Tab glue, tab assembly and battery

Abstract

The invention belongs to the technical field of batteries, and particularly relates to tab glue, a tab assembly and a battery, the tab glue comprises a first component and a second component, the first component is polyolefin and accounts for 80%-95% of the total mass of the tab glue, and the second component is polyolefin and accounts for 20%-30% of the total mass of the tab glue. The second component is a thermoplastic elastomer and accounts for 5-20% of the total mass of the tab glue; through cooperative use of the first component and the second component, when the temperature is relatively high, the thermoplastic elastomer can be shaped like plastics, and when the temperature is relatively low, the thermoplastic elastomer can keep the elasticity of rubber, so that the toughness and the impact resistance of the tab glue are effectively improved. When the battery is subjected to external impact stress or volume expansion caused by cyclic charging and discharging of the battery, the tab glue can effectively disperse stress concentration of the tab assembly, so that a buffering effect is achieved, the tab assembly is prevented from being broken, and the tab assembly is effectively protected.

Description

Technical Field

[0001] The invention belongs to the technical field of batteries, and in particular relates to a tab glue, a tab assembly and a battery. Background Art

[0002] As a new type of secondary battery, lithium-ion battery has the advantages of high energy density and power density, high operating voltage, light weight, small size, long cycle life, good safety, and green environmental protection. It has broad application prospects in portable appliances, power tools, large-scale energy storage, electric transportation power supply, etc.

[0003] However, during the use of the battery, the volume expansion caused by multiple drops and cyclic charge and discharge may cause the tabs or their welding parts to break. This problem poses a serious safety hazard and may cause dangerous situations such as smoke, fire and even explosion. Summary of the invention

[0004] The purpose of the present invention is to provide a tab glue, a tab assembly and a battery in view of the deficiencies in the prior art, so as to solve the technical problem in the prior art that the tab or welding part may be broken due to volume expansion caused by multiple drops and cyclic charge and discharge when the battery is used.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides an ear glue, comprising a first component and a second component, wherein:

[0007] The first component is polyolefin, accounting for 80% to 95% of the total mass of the ear glue;

[0008] The second component is a thermoplastic elastomer, which accounts for 5% to 20% of the total mass of the ear glue.

[0009] Preferably, the thermoplastic elastomer is one of polyurethane type, styrene type, polyester type or polyamide type, or a mixture of several of them.

[0010] In a second aspect, the present invention provides a tab assembly, comprising a tab body and the tab glue of the above embodiment, wherein the tab glue is arranged on the tab body.

[0011] Preferably, the pole ear body includes a first pole ear portion and a second pole ear portion bent outward and extending from one end of the first pole ear portion, the second pole ear portion is used to be connected to a battery cell, the other end of the first pole ear portion is used to pass through the top seal portion of the battery and extend out of the battery, the pole ear glue is arranged on the first pole ear portion, and the pole ear glue is located between the top seal portion of the battery and the first pole ear portion.

[0012] Preferably, the pole ear glue includes a first insulating member and a second insulating member. Along the thickness direction of the pole ear body, the first insulating member is arranged on the side of the first pole ear portion facing the deep pit surface of the battery, and the second insulating member is arranged on the side of the first pole ear portion away from the deep pit surface of the battery. The first insulating member and the second insulating member are arranged opposite to each other, and the length of the first insulating member and the length of the second insulating member are both greater than or equal to the width of the top seal portion of the battery.

[0013] Preferably, the length of the first insulating member is greater than the length of the second insulating member.

[0014] Preferably, the first insulating member includes a main body portion and an extension portion, wherein the extension portion extends from one end of the main body portion to the second pole lug portion, and the extension portion covers a portion of the second pole lug portion.

[0015] Preferably, the width of the extension portion, the width of the main body portion and the width of the first pole ear portion satisfy the relationship: d<f≤g, wherein d is the width of the first pole ear portion, f is the width of the extension portion, and g is the width of the main body portion.

