A type of battery

Abstract

This invention relates to the field of battery technology, specifically to a battery. The battery includes a casing and an electrode assembly, the electrode assembly being located within a receiving space formed by the casing. The casing includes a first through-hole, and the battery further includes a connecting mechanism connected to a first tab assembly, the connecting mechanism passing through the first through-hole. The connecting mechanism includes a conductive element and an insulating element, the conductive element being connected to the first tab assembly, and the insulating element being located between the casing and the conductive element. At least one of the interfaces between the conductive element and the insulating element and between the insulating element and the casing forms a bonding region. The bonding region includes a first surface of the conductive element facing the insulating element and / or a second surface of the casing facing the insulating element, the first surface and / or the second surface including a plurality of recesses, the orthographic projection of the insulating element covering the recesses, and the insulating element including protrusions embedded in the recesses. The battery of this invention is applicable to batteries of various thicknesses and can improve the sealing performance and connection strength of the connecting mechanism.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more specifically to a battery. Background Technology

[0002] In recent years, lithium-ion batteries have been widely used in mobile phones, laptops, new energy vehicles, and other fields. Currently, the energy density of pouch lithium-ion batteries is approaching its design limit, and metal-packaged batteries, which can further improve energy density based on pouch batteries, are gradually attracting attention.

[0003] Currently, the commonly used terminals in metal-packaged batteries include riveted terminals and PP terminals. When battery thickness decreases, riveted terminals struggle to achieve effective sealing due to manufacturing limitations. PP terminals require sufficient bonding area to ensure a tight seal. As battery thickness decreases, while maintaining compatibility with thinner batteries, the size of the excess PP adhesive shrinks, leading to a significant drop in sealing performance. Summary of the Invention

[0004] To overcome the difficulty of achieving effective sealing in thin batteries, this invention provides a battery. The battery of this invention is applicable to batteries of various thicknesses and can improve the sealing performance and connection strength of the connection mechanism, especially for thin batteries, improving the sealing performance of the connection mechanism in thin batteries.

[0005] This invention provides a battery comprising a casing and an electrode assembly, the electrode assembly being located within a receiving space formed by the casing; the electrode assembly comprising a first electrode, a second electrode, and a separator located between the first electrode and the second electrode; the first electrode comprising a first tab assembly, and the second electrode comprising a second tab assembly; the casing comprising a first through hole, and the battery further comprising a connecting mechanism connected to the first tab assembly, the connecting mechanism being disposed within the first through hole; the connecting mechanism comprising a conductive element and an insulating element, the conductive element being connected to the first tab assembly, and the insulating element being located between the casing and the conductive element; the casing and / or the conductive element being made of one or more of stainless steel, nickel, steel, aluminum, aluminum alloy, titanium, titanium alloy, nickel-titanium alloy, copper, and copper alloy. The insulating material includes one or more of the following: fluororesin, polyamide, polypropylene, polyethylene, polyvinylidene fluoride, polyethylene terephthalate, polycarbonate, and carbon fiber reinforced plastic. At least one of the interfaces between the conductive element and the insulating element and between the insulating element and the housing forms a bonding region, wherein the conductive element and the insulating element in the bonding region are thermoformed into an integral structure, and / or the insulating element and the housing in the bonding region are thermoformed into an integral structure; the bonding region includes a first surface of the conductive element facing the insulating element and / or a second surface of the housing facing the insulating element, the first surface and / or the second surface includes a plurality of recesses, the orthographic projection of the insulating element covers the recesses, and the insulating element includes a protrusion embedded in the recesses.

[0006] By employing the above technical solution, the present invention has at least the following advantages compared with the prior art: The connection mechanism in the battery of the present invention is disposed in the first through hole. The connection mechanism includes a conductive element and an insulating element. The conductive element is connected to the positive electrode tab assembly, that is, it forms an electrical connection with the electrode assembly. The insulating element is located between the shell and the conductive element to achieve insulation between the conductive element and the shell. Moreover, the insulating element can also alleviate the force along the length direction of the battery and the length direction of the connection mechanism during the drop test, and prevent the connection mechanism from being deformed due to excessive force, which would affect the current carrying capacity.

[0007] The bonding strength between the insulating component and the housing, as well as between the insulating component and the conductive component, directly affects the sealing performance of the connecting mechanism for the first through hole. To improve the sealing performance of the connection mechanism, at least one of the interfaces between the conductive element and the insulating element and between the insulating element and the housing is formed with a joint area. The joint area includes a first surface of the conductive element facing the insulating element and / or a second surface of the housing facing the insulating element. The first surface and / or the second surface includes a plurality of recesses. The orthographic projection of the insulating element covers the recesses. The insulating element includes a protrusion embedded in the recesses, such that a portion of the insulating element is embedded in the conductive element and / or the housing. This creates a mechanical interlock between the interface between the conductive element and the insulating element and between the housing and the insulating element, thereby enhancing the peel strength between the housing and the insulating element and between the conductive element and the insulating element. Furthermore, when the housing or the conductive element and the insulating element expand, the mechanical interlock also creates mutual restraint between the housing and the insulating element or between the conductive element and the insulating element, thereby suppressing expansion, reducing warping caused by the difference in thermal expansion coefficients between the housing and the insulating element or between the conductive element and the insulating element, and improving the connection strength and sealing performance between the housing and the insulating element or between the conductive element and the insulating element.

[0008] In summary, the connection mechanism of the present invention can form a high connection strength between the shell and the insulating component or between the conductive component and the insulating component through the mechanical anchoring force generated between the shell and the insulating component or between the conductive component and the insulating component, thereby improving the sealing performance of the connection mechanism. Moreover, it does not require an additional insulating layer on the outside of the shell, reducing the space occupied by the connection mechanism on the outside of the shell. In the thickness direction of the battery, it does not need to overflow a certain size from the contact surface between the connection mechanism and the side wall of the shell to ensure sealing performance, thus enabling smaller, lighter, and more flexible battery designs.

[0009] Other features and advantages of the present invention will be described in detail in the following detailed description section.

[0010] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. Attached Figure Description

[0011] Figure 1 The image shown is an exploded view of a battery that uses riveted terminal post technology in the prior art.

[0012] Figure 2 The image shown is a partial cross-sectional view of the PP pole technology used in the prior art.

[0013] Figure 3 The image shown is an exploded view of a battery according to one embodiment of the present invention.

[0014] Figure 4 As shown Figure 3 A magnified view of part A in the image.

[0015] Figure 5 As shown Figure 3 One of the partial cross-sectional views of A in the middle.

[0016] Figure 6 The image shown is one of the cross-sectional views of the joining region in one embodiment of the present invention.

[0017] Figure 7 The image shown is a second cross-sectional view of the joining region in one embodiment of the present invention.

[0018] Figure 8 The diagram shown is a schematic representation of the recess and protrusion in an example of the present invention.

[0019] Figure 9 The figure shown is a cross-sectional view of the recess in one embodiment of the present invention.

[0020] Figure 10 As shown Figure 3 Partial cross-sectional view of A in the middle (second part).

