An end cover assembly, an energy-storage apparatus, and an electricity-consumption device are provided. The end cover assembly is for an energy-storage apparatus and includes a top cover, a sealing cap, and an annular welding portion. The top cover has a first surface and further defines a liquid-injection hole extending through the first surface. The first surface includes a first sub-surface and a second sub-surface connected to the first sub-surface, the first sub-surface is around the liquid-injection hole, the second sub-surface is around a periphery of the first sub-surface, and roughness of the first sub-surface is greater than roughness of the second sub-surface. The sealing cap seals the liquid-injection hole and is connected to the top cover. The annular welding portion is located at a junction between the sealing cap and the top cover. The top cover is further provided with a first welding mark and a second welding mark.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. § 119(a) to Chinese Patent Application No. 202310091082.4, filed Feb. 9, 2023, the entire disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

This disclosure relates to the electronics field, and in particular to an end cover assembly, an energy-storage apparatus, and an electricity-consumption device.

BACKGROUND

For energy-storage apparatuses such as lithium batteries or sodium batteries, after end cover assemblies are assembled, electrolytes are filled through liquid-injection holes of the end cover assemblies, and after filling the electrolytes, sealing caps are welded to the liquid-injection hole to seal the liquid-injection hole. However, for the existing energy-storage apparatuses, poor welding often occurs after welding the sealing cap, resulting in low product yield.

SUMMARY

In a first aspect of the present disclosure, an end cover assembly for an energy-storage apparatus is provided. The end cover assembly includes a top cover, a sealing cap, and an annular welding portion. The top cover has a first surface and further defines a liquid-injection hole extending through the first surface. The first surface includes a first sub-surface and a second sub-surface connected to the first sub-surface, the first sub-surface is around the liquid-injection hole, the second sub-surface is around a periphery of the first sub-surface, and roughness of the first sub-surface is greater than roughness of the second sub-surface. The sealing cap seals the liquid-injection hole and is connected to the top cover. The annular welding portion is located at a junction between the sealing cap and the top cover. The top cover is further provided with a first welding mark at the first sub-surface. The first welding mark includes a first end portion and a second end portion opposite to the first end portion, the first end portion is connected to the welding portion, and the second end portion is located at a periphery of the welding portion and is spaced apart from the welding portion. The top cover is further provided with a second welding mark at the first sub-surface. The second welding mark includes a third end portion and a fourth end portion opposite to the third end portion, the third end portion is connected to the welding portion, and the fourth end portion is located at the periphery of the welding portion and is spaced apart from the welding portion.

In a second aspect of the present disclosure, an energy-storage apparatus is provided. The energy-storage apparatus includes an end cover assembly, an adapter sheet, and an electrode assembly. The end cover assembly includes a top cover, a sealing cap, and an annular welding portion. The top cover has a first surface and further defines a liquid-injection hole extending through the first surface. The first surface includes a first sub-surface and a second sub-surface connected to the first sub-surface, the first sub-surface is around the liquid-injection hole, the second sub-surface is around a periphery of the first sub-surface, and roughness of the first sub-surface is greater than roughness of the second sub-surface. The sealing cap seals the liquid-injection hole and is connected to the top cover. The annular welding portion is located at a junction between the sealing cap and the top cover. The top cover is further provided with a first welding mark at the first sub-surface. The first welding mark includes a first end portion and a second end portion opposite to the first end portion, the first end portion is connected to the welding portion, and the second end portion is located at a periphery of the welding portion and is spaced apart from the welding portion. The top cover is further provided with a second welding mark at the first sub-surface. The second welding mark includes a third end portion and a fourth end portion opposite to the third end portion, the third end portion is connected to the welding portion, and the fourth end portion is located at the periphery of the welding portion and is spaced apart from the welding portion. The adapter sheet is disposed at a side of the top cover away from the first surface and has one end electrically connected to the end cover assembly. The electrode assembly is disposed at a side of the adapter sheet away from the end cover assembly. The electrode assembly is electrically connected to one end of the adapter sheet away from the end cover assembly.

