the width direction of the conductor, and the width of each of the second extension portions in the width direction of the conductor is 1.2 to 3.5 mm.

[0012] According to one embodiment of the utility model, the package body includes a supporting layer, a metal layer, and a first adhesive layer, and the first adhesive layer of the first connecting part is connected to the third adhesive layer; preferably, the supporting layer includes one or more of a nylon layer, a polyethylene terephthalate layer, and a polyethylene naphthalate layer; preferably, the metal layer includes one or more of an aluminum layer, an aluminum alloy layer, a copper layer, and a steel layer; preferably, the first adhesive layer includes one or more of an acid-modified polypropylene layer, an ethylene-modified polypropylene layer, and a polypropylene layer; preferably, the tensile strength of the package body is greater than or equal to 69 MPa; preferably, the elongation of the package body is less than or equal to 55%.

[0013] According to one embodiment of the utility model, the 180° peeling force between the conductor and the first connecting part is greater than the 180° peeling force between the conductor and the second connecting part; preferably, the difference between the 180° peeling force between the conductor and the first connecting part and the 180° peeling force between the conductor and the second connecting part is 0.2~2.3N / mm; preferably, the 180° peeling force between the conductor and the first connecting part is 2.2~5.6N / mm; preferably, the 180° peeling force between the conductor and the second connecting part is 1.8~4.1N / mm.

[0014] According to one embodiment of the utility model, a distance between a side surface of the first connecting portion facing away from the first main body portion in the first direction and a side surface of the first main body portion facing away from the first connecting portion in the first direction is 2 mm to 10 mm; and / or a distance between a side surface of the second connecting portion facing away from the second main body portion in the first direction and a side surface of the second main body portion facing away from the second connecting portion in the first direction is 0 to 10 mm; and / or a thickness of the package body is 60 μm to 160 μm.

[0015] In the battery provided by the utility model, the first side is a deep pit side, and the second side is a shallow pit side (the distance between the first connection part and the first main body in the first direction is greater than the distance between the second connection part and the second main body in the first direction), at the sealing part of the battery (i.e. the connection part between the first connection part of the first side and the second connection part of the second side), the first insulating glue is used to connect the first connection part and the conductor on the deep pit side, and the second insulating glue is used to connect the second connection part and the conductor on the shallow pit side, and the melting point of the third glue layer is greater than the melting point of at least one of the first glue layer, the fourth glue layer and the sixth glue layer. In this way, the third glue layer with a higher melting point is connected to the packaging body (the first connection part) on the deep pit side, which can provide The bonding strength between the package body and the conductor on the deep pit side is increased, thereby improving the packaging strength of the sealing part and the packaging reliability of the battery, and avoiding tearing, breakage, and battery leakage caused by the package body and the conductor on the deep pit side when the battery is subjected to mechanical abuse such as falling and collision; at the same time, at least one of the first glue layer, the fourth glue layer, and the sixth glue layer is a low-melting-point layer with a lower melting point. When the battery encounters high temperature, the low-melting-point layer can be melted, thereby forming an opening in the sealing part where the conductor extends out, and the gas generated inside the battery is depressurized and heat is released through the opening, thereby preventing the battery from catching fire, exploding, and other problems, thereby improving the safety of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of a battery structure showing a first sealing portion of an embodiment of the utility model;

[0017] Figure 2 A schematic diagram of a battery structure showing a second sealing portion of an embodiment of the utility model;

[0018] Figure 3 A schematic diagram of a local structure of a battery showing a first conductor and a second conductor from the deep pit side according to an embodiment of the utility model;

[0019] Figure 4 A schematic diagram of a local structure of a battery showing a first conductor and a second conductor from a shallow pit side according to an embodiment of the utility model;

[0020] Figure 5 It is a schematic diagram of the projection structure of a battery along its thickness direction according to an embodiment of the utility model.

[0021] Explanation of the reference numerals: 1: packaging body; 11: first side portion; 111: first main body portion; 112: first extension portion; 113: first connection portion; 12: second side portion; 121: second main body portion; 122: second extension portion; 123: second connection portion; 2: battery cell; 21: conductor; 211: first conductor; 212: second conductor; 3: first insulating glue; 31: first glue layer; 32: second glue layer; 33: third glue layer; 301: first covering portion; 302: first extension portion; 4: second insulating glue; 41: fourth glue layer; 42: fifth glue layer; 43: sixth glue layer; 401: second covering portion; 402: second extension portion; 5: insulating glue; 100: sealing portion; 101: top sealing edge; 102: side sealing edge; 110: first sealing portion; 120: second sealing portion; T: thickness; w 1 、w 2 : Width; L 1 , L' 1 , L 2 : distance; x: first direction; y: second direction; z: third direction. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the scheme of the utility model, the utility model is further described in detail below. The specific implementation methods listed below are only for describing the principles and features of the utility model. The examples are only used to explain the utility model and do not limit the scope of the utility model. Based on the embodiments of the utility model, all other implementation methods obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0023] In related technologies, battery safety and packaging reliability and other performance need to be further improved.

[0024] Specifically, the battery includes a cell and a package that encapsulates the cell. The cell includes a positive electrode assembly, a negative electrode assembly, a separator, and an electrolyte. The cell is also provided with a tab, which includes a positive tab provided on the positive electrode assembly and a negative tab provided on the negative electrode assembly. Both the positive tab and the negative tab extend out of the package to be used for electrical connection between the battery and external electronic products. The package includes a sealing portion, and the tab extends out of the package from the sealing portion. The package is usually bonded to the tab by tab glue to form a closed environment inside the package to isolate moisture and air and ensure the sealing performance of the cell.

[0025] Among them, the package has a deep pit side and a shallow pit side. At the sealing part, the extension range of the deep pit side to the shallow pit side is greater than the extension range of the shallow pit side to the deep pit side, that is, the depression depth of the deep pit side is greater than the depression depth of the shallow pit side. Therefore, the center of the battery cell is more biased towards the deep pit side. When the battery is subjected to mechanical abuse such as falling and impact, the sealing part where the pole ear extends is formed by bonding a multi-layer structure with weak bonding strength. The package on the deep pit side and the pole ear are prone to tearing, breakage and other problems, which in turn lead to battery leakage (i.e. leakage of electrolyte) and other problems.

[0026] In addition, when the battery encounters a violent impact during use or is improperly used during charging and discharging, etc., the temperature of the battery cell may rise sharply (for example, the impact may cause the positive and negative electrode coatings to fall off the current collector, causing a short circuit between the positive and negative electrodes, and increasing the internal temperature of the battery; improper charging and discharging, such as overcharging of the battery cell, long-term continuous high voltage, and low stability of the battery cell may cause high temperature). Under high temperature, the electrolyte, CEI membrane and SEI membrane decompose, the side reactions of the positive and negative electrodes intensify, and the diaphragm shrinks due to the heat, further causing a short circuit between the positive and negative electrodes and increased heat generation, which leads to heat accumulation inside the battery, a sharp increase in temperature, and the generation of a large amount of gas, which may easily cause fire and explosion problems.

[0027] For example, lithium-ion batteries have the characteristics of high energy density, high voltage and long cycle life, and are widely used in products such as consumer electronics, electric vehicles and power tools. At present, higher and higher requirements are put forward for the fast charging and capacity performance of lithium-ion batteries. In order to improve the energy density of lithium-ion batteries, soft packaging materials (soft packaging films) are usually used to package the battery cells. At the same time, the negative electrode also adopts a silicon-doped negative electrode (that is, the negative electrode active material layer of the negative electrode sheet introduces silicon-based negative electrode active materials). Although such improvements can improve the energy density of lithium-ion batteries to a certain extent, they also aggravate the following problems: (1) Poor high-temperature safety. When lithium-ion batteries encounter high temperatures, heat accumulates inside them, which can easily cause fires. (2) Poor packaging reliability and sealing performance. For example, the silicon-doped negative electrode will expand during the battery cycle, resulting in bulging, which can easily cause damage to the package and leakage. At the same time, when the battery encounters mechanical abuse such as falling and impact, it is easy to cause the package to crack at the corners and surface damage, especially the sealing part where the tabs protrude. The package and the tabs on the deep pit side are more likely to tear and break, which can lead to battery leakage.

[0028] In view of this, the present invention provides a battery, such as Figures 1 to 5As shown, the battery comprises: a battery cell 2, provided with a conductor 21; a package body 1 that packages the battery cell 2, comprising a first side portion 11 and a second side portion 12, the first side portion 11 comprising a first main body portion 111 and a first connecting portion 113 that are connected to each other, the second side portion 12 comprising a second main body portion 121 and a second connecting portion 123 that are connected to each other, the first main body portion 111 and the second main body portion 121 are respectively located on opposite sides of the battery cell 2, the first connecting portion 113 is connected to the second connecting portion 123, the conductor 21 extends from the connecting portion between the first connecting portion 113 and the second connecting portion 123; the distance between the first connecting portion 113 and the first main body portion 111 in the first direction x is greater than the distance between the second connecting portion 123 and the second main body portion 121 in the first direction x, and the first direction x is parallel to the direction along the first main body portion 1 11 to the direction of the second main body part 121 (that is, the first main body part 111 and the second main body part 121 are respectively located on the opposite sides of the battery core in the first direction x (one side is the first main body part 111 and the other side is the second main body part 121)); a first insulating glue 3 is arranged between the conductor 21 and the first connecting part 113, and the first insulating glue 3 includes a first glue layer 31 connected to the conductor 21, and a third glue layer 33 connected to the first connecting part 113; a second insulating glue 4 is arranged between the conductor 21 and the second connecting part 123, and the second insulating glue 4 includes a fourth glue layer 41 connected to the conductor 21, and a sixth glue layer 43 connected to the second connecting part 123; the melting point of the third glue layer 33 is greater than the melting point of at least one of the first glue layer 31, the fourth glue layer 41 and the sixth glue layer 43.

[0029] In the embodiment of the utility model, the first insulating glue 3 and the second insulating glue 4 with a multi-layer structure are introduced into the sealing part 110 of the battery, which can improve the packaging strength and reliability of the battery while maintaining the high temperature safety and other performance of the battery.