[0016] Preferably, the first insulating member and the second insulating member satisfy the relationship:

[0017] and / or, 0.1≤cb≤2;

[0018] Wherein, a is the width of the first insulating member and / or the width of the second insulating member, b is the length of the second insulating member, and c is the length of the first insulating member.

[0019] In a third aspect, the present invention provides a battery, a packaging bag, a battery cell and a tab assembly of the above-mentioned embodiment, wherein the battery cell is arranged in the packaging bag, a top seal portion is provided on the packaging bag, one end of the tab body is connected to the battery cell, and the other end of the tab body extends through the top seal portion to the outside of the packaging bag, and the tab glue is arranged between the top seal portion and the tab body.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The ear glue of the present invention is used in combination with a first component and a second component. The first component is polyolefin, and the second component is a thermoplastic elastomer. The thermoplastic elastomer combines the advantages of thermoplastic rubber and thermoplastic. When the temperature is high, the thermoplastic elastomer can be shaped like plastic, and when the temperature is low, the thermoplastic elastomer can maintain the elasticity of rubber, thereby effectively improving the toughness and impact resistance of the ear glue. When the battery is subjected to external impact stress or volume expansion caused by battery cyclic charge and discharge, the ear glue can effectively disperse the stress concentration of the ear assembly, play a buffering role, avoid causing the ear assembly to break, and effectively protect the ear assembly. In addition, polyolefin accounts for 80% to 95% of the total mass of the ear glue, and the thermoplastic elastomer accounts for 5% to 20% of the total mass of the ear glue, which can better improve the toughness and impact resistance of the ear glue.

[0022] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0024] Figure 1 It is a schematic diagram of the structure of the battery of the present invention.

[0025] Figure 2 for Figure 1 Schematic diagram of the enlarged structure at point A in the middle.

[0026] Figure 3 This is one of the structural schematic diagrams of the tab body of the present invention.

[0027] Figure 4 This is the second structural schematic diagram of the tab body of the present invention.

[0028] Figure 5 This is the third structural schematic diagram of the tab body of the present invention.

[0029] The reference numerals are described as follows:

[0030] 100. Battery;

[0031] 10. Tab assembly; 11. Tab body; 111. first tab portion; 112. second tab portion; 12. tab glue; 121. first insulating member; 1211. main body; 1212. extension portion; 122. second insulating member;

[0032] 20. Battery cells;

[0033] 30. packaging bag; 31. top sealing part;

[0034] k, thickness direction of the tab body; j, length direction of the battery; e, width of the top seal. DETAILED DESCRIPTION

[0035] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of components as the criteria for distinction. For example, "including" mentioned throughout the specification and claims is an open term, so it should be interpreted as "including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve technical problems within a certain error range and basically achieve technical effects.

[0036] Furthermore, the terms “first”, “second”, etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance.

[0037] The term "and / or" in the present invention is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects before and after are in an "or" relationship.

[0038] In the invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0039] The following will be combined with the attached Figures 1 to 5 The technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] See also Figures 1 to 5The battery 100 of the embodiment of the present invention comprises a packaging bag 30, a battery cell 20 and a tab assembly 10. The battery cell 20 is arranged in the packaging bag 30. A top seal portion 31 is provided on the packaging bag 30. One end of the tab body 11 is connected to the battery cell 20. The other end of the tab body 11 passes through the top seal portion 31 and extends to the outside of the packaging bag 30. The tab glue 12 is arranged between the top seal portion 31 and the tab body 11.

[0041] The packaging bag 30 includes a first packaging film and a second packaging film. A groove is provided on the first packaging film. The first packaging film and the second packaging film are connected to each other to form a receiving cavity at the groove. The receiving cavity is used to accommodate the battery cell 20, the electrolyte and part of the tab assembly 10. The edges of the first packaging film and the second packaging film are connected to form a top sealing portion 31 and a side sealing portion.

[0042] The first packaging film and the second packaging film each include a packaging layer, a metal layer and a protective layer which are stacked. The packaging layer is arranged close to the battery cell 20 , while the protective layer is arranged away from the battery cell 20 .