In a third aspect of the present disclosure, an electricity-consumption device is provided. The electricity-consumption device includes an electricity-consumption device body and an energy-storage apparatus. The energy-storage apparatus supplies power to the electricity-consumption device body. The energy-storage apparatus includes an end cover assembly, an adapter sheet, and an electrode assembly. The end cover assembly includes a top cover, a sealing cap, and an annular welding portion. The top cover has a first surface and further defines a liquid-injection hole extending through the first surface. The first surface includes a first sub-surface and a second sub-surface connected to the first sub-surface, the first sub-surface is around the liquid-injection hole, the second sub-surface is around a periphery of the first sub-surface, and roughness of the first sub-surface is greater than roughness of the second sub-surface. The sealing cap seals the liquid-injection hole and is connected to the top cover. The annular welding portion is located at a junction between the sealing cap and the top cover. The top cover is further provided with a first welding mark at the first sub-surface. The first welding mark includes a first end portion and a second end portion opposite to the first end portion, the first end portion is connected to the welding portion, and the second end portion is located at a periphery of the welding portion and is spaced apart from the welding portion. The top cover is further provided with a second welding mark at the first sub-surface. The second welding mark includes a third end portion and a fourth end portion opposite to the third end portion, the third end portion is connected to the welding portion, and the fourth end portion is located at the periphery of the welding portion and is spaced apart from the welding portion. The adapter sheet is disposed at a side of the top cover away from the first surface and has one end electrically connected to the end cover assembly. The electrode assembly is disposed at a side of the adapter sheet away from the end cover assembly. The electrode assembly is electrically connected to one end of the adapter sheet away from the end cover assembly

REFERENCE NUMERALS

DETAILED DESCRIPTION

To enable those skilled in the art to better understand the solutions of the present disclosure, the technical solutions in embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present disclosure. The described embodiments are merely some of, rather than all, the embodiments of the present disclosure. Other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present disclosure shall fall within the scope of protection of the present disclosure.

The terms such as “first” and “second” in the specification and the claims of the present application and in the accompanying drawings are intended to distinguish different objects, rather than to describe a specific order. In addition, the terms of “include” and “have” and any variations thereof are intended to cover the non-exclusive inclusion. For example, the process, method, system, product or device, which includes a series of steps or units, is not limited to the listed steps or units, but optionally further includes unlisted steps or units, or optionally further includes other steps or units inherent to the process, method, product or device.

The technical solutions in the embodiments of the present disclosure will be described below with reference to the accompanying drawings.

It should be noted that, for ease of description, in the embodiments of the present disclosure, the same reference numerals denote the same components, and for the sake of brevity, the detailed description of the same components is omitted in different embodiments.

Referring toFIG.1, an electricity-consumption device300is provided in embodiments of the present disclosure. The electricity-consumption device300includes an electricity-consumption device body310and an energy-storage apparatus200. The energy-storage apparatus200supplies power to the electricity-consumption device body310.

The electricity-consumption device300in the embodiments of the present disclosure may be, but not limited to, a portable electronic device, such as a mobile phone, a tablet computer, a laptop, a desktop computer, a smart bracelet, a smart watch, an e-book reader, and a game console. The electricity-consumption device300may also be transportation means such as an automobile, a truck, a car, a van, a bullet train, a high-speed train, and an electric bicycle. In addition, the electricity-consumption device300may also be various household appliances, etc. It can be understood that the electricity-consumption device300illustrated in the drawings of the present disclosure is only one of the forms of the electricity-consumption device300, and should not be construed as a limitation on the electricity-consumption device300provided in the present disclosure.

Referring toFIG.2andFIG.3, an energy-storage apparatus200is provided in embodiments of the present disclosure. The energy-storage apparatus200includes an electrode assembly210, an adapter sheet230, and an end cover assembly100. The adapter sheet230is electrically connected to the electrode assembly210. The end cover assembly100is disposed at a side of the adapter sheet230away from the electrode assembly210and is electrically connected to the adapter sheet230.

The energy-storage apparatus200of the embodiments of the present disclosure may be, but not limited to, a lithium-ion secondary battery, a lithium-ion primary battery, a lithium-sulfur battery, a sodium/lithium-ion battery, a sodium-ion battery or a magnesium-ion battery, an energy-storage battery, and other energy-storage apparatus200. It can be understood that the energy-storage apparatus200illustrated in the drawings of the present disclosure is only one of the forms of the energy-storage apparatus200, and should not be construed as a limitation on the energy-storage apparatus200provided in the present disclosure.