[0030] Specifically, the distance between the first connecting portion 113 and the first main body portion 111 in the first direction x is greater than the distance between the second connecting portion 123 and the second main body portion 121 in the first direction x, that is, the sealing portion 100 of the battery is closer to the second side portion 12, that is, the extension range of the first side portion 11 toward the second side portion 12 is greater than the extension range of the second side portion 12 toward the first side portion 11, the first side portion 11 is the deep pit side, and the second side portion 12 is the shallow pit side.

[0031] Among them, the first insulating glue 3 is used to connect the first connecting part 113 and the conductor 21 on the deep pit side, and the second insulating glue 4 is used to connect the second connecting part 123 and the conductor 21 on the shallow pit side. The third glue layer 33 in the first insulating glue 3 is a high melting point layer with a higher melting point, which can improve the bonding strength between the first connecting part 113 and the conductor 21, and effectively avoid the connection part between the first connecting part 113 and the conductor 21 (that is, the connection part between the deep pit side and the conductor 21) from tearing, damage, and the resulting battery leakage. At the same time, the third glue layer 33 in the first insulating glue 3 is a high melting point layer with a higher melting point, which can improve the bonding strength between the first connecting part 113 and the conductor 21, and effectively avoid the connection part between the first connecting part 113 and the conductor 21 (that is, the connection part between the deep pit side and the conductor 21) from tearing, damage, and the resulting battery leakage. At least one of the first glue layer 31, the fourth glue layer 41 and the sixth glue layer 43 is a low melting point layer with a relatively low melting point. When the battery encounters a high temperature condition (such as a high temperature caused by a short circuit of the positive and negative electrodes due to mechanical effects such as an impact on the battery, a high temperature caused by thermal abuse such as improper charging and discharging, etc.), the low melting point layer can be melted, so that an opening is formed in the sealing portion 100 where the conductor 21 extends. The gas generated inside the battery is depressurized and heat is released through the opening, thereby preventing the battery from catching fire, exploding, and other problems, thereby improving the safety of the battery.

[0032] Therefore, the embodiments of the utility model can improve the packaging reliability of the battery. When the battery encounters mechanical abuse such as collision and falling, it is not easy to cause tearing, breakage, and battery leakage caused by this. At the same time, it can also improve the high-temperature safety of the battery and prevent the battery from catching fire and other thermal runaway phenomena. In particular, it can solve the problems of poor packaging reliability and poor high-temperature safety of lithium-ion batteries using silicon-doped negative electrodes and / or soft packaging materials.

[0033] refer to Figures 1 to 5 The first sealing portion 110 includes an insulating glue 5 , and the insulating glue 5 includes a first insulating glue 3 disposed between the conductor 21 and the first connecting portion 113 and a second insulating glue 4 disposed between the conductor 21 and the second connecting portion 123 .

[0034] Continue to refer Figures 1 to 5 The first connection part 113 is connected to the second connection part 123, and the connection part between the two is the sealing part 100 of the battery, that is, at the sealing part 100, the first connection part 113 and the second connection part 123 are attached to each other and connected together, specifically, they can be glued together, so that the package body is surrounded by a closed cavity, and the battery cell 2 is located in the closed cavity, thereby realizing the packaging of the battery cell 2.

[0035] Among them, the sealing part 100 includes a first sealing part 110 and a second sealing part 120, and the conductor 21 extends out of the package 1 from the first sealing part 110, that is, the first sealing part 110 is a sealing part 100 with a conductor (such as a pole ear) 21 extending out, and the second sealing part 120 is a sealing part 100 without a conductor 21 extending out.

[0036] like Figure 1 , Figure 3 , Figure 4 and Figure 5 As shown, at the first sealing portion 110, the conductor 21 and the first connecting portion 113 are connected by the first insulating glue 3, specifically, they are bonded by the first insulating glue 3, that is, the first glue layer 31 of the first insulating glue 3 is bonded to the conductor 21, and the third glue layer 33 of the first insulating glue 3 is bonded to the first connecting portion 113; at the same time, the conductor 21 and the second connecting portion 123 are connected by the second insulating glue 4, specifically, they are bonded by the second insulating glue 4, that is, the fourth glue layer 41 of the second insulating glue 4 is bonded to the conductor 21, and the sixth glue layer 43 of the second insulating glue 4 is bonded to the second connecting portion 123.

[0037] like Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, at the second sealing portion 120 , the first connection portion 113 and the second connection portion 123 are directly connected, that is, they are in direct contact, and there is no other film layer or other structure between them. Specifically, the first connection portion 113 and the second connection portion 123 can be bonded.

[0038] In addition, if Figure 3 , Figure 4 and Figure 5 As shown, the sealing part 100 of the battery includes a top sealing edge 101 and a side sealing edge 102 , and the conductor 21 generally extends out of the package body 1 from the top sealing edge 101 , that is, the first sealing part 110 is located at the top sealing edge 101 .

[0039] Continue to refer Figures 1 to 5 The top sealing edge 101 includes a first sealing portion 110 and a second sealing portion 120 , and the side sealing edge 102 is entirely the second sealing portion 120 .

[0040] Continue to refer Figure 3 , Figure 4 and Figure 5 The top sealing edge 101 may be located at one side of the battery in the second direction y, and the side sealing edges 102 may be located at two opposite sides of the battery in the third direction z.

[0041] Specifically, each two of the first direction x, the second direction y and the third direction z intersect, and may be specifically perpendicular to each other, that is, the first direction x intersects with the second direction y, and the two are substantially perpendicular; the second direction y intersects with the third direction z, and the two are substantially perpendicular; the third direction z intersects with the first direction x, and the two are substantially perpendicular.

[0042] Exemplarily, the first direction x is parallel to the thickness direction of the battery (battery cell 2 ), the second direction y is parallel to the length direction of the battery (battery cell 2 ), and the third direction z is parallel to the width direction of the battery (battery cell 2 ).

[0043] Continue to refer Figures 1 to 3 The first side portion 11 also includes a first extension portion 112 connected between the first main body portion 111 and the first connecting portion 113. The first end of the first extension portion 112 is connected to the first main body portion 111, and the other end extends toward the second side portion 12 and is connected to the first connecting portion 113. That is, the first side portion 11 is bent by the first extension portion 112, and the first main body portion 111 and the first connecting portion 113 are respectively located on opposite sides of the first extension portion 112 in the second direction y. One end of the first connecting portion 113 is connected to the first extension portion 112, and the other end (that is, the end of the first connecting portion 113 away from the first extension portion 112) can specifically extend outward in the second direction y in a direction away from the battery cell 2. Specifically, the first main body portion 111 and the first extension portion 112 form a first angle, which is, for example, about 90°; the first extension portion 112 and the first connection portion 113 form a second angle, which is, for example, about 90°; the first main body portion 111 and the first connection portion 113 can be basically parallel, but are not limited to this.

[0044] Continue to refer Figure 1 , Figure 2 and Figure 4 The second side portion 12 also includes a second extension portion 122 connected between the second main body portion 121 and the second connection portion 123. The second main body portion 121 and the second connection portion 123 are respectively located on opposite sides of the second extension portion 122 in the second direction y. One end of the second connection portion 123 is connected to the second extension portion 122, and the other end (i.e., the end of the second connection portion 123 away from the second extension portion 122) can specifically extend outward in the second direction y in a direction away from the battery cell 2. Among them, the second main body portion 121, the second extension portion 122, and the second connection portion 123 can be substantially parallel (in this case, the second side portion 12 is substantially a straight structure), or the second side portion 12 is bent through the second extension portion 122, that is, a third angle is formed between the second extension portion 122 and the second main body portion 121, and a fourth angle is formed between the second extension portion 122 and the second connection portion 123.

[0045] The length of the first extension portion 112 in the first direction x is greater than the length of the second extension portion 122 in the first direction x, so that the extension range of the first side portion 11 to the second side portion 12 is greater than the extension range of the second side portion 12 to the first side portion 11 .

[0046] refer to Figure 2 The distance between the side surface of the first connecting portion 113 facing away from the first main body portion 111 in the first direction x and the side surface of the first main body portion 111 facing away from the first connecting portion 113 in the first direction x (the distance in the first direction x) is L 1The distance between the side surface of the first connecting portion 113 facing the first main body portion 111 in the first direction x and the side surface of the first main body portion 111 facing away from the first connecting portion 113 in the first direction x (the distance in the first direction x) is L' 1 The distance between the side surface of the second connecting portion 123 facing away from the second main body portion 121 in the first direction x and the side surface of the second main body portion 121 facing away from the second connecting portion 123 in the first direction x (the distance in the first direction x) is L 2 The distance between the side surface of the second connecting portion 123 facing the second main body portion 121 in the first direction x and the side surface of the second main body portion 121 facing away from the second connecting portion 123 in the first direction x (the distance in the first direction x) is L' 2 (not shown in the figure), L 1 >L 2 , L' 1 >L' 2 As mentioned above, “the distance between the first connection portion 113 and the first main body portion 111 in the first direction x is greater than the distance between the second connection portion 123 and the second main body portion 121 in the first direction x” may specifically refer to L 1 >L 2 or L' 1 >L' 2 .

[0047] Among them, a side surface of the first main body portion 111 that is away from the first connecting portion 113 in the first direction x is also a side surface of the first main body portion 111 that is away from the battery cell 2, that is, the outer side surface of the first main body portion 111; a side surface of the second main body portion 121 that is away from the second connecting portion 123 in the first direction x is also a side surface of the second main body portion 121 that is away from the battery cell 2, that is, the outer side surface of the second main body portion 121.

[0048] Generally, the thickness of the first connection portion 113 and the second connection portion 123 are substantially equal, which is substantially equal to the thickness T of the package body 1 (the thickness of each region of the package body 1 (such as the first main body portion 111, the first connection portion 113, the second main body portion 121, the second connection portion 123, etc.) is substantially equal). 1 Basically equal to L' 1 and T (i.e. L 1 =L' 1 +T), L 2 Basically equal to L' 2 and T (i.e. L 2 =L' 2 +T).

[0049] Specifically, a distance L between a side surface of the first connection portion 113 facing away from the first main body portion 111 in the first direction x and a side surface of the first main body portion 111 facing away from the first connection portion 113 in the first direction x is 1 It may be in the range of 2 mm to 10 mm, for example, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm or a range consisting of any two of them.