[0021] Figure 11 As shown Figure 3 Part 3 of the partial cross-sectional views of A. Detailed Implementation

[0022] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the invention. Unless otherwise specified herein, data ranges include endpoints.

[0023] It should be noted that the numerical designations such as "first" and "second" in this invention are only used to distinguish different substances or methods of use, and do not represent a difference in order.

[0024] Currently, the commonly used terminals in metal-packaged batteries include riveted terminals and PP terminals, such as... Figures 1-2 As shown, the riveted terminal 100 includes a first abutment portion 101 located on the outer side, a second abutment portion 102 located on the inner side, and a post portion 103 connecting the first abutment portion 101 and the second abutment portion 102. The post portion is located within a through hole, and the first abutment portion 101 presses against the outer insulating pad 104 to achieve fixation. When the battery thickness decreases, the diameter of the first abutment portion also decreases, directly resulting in a reduction in the pressing area between the first abutment portion and the outer insulating pad, making it difficult to achieve an effective seal. Moreover, when the battery thickness decreases, in order to ensure the pressing area between the first abutment portion and the outer insulating pad, the diameter of the post portion needs to be compressed, resulting in a decrease in the current-carrying cross-sectional area, making it difficult to meet the overcurrent requirements.

[0025] PP terminals refer to terminals 2 and housing 1 with PP adhesive 3 bonded together. The terminals and housing sidewalls are fixed together using PP adhesive. The PP adhesive in the terminals needs sufficient bonding area to ensure a tight seal. When the battery thickness decreases, while maintaining compatibility with thinner batteries, the size of the excess PP adhesive decreases, resulting in a significant reduction in sealing performance.

[0026] To address the above issues, one embodiment of this application provides a battery comprising a casing and an electrode assembly, the electrode assembly being located within a receiving space formed by the casing. In a specific example, the casing may be made of metal materials such as aluminum, stainless steel, titanium alloy, or copper. The shape of the casing may be, for example, L-shaped, square, stepped, or rectangular.

[0027] In one specific example, the battery may be, for example, a lithium-ion battery, a sodium-ion battery, a lead-acid battery, or a solid-state battery. In further examples, the battery may be, for example, a button cell, a metal-cased battery, or a power battery.

[0028] The electrode assembly includes a first electrode, a second electrode, and a diaphragm located between the first electrode and the second electrode; the first electrode includes a first tab assembly, and the second electrode includes a second tab assembly.

[0029] In one specific example, the first electrode is a positive electrode and the second electrode is a negative electrode. The positive electrode includes a positive current collector and a positive active layer on the current collector. The positive electrode tab assembly includes a flexible positive electrode tab extending from one side of the current collector and a rigid positive electrode tab connected to multiple flexible positive electrode tabs. To save head space, in a further example, the rigid positive electrode tab is U-shaped.

[0030] In a specific example, the positive current collector may be, for example, aluminum foil, aluminum alloy foil, or composite current collector (e.g., aluminum-carbon composite current collector), and the thickness of the positive current collector may be, for example, 6μm-15μm (e.g., 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, or 15μm).

[0031] In a specific example, the positive electrode active layer may include a positive electrode active material, such as lithium nickel cobalt manganese oxide (LiNi). 0.90 Co 0.05 Mn 0.05 O2 (NCM955), LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM811), LiNi 0.6 Co 0.2 Mn 0.2 O2 (NCM622), LiNi 0.5 Co 0.2 Mn 0.3 O2 (NCM523), LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 At least one of the following: O2 (NCM111)), lithium nickel cobalt aluminum oxide, lithium iron phosphate, lithium vanadium phosphate, lithium cobalt phosphate, lithium manganese phosphate, lithium manganese iron phosphate, lithium-rich manganese-based materials, lithium cobalt oxide (LiCoO2), lithium iron silicate, lithium vanadium silicate, lithium cobalt silicate, lithium manganese silicate, spinel-type lithium manganese oxide, spinel-type lithium nickel manganese oxide, and lithium titanate.

[0032] In one specific example, the negative electrode sheet includes a negative electrode current collector and a negative electrode tab extending from one side of the negative electrode current collector; the negative electrode sheet also includes a negative electrode active layer located on at least one surface of the negative electrode current collector. In one specific example, the negative electrode current collector may be, for example, copper foil, copper alloy foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, or a composite current collector. In one example, the thickness of the negative electrode current collector may be, for example, 4μm-10μm (e.g., 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, or 10μm).

[0033] In one specific example, the negative electrode active layer may include a negative electrode active material, such as at least one selected from graphite, mesophase microcarbon spheres (MCMB), hard carbon, soft carbon, silicon, silicon-carbon composites, spherical silicon-carbon, bulk silicon-carbon, Li-Al alloys, and metallic lithium. In embodiments where the negative electrode active material layer includes a silicon-carbon composite, the silicon content by mass fraction is 5%-60% (e.g., 5%, 5.5%, 8%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 60%).

[0034] In one specific example, the separator includes a base membrane and adhesive layers on both sides of the base membrane. In a further embodiment, a ceramic layer and an adhesive layer are sequentially formed on a first side of the base membrane, and an adhesive layer is formed on a second side. The first side surface of the base membrane is disposed opposite to the positive electrode, and the second side surface of the base membrane is disposed opposite to the negative electrode. In some embodiments, the thickness of the separator is 5 μm-20 μm (e.g., 5 μm, 8 μm, 10 μm, 13 μm, 15 μm, 18 μm, or 20 μm).

[0035] In one specific example, the battery also includes an electrolyte comprising a lithium salt and a solvent, wherein the solvent comprises at least one selected from ethylene carbonate, diethyl carbonate, or fluoroethylene carbonate. In another embodiment, the electrolyte further includes a nitrile additive. The nitrile additive comprises a C3 percentage based on the total mass of the electrolyte. C3 is 0.5%-8%, for example, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, or 8%. In some embodiments, the nitrile additive comprises, for example, at least one selected from butadionitrile, adiponitrile, and 1,3,6-hexanetrionitrile.

[0036] The housing 1 includes a first through hole 121, and the battery also includes a connecting mechanism 4 connected to the first electrode assembly 5. The connecting mechanism 4 passes through the first through hole 121. In an example where the battery has a metal casing, such as Figure 3As shown, the housing 1 includes a bottom wall 11, a side wall 12, and a cover plate 13. A first through hole 121 is provided on the side wall 12. The bottom wall 11 and the side wall 12 form a receiving cavity for accommodating the battery cell. The side wall extends outward to form a first flange edge. The cover plate forms a second flange edge corresponding to the position of the first flange edge. The first flange edge and the second flange edge are aligned and connected to seal the receiving cavity.

[0037] In an example where the battery is a button cell, the housing includes a bottom shell and a top cover assembly, wherein a first through hole is provided on the top cover assembly, and the edges of the top cover assembly and the housing are welded together.

[0038] Among them, such as Figure 4 and Figure 5 As shown, the connecting mechanism includes four conductive elements 41 and insulating elements 42. The conductive elements 41 are connected to the first tab assembly 5, and the insulating elements 42 are located between the housing 1 and the conductive elements 41. At least one of the interfaces between the conductive elements 41 and the insulating elements 42 and between the insulating elements 42 and the housing 1 forms a bonding region 43. The conductive elements and insulating elements within the bonding region are thermoformed into an integral structure, and / or the insulating elements and the housing within the bonding region are thermoformed into an integral structure. It should be noted that an integral structure refers to the insulating elements and conductive elements, or the insulating elements and the housing, being thermoformed to melt at least one of them to form a composite component.