Optionally, the adapter sheet230may be, but not limited to, at least one of copper foil and aluminum foil.

Optionally, the adapter sheet230includes a positive-electrode adapter sheet231and a negative-electrode adapter sheet233. The electrode assembly210includes a positive-electrode sheet (not shown), a separator (not shown) and a negative-electrode sheet (not shown) arranged in sequence. The positive-electrode sheet and the negative-electrode sheet are both electrically connected to the end cover assembly100by means of the adapter sheet230. The positive-electrode sheet includes a positive current collector, a positive-electrode tab211electrically connected to the positive current collector, and a positive active layer disposed on a surface of the positive current collector. The positive-electrode sheet is electrically connected to the positive-electrode adapter sheet231by means of the positive-electrode tab211. The negative-electrode sheet includes a negative current collector, a negative-electrode tab213electrically connected to the negative current collector, and a negative active layer disposed on a surface of the negative current collector. The negative-electrode sheet is electrically connected to the negative-electrode adapter sheet233by means of the negative-electrode tab213.

It can be understood that the positive-electrode adapter sheet231and the negative-electrode adapter sheet233are different adapter sheets. The adapter sheet230for electrically connecting the positive-electrode tab211to the end cover assembly100is the positive-electrode adapter sheet231, and the adapter sheet230for electrically connecting the negative-electrode tab213to the end cover assembly100is the negative-electrode adapter sheet233.

In some embodiments, the energy-storage apparatus200of the present disclosure further includes a housing250. The housing250is connected to the end cover assembly100, and the housing250and the end cover assembly100cooperatively define an accommodating recess. The accommodating recess is used to accommodate the electrode assembly210and the adapter sheet230.

In some embodiments, the energy-storage apparatus200of the present disclosure further includes an electrolyte (not shown). The electrolyte is accommodated in the accommodating recess, and at least part of the positive-electrode sheet and at least part of the negative-electrode sheet are immersed in the electrolyte.

After the components of the energy-storage apparatus are assembled, the electrolyte is filled through a liquid-injection hole of the end cover assembly. After the electrolyte is filled, the liquid-injection hole is plugged with a rubber tack, and a sealing cap made of metal is welded to a top cover by means of laser welding above the liquid-injection hole to achieve secondary sealing for the liquid-injection hole so as to prevent the electrolyte from overflowing.

The top cover is generally made of metal, such as 3-series aluminum alloy. Aluminum alloy is a non-ferrous metal that has strong reflectivity to all kinds of light. Laser, as a high-energy beam, is more likely to reflect on the surface of the aluminum alloy. In other words, aluminum alloy, a non-ferrous metal, has high reflectivity and low absorptivity for laser. In addition, all metals have thermal conductivity, so aluminum alloy also has strong thermal conductivity, and is easy to reflect laser or quickly transfer the heat of laser during laser welding, so that the temperature of the part to-be-welded cannot meet the welding requirements, eventually resulting in welding failure of the sealing cap. Thus, during laser welding of the sealing cap, it is necessary to strictly control the power density of laser and the movement speed during welding to prevent reflection or transfer of laser, and it is desired to weld aluminum alloy with extremely high energy density beam in a very short time, which can prevent the problems such as reflection.

In addition, during welding of the sealing cap, the laser absorption of the welding material depends on some important properties of the material, such as absorptivity, reflectivity, thermal conductivity, melting temperature, and evaporation temperature, in which the absorptivity is most important. The factors that affect the laser beam absorptivity of the material include two aspects. The first is the coefficient of resistance of the material. From the measurement of the absorptivity of the polished surface of the material, it has been found that the absorptivity of the material is directly proportional to the square root of the coefficient of resistance, and the coefficient of resistance varies with the temperature. Secondly, the surface state (or smoothness) of the material has an important influence on the beam absorptivity, and thus significantly influences the welding effect.