[0043] It can be understood that the top seal portion 31 and the side seal portion are the parts that are sealed by a hot pressing process after the packaging bag 30 contains the electrode assembly and the electrolyte.

[0044] See also Figures 1 to 5 The tab assembly 10 of the embodiment of the present invention includes a tab body 11 and a tab glue 12 , and the tab glue 12 is arranged on the tab body 11 .

[0045] The tab glue 12 of the embodiment of the present invention comprises a first component and a second component, wherein the first component is polyolefin, accounting for 80% to 95% of the total mass of the tab glue; the second component is thermoplastic elastomer, accounting for 5% to 20% of the total mass of the tab glue.

[0046] Compared with the prior art, the tab glue of the embodiment of the present invention is used in combination with the first component and the second component. The first component is polyolefin, and the second component is thermoplastic elastomer. The thermoplastic elastomer combines the advantages of thermoplastic rubber and thermoplastic. When the temperature is high, the thermoplastic elastomer can be shaped like plastic, and when the temperature is low, the thermoplastic elastomer can maintain the elasticity of rubber, thereby effectively improving the toughness and impact resistance of the tab glue 12. When the battery 100 is subjected to external impact stress or the volume expansion caused by the cyclic charge and discharge of the battery 100, the tab glue 12 can effectively disperse the stress concentration of the tab assembly 10, play a buffering role, avoid the tab assembly 10 from breaking, and effectively protect the tab assembly 10. In addition, polyolefin accounts for 80% to 95% of the total mass of the tab glue, and the thermoplastic elastomer accounts for 5% to 20% of the total mass of the tab glue, which can better improve the toughness and impact resistance of the tab glue 12.

[0047] It should be noted that the selection of polyolefin is conducive to improving the processing performance and mechanical properties of the tab glue 12 while maintaining good flexibility and chemical resistance, so that the tab glue 12 can deform to a certain extent when subjected to external force, thereby absorbing and dispersing impact energy and reducing stress concentration.

[0048] In some embodiments, the thermoplastic elastomer is a mixture of one or more of polyurethane, styrene, polyester or polyamide. Polyurethane (TPU), styrene (TPS), polyester (TPEE) or polyamide (TPA) all have good elasticity and toughness, can quickly restore shape when subjected to external force, and are not easy to break or deform. In addition, polyurethane (TPU), styrene (TPS), polyester (TPEE) or polyamide (TPA) also have thermoplasticity, can soften and shape at high temperature, and are easy to process and shape. This reduces production costs and improves production efficiency.

[0049] See also Figures 1-2 In some embodiments, the tab body 11 includes a first tab portion 111 and a second tab portion 112 that is bent outwardly and extends from one end of the first tab portion 111. The second tab portion 112 is used to connect to the battery cell 20 of the battery 100. The other end of the first tab portion 111 is used to pass through the top seal portion 31 of the battery 100 and extend out of the battery 100. The tab glue 12 is disposed on the first tab portion 111, and the tab glue 12 is located between the top seal portion 31 of the battery 100 and the first tab portion 111. Through the coordinated use of the first tab portion 111 and the second tab portion 112, one end of the first tab portion 111 is connected to the battery cell 20 through the second tab portion 112, and the other end of the first tab portion 111 passes through the top seal portion 31 of the battery 100 and extends out of the packaging bag 30 of the battery 100, effectively enabling the second tab portion 112 to be connected to an external power source. At the same time, the tab glue 12 is arranged on the first tab portion 111 and is located between the top seal portion 31 and the first tab portion 111, effectively playing a good insulating role. This design prevents the short circuit problem caused by the tab body 11 directly contacting the packaging bag 30 or other metal parts, and improves the safety performance of the battery 100. In addition, the tab glue 12 can also protect the tab body 11 and prevent it from being damaged during the packaging and use of the battery 100.