[0039] The material of the housing and / or conductive components includes one or more of stainless steel, nickel, steel, aluminum, aluminum alloy, titanium, titanium alloy, nickel-titanium alloy, copper, and copper alloy. In another possible implementation, the material of the insulating components includes one or more of fluororesin, polyamide, polyethylene terephthalate, polycarbonate, and carbon fiber reinforced plastic.

[0040] In a specific example, the bonding area refers to the area where the conductive element 41 is irradiated with a laser on the side facing away from the insulating layer 42 or the side facing away from the insulating layer 42 of the housing 1. This causes the conductive element or housing to generate high temperatures, which are then conducted to the insulating element. At these high temperatures, the side of the insulating element near the housing and / or the side of the insulating element near the conductive element melts, and tiny bubbles are generated inside. The generation of bubbles or the high internal pressure generated by the rapid expansion of the melted area of ​​the insulating element causes the interface between the melted insulating element and the housing or the interface of the conductive element to adhere tightly together. At the same time, the molten insulating element is pushed into the interface of the housing or the interface of the conductive element. As a result, the interface between the partially melted insulating element and the housing and / or the interface between the insulating element and the conductive element generates physical van der Waals forces, mechanical connections (anchoring effect), and chemical bonds.

[0041] Among them, such as Figure 4 and Figure 5As shown, the bonding area includes a first surface 411 of the conductive element 41 facing the insulating element 42 and / or a second surface 122 of the housing 1 facing the insulating element 42. The first surface 411 and / or the second surface 122 include a plurality of recesses 431. The orthographic projection of the insulating element 42 covers the recesses, and the insulating element includes a protrusion 421 embedded in the recesses. In a specific example, a portion of the molten insulating element flows into the recesses of the first surface and / or the second surface to achieve a double bond at the interface between the insulating element and the housing or between the insulating element and the conductive element. When the temperature drops to room temperature, the insulating element flowing into the recesses of the first surface and / or the second surface solidifies in the recesses, further achieving an anchoring effect.

[0042] In this embodiment, the connection mechanism 4 in the battery is inserted into the first through hole 121. The connection mechanism 4 includes a conductive element 41 and an insulating element 42. The conductive element 41 is connected to the positive electrode tab assembly 5, that is, it forms an electrical connection with the electrode assembly. The insulating element 42 is located between the housing 1 and the conductive element 41 to achieve insulation between the conductive element and the housing. Moreover, the insulating element can also alleviate the force along the length direction of the battery and the length direction of the connection mechanism during the drop test, and prevent the connection mechanism from being deformed due to excessive force, which would affect the current carrying capacity.

[0043] The bonding strength between the insulating component and the housing, as well as between the insulating component and the conductive component, directly affects the sealing performance of the connecting mechanism for the first through hole. To improve the sealing performance of the connection mechanism, at least one of the interfaces between the conductive element and the insulating element and between the insulating element and the housing is formed with a joint area. The joint area includes a first surface of the conductive element facing the insulating element and / or a second surface of the housing facing the insulating element. The first surface and / or the second surface includes a plurality of recesses. The orthographic projection of the insulating element covers the recesses. The insulating element includes a protrusion that is embedded in the recesses, such that a portion of the insulating element is embedded in the conductive element and / or the housing. This creates a mechanical interlock between the interface between the conductive element and the insulating element and between the housing and the insulating element, thereby enhancing the peel strength between the housing and the insulating element and the peel strength between the conductive element and the insulating element. Moreover, when the housing or the conductive element and the insulating element expand, the mechanical interlock also creates mutual restraint between the housing and the insulating element or between the conductive element and the insulating element, thereby suppressing expansion, reducing warping caused by the difference in the coefficients of thermal expansion between the housing and the insulating element or between the conductive element and the insulating element, and improving the connection strength and sealing performance between the housing and the insulating element or between the conductive element and the insulating element.

[0044] In summary, the connection mechanism of the present invention can form a high connection strength between the shell and the insulating component or between the conductive component and the insulating component through the mechanical anchoring force generated between the shell and the insulating component or between the conductive component and the insulating component, thereby improving the sealing performance of the connection mechanism. Moreover, it does not require an additional insulating layer on the outside of the shell, reducing the space occupied by the connection mechanism on the outside of the shell. In the thickness direction of the battery, it does not need to overflow a certain size from the contact surface between the connection mechanism and the side wall of the shell to ensure sealing performance, thus enabling smaller, lighter, and more flexible battery designs.

[0045] Compared to the existing riveted pole technology, this embodiment uses a joint area to achieve the connection between the shell and the insulating component, as well as between the insulating component and the conductive component. The size required for the joint area is smaller, much smaller than the area of ​​the first abutment part and the pressing area of ​​the outer insulating pad required by the riveted pole technology, to achieve a firm connection. Therefore, it is not necessary to deliberately compress the diameter of the pole part in order to ensure the pressing area. In other words, this embodiment can ensure that the current carrying area of ​​the connection mechanism remains unchanged, thereby meeting the overcurrent requirements.

[0046] Compared to the existing PP electrode technology, this embodiment uses a bonding area to achieve the connection between the housing and the insulating component, as well as between the insulating component and the conductive component. The bonding area requires a smaller size. For example, the size of the bonding area at the interface between the conductive component and the insulating component is smaller than the size of the interface between the conductive component and the insulating component, and the size of the bonding area at the interface between the housing and the insulating component is smaller than the size of the interface between the housing and the insulating component. It does not require the size of the adhesive overflow portion as in the PP electrode technology, thus ensuring sufficient sealing performance.

[0047] In one possible implementation, such as Figure 8 As shown, a protrusion 432 is included between two adjacent recesses 431, and the height D of the protrusion 432 is... 4 The thickness is 10μm-200μm (e.g., 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 110μm, 120μm, 130μm, 140μm, 150μm, 160μm, 170μm, 180μm, 190μm, 200μm, or within any two of the above values). The height of the protrusion refers to the maximum vertical distance from the apex of the protrusion to the first / second surface in the thickness direction of the joint area. For example... Figure 6-8As shown, in one specific example, the end of the protrusion 432 has a first protrusion and a second protrusion, wherein the second protrusion is located between the first protrusion and the first / second surface, and the maximum width of the first protrusion is greater than the width of the second protrusion. In one specific example, the first protrusion is arc-shaped or elliptical; in an example where the first protrusion is elliptical, the major axis of the first protrusion extends along the thickness direction of the protrusion. By forming the first protrusion, the contact area between the insulating layer and the first protrusion in the length direction can be increased, thereby improving the peel strength between the metal layer and the insulating layer.