[0050] Specifically, a distance L between a side surface of the second connection portion 123 facing away from the second main body portion 121 in the first direction x and a side surface of the second main body portion 121 facing away from the second connection portion 123 in the first direction x is 2 It can be 0 to 10 mm, for example, 0 (i.e., the second main body portion 121, the second extension portion 122, and the second connection portion 123 are substantially parallel), 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm or a range consisting of any two of them.

[0051] Specifically, the thickness T of the package body 1 may be 60 μm to 160 μm, for example, 60 μm, 80 μm, 100 μm, 120 μm, 140 μm, 150 μm, 160 μm or a range consisting of any two thereof.

[0052] Specifically, the bonding force between the conductor 21 and the first connection portion 113 may be greater than the bonding force between the conductor 21 and the second connection portion 123. The bonding force may be the 180° peeling force measured by the 180° peeling force test method, that is, the 180° peeling force F between the conductor 21 and the first connection portion 113. 1 Greater than the 180° peeling force F between the conductor 21 and the second connecting portion 123 2 (i.e. the package tension F on the deep pit side 1 Greater than the package tension F on the shallow pit side 2 ), the difference between the two (F 1 -F 2 ) may be greater than or equal to 0.2 N / mm, specifically 0.2 to 2.3 N / mm, for example 0.2 N / mm, 0.4 N / mm, 0.8 N / mm, 1 N / mm, 1.3 N / mm, 1.5 N / mm, 1.8 N / mm, 2 N / mm, 2.3 N / mm or any two thereof, preferably F 1 -F 2 It is 0.4~2.3N / mm.

[0053] In some embodiments, the 180° peeling force F between the conductor 21 and the first connecting portion 113 is 1It may be 2.2 to 5.6 N / mm, for example, 2.2 N / mm, 2.5 N / mm, 3 N / mm, 3.5 N / mm, 3.8 N / mm, 4 N / mm, 4.2 N / mm, 4.5 N / mm, 5 N / mm, 5.6 N / mm or a range consisting of any two thereof.

[0054] In some embodiments, the 180° peeling force F between the conductor 21 and the second connecting portion 123 is 2 The molecular weight may be in the range of 1.8 to 4.1 N / mm, for example, 1.8 N / mm, 2.3 N / mm, 3 N / mm, 3.2 N / mm, 3.5 N / mm, 3.7 N / mm, 4 N / mm, 4.1 N / mm or a range consisting of any two thereof.

[0055] In the embodiment of the utility model, a conventional tensile testing machine in the art (such as a universal tensile testing machine (digital tensile testing machine)) can be used to perform a 180° peeling force test. The 180° peeling force F 1 、F 2 All represent the peeling force per unit length (i.e. F 1 F represents the tensile force used to separate the conductor 21 and the first connecting portion 113 per unit length by using a tensile testing machine, 2 = 180° peeling force F between the conductor 21 and the first connecting portion 113 1 Taking the test process of as an example, during the test, the composite structure formed by bonding the conductor 21 and the first connecting portion 113 together is removed from the battery and cut into a sample to be tested of a preset shape and size (the width of the sample to be tested is w 0 ), the sample to be tested is placed on the tensile machine for a 180° peeling force test. During the test, the upper and lower ends of the tensile machine perform a 180° tension test on the sample to be tested. The test part is the wide side of one side of the sample to be tested in the width direction (the wide side of the conductor 21 is covered by the upper end of the tensile machine, and the wide side of the first connecting part 113 is covered by the lower end of the tensile machine, that is, the entire wide side of the conductor 21 and the entire wide side of the first connecting part 113 are subjected to tension). The upper end of the tensile machine pulls the conductor 21 upward, and the lower end pulls the first connecting part 113 downward, so as to pull and peel the conductor 21 and the first connecting part 113. The maximum tension in the peeling process (usually the tension corresponding to the separation phenomenon between the conductor 21 and the first connecting part 113) is measured as F 10 , and then according to F 1 =F 0 / w 0 The 180° peeling force F between the conductor 21 and the first connecting portion 113 is obtained. 1 .

[0056] In a specific implementation, the battery cell can be packaged by a heat sealing process, and the packaging process may include: cutting the substrate used to form the package body 11 into a sheet (package body 1) of a preset shape and size, and then folding the sheet in half along its length direction to form a first side portion 11 and a second side portion 12, respectively, placing the battery cell between the first side portion 11 and the second side portion 12, and then fitting the edge sealing (first connecting portion 113) of the first side portion 11 and the edge sealing (second connecting portion 123) of the second side portion 12, and making the first connecting portion 113, the first insulating glue 3, the conductor 21, the second insulating glue 4 and the second connecting The connecting parts 123 are stacked in sequence, and then heat-sealed under preset temperature and pressure conditions, so that the first connecting part 113, the first insulating glue 3, the conductor 21, the second insulating glue 4 and the second connecting part 123 of the first sealing part 110 are heat-sealed together (that is, the first connecting part 113, the first insulating glue 3, the conductor 21, the second insulating glue 4 and the second connecting part 123 are bonded in sequence), and the first connecting part 113 and the second connecting part 123 of the second sealing part 120 are heat-sealed together (that is, the first connecting part 113 and the second connecting part 123 are bonded), so as to realize the packaging of the battery cell 2.

[0057] In addition, if Figure 1 As shown, the first insulating adhesive 3 may further include a second adhesive layer 32 located between the first adhesive layer 31 and the third adhesive layer 33, the melting point of the second adhesive layer 32 is greater than the melting point of the first adhesive layer 31, and the melting point of the second adhesive layer 32 may be greater than or equal to the melting point of the third adhesive layer 33. In this way, the second adhesive layer 32 serves as a skeleton support for the first insulating adhesive 3, and the second adhesive layer 32 and the third adhesive layer 33 have high melting points, which can avoid the first insulating adhesive 3 being squeezed out too much during the heat-sealing process of the sealing part 100 (i.e., the process of heat-sealing the first connecting part 113, the first insulating adhesive 3 and the conductor 21 together), resulting in too little adhesive between the first connecting part 113 and the conductor 21, and thus preventing the sealing part 100 from being sealed. This avoids the increased probability of breakdown of the conductor 21 and the first connecting part 113 under high pressure due to too little glue between the conductor 21 and the first connecting part 113, which in turn causes a short circuit and an increased risk of electrochemical corrosion, as well as the resulting weak bonding force between the conductor 21 and the first connecting part 113 and low packaging strength of the sealing part 100, thereby further improving the packaging reliability of the battery; at the same time, as mentioned above, the first glue layer 31 is a low melting point layer with a relatively low melting point, which is conducive to forming an opening through the first glue layer 31 when the battery encounters high temperature, thereby achieving directional pressure relief of the battery through the opening, thereby avoiding problems such as fire and explosion of the battery.

[0058] In addition, if Figure 1As shown, the second insulating adhesive 4 may further include a fifth adhesive layer 42 located between the fourth adhesive layer 41 and the third adhesive layer 43, and the melting point of the fifth adhesive layer 42 is greater than the melting point of at least one of the fourth adhesive layer 41 and the sixth adhesive layer 43. In this way, the melting point of the fifth adhesive layer 42 is relatively high, which can avoid the second insulating adhesive 4 being squeezed out too much during the heat sealing process of the sealing part 100 (i.e., the process of heat-sealing the conductor 21, the second insulating adhesive 4 and the second connecting part 123 into one), resulting in too little adhesive between the second connecting part 123 and the conductor 21, as well as the resulting weak bonding force between the two, low packaging strength of the sealing part 100, and other problems, thereby further improving the packaging reliability of the battery. At the same time, as mentioned above, at least one of the fourth glue layer 41 and the sixth glue layer 43 has a lower melting point, that is, at least one of the fourth glue layer 41 and the sixth glue layer 43 is a low melting point layer. When the battery encounters a high temperature condition (such as the high temperature caused by the short circuit of the positive and negative electrodes caused by mechanical effects such as impact, the high temperature caused by thermal abuse such as improper charging and discharging, etc.), the low melting point layer can be melted, so that an opening is formed in the first sealing part 110, and the gas generated inside the battery is depressurized and heat is released through the opening, thereby further preventing the battery from catching fire, exploding, and other problems, and improving the thermal safety and other performance of the battery.

[0059] After further research, it is found that the melting point of the fifth adhesive layer 42 is greater than the melting point of the fourth adhesive layer 41 and the melting point of the sixth adhesive layer 43, that is, the fourth adhesive layer 41 and the sixth adhesive layer 43 are both low melting point layers. In this way, when the battery encounters high temperature, the fourth adhesive layer 41 and the sixth adhesive layer 43 can be melted, which is more conducive to the formation of an opening in the first sealing part 110. The gas generated inside the battery is depressurized and heat is released through the opening, further preventing the battery from catching fire, exploding and other problems, and improving the thermal safety and other performance of the battery.

[0060] Specifically, the package body 1 may include a flexible packaging material (flexible packaging film), for example, a packaging film containing a metal layer (such as an aluminum-plastic film, a copper-plastic film), etc.

[0061] Generally, the package body 1 may include a supporting layer (outer layer), a metal layer, and a first adhesive layer (inner layer), wherein the first adhesive layer is the inner layer of the package body 1, that is, the first adhesive layer is located on the side of the package body 1 facing the battery core 2, and at the first sealing portion 110, the first adhesive layer of the first connection part 113 is bonded to the third adhesive layer 33 of the first insulating glue 3, and the first adhesive layer of the second connection part 123 is bonded to the sixth adhesive layer 43 of the second insulating glue 4; at the second sealing portion 120, the first adhesive layer of the first connection part 113 is bonded to the first adhesive layer of the second connection part 123, and they can be specifically heat-sealed together through a heat sealing process.

[0062] In addition, the package body 1 also includes a second adhesive layer arranged between the support layer and the metal layer, and a third adhesive layer arranged between the metal layer and the first adhesive layer. The support layer and the metal layer are bonded by the second adhesive layer, and the metal layer and the first adhesive layer are bonded by the third adhesive layer. The second adhesive layer and the third adhesive layer can be conventional adhesive materials in the field. For example, the second adhesive layer includes a polyurethane adhesive, and its thickness is, for example, 3 to 4 μm. The third adhesive layer includes a polyacrylic acid adhesive, and its thickness is, for example, 3 to 4 μm.