[0050] See also Figures 1 to 5In some embodiments, the tab glue 12 includes a first insulating member 121 and a second insulating member 122. Along the thickness direction k of the tab body 11, the first insulating member 121 is arranged on the side of the first tab portion 111 facing the deep pit surface of the battery 100, and the second insulating member 122 is arranged on the side of the first tab portion 111 away from the deep pit surface of the battery 100. The first insulating member 121 and the second insulating member 122 are arranged opposite to each other, and the length of the first insulating member 121 and the length of the second insulating member 122 are both greater than or equal to the width e of the top seal portion 31 of the battery 100. Through the coordinated use of the first insulating member 121 and the second insulating member 122, the first insulating member 121 is arranged on the side of the first tab portion 111 facing the deep pit surface of the battery 100, and the second insulating member 122 is arranged on the side of the first tab portion 111 away from the deep pit surface of the battery 100, which effectively provides comprehensive insulation protection for the first tab portion 111. This design can effectively prevent direct contact between the first pole ear portion 111 and the packaging bag 30 or other metal parts, thereby avoiding the occurrence of short circuit problems. In addition, since the length of the first insulating member 121 and the length of the second insulating member 122 are both greater than or equal to the width e of the top seal portion 31 of the battery 100, the first insulating member 121 and the second insulating member 122 can completely cover the overlapping portion of the first pole ear portion 111 and the top seal portion 31. This not only improves the reliability of insulation, but also ensures the safety of the pole ear body 11 during the packaging and use of the battery 100.

[0051] It is understandable that the deep pit surface of the battery 100 means that before the packaging process of the battery 100 begins, the aluminum-plastic film is specially punched to form a side covering the battery cell 20, which corresponds to the groove portion on the first packaging film in the present invention.

[0052] The inventors have found that, at present, when multiple batteries 100 are assembled to form a battery group 100, the top seal 31 of the battery 100 will bend in the direction of the deep pit and fit on the top of the battery 100, and the protective plate is arranged along a length direction j perpendicular to the battery. This design allows the energy density of the battery group 100 to be increased by 1% to 2%. However, after the top seal 31 is bent, the head of the battery cell 20 is prone to depression. Through CT testing, it can be observed that in the depressed area, the aluminum layer in the packaging bag 30 has obvious bulges. The lowest point of this bulge will come into contact with the nickel pole ear, causing corrosion problems.

[0053] For this reason, please see Figure 3, by setting the length of the first insulating member 121 and the length of the second insulating member 122, the length of the first insulating member 121 is greater than the length of the second insulating member 122. Since the length of the first insulating member 121 is longer, the first insulating member 121 can more fully cover the bend of the pole ear body 11. In this way, even if the aluminum layer bulges in the depression, the first insulating member 121 can ensure that the bulged aluminum layer does not directly contact the nickel pole ear, thereby effectively avoiding the corrosion problem caused by contact. This not only extends the service life of the battery 100, but also improves the safety and reliability of the battery 100 group. On this basis, by adjusting the length of the first insulating member 121, the overall structure of the battery 100 is not significantly affected, so the energy density of the battery 100 group can be maintained or even further improved. In addition, the increase in the length of the first insulating member 121 not only helps to avoid corrosion, but also enhances the stability of the battery 100 group to a certain extent. The first insulating member 121 can provide additional support and cushioning for the battery cell 20 , reduce the relative movement of the battery cell 20 under vibration or impact conditions, and thus reduce the risk of damage to the battery pack 100 due to internal looseness.

[0054] See also Figures 2 to 5 In some embodiments, the first insulating member 121 includes a main body 1211 and an extension 1212, wherein the extension 1212 extends from one end of the main body 1211 to the second pole ear 112, and the extension 1212 covers a portion of the second pole ear 112. By using the main body 1211 and the extension 1212 in coordination, the extension 1212 extends from one end of the main body 1211 to the second pole ear 112, effectively increasing the length of the first insulating member 121, thereby ensuring that the first insulating member 121 can more fully cover the bend of the pole ear body 11, so that the first insulating member 121 can ensure that the aluminum layer does not directly contact the nickel pole ear, thereby effectively avoiding the corrosion problem caused by contact.