Referring toFIG.4andFIG.5, an end cover assembly100is further provided in embodiments of the present disclosure. The end cover assembly100is for the energy-storage apparatus200and includes a top cover10. The top cover10has a first surface11, and the top cover10further defines a liquid-injection hole12extending through the first surface11. The first surface11includes a first sub-surface111and a second sub-surface113connected to the first sub-surface111, the first sub-surface111is around the liquid-injection hole12, the second sub-surface113is around the periphery of the first sub-surface111, and the roughness of the first sub-surface111is greater than the roughness of the second sub-surface113.

It should be noted that when the end cover assembly100is mounted to the energy-storage apparatus200, the top cover10is connected to the housing250to define the accommodating recess.

Optionally, the top cover10may be made of, but not limited to, aluminum or an aluminum alloy, etc. The end cover assembly100of the embodiments of the present disclosure includes the top cover10. The top cover10has a first surface11, and the top cover10further defines the liquid-injection hole12extending through the first surface11. The first surface11includes a first sub-surface111and a second sub-surface113connected to each other, the first sub-surface111is around the liquid-injection hole12, the second sub-surface113is around the periphery of the first sub-surface111, and the roughness of the first sub-surface111is greater than the roughness of the second sub-surface113. Since the roughness of the first sub-surface111is greater than the roughness of the second sub-surface113, when the sealing cap is subsequently welded to seal the liquid-injection hole12, the reflection of laser by the top cover10can be reduced, so as to reduce the laser absorptivity of the welding material of the top cover10, avoiding the problem that the temperature cannot reach a welding temperature caused by the reduced laser absorptivity of the welding material due to the reflection of laser by the top cover10. In addition, since the roughness of the first sub-surface111is greater than the roughness of the second sub-surface113, when a top patch is attached to the first surface11of the top cover10, gas between the top patch and the first sub-surface111of the top cover10can be discharged through a rough micro-gap of the first sub-surface111to avoid formation of local bubbles, which can increase the binding force (i.e., the adhesive force) between the top patch and the first sub-surface111, improving the sealing effect on the liquid-injection hole12. Furthermore, during the process of filling the electrolyte into the energy-storage apparatus200through the liquid-injection hole12at high speed, a small amount of electrolyte will splash around the liquid-injection hole12. However, the subsequent laser welding of the sealing cap30requires high cleanliness of the metal surface. If there are impurities, such as the electrolyte or dust, remaining on the metal surface, when the laser beam scans to the impurities (e.g., the fine particles of electrolyte), the impurities will vaporize to explode instantly, which is likely to cause defects such as pores or splashes at the welded part.

Optionally, the first sub-surface111is formed by means of low-power laser scanning that removes impurities such as the electrolyte or dust remaining around the liquid-injection hole by ablation while forming the rough surface (i.e., the first sub-surface111), so that the welding surface is cleaned in advance for the subsequent high-power laser welding process of the sealing cap30to improve the uniformity and sealing performance of welding, thereby prolonging the service life of the energy-storage apparatus200.

Optionally, the sealing cap may be made of, but not limited to, aluminum or an aluminum alloy, etc.

Optionally, the roughness Ra of the first sub-surface111is in a range of 3.2≤Ra≤50. Specifically, the roughness Ra of the first sub-surface111may be, but not limited to,3.2,5,8,10,15,20,25,30,35,40,45,50, etc. If the roughness of the first sub-surface111is too small, the laser reflectivity of the first sub-surface111is excessively large, affecting the laser absorptivity of the laser welding material, so that during welding of the sealing cap to the top cover10, the temperature cannot reach the welding temperature, affecting the sealing effect of the sealing cap on the liquid-injection hole12. If the roughness of the first sub-surface111is too large, when the top patch is attached to the first surface11, an adhesive layer for attaching the top patch is insufficient to extend into the bottom of a trench (i.e., the gap of the first sub-surface111) for attachment, reducing the sealing performance of the liquid-injection hole12.

In a specific embodiment, the first sub-surface111is a rough surface, and the second sub-surface113is a smooth surface (i.e., the surface that is smooth).