[0063] Specifically, the support layer can be used as a wear-resistant protective layer, which may specifically include one or more of nylon, polyethylene terephthalate (PET), and polyethylene naphthalate (PEN). For example, the support layer includes one or more of a nylon layer, a polyethylene terephthalate layer (PET layer), and a polyethylene naphthalate layer (PEN layer).

[0064] In the embodiment of the utility model, each material layer is a layer formed by a corresponding material. Taking the nylon layer as an example, the nylon layer is mainly formed by nylon, and its material is nylon.

[0065] Specifically, the metal layer may include a rigid metal layer, specifically may include one or more of aluminum, aluminum alloy, copper, and steel. Exemplarily, the metal layer may include one or more of an aluminum layer (aluminum foil), an aluminum alloy layer, a copper layer (copper foil), and a steel layer.

[0066] For example, the package body 1 is an aluminum-plastic film (the metal layer therein is an aluminum layer), or the package body 1 is a copper-plastic film (that is, the metal layer therein is a copper layer), but it is not limited thereto.

[0067] By adopting the above-mentioned package 1, the thermal conductivity and tensile strength of the package 1 can be increased. Therefore, when the battery encounters high temperature, it is beneficial to accelerate the heat dissipation of the battery. At the same time, the gas generated inside the battery is not easy to break through the package 1, which is conducive to achieving directional opening from the first sealing part (the weakest part of the battery) 110 for pressure relief, avoiding the occurrence of fire, explosion and the like in the battery, and at the same time, it can also improve the battery's resistance to external impact and drop resistance.

[0068] Specifically, the package 1 containing the above-mentioned metal layer (such as a copper layer) is a high-strength, high-thermal-conductivity soft packaging film, which can accelerate heat dissipation when the battery temperature rises. At the same time, when the battery temperature continues to rise, causing the internal electrolyte of the battery to decompose and the positive and negative electrode materials to react to produce a large amount of gas, the above-mentioned metal layer has the properties of high tensile strength and low elongation, so that the strength of the package 1 is enhanced, the ductility is reduced, and the battery expansion is suppressed. The gas inside the battery is not easy to break through the package 1, and the internal pressure of the battery is increased, which is conducive to the internal gas of the battery to impact the weakest part of the battery, that is, the first sealing part 110. The low melting point glue layer of the first sealing part 110 melts, thereby forming an opening at the first sealing part 110, so that the internal gas of the battery is released directionally from the first sealing part 110, avoiding the battery from continuing to heat up and causing fire, explosion and other problems; at the same time, the package 1 has a high tensile strength, which is also conducive to improving the battery's resistance to external force impact and drop resistance.

[0069] In some embodiments, the tensile strength of the package body 1 may be greater than or equal to 69 MPa, for example, greater than or equal to 80 MPa, or greater than or equal to 90 MPa, or greater than or equal to 100 MPa, or greater than or equal to 110 MPa, etc.

[0070] In some embodiments, the elongation (tensile elongation) of the package body 1 is less than or equal to 55%, for example, less than or equal to 50%, or less than or equal to 45%, or less than or equal to 40%, or less than or equal to 35%, or less than or equal to 30%, or less than or equal to 25%, or less than or equal to 20%, etc.

[0071] Specifically, the tensile strength (or tensile strength) indicates the maximum ability of a pattern to resist damage under tensile force, which is the ratio of the maximum force Fb that the pattern withstands when it is broken during the stretching process of the pattern and the cross-sectional area So of the pattern (i.e., tensile strength σ = Fb / So). The elongation refers to the ratio of the deformation amount (the difference between the length of the pattern after stretching and the length before stretching) of the pattern when it breaks during the stretching process of the pattern and the original length of the pattern (the length before stretching). The tensile strength and elongation of the package 1 can be measured by conventional methods in the field in the embodiment of the utility model, and there is no special limitation on this.

[0072] In an embodiment of the utility model, the first adhesive layer may include a polymer layer, and specifically may include one or more of acid-modified polypropylene, ethylene-modified polypropylene, and polypropylene. Exemplarily, the first adhesive layer includes one or more of an acid-modified polypropylene layer (whose material is acid-modified polypropylene), an ethylene-modified polypropylene layer (whose material is ethylene-modified polypropylene), and a polypropylene layer (whose material is polypropylene).

[0073] After further research, it was found that the melting points of the first adhesive layer and the third adhesive layer 33 are similar, and the materials are basically the same. For example, the first adhesive layer and the third adhesive layer are both made of polypropylene (PP) or ethylene-modified polypropylene, etc. In this way, during the heat sealing process, the PP molecules of the first adhesive layer and the third adhesive layer 33 are "similarly compatible" at high temperatures and are more likely to cross-link, which can further improve the bonding strength between the first connecting portion 113 and the conductor 21, that is, improve the packaging strength on the deep pit side, and avoid tearing, breakage, and battery leakage caused by the deep pit side.

[0074] Specifically, the difference (absolute value) between the melting points of the first adhesive layer and the third adhesive layer 33 may be 0-40° C., such as 0, 1° C., 5° C., 8° C., 10° C., 13° C., 15° C., 18° C., 20° C., 25° C., 30° C., 33° C., 40° C., or any two thereof. The melting point of the first adhesive layer may be greater than, equal to, or less than the melting point of the third adhesive layer 33.

[0075] In addition, the melting point of the first adhesive layer may be greater than the melting points of the first adhesive layer 31 , the fourth adhesive layer 41 and the sixth adhesive layer 43 .

[0076] Specifically, the melting point of the first adhesive layer 31 may be 95-130° C., for example, 95° C., 100° C., 105° C., 110° C., 115° C., 120° C., 125° C., 130° C. or a range consisting of any two thereof.

[0077] In some embodiments, the first adhesive layer 31 may include one or more of propylene-ethylene copolymer, butene-modified polypropylene, polyethylene, maleic anhydride grafted modified polypropylene (maleic anhydride modified polypropylene), metallocene-modified polypropylene, and maleic anhydride grafted modified polyethylene. Exemplarily, the first adhesive layer 31 may include one or more of a propylene-ethylene copolymer layer, a butene-modified polypropylene layer, a polyethylene layer, a maleic anhydride grafted modified polypropylene layer, a metallocene-modified polypropylene layer, and a maleic anhydride grafted modified polyethylene layer.

[0078] Specifically, the melting point of the second adhesive layer 32 may be 140-170° C., for example, 140° C., 145° C., 150° C., 155° C., 160° C., 165° C., 170° C. or any two thereof.

[0079] In some embodiments, the second adhesive layer 32 includes one or more of polypropylene and anhydride grafted modified polypropylene. Exemplarily, the second adhesive layer 32 includes one or more of a polypropylene layer and anhydride grafted modified polypropylene layer.

[0080] Specifically, the melting point of the third adhesive layer 33 may be 120-165° C., for example, 120° C., 125° C., 130° C., 135° C., 140° C., 145° C., 150° C., 155° C., 160° C., 165° C. or any two thereof.

[0081] In some embodiments, the third adhesive layer 33 may include one or more of polypropylene, anhydride grafted modified polypropylene, and ethylene modified polypropylene. For example, the third adhesive layer 33 may include one or more of a polypropylene layer, anhydride grafted modified polypropylene layer, and ethylene modified polypropylene layer.

[0082] In addition, the difference in melting point between the fifth adhesive layer 42 and the fourth adhesive layer 41 may be 10-75° C., such as 10° C., 20° C., 30° C., 40° C., 50° C., 60° C., 70° C. or any two thereof.

[0083] In addition, the difference in melting point between the fifth adhesive layer 42 and the sixth adhesive layer 43 is 10-75° C., for example, 10° C., 20° C., 30° C., 40° C., 50° C., 60° C., 70° C. or any two thereof.

[0084] Specifically, the melting point of the fourth adhesive layer 41 may be 95-130° C., for example, 95° C., 100° C., 105° C., 110° C., 115° C., 120° C., 125° C., 130° C. or any two thereof.

[0085] In some embodiments, the fourth adhesive layer 41 includes one or more of propylene-ethylene copolymer, butene-modified polypropylene, polyethylene, maleic anhydride grafted modified polypropylene, metallocene-modified polypropylene, and maleic anhydride grafted modified polyethylene. Exemplarily, the fourth adhesive layer 41 includes one or more of a propylene-ethylene copolymer layer, a butene-modified polypropylene layer, a polyethylene layer, a maleic anhydride grafted modified polypropylene layer, a metallocene-modified polypropylene layer, and a maleic anhydride grafted modified polyethylene layer.

[0086] Specifically, the melting point of the fifth adhesive layer 42 may be 140-170° C., for example, 140° C., 145° C., 150° C., 155° C., 160° C., 165° C., 170° C. or any two thereof.

[0087] In some embodiments, the fifth adhesive layer 42 includes one or more of polypropylene and anhydride grafted modified polypropylene. Exemplarily, the fifth adhesive layer 42 includes one or more of a polypropylene layer and anhydride grafted modified polypropylene layer.

[0088] Specifically, the melting point of the sixth adhesive layer 43 may be 95-130° C., for example, 95° C., 100° C., 105° C., 110° C., 115° C., 120° C., 125° C., 130° C. or any two thereof.

[0089] In some embodiments, the sixth adhesive layer 43 includes one or more of propylene-ethylene copolymer, butene-modified polypropylene, polyethylene, maleic anhydride grafted modified polypropylene, metallocene-modified polypropylene, and maleic anhydride grafted modified polyethylene. Exemplarily, the sixth adhesive layer 43 includes one or more of a propylene-ethylene copolymer layer, a butene-modified polypropylene layer, a polyethylene layer, a maleic anhydride grafted modified polypropylene layer, a metallocene-modified polypropylene layer, and a maleic anhydride grafted modified polyethylene layer.

[0090] In the embodiment of the present invention, the melting point may be the melting peak (i.e., the temperature corresponding to the maximum heat absorption of a substance) measured by a differential scanning calorimeter (DSC).