[0048] In one possible implementation, along the first direction X, the size of the bonding region at the interface between the conductive element and the insulating element is smaller than the size of the interface between the conductive element and the insulating element, and / or, the size of the bonding region at the interface between the housing and the insulating element is smaller than the size of the interface between the housing and the insulating element. In a specific example, along the first direction X, the size C of the bonding region... 1 The joint area is 50μm-3mm (e.g., 50μm, 100μm, 300μm, 500μm, 800μm, 1mm, 1.3mm, 1.5mm, 1.8mm, 2mm, 2.3mm, 2.5mm, 2.8mm, 3mm), which ensures a mechanical interlock between the shell and the insulating component, or between the conductive component and the insulating component, thereby enhancing the peel strength between them. Compared to existing bonding technologies that require a sufficiently long area to ensure bonding strength, the joint area of ​​the above-mentioned size only requires a smaller size range to achieve sufficient peel strength between the shell and the insulating component, or between the conductive component and the insulating component, making this joint area suitable for bonding small-sized or more precise batteries. Compared to existing riveting techniques, rivet components become larger and heavier due to the size and weight of the fastened parts, and offer less design freedom. The mating area of ​​this type only requires a smaller dimensional range, without needing to adjust the weight or size of the components. It only has smaller dimensional requirements for the interface between the housing and the insulation, or between the conductive and insulating components, thus enabling smaller, lighter, and more flexible battery designs. In a specific example, the first direction could be, for example, the thickness direction of the battery, or the length direction of the battery, or the width direction of the battery. It is understood that, as... Figure 5 and Figure 10 As shown, the size of the first bonding area 433 refers to the size of the first bonding area in the thickness direction of the battery, the size of the second bonding area 434 refers to the size of the second bonding area in the length direction of the battery, the size of the third bonding area 435 refers to the size of the third bonding area in the thickness direction of the battery, and the size of the fourth bonding area 436 refers to the size of the fourth bonding area in the length direction of the battery.

[0049] In one possible implementation, the junction region simultaneously satisfies the following relationship: 5% ≤ (D 1 / H 1 )×100%≤70% (e.g., 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%), 0.1≤H 1 / H 2 ≤5 (e.g., 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5), where D 1 H represents the depth of the recess, which is the maximum vertical distance from the bottom of the recess to the first surface and / or the second surface in the thickness direction of the recess; the unit is μm. 1 The thickness of the conductive component or casing, in μm (H). 2 The thickness of the insulating component is measured in μm. This means the depth of the recess should be at least 5% of the thickness of the conductive component or housing to ensure sufficient depth to accommodate the melted insulating component. This prevents excessive expansion of bubbles generated during the decomposition of the insulating component, ensuring connection quality and strength. A ratio between 0.1 and 5 between the thickness of the conductive component or housing and the thickness of the insulating component reduces warping caused by differences in the coefficients of thermal expansion between the conductive component or housing and the insulating component, thereby enhancing adhesion between the housing and the insulating component, or between the conductive component and the insulating component.

[0050] To prevent excessive deformation of the conductive component or housing, which could lead to warping due to mechanical interlocking between the housing and the insulating component or between the conductive component and the insulating component, the bonding area of ​​this invention also controls the ratio of the thickness of the conductive component or housing to the insulating component, as well as the ratio of the depth of the recess to the thickness of the conductive component or housing. This improves the matching degree between the recess of the conductive component or housing and the insulating component, appropriately increasing the deformation capacity of the metal layer. Thus, when the insulating component deforms (e.g., expands or contracts), on the one hand, the appropriate deformation capacity of the conductive component or housing allows for mutual restraint between the conductive component or housing and the insulating component under the mechanical interlocking effect, reducing warping caused by differences in thermal expansion coefficients and further enhancing the connection strength of the bonding area at the interface between the housing and the insulating component and between the conductive component and the insulating component; on the other hand, the appropriate deformation capacity of the conductive component or housing will not excessively follow the deformation of the insulating component, thus preventing warping.

[0051] In one possible implementation, the shape of the junction area includes at least one of ellipse, circle, triangle, square, rectangle, runway shape, or polygon.

[0052] In one possible implementation, the transmittance of the insulating component is greater than or equal to 30% (e.g., 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%). Specifically, the transmittance of the insulating component to commonly used laser wavelengths is greater than or equal to 30%, thereby improving the flexibility of laser irradiation technology. Laser irradiation can be performed from the side of the insulating layer away from the shell or the side of the insulating layer away from the conductive component. Through the insulating component with a transmittance of greater than or equal to 30%, sufficient laser energy can penetrate the insulating component, be absorbed by the shell or conductive component, and be converted into heat energy, causing the side of the insulating layer opposite to the shell or conductive component to melt, thereby connecting the molten insulating component to the shell or conductive component.

[0053] The transmittance of the insulating component can be defined by the following equation: T=Φ et / Φ ei , where Φ et It is the radiative flux transmitted through the surface, and Φ ei This refers to the radiant flux received by the surface. For specific transmittance, please refer to "Determination of transmittance and haze of transparent plastics" (GB / T 2410-2008).

[0054] In one possible implementation, the depth D of the recess... 1 The thickness H is 10μm-300μm (e.g., 10μm, 30μm, 50μm, 80μm, 100μm, 130μm, 150μm, 180μm, 200μm, 230μm, 250μm, 280μm, 300μm) to ensure sufficient insulation flows into the recess, improving the connection strength between the insulation and the housing or between the insulation and the conductive element. In another possible implementation, the thickness H of the housing or conductive element... 1 The thickness is 100μm-300μm (e.g., 100μm, 130μm, 150μm, 180μm, 200μm, 230μm, 250μm, 280μm, 300μm), thus preventing the shell or conductive component from being too thick, resulting in slow heat transfer and a slower rate of heat conduction to the insulating component. This could lead to incomplete or insufficient melting of the insulating component, preventing a strong bond between the insulating component and the shell or conductive component. Simultaneously, it also avoids the shell or conductive component being too thin, which would cause excessive deformation during laser irradiation, easily leading to warping of the shell or conductive component due to thermal expansion and deformation of the insulating component. In another possible implementation, the width B of the recess... 1The width is 0.05mm-0.8mm (e.g., 0.05mm, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm) to ensure sufficient insulation flows into the recess, improving the connection strength between the insulation and the housing or conductive components. The width of the recess refers to the maximum distance between two points in the orthographic projection of the recess onto the first or second surface. Specifically, three recesses can be arbitrarily selected, and the average width of the three recesses is taken as the measurement result of the recess width. The average depth of the three recesses is taken as the measurement result of the recess depth.

[0055] In one possible implementation, the thickness H of the insulating element 2 The thickness ranges from 50μm to 2000μm (e.g., 50μm, 100μm, 300μm, 500μm, 800μm, 1000μm, 1300μm, 1500μm, 1800μm, 2000μm), thereby ensuring the structural strength of the insulating component and preventing the formation of joint areas on both surfaces in some areas of the insulating component. This avoids the thermal effects during the formation process from damaging the overall structure of the insulating component and affecting the sealing performance.