Referring toFIG.6, in some embodiments, the first sub-surface111is annular, and the first sub-surface111has a linewidth L1in a range of 1.5 mm≤L1≤8.5 mm. Specifically, the linewidth L1of the first sub-surface111may be, but not limited to, 1.5 mm, 2.0 mm, 2.5 mm, 2.8 mm, 3.0 mm, 3.2 mm, 3.5 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 8.5 mm, etc. If the linewidth of the first sub-surface111is too small, the impurities such as the electrolyte are likely to splash out of the first sub-surface111during filling. The larger the linewidth of the first sub-surface111is, the more it can ensure that the error of the laser beam is within the range of the first sub-surface111during welding of the sealing cap to the liquid-injection hole12, so as to avoid the problem that the temperature cannot reach a standard welding temperature caused by the reduced laser absorptivity of the welding material due to the reflection by the second sub-surface113(a clean surface). The excessively large linewidth of the first sub-surface111will cause the waste of laser scanning energy and also prolong the machining time, thus increasing the machining cost of the energy-storage apparatus200.

Optionally, the first sub-surface111is annular, the liquid-injection hole12is circular, and the ratio of an outer radius R1of the first sub-surface111to the radius R2of the liquid-injection hole12is in a range of 1.2≤R1/R2≤4.8. Specifically, the ratio of the outer radius R1of the first sub-surface111to the radius R2of the liquid-injection hole12may be, but not limited to, 1.2, 1.5, 1.8, 2.0, 2.5, 2.8, 3.0, 3.2, 3.5, 3.75, 4.0, 4.25, 4.5, 4.8, etc. The larger the diameter of the liquid-injection hole12is, the more electrolyte passing through per unit time, and the further the electrolyte splashed outwards. If R1/R2is too small, the electrolyte is likely to splash out of the first sub-surface111during filling. The excessively large R1/R2will cause the waste of laser canning energy and also prolong the machining time, thus increasing the cost of the energy-storage apparatus200.

Referring toFIG.7andFIG.8, in some embodiments, the end cover assembly100further includes a sealing cap30and an annular welding portion31located at the junction between the sealing cap30and the top cover10. The sealing cap30seals the liquid-injection hole12and is connected to the top cover10. The top cover10is further provided with a first welding mark33located at the first sub-surface111. The first welding mark33includes a first end portion331and a second end portion333opposite to the first end portion331. The first end portion331is connected to the welding portion31, and the second end portion333is located at the periphery of the welding portion31and is spaced apart from the welding portion31.

It should be noted that the welding portion31and the first welding mark33are both formed during welding of the sealing cap30and the top cover10. During welding of the sealing cap30to the top cover10, the welding material is welded a circle around the periphery of the sealing cap30to form the annular welding portion31, and after the annular welding portion31is formed, welding is continued on the top cover10to form the first welding mark33. It can be understood that the first welding mark33is the ending point of laser welding.

During laser welding of the sealing cap30to the top cover10, there is a large shrinkage force before the welding material is completely solidified, so that at the end of welding, the relatively large temperature difference at the end is likely to cause end cracks. The arrangement of the first welding mark33at a position away from the annular welding portion31(there is no need for welding two materials together) can allow the whole annular welding portion31to be uniform, improving the sealing performance of the liquid-injection hole12. The arrangement of the starting and ending points of welding on the first sub-surface111outside the welding portion31can better prevent the risk of sealing failure due to fine cracks caused by the concentration of stress of the welding portion31on the part-to-be welded.

Optionally, the second end portion333is located within the range of the first sub-surface111. This can better prevent the second sub-surface113from reflecting laser after the welding is outside the range of the first sub-surface111(i.e., the welding reaching the second sub-surface113).

Optionally, before the sealing cap30is welded, the surface of the top cover10is cleaned. The aluminum alloy is active and is easy to be oxidized, and a large amount of dust, moisture, etc. are likely to adhere to its surface, so that during welding, if it is not prepared well, the matters adhered to the surface will easily remain on the surface of the aluminum alloy along with the rapid laser welding, thus affecting the quality and welding effect of the aluminum alloy. Therefore, before welding of the aluminum alloy, it is necessary to clean the surface of the aluminum alloy to remove oil stains and the like on the surface. Also, in order to prevent safety threats, such as explosion, caused by oxidation during welding, it is also necessary to thoroughly clean the metal surface to completely remove the oxide film.