[0091] In addition, the sixth adhesive layer 43 may also contain fluorescent materials (i.e., the sixth adhesive layer may include a fluorescent adhesive layer that can generate fluorescence). For example, the fluorescent adhesive layer may include a propylene-ethylene copolymer layer that can generate fluorescence, a butene-modified polypropylene layer that can generate fluorescence, a polyethylene layer that can generate fluorescence, a maleic anhydride grafted modified polypropylene layer that can generate fluorescence, a metallocene-modified polypropylene layer that can generate fluorescence, and a maleic anhydride grafted modified polyethylene layer that can generate fluorescence. In this way, it is convenient to check whether there is excessive glue extrusion during heat sealing, which causes the sixth adhesive layer 43 to be excessively squeezed out or even completely squeezed out, thereby avoiding the problem of too little glue between the conductor 21 and the second connecting part 123, and the resulting low packaging strength. At the same time, the fluorescent material is introduced into the sixth adhesive layer 43, and the fluorescence is generated by the fluorescent material, which is convenient for distinguishing the first insulating adhesive 3 and the second insulating adhesive 4, and avoiding confusion during use.

[0092] Specifically, the fluorescent material can emit one or more of blue light, red light, and green light under laser irradiation, and can specifically include one or more of coumarins, phenylenediamine, cyanines, pyrazoline, distilbenes, benzophenones, and inorganic luminescent materials.

[0093] Specifically, the mass of the fluorescent material may account for 0.5% to 8% of the total mass of the sixth adhesive layer 43 . In a specific implementation, the content of the fluorescent material in the sixth adhesive layer 43 may be measured by X-ray energy dispersive spectrometry (EDS).

[0094] Continue to refer Figure 3 and Figure 5The first insulating glue 3 may include a first covering portion 301 covering the conductor 21, and a first extension portion 302 extending beyond the conductor 21 in the width direction of the conductor 21. The first extension portions 302 are respectively present on opposite sides of the first covering portion 301 in the width direction of the conductor 21, that is, the first insulating glue 3 extends beyond the conductor 21 on opposite sides of the width direction of the conductor 21. The first insulating glue 3 is formed by sequentially connecting the first extension portion 302 located on one side of the conductor 21, the first covering portion 301, and the first extension portion 302 located on the other side of the conductor 21.

[0095] Specifically, the width of each first extension portion 301 in the width direction of the conductor 21 can be 1.2 to 3.5 mm, for example, 1.2 mm, 1.25 mm, 1.5 mm, 1.8 mm, 2 mm, 2.3 mm, 2.5 mm, 2.8 mm, 3 mm, 3.3 mm, 3.5 mm or a range consisting of any two of them.

[0096] In addition, the width w of the first insulating glue 3 along the length direction of the conductor 21 is 1 It may be in the range of 3.5 to 6 mm, for example, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm or a range consisting of any two thereof.

[0097] By controlling the width of the portion of the first insulating glue 3 that exceeds the conductor 21 in the width direction of the conductor 21 (the first extension portion 302) and the width of the first insulating glue 3 in the length direction of the conductor 21 within the above-mentioned range, it is possible to ensure that there is a larger bonding area between the conductor 21 and the first connecting portion 113, thereby improving the bonding strength between the conductor 21 and the first connecting portion 113, further improving the packaging reliability, and avoiding the waste of glue material caused by the first insulating glue 3 being too large.

[0098] In addition, the total thickness of the first insulating glue 3 (i.e., the sum of the thicknesses of all glue layers constituting the first insulating glue 3) can be 40 to 200 μm, for example, 40 μm, 50 μm, 70 μm, 90 μm, 100 μm, 120 μm, 150 μm, 180 μm, 200 μm or a range consisting of any two of them, which is beneficial to further improve the bonding force between the first connecting portion 113 and the conductor 21 and improve the packaging reliability.

[0099] Generally, in the first insulating adhesive 3, the thickness of the second adhesive layer 32 is greater than the thickness of the first adhesive layer 31, and the difference between the two can be 8 to 20 μm, for example, 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm or a range consisting of any two thereof; the thickness of the second adhesive layer 32 is greater than the thickness of the third adhesive layer 33, and the difference between the two can be 8 to 20 μm, for example, 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm or a range consisting of any two thereof; the thickness of the first adhesive layer 21 can be less than, equal to or greater than the thickness of the third adhesive layer 33.

[0100] Continue to refer Figure 4 and Figure 5 The second insulating glue 4 may include a second covering portion 401 covering the conductor 21, and a second extension portion 402 extending beyond the conductor 21 in the width direction of the conductor 21. The second extension portions 402 are respectively present on opposite sides of the second covering portion 401 in the width direction of the conductor 21. That is, the second insulating glue 4 extends beyond the conductor 21 on opposite sides of the width direction of the conductor 21. The second insulating glue 4 is formed by sequentially connecting the second extension portion 402 located on one side of the conductor 21, the second covering portion 401, and the second extension portion 402 located on the other side of the conductor 21.

[0101] Specifically, the width of each second extension portion 402 in the width direction of the conductor 21 can be 1.2 to 3.5 mm, for example, 1.2 mm, 1.25 mm, 1.5 mm, 1.8 mm, 2 mm, 2.3 mm, 2.5 mm, 2.8 mm, 3 mm, 3.3 mm, 3.5 mm or a range consisting of any two of them.

[0102] In addition, the width w of the second insulating glue 4 along the length direction of the conductor 21 is 2 It may be in the range of 3.5 to 6 mm, for example, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm or a range consisting of any two thereof.

[0103] By controlling the width of the portion of the second insulating glue 4 that exceeds the conductor 21 in the width direction of the conductor 21 (the second extension portion 402) and the width of the second insulating glue 4 in the length direction of the conductor 21 to be within the above-mentioned range, it is possible to ensure that there is a larger bonding area between the conductor 21 and the second connecting portion 123, thereby improving the bonding strength between the conductor 21 and the second connecting portion 123, further improving the packaging reliability, and avoiding the waste of glue material due to the second insulating glue 4 being too large.

[0104] In addition, the thickness of the second insulating glue 4 (i.e., the sum of the thicknesses of all glue layers constituting the second insulating glue 4) can be 40 to 200 μm, for example, 40 μm, 50 μm, 70 μm, 90 μm, 100 μm, 120 μm, 150 μm, 180 μm, 200 μm or a range consisting of any two of them, which is beneficial to further improve the bonding force between the second connecting portion 123 and the conductor 21 and improve the packaging reliability.

[0105] Generally, in the second insulating adhesive 4, the thickness of the fifth adhesive layer 42 is greater than the thickness of the fourth adhesive layer 41, and the difference between the two can be 8 to 20 μm, for example, 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm or a range consisting of any two thereof; the thickness of the fifth adhesive layer 42 is greater than the thickness of the sixth adhesive layer 43, and the difference between the two can be 8 to 20 μm, for example, 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm or a range consisting of any two thereof; the thickness of the fourth adhesive layer 41 can be less than, equal to or greater than the thickness of the sixth adhesive layer 43.

[0106] Continue to refer Figures 1 to 5 The conductor 21 basically extends out of the package along its length direction, and the length direction of the conductor 21 (also the extension direction of the conductor 21), the direction from the battery cell 2 to the conductor 21, and the second direction y are parallel to each other; the width direction of the conductor 21 is parallel to the third direction z.

[0107] Specifically, the conductor 21 can be a tab of the battery. Generally, the battery cell 2 includes a positive electrode sheet and a negative electrode sheet, and the conductor 21 includes a first conductor 211 and a second conductor 212. The first conductor 211 is connected to the positive electrode sheet, which can be a positive tab, and the second conductor 211 is connected to the negative electrode sheet, which can be a negative tab.

[0108] Among them, the first conductor 211 and the second conductor 212 are respectively connected by the first insulating glue 3 and the first connecting part 113, and are respectively connected by the second insulating glue 4 and the second connecting part 123, that is, the first insulating glue 3 is provided between the first conductor 211 and the first connecting part 113, and the second insulating glue 4 is provided between the first conductor 211 and the second connecting part 123; the first insulating glue 3 is provided between the second conductor 212 and the first connecting part 113, and the second insulating glue 4 is provided between the second conductor 212 and the second connecting part 123.

[0109] In general, if Figure 3 , Figure 4 and Figure 5As shown, the first insulating glue 3 located between the first conductor 211 and the first connecting part 113 is independent of the first insulating glue 3 located between the second conductor 212 and the first connecting part 113, that is, the two are not connected; the second insulating glue 4 located between the first conductor 211 and the second connecting part 123 is independent of the second insulating glue 4 located between the second conductor 212 and the second connecting part 123, that is, the two are not connected.

[0110] Specifically, Figure 3 , Figure 4 and Figure 5 As shown, the first conductor 211 and the second conductor 212 may be located at the same side of the battery core 2 , and may be specifically distributed along the third direction z.

[0111] The battery of the embodiment of the present invention may include a lithium-ion battery.

[0112] Specifically, the positive electrode sheet includes a positive electrode collector and a positive electrode active material layer located on the surface of the positive electrode collector. The positive electrode active material layer can be arranged on one surface of the positive electrode collector, or on both the front and back surfaces of the positive electrode collector. The positive electrode active material layer includes a positive electrode active material, a conductive agent and a binder. The positive electrode active material may include a lithium-containing active material, for example, one or more of lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, a ternary material, lithium iron phosphate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium vanadium phosphate, and lithium-rich manganese-based materials. The ternary material may include lithium nickel cobalt manganese oxide and / or lithium nickel cobalt aluminum oxide, etc. The positive electrode collector may include aluminum foil, carbon-coated aluminum foil, and other conventional positive electrode collectors in the field.

[0113] Specifically, based on the total mass of the positive electrode active material layer, the mass fraction of the positive electrode active material may be 70% to 99%, the mass fraction of the conductive agent may be 0.5% to 15%, and the mass fraction of the binder may be 0.5% to 15%.

[0114] Specifically, the negative electrode sheet may be a graphite negative electrode or a silicon-doped negative electrode, which may specifically include a negative electrode current collector, and a negative electrode active material layer arranged on the surface of the negative electrode current collector. The negative electrode active material layer may be arranged on one surface of the negative electrode current collector, or on both the positive and negative surfaces of the negative electrode current collector. The negative electrode active material layer includes a negative electrode active material, a binder and a conductive agent. The negative electrode active material may include one or more of graphite, mesophase carbon microbeads, soft carbon, hard carbon, silicon material, silicon oxygen material, silicon carbon material, lithium titanate, etc.; the negative electrode current collector may be a conventional negative electrode current collector in the art, such as copper foil, etc.