[0056] In one possible implementation, the first surface and / or the second surface are formed with chemical bonds, including -CH2-O-Fe-, One or more of the following: that is, at high temperatures, the first surface of the conductive component and / or the second surface of the shell become more active, and the first surface of the conductive component and / or the second surface of the shell and the surface of the insulating component form molecular bonds. The chemical bond energy of these molecular bonds is as high as 250 kJ / mol-1000 kJ / mol, far exceeding physical adsorption. At the same time, the covalent bond size is extremely small (<0.27 nm), further enhancing the bonding strength and sealing performance.

[0057] In one possible implementation, such as Figure 6 and Figure 7As shown, the conductive element 41 further includes a third surface 413 away from the insulating element 42, and the roughness of the first surface 411 is greater than the roughness of the third surface 413. In another possible implementation, the housing 1 further includes a fourth surface 124 away from the insulating element 42, and the roughness of the second surface 122 is greater than the roughness of the fourth surface 124. By increasing the roughness of the first surface and / or the second surface, the anchoring effect and chemical bonding effect between the housing or conductive element and the resin layer are increased, thereby improving the peel strength between the housing or conductive element and the resin layer. In a specific example, the roughness of the first surface and / or the second surface is less than or equal to 3 μm (e.g., 3 μm, 2.5 μm, 2 μm, 1.5 μm, 1 μm, 0.5 μm, 0.1 μm). The roughness of the first surface and / or the second surface can be calculated, for example, by the method of JISC 6515-1998 (maximum height roughness).

[0058] In one possible implementation, such as Figure 9 As shown, the recess 431 includes an inwardly recessed bottom end portion 4311 and an inner wall surface 4312 connecting the bottom end portion 4311 and the first surface 411 and / or the second surface 122. In a specific example, such as Figure 6 and Figure 7 As shown, the inner wall is arranged around the bottom end, and the cross-sectional shape of the recess is an inverted triangle or an inverted cone.

[0059] In the cross section along the length of the joint area, the intersection of the inner wall surface 4312 with the first surface 411 and / or the second surface 122 is the first point 43121, and the intersection of the inner wall surface 4312 with the bottom end 4311 of the recess is the second point 43122. The line connecting the first point and the second point forms the reference line 43123. The inner wall surface 4312 is formed with an inwardly recessed sub-recess 4313 and an outwardly protruding sub-protrusion 4314. By forming sub-recesses and sub-protrusions on the inner wall of the recess, the molten insulating component flows into the irregular inner wall of the recess and solidifies. The sub-recesses and sub-protrusions form "barbs" and "anchoring" structures, which increases the binding force of the recess on the insulating component and enhances the connection strength between the shell and / or the conductive component and the insulating component. Furthermore, by forming sub-recesses and sub-protrusions, it is understandable that the contact area between the inner wall of the recess and the molten insulating component is increased, thereby forming a stronger physical and chemical bond.

[0060] In one possible implementation, such as Figure 9 As shown, the average width B of the sub-recess is 2The depth is 1μm-50μm (e.g., 1μm, 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, or 50μm) to ensure that the molten insulation fully fills the sub-recess, preventing the molten insulation from breaking within the recess due to excessive width. In a specific example, the average depth D of the sub-recess... 2 The depth should be 1μm-30μm (e.g., 1μm, 5μm, 10μm, 15μm, 20μm, 25μm, or 30μm) to prevent excessive depth, which could cause the molten insulation to flow too far to the bottom wall of the sub-recess, making it prone to breakage in the middle. In another specific example, the average height D of the sub-protrusion... 3 The diameter is 1μm-30μm (e.g., 1μm, 5μm, 10μm, 15μm, 20μm, 25μm or 30μm) to ensure that the molten insulation completely covers the protrusion and prevents the height from being too high, which would affect the downward flow of the molten insulation to fill the recess.

[0061] The average width of the sub-recesses can be obtained by cutting the joint at any three positions along the width direction of the joint area, resulting in three cross-sections of the joint area. The average width of all sub-recesses in these three cross-sections is the average width of the sub-recesses; the average depth of all sub-recesses is the average depth of the sub-recesses; the average height of all sub-protrusions is the average height of the sub-protrusions; and the average width of all sub-recesses is the average width of the sub-protrusions. Specifically, the width of a sub-recess refers to the maximum distance between the two edge lines of the sub-recess in a direction parallel to the baseline; the depth of a sub-recess refers to the maximum distance from the bottom of the sub-recess to the baseline in a direction perpendicular to the baseline; and the height of a sub-protrusion refers to the maximum distance from the top of the sub-protrusion to the baseline in a direction perpendicular to the baseline.

[0062] In one possible implementation, the ratio of the average depth of the recess to the average height of the convex portion is 0.1-20 (e.g., 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20). This ensures that the molten insulation completely fills the recess while tightly wrapping the convex portion, forming a three-dimensional "hook-like" interlocking structure. The recess and convex portion transform the force transmission path from a single shear plane into a complex three-dimensional network, distributing the load borne by the interface between the metal layer and the insulation component in more directions and suppressing crack initiation and propagation. If the ratio is too small—that is, the depth of the recess is too shallow or the height of the convex portion is too high—the molten insulation cannot fully wrap the convex portion, resulting in a small effective anchoring volume, which easily forms stress concentration points and can lead to excessive stress on the insulation component, causing cracks or even breakage. If the ratio is too large, that is, the height of the recess is too large or the depth of the protrusion is too low, the insulating component may not be able to fill the deep pit due to fluidity or cooling, resulting in internal voids and reducing the effective bonding area.

[0063] In one possible implementation, such as Figure 10 and Figure 11 As shown, the conductive member 41 includes a straight portion 415 and a connecting portion 416 protruding outward from the straight portion 415, the connecting portion 416 being located within the first through hole 121; the insulating member 42 includes a first adhesive portion 424 and a second adhesive portion 425 protruding from the surface of the first adhesive portion 424, the first adhesive portion 424 being located between the straight portion 415 and the side wall of the housing 1; the second adhesive portion 425 being located between the connecting portion 416 and the inner side wall of the first through hole 121. The bonding region 43 includes at least one of a first bonding region 433 located between the straight portion 415 and the first adhesive portion 424, a second bonding region 434 located between the connecting portion 416 and the second adhesive portion 425, a third bonding region 435 located between the side wall of the housing 1 and the first adhesive portion 424, and a fourth bonding region 436 located between the inner side wall of the first through hole 121 and the second adhesive portion 425.

[0064] In a specific example, the conductive component 41 and the insulating component 42 can be connected first. For example, the conductive component 41 and the insulating component 42 can be bonded together, wherein the straight portion 415 of the conductive component 41 is bonded to the first adhesive portion 424 of the insulating component. A ring laser is irradiated through the surface of the straight portion 415 away from the first adhesive portion 424, causing the conductive component 41 to generate high temperature. The heat is then conducted to the insulating component 42. At the high temperature, the surface of the insulating component near the conductive component 41 melts, forming a first bonding area 433. In addition, the connecting portion 416 of the conductive component 41 and the second adhesive portion 425 of the insulating component 42 are bonded together. A ring laser is irradiated through the surface of the second adhesive portion 425 away from the connecting portion 416, so that sufficient laser energy can penetrate the insulating component, be absorbed by the connecting portion and converted into heat energy, causing the second adhesive portion 425 opposite to the connecting portion 416 to melt, forming a second bonding area 434.