In some embodiments, the first sub-surface111is annular, the sealing cap30is circular, and the ratio of the outer radius R1of the first sub-surface111to the radius R3of the sealing cap30is in a range of 1.45≤R1/R3≤3.65. Specifically, the ratio of the outer radius R1of the first sub-surface111to the radius R3of the sealing cap30may be, but not limited to, 1.45, 1.6, 1.75, 1.88, 2.0, 2.25, 2.5, 2.8, 3.0, 3.2, 3.4, 3.65, etc. If the ratio of the outer radius R1of the first sub-surface111to the radius R3of the sealing cap30is too small, the linewidth of the first sub-surface111is insufficient for close attachment of the top patch to the first sub-surface111during attachment of the top patch. If the ratio of the outer radius R1of the first sub-surface111to the radius R3of the sealing cap30is large, the linewidth of the first sub-surface111is too large, so that when the top patch is attached, the gas between the top patch and the first sub-surface111of the top cover10cannot be completely discharged through the rough micro-gap of the first sub-surface111, which is likely to form local bubbles, reducing the sealing effect on the liquid-injection hole12. When the ratio of the outer radius R1of the first sub-surface111to the radius R3of the sealing cap30is 1.45 to 3.65, it is possible to ensure that the linewidth is sufficient to enhance the close attachment of the top patch to the first sub-surface111, and also avoid excessively large linewidth of the first sub-surface111that will reduce the sealing effect on the liquid-injection hole12due to formation of local bubbles caused by the gas between the top patch and the first sub-surface111of the top cover10being unable to be completely discharged through the rough micro-gap of the first sub-surface111during attachment of the top patch.

Referring toFIG.9andFIG.10, in some embodiments, the top cover10is further provided with a second welding mark35located at the first sub-surface111. The second welding mark35includes a third end portion351and a fourth end portion353opposite to the fourth end portion353, the third end portion351is connected to the welding portion31, and the fourth end portion353is located at the periphery of the welding portion31and is spaced apart from the welding portion31. The first end portion331is spaced apart from or overlapped with the third end portion351, and the second end portion333and the fourth end portion353are respectively arranged at two opposite sides of a line connecting the first end portion331and the center of the liquid-injection hole12.

It should be noted that, in this embodiment, the welding portion31, the first welding mark33, and the second welding mark35are each formed when the sealing cap30is welded to the top cover10. When the sealing cap30is welded to the top cover10, the second welding mark35is firstly formed at the side of the first sub-surface111of the top cover10away from the sealing cap30, the annular welding portion31is then formed between the sealing cap30and the top cover10, and the first welding mark33is finally formed at the side of the first sub-surface111of the top cover10away from the annular welding portion31. The first welding mark33and the second welding mark35are approximate to line segments of a straight line that each are roughly tangent to the annular welding portion31. It can be understood that the first welding mark33is the ending point of laser welding, and the second welding mark35is a starting point of laser welding.

During welding of the sealing cap30, when laser welding is performed at the starting position, the temperature of the welding material is not enough, so that the material to be welded cannot reach a molten state desired for good welding, reducing the sealing performance of the liquid-injection hole12. The arrangement of the second welding mark35can allow welding to be performed at a high welding temperature when the welding portion31is formed, so that the sealing cap30can be better welded to the top cover10to better seal the liquid-injection hole12. Also, in order to also shorten the welding process time (i.e., it is unexpected to prolong the movement time of a laser head during initial welding), the starting point of welding is also set on the outside of the annular welding portion31, so as to minimize the welding stroke while ensuring the sufficient temperature during forming of the welding portion31by welding, thereby improving the welding efficiency.

In other embodiments, the problem of insufficient initial welding temperature can be solved by means of reducing the movement speed of the laser head or welding a circle from the initial position and then surrounding and covering a small section of the initial welded part to achieve uniform welding, and it is not necessary to space the starting point away.