[0115] Specifically, based on the total mass of the negative electrode active material layer, the mass fraction of the negative electrode active material may be 70% to 99%, the mass fraction of the conductive agent may be 0.5% to 15%, and the mass fraction of the binder may be 0.5% to 15%.

[0116] In the embodiment of the utility model, the conductive agent in the positive electrode sheet and the negative electrode sheet can be a conventional conductive material in the art, for example, one or more of conductive carbon black (SP), acetylene black, carbon nanotubes, conductive graphite, and graphene.

[0117] In the embodiment of the utility model, the binder in the positive electrode sheet and the negative electrode sheet can be a conventional binding material in the art, for example, one or more of polyvinylidene fluoride (PVDF), a copolymer of vinylidene fluoride and hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, carboxymethyl cellulose sodium (CMC), polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene, polyhexafluoropropylene and styrene-butadiene rubber (SBR).

[0118] In addition, the conductor 21 can be welded to the electrode sheet in the battery cell 2, and a protective glue is provided at the welding position between the conductor 21 and the electrode sheet to prevent the welding burrs from piercing the diaphragm and causing the positive and negative electrodes to short-circuit. Specifically, the first conductor 211 is welded on the positive electrode sheet (specifically, welded on the positive electrode collector), wherein, at the welding position between the first conductor 211 and the positive electrode sheet, protective glue is respectively provided on the side of the first conductor 211 facing away from the positive electrode sheet, and on the side of the positive electrode sheet facing away from the first conductor 211, that is, protective glue is respectively provided on the front and back sides of the welding position between the first conductor 211 and the positive electrode sheet; the second conductor 212 is welded on the negative electrode sheet (specifically, welded on the negative electrode collector), wherein, at the welding position between the second conductor 212 and the negative electrode sheet, protective glue is respectively provided on the side of the second conductor 212 facing away from the negative electrode sheet, and on the side of the negative electrode sheet facing away from the second conductor 212, that is, protective glue is respectively provided on the front and back sides of the welding position between the second conductor 212 and the negative electrode sheet.

[0119] In the embodiment of the utility model, the protective glue used can be conventional ear glue in the art, and there is no particular limitation on this.

[0120] In addition, the battery cell 2 further includes a separator, which is located between the positive electrode sheet and the negative electrode sheet and is used to separate the positive electrode sheet and the negative electrode sheet to prevent the two from contacting and short-circuiting. The separator area is larger than the surface area of ​​the negative electrode sheet, and the surface area of ​​the negative electrode sheet is larger than the surface area of ​​the positive electrode sheet, that is, the separator width is larger than the negative electrode sheet width, and the negative electrode sheet width is larger than the positive electrode sheet width. On a plane perpendicular to the thickness direction of the battery cell 2, the projection of the separator covers the projection of the negative electrode sheet, and the projection of the negative electrode sheet covers the projection of the positive electrode sheet.

[0121] The embodiments of the present invention may adopt conventional diaphragms in the art. For example, the diaphragm may include one or more of a polypropylene diaphragm (PP), a polyethylene diaphragm (PE), a polypropylene / polyethylene double-layer composite film (PP / PE), a polyimide electrospinning diaphragm (PI), a polypropylene / polyethylene / polypropylene three-layer composite film (PP / PE / PP), a cellulose non-woven fabric diaphragm, and a diaphragm with a ceramic coating.

[0122] The above-mentioned battery cell 2 can be a wound battery cell, that is, in the battery cell 2, the positive electrode sheet and the negative electrode sheet each have a wound structure, that is, the positive electrode sheet includes a plurality of first straight portions, and a first bent portion connected between every two adjacent first straight portions, and the negative electrode sheet includes a plurality of second straight portions, and a second bent portion connected between every two adjacent second straight portions, the plurality of first straight portions and the plurality of second straight portions are stacked, and the plurality of first straight portions and the plurality of second straight portions are staggered, and the first straight portions and the second straight portions are separated by a diaphragm.

[0123] Alternatively, the above-mentioned battery cell 2 can also be a stacked battery cell, that is, the battery cell 2 includes multiple positive electrode sheets and multiple negative electrode sheets, the multiple positive electrode sheets and the multiple negative electrode sheets are stacked, and the multiple positive electrode sheets and the multiple negative electrode sheets are staggered, and the positive electrode sheets and the negative electrode sheets are separated by a diaphragm, that is, each positive electrode sheet is separated from the negative electrode sheet by a diaphragm, and each negative electrode sheet is separated from the positive electrode sheet by a diaphragm.

[0124] Generally, the thickness direction of the positive electrode sheet, the thickness direction of the negative electrode sheet, the thickness direction of the conductor 21 (the first conductor 211, the second conductor 212), the thickness direction of the battery cell 2, and the first direction x are parallel to each other. In addition, in a wound battery cell, the width direction of the positive electrode sheet, the width direction of the negative electrode sheet, and the second direction y are parallel to each other; in a stacked battery cell, the width direction of the positive electrode sheet, the width direction of the negative electrode sheet can be parallel to the second direction y, or the width direction of the positive electrode sheet, the width direction of the negative electrode sheet, and the third direction z are parallel to each other.

[0125] The battery also includes an electrolyte. The embodiment of the utility model can use a conventional electrolyte in the art. For example, the electrolyte is a non-aqueous electrolyte, which can specifically include an organic solvent and a lithium salt. The organic solvent can include ethylene carbonate, propylene carbonate (PC), butylene carbonate, fluoroethylene carbonate (FEC), dimethyl carbonate (DMC), diethyl carbonate (DEC), difluoroethylene carbonate (DFEC), dipropyl carbonate, ethyl methyl carbonate (EMC), etc. One or more; the lithium salt includes, for example, lithium hexafluorophosphate (LiPF 6 ), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), etc.

[0126] In the embodiment of the utility model, the positive electrode sheet and the negative electrode sheet can be prepared by conventional methods in the field, such as by a coating method. Taking the positive electrode sheet as an example, the positive electrode active material, the conductive agent and the binder and other materials can be placed in a solvent to form a positive electrode slurry. The solvent used includes, for example, N-methylpyrrolidone (NMP). The positive electrode slurry is then applied to the surface of the positive electrode collector. After drying, rolling and other processes, a positive electrode active material layer is formed on the surface of the positive electrode collector. Then, the obtained positive electrode foil can be sliced ​​as needed and cut into positive electrode sheets of the desired shape and size.

[0127] In the embodiments of the present invention, the battery can be manufactured by conventional methods in the field. For example, after the positive electrode sheet, the separator, and the negative electrode sheet are made into a battery cell 2 (for example, made into a stacked battery cell 2 or wound into a wound battery cell 2), the battery is manufactured through packaging, liquid injection, formation and other processes. These steps / processes are all conventional operations in the field. The present invention does not impose any special restrictions on this and will not be described in detail.

[0128] Unless otherwise specified, in the following embodiments, the thickness range of the adhesive layer (such as 20-24 μm) is the result obtained by testing the thickness of different regions of the adhesive layer, that is, the thickness of different regions of the adhesive layer is basically within the range of the measured adhesive layer thickness.

[0129] Example 1

[0130] 1. Preparation of positive electrode

[0131] Lithium cobalt oxide, carbon black and PVDF were placed in NMP in a mass ratio of 97:1:2.5 and stirred evenly to prepare a positive electrode slurry;

[0132] The positive electrode slurry is coated on the front and back surfaces of an aluminum foil with a thickness of 8 μm. After drying and rolling, a positive electrode active material layer is formed on the front and back surfaces of the aluminum foil to prepare a positive electrode sheet; wherein the positive electrode sheet reserves an empty foil for welding the conductor (positive electrode tab).

[0133] 2. Preparation of negative electrode sheet

[0134] Graphite, carbon black and styrene-butadiene rubber (SBR) emulsion are placed in deionized water and stirred evenly to prepare a negative electrode slurry; wherein the mass ratio of graphite, carbon black and SBR is 97:1:2.5;

[0135] The negative electrode slurry is coated on the front and back surfaces of a copper foil with a thickness of 10 μm. After drying and rolling, a negative electrode active material layer is formed on the front and back surfaces of the copper foil to prepare a negative electrode sheet; wherein the negative electrode sheet reserves a hollow foil for welding the conductor (negative electrode tab).

[0136] 3. Assemble the battery

[0137] (1) The positive electrode sheet, the separator and the negative electrode sheet are stacked in sequence and then wound synchronously to form a wound battery cell (wound core); wherein the positive electrode tab (first conductor 211) is welded at the reserved empty foil of the positive electrode sheet, and protective glue is applied to both the front and back sides of the welding part of the positive electrode tab to prevent the welding mark burrs from piercing the separator and causing the positive and negative electrodes to short-circuit; the negative electrode tab (second conductor 212) is welded at the reserved empty foil of the negative electrode sheet, and protective glue is applied to both the front and back sides of the welding part of the negative electrode tab to prevent the welding mark burrs from piercing the separator and causing the positive and negative electrodes to short-circuit.

[0138] Among them, the positive electrode tab and the negative electrode tab are located on the same side of the battery cell. The positive electrode tab is made of aluminum, with a thickness of 0.1mm and a width of 6mm; the negative electrode tab is made of copper-plated nickel, with a thickness of 0.1mm and a width of 6mm.

[0139] The area of ​​the diaphragm is larger than the surface area of ​​the negative electrode sheet, and the surface area of ​​the negative electrode sheet is larger than the surface area of ​​the positive electrode sheet.

[0140] (2) The core roll is packaged with a packaging body 1, which is punched from a copper plastic film c. After the core roll is placed in the packaging body 1, the first side portion 11 and the second side portion 12 are sealed together by heat sealing, wherein the width of the sealing portion 100 (the first sealing portion 110) where the pole ear protrudes is 1.4 mm, and the width of the sealing portion 100 (the second sealing portion 120) in the remaining area is 2 mm; subsequently, after processes such as liquid injection, aging, formation, secondary sealing, and OCV (open circuit voltage test), a lithium-ion battery is obtained.