[0065] The conductive component 41 and the insulating component 42 are then placed inside the first sub-wall 1211 of the housing 1. A ring laser is then used to irradiate the surface of the housing 1 opposite to the first adhesive portion 424, causing the housing to reach a high temperature. At this high temperature, the surface of the insulating component near the housing melts, forming a third bonding region 435. Subsequently, a ring laser is used to irradiate the surface of the first sub-wall 1211 opposite to the second adhesive portion 425, causing the first sub-wall 1211 to reach a high temperature. At this high temperature, the surface of the insulating component 42 near the first sub-wall 1211 melts, forming a fourth bonding region 436.

[0066] In one possible implementation, the sidewall at the first through hole 121 extends along the first direction X to form a first sub-wall 1211, such as... Figure 10 and Figure 11As shown, the first sub-wall 1211 may extend from the sidewall of the first through hole 121 toward the direction away from the electrode assembly. The second adhesive portion 425 includes a first portion 4251 located between the first sub-wall 1211 and the connecting portion 416, and a fourth bonding area 436 located between the first portion 4251 and the first sub-wall 1211. In a specific example, the first direction is the length direction of the battery. By providing the first sub-wall, the contact area between the conductive and insulating components and between the housing and the insulating components is increased, further improving the sealing between the conductive and insulating components and between the housing and the insulating components; at the same time, it can also prevent the connecting mechanism from being subjected to forces along the length direction during drop tests; furthermore, the first sub-wall can protect the conductive and insulating components from damage caused by impacts from external electronic devices. Furthermore, with the first sub-wall 1211 installed, the fourth joining area 436 is located between the first portion 4251 of the second adhesive part and the first sub-wall 1211, and the second joining area 434 is located between the connecting part 416 and the first portion 4251 of the second adhesive part. This allows for a corresponding extension of the dimensions of the fourth joining area and the second joining area, thereby improving the connection strength between the connecting part and the insulating member, as well as between the insulating member and the housing. Moreover, the dimensions of the second joining area and the fourth joining area are smaller than the interface between the connecting part and the second adhesive part, or the interface between the second adhesive part and the first sub-wall. That is, the second joining area and the fourth joining area do not extend to the end of the interface between the connecting part and the second adhesive part, or the end of the interface between the second adhesive part and the first sub-wall, thus preventing external moisture from affecting the second joining area and the fourth joining area.

[0067] In one possible implementation, along the first direction, the orthographic projections of the first and third bonding regions on the sidewall of the housing at least partially overlap. In another specific example, along the second direction, the orthographic projections of the second and fourth bonding regions at least partially overlap. This ensures sealing performance while reducing the extension length of the conductive component along the first direction, preventing excessive extension length from affecting the utilization of the battery head space. Simultaneously, it reduces the extension length of the terminal assembly, avoiding encroachment on the external space of the battery and affecting the assembly of external protection boards or other circuit components, further improving the battery's energy density. In one specific example, the first direction may be, for example, the length direction of the battery, and the second direction may be, for example, the thickness direction of the battery.

[0068] In one possible implementation, the thickness of the insulating element is less than 0.15 mm (e.g., 0.15 mm, 0.14 mm, 0.13 mm, 0.12 mm, 0.11 mm, 0.1 mm, 0.09 mm, 0.08 mm, 0.07 mm, 0.06 mm, 0.05 mm, 0.04 mm, 0.03 mm, 0.02 mm, 0.01 mm), and along the first direction, the length overlap rate between the first and third bonding regions is less than or equal to 70% (e.g., 70%, 65%, 60%, 55%, 50%, 45%, 40%, 35%, 30%, 25%, 20%, 15%, 10%, 5%, 1%, 0.1%, 0%). In another specific example, the K of the insulating element... 1 The thickness is less than 0.15 mm (e.g., 0.15 mm, 0.14 mm, 0.13 mm, 0.12 mm, 0.11 mm, 0.1 mm, 0.09 mm, 0.08 mm, 0.07 mm, 0.06 mm, 0.05 mm, 0.04 mm, 0.03 mm, 0.02 mm, 0.01 mm), and along the second direction, the length overlap rate between the second joint area and the fourth joint area is less than or equal to 70% (e.g., 70%, 65%, 60%, 55%, 50%, 45%, 40%, 35%, 30%, 25%, 20%, 15%, 10%, 5%, 1%, 0.1%, 0%). In solutions where the insulating adhesive is relatively thin, if the length overlap rate between the first and third bonding areas or the second and fourth bonding areas is greater than a certain value, it is easy for bonding areas to be formed on both surfaces of the insulating component. This would cause the heat and laser energy generated when bonding areas are formed on the two surfaces at the same location to affect each other, thereby affecting the structural strength of the insulating component and the sealing performance between the insulating component and the shell, as well as between the insulating component and the conductive component.

[0069] In some specific instances, the thickness of the insulating element is less than 0.15 mm, and along the first direction, the first bonding area and the third bonding area do not overlap.

[0070] In other specific instances, the thickness of the insulating element is less than 0.15 mm, and the length overlap rate between the first and third bonding areas along the first direction is 0.1%-70%.

[0071] In some specific instances, the thickness of the insulating element is less than 0.15 mm, and along the second direction, the second bonding area does not overlap with the fourth bonding area.

[0072] In other specific instances, the thickness of the insulating element is less than 0.15 mm, and along the second direction, the length overlap rate between the second and fourth joint areas is 0.1%-70%.

[0073] In one possible implementation, such as Figure 11As shown, the first tab assembly 5 includes a first tab 51 located on the first electrode plate and an electrical connector 52 connected to the first tab 51; the electrical connector 52 is connected to the side surface of the straight portion 415 opposite to the insulating member 42 to form a connection area 521; the connection area 521 and the orthographic projection of the first bonding area 433 on the side wall of the housing do not overlap. In a specific example, the electrical connector and the side surface of the straight portion opposite to the insulating member can be connected by laser welding, for example, and the connection area is the solder area between the electrical connector and the straight portion. The non-overlapping of the orthographic projections of the solder area and the first bonding area on the side wall of the housing is mainly to prevent interference between the two, which could lead to incomplete soldering or poor soldering between the electrical connector and the straight portion.

[0074] In one possible implementation, the ratio of the thickness of the straight portion to the thickness of the sidewall of the housing along the first direction is greater than or equal to 1 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10).

[0075] The present invention will be described in detail below through embodiments. The embodiments described herein are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0076] The following examples illustrate the battery of the present invention.

[0077] Example 1 (1) Preparation of positive electrode sheet Lithium cobalt oxide, a positive electrode conductive agent (conductive carbon black and carbon nanotubes mixed at a mass ratio of 2:1), and a positive electrode binder (polyvinylidene fluoride) were mixed at a mass ratio of 97:1.5:1.5. N-methylpyrrolidone (NMP) was added, and the mixture was stirred evenly to prepare a positive electrode slurry. The positive electrode slurry was coated on the surface of aluminum foil, dried, and rolled to obtain a positive electrode sheet.