[0055] In some embodiments, the width of the extension portion 1212, the width of the body portion 1211, and the width of the first pole ear portion 111 satisfy the relationship: d<f≤g, where d is the width of the first pole ear portion 111, f is the width of the extension portion 1212, and g is the width of the body portion 1211. By making the width of the extension portion 1212 and the width of the body portion 1211 greater than the width of the first pole ear portion 111, it is ensured that the extension portion 1212 and the body portion 1211 can completely cover the edge portion of the first pole ear portion 111, thereby effectively preventing short circuits caused by the exposure of the first pole ear portion 111 or corrosion caused by direct contact between the first pole ear portion 111 and the aluminum layer. By making the width of the extension portion 1212 smaller than or equal to the width of the main body portion 1211, since the extension portion 1212 is used to cover the bending part of the pole ear body 11, it is only necessary to ensure that the width of the extension portion 1212 is greater than the width of the first pole ear portion 111, so as to avoid corrosion caused by direct contact between the first pole ear portion 111 and the aluminum layer. Therefore, the width of the extension portion 1212 can be smaller than the width of the main body portion 1211, that is, the areas on both sides of the extension portion 1212 that do not cover the first pole ear portion 111 are cut off, which can effectively reduce the space occupied by the extension portion 1212 and the overall weight of the first insulating member 121, thereby improving the energy density of the battery 100.

[0056] See also Figures 3 to 5 In some embodiments, the first insulating member 121 and the second insulating member 122 satisfy the relationship:

[0057] and / or, 0.1≤cb≤2;

[0058] Wherein, a is the width of the first insulating member 121 and / or the width of the second insulating member 122 , b is the length of the second insulating member 122 , and c is the length of the first insulating member 121 .

[0059] This design ensures that when the first insulating member 121 covers the bending part of the tab body 11 , no uncovered part will be left due to insufficient length of the first insulating member 121 , thereby avoiding the risk of internal short circuit in the battery 100 .

[0060] It can be understood that when the length of the first insulating member 121 and the length of the second insulating member 122 satisfy the relationship: 0.1≤cb≤2, it means that the length of the extension 1212 of the first insulating member 121 is 0.1-2 mm. By setting the length of the extension 1212, the length of the extension 1212 is 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm or 2 mm. However, it is not limited to the listed values, and other values ​​within the numerical range are also applicable.

[0061] The performance of the tab glue 12 provided by the present invention is described below through specific examples and comparative examples.

[0062] Embodiment 1:

[0063] The tab glue 12 includes a first component and a second component, wherein the first component is polyolefin, accounting for 95% of the total mass of the tab glue, and the second component is thermoplastic elastomer, accounting for 5% of the total mass of the tab glue.

[0064] Embodiment 2:

[0065] The difference from Example 1 is that the polyolefin accounts for 92% of the total mass of the tab glue, and the thermoplastic elastomer accounts for 8% of the total mass of the tab glue.

[0066] Embodiment 3:

[0067] The difference from Example 1 is that the polyolefin accounts for 90% of the total mass of the tab glue, and the thermoplastic elastomer accounts for 10% of the total mass of the tab glue.

[0068] Embodiment 4:

[0069] The difference from Example 1 is that the polyolefin accounts for 88% of the total mass of the tab glue, and the thermoplastic elastomer accounts for 12% of the total mass of the tab glue.

[0070] Embodiment 5:

[0071] The difference from Example 1 is that the polyolefin accounts for 85% of the total mass of the tab glue, and the thermoplastic elastomer accounts for 15% of the total mass of the tab glue.

[0072] Embodiment 6:

[0073] The difference from Example 1 is that the polyolefin accounts for 82% of the total mass of the tab glue, and the thermoplastic elastomer accounts for 18% of the total mass of the tab glue.

[0074] Embodiment 7:

[0075] The difference from Example 1 is that the polyolefin accounts for 80% of the total mass of the tab glue, and the thermoplastic elastomer accounts for 20% of the total mass of the tab glue.

[0076] Comparative Example 1:

[0077] The tab glue 12 includes polyolefin, wherein the polyolefin accounts for 100% of the total mass of the tab glue.