[0141] Among them, the total thickness of the copper-plastic film c is about 88μm, and the copper-plastic film c includes an outer layer, a metal layer and an inner layer which are stacked in sequence. The outer layer is a nylon layer with a thickness of about 15μm, the metal layer is a copper foil with a thickness of about 35μm, the thickness of the inner layer is about 30μm, the material of the inner layer is ethylene-modified polypropylene, and the melting point of the inner layer is about 140°C (140±5°C); the outer layer and the metal layer are bonded by a second adhesive layer, the material of the second adhesive layer is a polyurethane adhesive, and the thickness of the second adhesive layer is about 3-4μm; the metal layer and the inner layer are bonded by a third adhesive layer, the material of the third adhesive layer is a polyacrylic acid adhesive, and the thickness of the third adhesive layer is about 3-4μm.

[0142] The structure of lithium-ion batteries Figures 1 to 5As shown, the package body 1 includes a first side portion 11 and a second side portion 12, the first side portion 11 includes a first main body portion 111, a first extension portion 112 and a first connection portion 113 connected in sequence, the second side portion 12 includes a second main body portion 121, a second extension portion 122 and a second connection portion 123 connected in sequence, the first main body portion 111 and the second main body portion 121 are respectively located on opposite sides of the battery core 2 in the first direction x, and the distance between the first connection portion 113 and the first main body portion 111 in the first direction x is greater than the distance between the second connection portion 123 and the second main body portion 121 in the first direction x (L 1 >L 2 ), the first connecting portion 113 is connected to the second connecting portion 123, and the conductor 21 (positive electrode tab 211, negative electrode tab 212) extends from the connecting portion (first sealing portion 110) between the first connecting portion 113 and the second connecting portion 123, and extends from the top sealing edge 101.

[0143] The depth of the deep pit side (the distance L between the side surface of the first connecting portion 113 facing away from the first main body portion 111 in the first direction x and the side surface of the first main body portion 111 facing away from the first connecting portion 113 in the first direction x) 1 ) is 3 mm, the depth of the shallow pit side (the distance L between the side surface of the second connecting portion 123 away from the second main body portion 121 in the first direction x and the side surface of the second main body portion 121 away from the second connecting portion 123 in the first direction x) 2 ) is 1mm.

[0144] A first insulating glue 3 is provided between the positive electrode tab 211 and the first connecting portion 113 , a second insulating glue 4 is provided between the positive electrode tab and the second connecting portion 123 , a first insulating glue 3 is provided between the negative electrode tab and the first connecting portion 113 , and a second insulating glue 4 is provided between the negative electrode tab and the second connecting portion 123 .

[0145] The first insulating adhesive 3 is composed of a first adhesive layer 31, a second adhesive layer 32 and a third adhesive layer 33 stacked in sequence. The thickness of the first insulating adhesive 3 is about 80 μm. The width w of the first insulating adhesive 3 in the length direction of the conductor 21 is about 100 μm. 1 The first insulating adhesive 3 extends beyond the conductor 21 on both sides of the conductor 21 in the width direction, and the width of the extending portion on each side (i.e., the first extension portion 302) in the width direction of the conductor 21 is 2.5 mm; the composition of the first insulating adhesive 3 is as follows: the material of the first adhesive layer 31 is maleic anhydride modified polypropylene, the melting point is 120±5°C, and the thickness is 20-24μm; the material of the second adhesive layer 32 is polypropylene, the melting point is 160±5°C, and the thickness is 32-40μm; the material of the third adhesive layer 33 is polypropylene, the melting point is 160±5°C, and the thickness is 20-24μm.

[0146] The second insulating adhesive 4 is composed of a fourth adhesive layer 41, a fifth adhesive layer 42 and a sixth adhesive layer 43 stacked in sequence. The thickness of the second insulating adhesive 4 is about 80 μm. The width w of the second insulating adhesive 4 in the length direction of the conductor 21 is about 100 μm. 2 The second insulating adhesive 4 extends beyond the conductor 21 on both sides of the conductor 21 in the width direction, and the width of the extending portion on each side (i.e., the second extension portion 402) in the width direction of the conductor 21 is 2.5 mm; the second insulating adhesive 4 is composed of the following: the fourth adhesive layer 41 is made of maleic anhydride modified polypropylene with a melting point of 120±5°C and a thickness of 20 to 24 μm; the fifth adhesive layer 42 is made of polypropylene with a melting point of 160±5°C and a thickness of 32 to 40 μm; the sixth adhesive layer 43 is made of maleic anhydride modified polypropylene with a melting point of 120±5°C and a thickness of 20 to 24 μm, and the sixth adhesive layer 43 is doped with diphenylethylene (fluorescent material).

[0147] Embodiment 2 to Embodiment 9, Comparative Example 1 to Comparative Example 4: The difference from Embodiment 1 is that the aluminum-plastic film, the material and melting point of the first adhesive layer, the material and melting point of the third adhesive layer, the material and melting point of the fourth adhesive layer, or the material and melting point of the sixth adhesive layer are different, see Table 1 and Table 2 for details. Except for the differences shown in Table 1 and Table 2, the other conditions are the same.

[0148] In Table 1, the materials of the adhesive layers corresponding to the melting points are as follows: (1) the melting point is 120±℃, the material is maleic anhydride modified polypropylene; (2) the melting point is 140±℃, the material is ethylene modified polypropylene; (3) the melting point is 160±℃, the material is polypropylene.

[0149] The batteries of each embodiment and comparative example were tested by the following process:

[0150] (1) Heat sealing tensile force (packaging tensile force) test: Use a universal tensile testing machine (digital display tensile testing machine) to test the packaging tensile force F on the deep pit side. 1 And the package tension F on the shallow pit side 2 During the test, the upper and lower ends of the tensile machine were tightened 180°, where the upper end of the tensile machine pulled the conductor (ear) and the lower end pulled the package; the test was repeated 10 times, and the average value was taken as the final test result, see Table 3 (Package tension F on the deep pit side corresponding to the positive ear) 1 Package tension F on the deep pit side corresponding to the negative electrode tab 1 Basically the same, the packaging tension F on the shallow pit side corresponding to the positive pole ear 2 Package tension F on the shallow pit side corresponding to the negative electrode tab 2 are basically the same).

[0151] (2) 130-degree hot box test: At 25°C±3°C, discharge the battery at 0.2C to a cut-off voltage of 3.0V and leave it for 10 minutes. Then charge it at 0.5C constant current and constant voltage to an upper limit voltage of 4.2V, with a cut-off current of 0.02C. Then place the fully charged battery in a test chamber, and heat the chamber at a temperature rise rate of (5±2)°C / min. When the temperature in the chamber reaches 130°C±2°C, keep the temperature constant for 60 minutes. Observe whether the battery cell catches fire. If it catches fire, it fails. If it does not catch fire, it passes. The battery’s 130°C hot box test pass rate η is measured. 130 (η 130 = Number of batteries that passed / total number of batteries tested, total number of batteries tested = number of batteries that passed + number of batteries that failed) see Table 3.

[0152] (3) 135-degree hot box test: At 25°C±3°C, discharge the battery at 0.2C to a cut-off voltage of 3.0V and leave it for 10 minutes. Then charge it at 0.5C constant current and constant voltage to an upper limit voltage of 4.2V, with a cut-off current of 0.02C. Then put the fully charged battery into a test box, and heat the box at a temperature rise rate of (5±2)°C / min. When the temperature in the box reaches 135°C±2°C, keep the temperature constant for 60 minutes. Observe whether the battery catches fire. If it catches fire, it fails. If it does not catch fire, it passes. The battery’s 135°C hot box test pass rate η is measured. 135 (η 135 = Number of batteries that passed / total number of batteries tested) see Table 3.

[0153] 4) Drop test: At 25℃±3℃, discharge the battery at 0.2C to the lower limit voltage and let it stand for 10 minutes; then place the battery in a 25℃ constant temperature box and fully charge it at 0.7C constant current with a cut-off current of 0.02C; after fully charged, drop it within 12 to 24 hours: drop the top seal (the seal with the tabs extended) from a height of 1.5m 15 times (i.e., when falling, the top seal 101 faces downwards), and observe whether the battery leaks. If it does not leak, it is qualified, and if it leaks, it is unqualified. Record the qualified ratio η 0 (η 0 = Number of qualified batteries / total number of batteries tested), the results are shown in Table 3.

[0154] Table 1

[0155]

[0156] In Table 1, the relevant parameters of aluminum-plastic film a, aluminum-plastic film b, and copper-plastic film c are shown in Table 2.

[0157] Table 2

[0158]

[0159] Table 3

[0160] Example <![CDATA[η 130 ]]> <![CDATA[η 135 ]]> <![CDATA[η 0 ]]> <![CDATA[F 1 (N / mm)]]> <![CDATA[F 2 (N / mm)]]> Example 1 20 / 20 18 / 20 17 / 20 4.10 3.30 Example 2 20 / 20 17 / 20 18 / 20 4.00 3.20 Example 3 20 / 20 20 / 20 20 / 20 4.40 3.70 Example 4 20 / 20 20 / 20 19 / 20 4.10 3.40 Example 5 18 / 20 16 / 20 18 / 20 4.20 4.00 Example 6 16 / 20 14 / 20 17 / 20 3.90 3.10 Example 7 20 / 20 18 / 20 18 / 20 4.80 3.50 Example 8 18 / 20 14 / 20 15 / 20 3.80 3.60 Example 9 19 / 20 15 / 20 16 / 20 4.10 3.70 Comparative Example 1 7 / 20 5 / 20 14 / 20 2.20 2.30 Comparative Example 2 6 / 20 4 / 20 13 / 20 1.80 2.50 Comparative Example 3 20 / 20 20 / 20 15 / 20 2.00 2.80 Comparative Example 4 20 / 20 20 / 20 14 / 20 1.90 2.90

[0161] It can be seen from Tables 1 to 3 that, relative to Comparative Examples 1 to 4, in Examples 1 to 9, by using the aluminum-plastic film or copper-plastic film as the packaging body, and simultaneously providing the first insulating glue 3 between the conductor 21 and the first connecting portion 113, and providing the second insulating glue 4 between the conductor 21 and the second connecting portion, and controlling the melting point of the third glue layer 33 to be greater than the melting point of at least one of the first glue layer 31, the fourth glue layer 41, and the sixth glue layer 42, the packaging tensile force F on the deep pit side is 1 Greater than the package tension F on the shallow pit side 2 , which can significantly enhance the packaging strength of the deep pit side tabs and improve the battery drop resistance (drop test pass rate η 0 Not less than 15 / 20), to prevent the battery from being torn or damaged at the tab on the deep pit side when it falls, thereby forming an opening and causing leakage, while maintaining the battery's high thermal stability (130℃ hot box test pass rate η 130 Not less than 16 / 20, 135℃ hot box test pass rate η 135 No less than 14 / 20).