Optionally, the welding portion31is annular, the length L2of the first welding mark33satisfies 1.5 mm≤L2≤√{square root over (R12−R42)}, and the length L3of the second welding mark35satisfies 1.5 mm≤L3≤√{square root over (R12−R42)}, where R1is the outer radius of the first sub-surface111, and R4is the outer radius of the welding portion31. In this way, when the welding portion31is formed by welding, the temperature is sufficient, so that the sealing cap30can be better welded to the top cover10to better seal the liquid-injection hole12, and the first welding mark33and the second welding mark35can also be controlled within the range of the first sub-surface111, avoiding the problem of light reflection during welding due to the marks being beyond the range of the first sub-surface111.

Optionally, the length L2of the first welding mark33is in a range of 1.5 mm≤L2≤5.5 mm; and specifically, the length L2of the first welding mark33may be, but not limited to, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, etc. If the first welding mark33is too short, it is likely to cause end cracks, affecting welding of the sealing cap30to the top cover10, thus affecting the sealing effect. If the first welding mark33is too long and is out of the range of the first sub-surface111, it is likely to cause the problem of light reflection during welding.

Optionally, the length L3of the second welding mark35is in a range of 1.5 mm≤L3≤5.5 mm. Specifically, the length L3of the second welding mark35may be, but not limited to, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, etc. If the second welding mark35is too short, the temperature of the welding material is insufficient during forming of the welding portion31by welding, which affects welding of the sealing cap30to the top cover10, thus affecting the sealing effect. If the second welding mark35is too long and is out of the range of the second sub-surface113, it is likely to cause the problem of light reflection during welding.

In a specific embodiment, the welding portion31is annular, the first welding mark33and the second welding mark35are straight, and the first welding mark33and the second welding mark35are both tangent to the welding portion31. The first welding mark33and the second welding mark35are straight, and the straight welding marks can shorten the movement path of the laser welding head, improving the welding efficiency.

In another specific embodiment, the welding portion31is annular, and the first welding mark33is straight and is tangent to the welding portion31; and the second welding mark35is arc, and the second welding mark35is tangent to the welding portion31. When the sealing cap30is welded to the top cover10for laser welding, it is not necessary to align the starting position to a specific position, and the position tangent to the sealing cap30may be adjusted by means of an arc, so that the welding operation is more convenient, and the requirement for the accuracy of the starting position is low.

Referring toFIG.11andFIG.12, in some embodiments, the ratio of an outer radius R4of the welding portion31to the length L2of the first welding mark33is in a range of 0.4≤R4/L2≤2.8. Specifically, the ratio of the outer radius R4of the welding portion31to the length L2of the first welding mark33may be, but not limited to, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.4, 2.6, 2.8, etc. If the ratio of the outer radius R4of the welding portion31to the length L2of the first welding mark33is too large, the first welding mark33is too short, which is likely to cause end cracks, affecting welding of the sealing cap30on the top cover10, thus affecting the sealing effect. If the ratio of the outer radius R4of the welding portion31to the length L2of the first welding mark33is too small, the first welding mark33is too long and is out of the range of the first sub-surface111, it is likely to cause the problem of light reflection during welding. When the ratio of the outer radius R4of the welding portion31to the length L2of the first welding mark33is 0.4 to 2.8, during forming of the welding portion31by welding, the temperature is sufficient, so that the sealing cap30can be better welded to the top cover10to better seal the liquid-injection hole12, and the first welding mark33can also be controlled within the range of the first sub-surface111, avoiding the problem of light reflection during welding due to the marks being beyond the range of the first sub-surface111.

Optionally, in some embodiments, the first welding mark33is straight, and an angle α between a line connecting the center of the sealing cap30and the first end portion331and the first welding mark33is in a range of 700≤α≤120°. Specifically, the angle α between the line connecting the center of the sealing cap30and the first end portion331and the first welding mark33may be, but not limited to, 70°, 75°, 80°, 85°, 90°, 95°, 100°, 105°, 110°, 115°, 120°, etc. In this angle range, the path of laser welding is smoother, so as to avoid reduction of the overall welding uniformity and reduction of the sealing performance of welding caused by the accumulation of molten metal at the welded part due to a relatively large turning angle.