[0078] The toughness of the tab glue 12 prepared in each embodiment and comparative example was measured by elongation at break, and the impact resistance test of the tab glue 12 prepared in each embodiment and comparative example was performed to measure the impact thickness change rate. The test results are shown in Table 1.

[0079] The toughness of the ear glue 12 is tested by elongation at break. The specific method is: the sample width is 15mm, the length is greater than 150mm, and the gauge length is 100mm. The sample is installed on a universal testing machine with a test speed of 500±30mm / min. The elongation at break is calculated by recording the changes in force and displacement during the test.

[0080] The impact resistance test of the ear glue 12 is as follows: use a falling ball impact tester, place the sample on the test platform, and let a 50g standard steel ball fall freely from a height of 20cm to impact the sample. Record the sample thickness before and after the impact, and calculate the impact thickness change rate.

[0081] Table 1 Performance comparison of different ratios of polyolefin and thermoplastic elastomer

[0082]

[0083] As can be seen from Table 1, the tab glue of Comparative Example 1 is polyolefin, and the tab glue of Examples 1 to 7 includes polyolefin and thermoplastic elastomer. From Comparative Example 1 to Example 7, the percentage of polyolefin in the total mass of the tab glue gradually decreases, while the percentage of thermoplastic elastomer in the total mass of the tab glue gradually increases.

[0084] Elongation at break is an important indicator for measuring the toughness of a material. As can be seen from Table 1, as the content of the thermoplastic elastomer increases, the elongation at break shows an upward trend. It increases from 37% in Comparative Example 1 to 156% in Example 7, which indicates that the addition of the thermoplastic elastomer significantly improves the toughness of the tab rubber.

[0085] In particular, between Example 3 and Example 7, the elongation at break increases significantly, indicating that within this ratio range, the thermoplastic elastomer has a more significant effect on improving the toughness of the ear rubber.

[0086] The impact thickness change rate reflects the degree of deformation of the material when it is impacted. As can be seen from Table 1, contrary to the elongation at break, the impact thickness change rate shows a downward trend with the increase of the thermoplastic elastomer content. It decreases from 29.7% in Comparative Example 1 to 2.8% in Example 7, which indicates that the addition of thermoplastic elastomer reduces the degree of deformation of the ear glue when it is impacted.

[0087] Similarly, between Example 3 and Example 7, the reduction in the impact thickness change rate is relatively large, indicating that within this ratio range, the thermoplastic elastomer has a more significant effect on improving the impact resistance of the ear rubber.

[0088] In summary, the data in Table 1 show that by adjusting the ratio of polyolefin to thermoplastic elastomer, the elongation at break and impact thickness change rate of the material can be significantly affected. The addition of thermoplastic elastomer not only improves the toughness of the material, but also reduces its deformation degree when subjected to impact.

[0089] The ear glue of Example 1 was tested for sealing properties.

[0090] Sealing test 1: After the ear glue was immersed in 85°C electrolyte for 4 hours and subjected to mercurochrome penetration test, no penetration channel was shown, thereby proving that the ear glue of the present invention has extremely high sealing performance.

[0091] Sealing test 2: The battery cells prepared with the ear glue of Example 1 were subjected to a mercurochrome penetration test after top packaging. The results showed that no penetration channel appeared, thereby proving that the ear glue of the present invention has extremely high sealing performance.

[0092] The battery cell made of the ear glue of Comparative Example 1 is marked as M, and the battery cell made of the ear glue of Example 1 is marked as J.

[0093] The package tensile test was performed on M and J. The test results are shown in Table 2.

[0094] Table 2 Comparison of package tension between M and J

[0095]

[0096] It can be seen from Table 2 that under two different test conditions, the packaging tensile force data of the battery cell made of the tab glue of Comparative Example 1 and the battery cell made of the tab glue of Example 1.