[0162] Among them, in Examples 1 to 9, high-strength, high-thermal-conductivity soft packaging films (copper-plastic film c, aluminum-plastic film a and aluminum-plastic film b) are used to enhance the thermal conductivity of the battery and facilitate heat dissipation of the battery. At the same time, during the hot box test at 130°C and 135°C, the battery temperature rises at high temperatures, causing electrolyte decomposition and intensified chemical reactions of the positive and negative electrodes inside the battery, resulting in a large amount of gas generated inside the battery. Since the strength of the packaging film is enhanced (tensile strength is not less than 69.1 MPa, elongation is not greater than 54.2%), the ductility is reduced, which can inhibit the expansion of the battery. At the same time, the gas inside the battery cannot break through the packaging film and release, and the internal pressure of the battery increases, causing the gas inside the battery to impact the weakest area of ​​the battery (i.e., the first sealing portion 110), thereby causing the low melting point layer at the first sealing portion 110 to melt, and forming a directional opening at the first sealing portion 110. The gas inside the battery is directional pressure-released through the directional opening to prevent the battery from continuing to heat up and causing fire, explosion and other problems.

[0163] In addition, it can be seen from Examples 1 and 5, as well as Examples 2 and 6 that the first adhesive layer 31 of the first insulating adhesive 3, the fourth adhesive layer 41 and the sixth adhesive layer 43 of the second insulating adhesive 4 in Examples 1 to 3 of Examples 3 and 7 to 9 are respectively low melting point layers, which can all melt under high temperature conditions, and are more conducive to forming an opening at the first sealing portion 110, thereby achieving directional pressure relief at the first sealing portion 110, avoiding problems such as fire and explosion of the battery, thereby further improving the thermal stability of the battery while maintaining the battery's high drop resistance.

[0164] In addition, by adding fluorescent material to the sixth adhesive layer 43 of the second insulating adhesive 4, the recognition of the second insulating adhesive 4 can be increased to avoid confusion between the first insulating adhesive 3 and the second insulating adhesive 4. At the same time, during the heat sealing process, the sixth adhesive layer 43 can be prevented from being over-melted due to excessive heat, resulting in excessive extrusion (or even complete extrusion), which in turn leads to a weakening of the effectiveness of forming a directional opening in the first sealing portion 110 through the melting of the sixth adhesive layer 43 in a high temperature environment.

[0165] In the description of the present utility model, terms such as "first" and "second" are used only for descriptive purposes, such as distinguishing between components to more clearly illustrate / explain the technical solution, and cannot be understood as indicating or implying the number of technical features indicated or the order with substantive significance.

[0166] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. A battery, characterized in that: include: A battery cell having a conductor; The package body encapsulating the battery cell comprises a first side portion and a second side portion, the first side portion comprises a first main body portion and a first connecting portion connected to each other, the second side portion comprises a second main body portion and a second connecting portion connected to each other, the first main body portion and the second main body portion are respectively located on opposite sides of the battery cell, the first connecting portion is connected to the second connecting portion, and the conductor extends from a connecting portion between the first connecting portion and the second connecting portion; the distance between the first connecting portion and the first main body portion in a first direction is greater than the distance between the second connecting portion and the second main body portion in the first direction, and the first direction is parallel to a direction from the first main body portion to the second main body portion; A first insulating adhesive is disposed between the conductor and the first connecting portion; the first insulating adhesive comprises a first adhesive layer connected to the conductor and a third adhesive layer connected to the first connecting portion; A second insulating adhesive is provided between the conductor and the second connecting portion; the second insulating layer comprises a fourth adhesive layer connected to the conductor and a sixth adhesive layer connected to the second connecting portion; The melting point of the third adhesive layer is greater than the melting point of at least one of the first adhesive layer, the fourth adhesive layer, and the sixth adhesive layer.

2. The battery according to claim 1, characterized in that The package body includes a first adhesive layer, the first adhesive layer of the first connection portion is connected to the third adhesive layer, and the first adhesive layer of the second connection portion is connected to the sixth adhesive layer.

3. The battery according to claim 2, characterized in that The difference between the melting point of the first adhesive layer and the melting point of the third adhesive layer is 0-40°C.

4. The battery according to claim 1, characterized in that The melting point of the first adhesive layer is 95-130°C; And / or, the melting point of the third adhesive layer is 120-165° C.; And / or, the first adhesive layer includes one or more of a propylene-ethylene copolymer layer, a butene-modified polypropylene layer, a polyethylene layer, a maleic anhydride-grafted modified polypropylene layer, a metallocene-modified polypropylene layer, and a maleic anhydride-grafted modified polyethylene layer; And / or, the third adhesive layer includes one or more of a polypropylene layer, an anhydride grafted modified polypropylene layer, and an ethylene modified polypropylene layer; And / or, the melting point of the fourth adhesive layer is 95-130° C.; And / or, the melting point of the sixth adhesive layer is 95-130° C.; And / or, the fourth adhesive layer includes one or more of a propylene-ethylene copolymer layer, a butene-modified polypropylene layer, a polyethylene layer, a maleic anhydride-grafted modified polypropylene layer, a metallocene-modified polypropylene layer, and a maleic anhydride-grafted modified polyethylene layer; And / or, the sixth adhesive layer includes one or more of a propylene-ethylene copolymer layer, a butene-modified polypropylene layer, a polyethylene layer, a maleic anhydride-grafted modified polypropylene layer, a metallocene-modified polypropylene layer, and a maleic anhydride-grafted modified polyethylene layer.

5. The battery according to claim 1, characterized in that The first insulating adhesive further includes a second adhesive layer located between the first adhesive layer and the third adhesive layer.

6. The battery according to claim 5, characterized in that The melting point of the second adhesive layer is greater than the melting point of the first adhesive layer; and / or, the melting point of the second adhesive layer is greater than or equal to the melting point of the third adhesive layer; And / or, the melting point of the second adhesive layer is 140-170°C; And / or, the second adhesive layer includes one or more of a polypropylene layer and anhydride grafted modified polypropylene layer.

7. The battery according to claim 1, characterized in that The second insulating adhesive further includes a fifth adhesive layer located between the fourth adhesive layer and the sixth adhesive layer.

8. The battery according to claim 7, characterized in that The melting point of the fifth adhesive layer is greater than the melting point of the fourth adhesive layer and / or the sixth adhesive layer; and / or, the difference in melting point between the fifth adhesive layer and the fourth adhesive layer is 10-75° C.; and / or, the difference in melting point between the fifth adhesive layer and the sixth adhesive layer is 10-75° C.; And / or, the melting point of the fifth adhesive layer is 140-170° C.; And / or, the fifth adhesive layer includes one or more of a polypropylene layer and an anhydride grafted modified polypropylene layer.

9. The battery according to claim 1, characterized in that The sixth adhesive layer includes a fluorescent adhesive layer.

10. The battery according to claim 1, characterized in that The thickness of the first insulating adhesive is 40-200 μm; And / or, the width of the first insulating glue along the length direction of the conductor is 3.5-6 mm; And / or, the first insulating glue includes a first covering portion covering the conductor, and a first extension portion extending beyond the conductor in a width direction of the conductor, the first extension portions are respectively present on two opposite sides of the first covering portion in the width direction of the conductor, and a width of each of the first extension portions in the width direction of the conductor is 1.2-3.5 mm; And / or, the thickness of the second insulating adhesive is 40-200 μm; And / or, the width of the second insulating glue along the length direction of the conductor is 3.5-6 mm; And / or, the second insulating glue includes a second covering portion covering the conductor, and a second extension portion extending beyond the conductor in the width direction of the conductor, the second extension portions are respectively present on both sides of the second covering portion in the width direction of the conductor, and the width of each of the second extension portions in the width direction of the conductor is 1.2~3.5mm.

11. The battery according to any one of claims 1 to 7, characterized in that: The package body includes a support layer, a metal layer, and a first adhesive layer, and the first adhesive layer of the first connecting portion is connected to the third adhesive layer.

12. The battery according to claim 11, characterized in that The support layer includes one or more of a nylon layer, a polyethylene terephthalate layer, and a polyethylene naphthalate layer; And / or, the metal layer includes one or more of an aluminum layer, an aluminum alloy layer, a copper layer, and a steel layer; and / or, the first adhesive layer comprises one or more of an acid-modified polypropylene layer, an ethylene-modified polypropylene layer, and a polypropylene layer; And / or, the tensile strength of the package is greater than or equal to 69 MPa; And / or, the elongation of the package body is less than or equal to 55%.

13. The battery according to any one of claims 1 to 7, characterized in that: The 180° peeling force between the conductor and the first connecting portion is greater than the 180° peeling force between the conductor and the second connecting portion.

14. The battery according to claim 13, characterized in that The difference between the 180° peeling force between the conductor and the first connecting portion and the 180° peeling force between the conductor and the second connecting portion is 0.2-2.3 N / mm; and / or, a 180° peeling force between the conductor and the first connecting portion is 2.2-5.6 N / mm; And / or, a 180° peeling force between the conductor and the second connecting portion is 1.8-4.1 N / mm.

15. The battery according to any one of claims 1 to 7, characterized in that: A distance between a side surface of the first connecting portion facing away from the first main body portion in the first direction and a side surface of the first main body portion facing away from the first connecting portion in the first direction is 2 mm to 10 mm; and / or, a distance between a side surface of the second connecting portion facing away from the second main body portion in the first direction and a side surface of the second main body portion facing away from the second connecting portion in the first direction is 0-10 mm; And / or, the thickness of the package body is 60 μm to 160 μm.

Images