[0078] (2) Preparation of negative electrode sheet Artificial graphite, silicon-carbon material (including a porous carbon matrix and silicon material located in the pores of the porous carbon matrix, with a sphericity of 0.93), carbon nanotubes, lithium carboxymethyl cellulose, styrene-butadiene rubber, and polyacrylic acid were mixed in a mass ratio of 54.9:42:0.5:0.8:0.5:1.3, and deionized water was added to prepare a negative electrode slurry. The negative electrode slurry was coated on both sides of a copper foil, and then dried and rolled to obtain a negative electrode sheet. The elemental silicon content in the negative electrode active coating is 20%.

[0079] (3) Preparation of electrolyte In an argon-filled glove box (moisture <1 ppm, oxygen <1 ppm), organic solvents (ethylene carbonate, propylene carbonate, propyl propionate, and ethyl propionate in a mass ratio of 15:15:50:20, totaling 71.5 parts by weight) were mixed to form a homogeneous solvent. Then, 15.5 parts by weight of lithium salt (LiPF6), 2 parts by weight of 1,3-propanesulfonyl lactone, 3 parts by weight of 1,3,6-hexanetrionitrile, and 8 parts by weight of fluoroethylene carbonate were slowly added. After thorough stirring, a lithium-ion battery electrolyte was obtained.

[0080] (4) Preparation of the diaphragm Polyethylene was selected as the 5μm substrate layer and polyvinylidene fluoride was selected as the adhesive layer. An alumina ceramic layer with a thickness of 2μm was set on the side of the adhesive layer close to the substrate layer to obtain a porous membrane.

[0081] (5) Preparation of lithium-ion batteries The positive electrode sheet prepared in step (1), the separator prepared in step (4), and the negative electrode sheet prepared in step (2) are stacked to obtain a core; after encapsulation, baking, liquid injection, formation, secondary sealing, sorting, and OCV, a lithium-ion battery is obtained. Among them, the electrode post includes a conductive component and an insulating component, wherein there is a bonding area between the insulating component and the shell, and there is a bonding area between the insulating component and the conductive component. Specifically, it can be done in the following way: first, the insulating component and the conductive component are connected. Specifically, the surface of the conductive component away from the insulating component is irradiated with a laser, so that the conductive component generates a high temperature. The heat is then conducted to the insulating component. At the high temperature, the surface of the insulating component near the conductive component melts to form a first bonding area; then the surface of the insulating component away from the conductive component is attached to the outside of the shell wall, and the surface of the shell away from the insulating component is irradiated with a laser, so that the shell wall generates a high temperature. The heat is then conducted to the insulating component. At the high temperature, the surface of the insulating component near the shell wall melts to form a second bonding area.

[0082] The casing is made of stainless steel, the conductive parts are made of aluminum, and the insulating parts are made of polypropylene. The light transmittance of the insulating parts is 60%, and the depth of the recess is D. 1 The diameter is 50 μm, the width of the recess is 0.62 mm, and the thickness of the insulating component is H. 2 The thickness of the shell and the thickness of the conductive component are both 100 μm. 1 The same, both are 200μm, (D 1 / H 1 )×100%=(50 / 200)×100%=25%, H 1 / H 2 =200 / 100=2; The roughness of the first surface is 1.5 μm, the roughness of the second surface is 1.5 μm, the ratio of the thickness of the straight portion to the thickness of the sidewall of the shell along the first direction is 5, the length overlap rate of the first joint area and the third joint area along the first direction is 50%, and the length overlap rate of the second joint area and the fourth joint area along the second direction is 50%.

[0083] Example 2 group This set of examples is used to illustrate when (D) 1 / H 1 )×100% and / or H 1 / H 2 The impact of changes.

[0084] This embodiment group is carried out with reference to Embodiment 1, except that (D) is changed. 1 / H 1 )×100% and / or H 1 / H 2 For details, please refer to Table 1-1.

[0085] Table 1-2 Example 3 Group Example 3a The same procedure was followed as in Example 1, except that the light transmittance of the insulating component was adjusted to 30% by adjusting the material of the insulating component.

[0086] Example 3b The same procedure was followed as in Example 1, except that the light transmittance of the insulating component was adjusted to 25% by adjusting the material of the insulating component.

[0087] Example 4 group Example 4a The same procedure was carried out as in Embodiment 1, except that the ratio of the thickness of the straight portion to the thickness of the sidewall of the housing along the first direction was 1.

[0088] Example 4b The same procedure was carried out as in Embodiment 1, except that the ratio of the thickness of the straight portion to the thickness of the sidewall of the housing along the first direction was 0.8.

[0089] Example 5 Referring to Embodiment 1, the difference is that the electrode post includes a conductive element and an insulating element. The conductive element includes a straight portion and a connecting portion protruding outward from the straight portion. The connecting portion is located within a first through hole, and there is a bonding area between the interface between the insulating element and the housing, and between the interface between the insulating element and the conductive element. A connecting mechanism is installed within the first through hole and is connected to the first electrode assembly. The connecting mechanism can be performed as follows: First, the conductive element and the insulating element are bonded together, wherein the straight portion of the conductive element and the first adhesive portion of the insulating element are bonded together. A ring laser is applied to the surface of the straight portion away from the first adhesive portion, causing the conductive element to generate a high temperature. The heat is then conducted to the insulating element, and at the high temperature, the surface of the insulating element near the conductive element melts, forming a first bonding area. In addition, the connecting portion of the conductive element and the second adhesive portion of the insulating element are bonded together. A ring laser is applied to the surface of the second adhesive portion away from the connecting portion, allowing sufficient laser energy to penetrate the insulating element, be absorbed by the connecting portion, and be converted into heat energy, causing the second adhesive portion opposite to the connecting portion to melt, forming a second bonding area.

[0090] The conductive and insulating components are then placed inside the first sub-wall of the housing. A ring laser is then used to irradiate the surface of the housing away from the first adhesive portion, causing the housing to reach a high temperature. At this high temperature, the surface of the insulating component near the housing melts, forming a third bonding area. Subsequently, a ring laser is used to irradiate the surface of the first sub-wall away from the second adhesive portion, causing the first sub-wall to reach a high temperature. At this high temperature, the surface of the insulating component near the first sub-wall melts, forming a fourth bonding area.

[0091] Comparative Example 1 The same procedure is followed as in Example 1, except that there is no joint area at the interface between the insulating component and the housing, and there is also no joint area at the interface between the insulating component and the conductive component.

[0092] Test case The batteries prepared by the examples and comparative examples were tested as follows.

[0093] (1) Drop test In an environment of 25℃±3℃, the battery is discharged at 0.2C to the lower limit voltage of 3.0V and left to stand for 10 minutes. Then, the battery is placed in a 25℃ constant temperature chamber and charged at a constant current of 0.7C to the upper limit voltage of 4.48V. After 50 cycles, the fully charged battery is subjected to a drop test within 12h-24h. The battery is dropped onto a concrete surface from a height of 1.5m, and each surface and corner is dropped once. During the test, the battery is dropped with a clamping arm for directional drop. The voltage is tested immediately after the drop test and again after resting for 12h. The battery is considered to have passed when it does not catch fire, explode, or emit smoke, the casing is not broken, and there is no leakage, and the voltage (the voltage tested immediately after the drop test and the voltage tested after resting for 12h) is not less than 90% of the voltage before the test. Each embodiment and comparative example tested 20 batteries, and the results were expressed as "number of failures / 20", where "0 / 20" means all 20 tests passed, "5 / 20" means 5 out of 20 tests failed, and so on.