[0097] Under normal temperature conditions, the average packaging tensile force of the battery cells made with the ear glue of Comparative Example 1 is 14.436N, the standard deviation is 2.574, and the 95% confidence interval is (13.311, 15.572)N. The average packaging tensile force of the battery cells made with the ear glue of Example 1 is 15.220N, the standard deviation is 2.446, and the 95% confidence interval is (14.084, 16.356)N. It can be seen that the average packaging tensile force of the battery cells made with the ear glue of Example 1 is higher than the average packaging tensile force of the battery cells made with the ear glue of Comparative Example 1, and the standard deviation is slightly smaller, indicating that the packaging tensile force of the battery cells made with the ear glue of Example 1 at room temperature is not only higher, but also the data is more stable.

[0098] Under the conditions of storage for 30 days at a temperature of 65°C, a humidity of 90%, and a SOC of 100%, the average packaging tension of the battery cells made with the ear glue of Comparative Example 1 is 12.717N, the standard deviation is 1.901, and the 95% confidence interval is (11.767, 13.644)N. The average packaging tension of the battery cells made with the ear glue of Example 1 is 13.175N, the standard deviation is 2.317, and the 95% confidence interval is (12.043, 14.307)N. It can be seen that under such more stringent test conditions, the average packaging tension of the battery cells made with the ear glue of Example 1 is still higher than the packaging tension of the battery cells made with the ear glue of Comparative Example 1, but the standard deviation has increased. Although the battery cells made with the ear glue of Example 1 maintain a relatively high packaging tension, the discreteness of the data has increased.

[0099] From the perspective of the 95% confidence interval, under the two test conditions, the upper and lower limits of the 95% confidence interval of the battery cell made with the ear glue of Example 1 are higher than the upper and lower limits of the 95% confidence interval of the battery cell made with the ear glue of Comparative Example 1, which further supports the conclusion that the packaging tensile force of the battery cell made with the ear glue of Example 1 has better performance.

[0100] At the same time, it is noted that under more stringent test conditions (65°C temperature, 90% humidity, and storage at 100% SOC for 30 days), the width of the 95% confidence intervals for both groups increased, reflecting the impact of the test conditions on the package tensile data.

[0101] In summary, whether at room temperature or under more stringent test conditions, the battery cells made using the ear glue of Example 1 exhibit higher packaging tension than the battery cells made using the ear glue of Comparative Example 1. Although the data discreteness of the battery cells made using the ear glue of Example 1 increases under more stringent conditions, its packaging tension remains at a high level. These results show that the ear glue of Example 1 helps to improve the packaging strength and reliability of the battery cells, thereby enhancing the overall performance of the battery cells.

[0102] M and J were stored in a hot box at 130°C to 135°C for 1 hour. The test results are shown in Table 3.

[0103] Table 3 Comparison of hot box test pass rates of M and J under different temperature conditions

[0104] Storage conditions (hot box temperature & duration) M J 130℃ hot box, store for 1 hour 10 / 10(100％) 10 / 10(100％) 132℃ hot box, store for 1 hour 7 / 10(70％) 10 / 10(100％) 135℃ hot box, store for 1 hour 2 / 10(20％) 8 / 10(80％)

[0105] It can be seen from Table 3 that under different temperature conditions, the battery cells made of the tab glue of Comparative Example 1 and the battery cells made of the tab glue of Example 1 passed the test.

[0106] Under the condition of 130℃ hot box storage for 1 hour, the battery cells made of the ear glue of comparative example 1 and the battery cells made of the ear glue of embodiment 1 both showed good pass rates, both of which were 10 / 10 pass. As the temperature increased, the pass rates of both groups of battery cells decreased.

[0107] Under the condition of 132°C hot box storage for 1 hour, the pass rate of the battery cells made of the ear glue of Comparative Example 1 dropped to 70% (7 / 10 pass), indicating that some battery cells could not withstand the test under this temperature condition. However, all the battery cells made of the ear glue of Example 1 passed the test (10 / 10 pass).

[0108] Under the condition of 135°C hot box storage for 1 hour, the pass rate of the battery cell made of the ear glue of Comparative Example 1 further dropped to 20% (2 / 10 pass), indicating that at higher temperatures, the safety performance of the battery cell made of the ear glue of Comparative Example 1 is significantly reduced. The pass rate of the battery cell made of the ear glue of Example 1 also dropped to 80% (8 / 10 pass), but compared with the 20% pass rate of the battery cell made of the ear glue of Comparative Example 1, its performance is still superior.