[0094] (2) Leakage test The battery was placed in a 25°C environment and left to stand for 2 hours. When the battery temperature was 25°C ± 2°C, it was charged at a constant current of 0.7C to the upper limit voltage of 4.48V, and then charged at a constant voltage of 4.5V to 0.05C, and left to stand for 5 minutes. Then it was discharged at a constant current of 0.5C to 3.0V, and left to stand for 5 minutes. This is one charge-discharge cycle. 500 charge-discharge cycles were performed. The battery was observed for leakage. The battery was then disassembled to observe whether there were scratches inside the battery casing. The battery passed the test if there was no leakage and the casing had no obvious scratches. 20 battery samples were tested for each example and comparative example. The results were expressed as "number of failures / 20", where "0 / 20" means that all 20 tests passed, "5 / 20" means that 5 out of 20 tests failed, and so on.

[0095] The results are recorded in Table 2.

[0096] Table 2 As can be seen from Table 2, by comparing the comparative examples and the embodiments, it can be seen that the drop test pass rate of the battery in the embodiments is significantly improved, and the leakage after cycling is significantly reduced. This indicates that at least one of the interfaces between the conductive component and the insulating component and the interface between the insulating component and the housing forms a joint area, which improves the connection strength and sealing performance between the housing and the insulating component or between the conductive component and the insulating component.

[0097] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A battery, characterized in that, The battery includes a housing and an electrode assembly, the electrode assembly being located in a receiving space formed by the housing; The electrode assembly includes a first electrode, a second electrode, and a diaphragm located between the first electrode and the second electrode; the first electrode includes a first tab assembly, and the second electrode includes a second tab assembly. The housing includes a first through hole, and the battery further includes a connection mechanism connected to the first electrode assembly, the connection mechanism passing through the first through hole; The connection mechanism includes a conductive element and an insulating element. The conductive element is connected to the first electrode assembly, and the insulating element is located between the housing and the conductive element. The material of the housing and / or conductive components includes one or more of the following: stainless steel, nickel, steel, aluminum, aluminum alloy, titanium, titanium alloy, nickel-titanium alloy, copper, and copper alloy. The insulating material includes one or more of the following: fluororesin, polyamide, polypropylene, polyethylene, polyvinylidene fluoride, polyethylene terephthalate, polycarbonate, and carbon fiber reinforced plastic. At least one of the interfaces between the conductive element and the insulating element and between the insulating element and the housing forms a bonding area, wherein the conductive element and the insulating element in the bonding area are thermoformed into an integral structure, and / or the insulating element and the housing in the bonding area are thermoformed into an integral structure. The bonding area includes a first surface of the conductive element facing the insulating element and / or a second surface of the housing facing the insulating element, the first surface and / or the second surface including a plurality of recesses, the orthographic projection of the insulating element covering the recesses, and the insulating element including a protrusion embedded in the recesses.

2. The battery according to claim 1, characterized in that, The joint region simultaneously satisfies the following relationship: 5% ≤ (D 1 / H 1 )×100%≤70%, 0.1≤H 1 / H 2 ≤5, where D 1 H represents the depth of the recess, in μm. 1 The thickness of the conductive component or housing is expressed in μm (H). 2 The thickness of the insulating component is expressed in μm. And / or, the depth D of the recess 1 The range is 10μm-300μm; And / or, the thickness H of the housing or conductive element 1 The range is 100μm-300μm; And / or, the thickness H of the insulating element 2 The range is 50μm-2000μm; And / or, the width of the recess is 0.05mm-0.8mm.

3. The battery according to claim 1, characterized in that, The shape of the junction area includes at least one of ellipse, circle, triangle, square, rectangle, racetrack shape or polygon; And / or, the light transmittance of the insulating element is greater than or equal to 30%; And / or, a protrusion is included between two adjacent recesses, the height of the protrusion being 10μm-200μm.

4. The battery according to claim 1, characterized in that, Along the first direction, the ratio of the thickness of the straight portion to the thickness of the sidewall of the housing is greater than or equal to 1.

5. The battery according to claim 1, characterized in that, The first surface and / or the second surface are formed with chemical bonds, including -CH2-O-Fe-, One or more of the following; And / or, the conductive element further includes a third surface remote from the insulating element, wherein the roughness of the first surface is greater than the roughness of the third surface; And / or, the housing further includes a fourth surface remote from the insulator, wherein the roughness of the second surface is greater than that of the fourth surface; And / or, the roughness of the first surface and / or the second surface is less than or equal to 3 μm.

6. The battery according to claim 1, characterized in that, The recess includes an inwardly recessed bottom end and an inner wall surface connecting the bottom end and the first surface; In the cross section along the length of the joint area, the intersection of the inner wall surface and the first surface is the first point, and the intersection of the inner wall surface and the bottom end of the recess is the second point. The line connecting the first point and the second point forms a reference line. The inner wall surface has an inwardly recessed sub-recess and an outwardly protruding sub-protrusion.

7. The battery according to claim 1, characterized in that, The conductive element includes a straight portion and a connecting portion protruding outward from the straight portion, the connecting portion being located inside the first through hole; The insulating component includes a first adhesive portion and a second adhesive portion protruding from the surface of the first adhesive portion, the first adhesive portion being located between the straight portion and the side wall of the housing; the second adhesive portion being located between the connecting portion and the inner side wall of the first through hole; The bonding area includes at least one of the following: a first bonding area located between the straight portion and the first adhesive portion; a second bonding area located between the connecting portion and the second adhesive portion; a third bonding area located between the side wall of the housing and the first adhesive portion; and a fourth bonding area located between the inner side wall of the first through hole and the second adhesive portion.

8. The battery according to claim 7, characterized in that, Along the first direction, the first joint area and the third joint area at least partially overlap on the orthographic projection of the third joint area onto the side wall of the housing; And / or, along the second direction, the orthographic projection of the second junction region at least partially overlaps with the orthographic projection of the fourth junction region; And / or, the sidewall at the first through hole extends along the first direction to form a first sub-wall, the second adhesive portion includes a first portion located between the first sub-wall and the connecting portion, and the fourth bonding area is located between the first portion and the first sub-wall.

9. The battery according to claim 7, characterized in that, The thickness of the insulating component is less than 0.15 mm, and along the first direction, the length overlap rate between the first bonding area and the third bonding area is less than or equal to 70%. And / or, the thickness of the insulating element is less than 0.15 mm, and along the second direction, the length overlap rate between the second bonding area and the fourth bonding area is less than or equal to 70%.

10. The battery according to claim 7, characterized in that, The first electrode assembly includes a first electrode located on the first electrode plate and an electrical connector connected to the first electrode; the electrical connector and the side surface of the straight portion opposite to the insulating member are connected to form a connection area; The connection area does not overlap with the orthographic projection of the first joining area onto the side wall of the housing.

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