[0109] Under the same temperature conditions, the pass rate of the battery cell made of the ear glue of Example 1 is generally higher than the pass rate of the battery cell made of the ear glue of Comparative Example 1, especially at a higher temperature (135°C hot box, stored for 1 hour), the difference is more obvious. This shows that the battery cell made of the ear glue of Example 1 can still maintain good hot box safety performance under high temperature storage conditions.

[0110] In summary, the battery cell made of the ear glue of Example 1 has a significant effect in improving the safety performance of the battery cell hot box, and can maintain a high pass rate at a higher temperature, thereby improving the reliability and safety of the battery cell.

[0111] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive from any point of view. The scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A tip glue, characterized in that: It comprises a first component and a second component, wherein: The first component is polyolefin, accounting for 80% to 95% of the total mass of the ear glue; The second component is a thermoplastic elastomer, which accounts for 5% to 20% of the total mass of the ear glue.

2. The ear glue according to claim 1, characterized in that: The thermoplastic elastomer is one of polyurethane type, styrene type, polyester type or polyamide type, or a mixture of several of them.

3. A tab assembly, characterized in that: It comprises a tab body (11) and the tab glue according to any one of claims 1 to 2, wherein the tab glue (12) is arranged on the tab body (11).

4. The tab assembly according to claim 3, characterized in that: The pole ear body (11) comprises a first pole ear portion (111) and a second pole ear portion (112) bent outwardly and extending from one end of the first pole ear portion (111); the second pole ear portion (112) is used to be connected to a battery cell (20) of a battery (100); the other end of the first pole ear portion (111) is used to pass through a top seal portion (31) of the battery (100) and extend out of the battery (100); the pole ear glue (12) is arranged on the first pole ear portion (111), and the pole ear glue (12) is located between the top seal portion (31) of the battery (100) and the first pole ear portion (111).

5. The tab assembly according to claim 4, characterized in that: The pole ear glue (12) comprises a first insulating member (121) and a second insulating member (122). Along the thickness direction (k) of the pole ear body (11), the first insulating member (121) is arranged on the side of the first pole ear portion (111) facing the deep pit surface of the battery (100), and the second insulating member (122) is arranged on the side of the first pole ear portion (111) away from the deep pit surface of the battery (100). The length of the first insulating member (121) and the length of the second insulating member (122) are both greater than or equal to the width (e) of the top seal portion (31) of the battery (100).

6. The tab assembly according to claim 5, characterized in that: The length of the first insulating member (121) is greater than the length of the second insulating member (122).

7. The tab assembly according to claim 5 or 6, characterized in that: The first insulating member (121) comprises a main body portion (1211) and an extension portion (1212), wherein the extension portion (1212) extends from one end of the main body portion (1211) to the second pole lug portion (112), and the extension portion (1212) covers a portion of the second pole lug portion (112).

8. The tab assembly according to claim 7, characterized in that: The width of the extension portion (1212), the width of the main body portion (1211) and the width of the first pole ear portion (111) satisfy the relationship: d<f≤g, wherein d is the width of the first pole ear portion (111), f is the width of the extension portion (1212), and g is the width of the main body portion (1211).

9. The tab assembly according to claim 5, characterized in that: The first insulating member (121) and the second insulating member (122) satisfy the relationship: and / or, 0.1≤cb≤2; Wherein, a is the width of the first insulating member (121) and / or the width of the second insulating member (122), b is the length of the second insulating member (122), and c is the length of the first insulating member (121).

10. A battery, characterized in that: A packaging bag (30), a battery cell (20), and a tab assembly as claimed in any one of claims 3 to 9, wherein the battery cell (20) is arranged in the packaging bag (30), a top seal portion (31) is provided on the packaging bag (30), one end of the tab body (11) is connected to the battery cell (20), and the other end of the tab body (11) passes through the top seal portion (31) and extends to the outside of the packaging bag (30), and the tab glue (12) is arranged between the top seal portion (31) and the tab body (11).

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