In some embodiments, the ratio of the outer radius R4of the welding portion31to the length L3of the second welding mark35is in a range of 0.4≤R4/L3≤2.8. Specifically, the ratio of the outer radius R4of the welding portion31to the length L3of the second welding mark35may be, but not limited to, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.4, 2.6, 2.8, etc. If the ratio of the outer radius R4of the welding portion31to the length L2of the second welding mark35is too large, the second welding mark35is too short, which is likely to cause end cracks, affecting welding of the sealing cap30to the top cover10, thus affecting the sealing effect. If the ratio of the outer radius R4of the welding portion31to the length L2of the second welding mark35is too small, the second welding mark35is too long and is out of the range of the first sub-surface111, which is likely to cause the problem of light reflection during welding. When the ratio of the outer radius R4of the welding portion31to the length L2of the second welding mark35is 0.4 to 2.8, during forming of the welding portion31by welding, the temperature is sufficient, so that the sealing cap30can be better welded to the top cover10to better seal the liquid-injection hole12, and the second welding mark35can also be controlled within the range of the first sub-surface111, avoiding the problem of light reflection during welding due to the marks being beyond the range of the first sub-surface111.

Optionally, the second welding mark35is straight, and an angle β between a line connecting the center of the sealing cap30and the third end portion351and the second welding mark35is in a range of 70°≤β≤120°. Specifically, the angle β between the line connecting the center of the sealing cap30and the third end portion351and the second welding mark35may be, but not limited to, 70°, 75°, 80°, 85°, 90°, 95° 100°, 105°, 110°, 115°, 120°, etc. In this angle range, the path of laser welding is smoother, so as to avoid reduction of the overall welding uniformity and reduction of the sealing performance of welding caused by the accumulation of molten metal at the welded part due to a relatively large turning angle.

Referring toFIG.6again, optionally, the first surface11further includes an abutting sub-surface115. The abutting sub-surface115is around the periphery of the liquid-injection hole12, the first sub-surface111is around the periphery of the abutting sub-surface115and is connected to the abutting sub-surface115, and when the sealing cap30is arranged on the first surface11, the sealing cap30abuts against the abutting sub-surface115. By means of providing the abutting sub-surface115, the sealing cap30abuts against the abutting sub-surface115, such that the liquid-injection hole12can be better sealed.

Optionally, the abutting sub-surface115is recessed from the first sub-surface111, the sealing cap30is located in a recess formed by the abutting sub-surface115, and the surface of the sealing cap30close to the first surface11is flush with the first sub-surface111. This can prevent the sealing cap30from exceeding the top cover10, so that the surface of the top cover10is flatter and can thus be better attached to the top patch during attachment of the top patch, so that the liquid-injection hole12can be better sealed.

It can be understood that the liquid-injection hole12extends through the abutting sub-surface115.

Referring toFIG.13, in some embodiments, the top cover10further has a second surface13away from the first surface11, and the liquid-injection hole12further extends through the second surface13. The second surface13includes a third sub-surface131and a fourth sub-surface133connected to the third sub-surface131. The third sub-surface131is around the periphery of the liquid-injection hole12, the fourth sub-surface133is around the periphery of the third sub-surface131, and the third sub-surface131exceeds the fourth sub-surface133to form a protrusion14.

It should be noted that when the end cover assembly100is for the energy-storage apparatus200, the first surface11is closer to an appearance surface of the energy-storage apparatus200than the second surface13, that is, the surface to which the top patch is attached.

In this embodiment, when the end cover assembly100is mounted to the energy-storage apparatus200, when the electrolyte is filled through the liquid-injection hole12, the electrolyte is filled into the energy-storage apparatus200from the side of the liquid-injection hole12close to the first surface11, and the protrusion14provided on the second surface13has the effect of guiding and limiting the electrolyte and can better prevent the electrolyte from flowing to the second surface13of the top cover10, which will cause the waste of the electrolyte and increase the risk of corrosion of the top cover10.

Referring toFIG.14, in other embodiments, the second surface13further includes a fifth sub-surface135. The fifth sub-surface135is around the periphery of the fourth sub-surface133and is connected to the fourth sub-surface133, the fifth sub-surface135exceeds the fourth sub-surface133, the third sub-surface131exceeds the fifth sub-surface135, and the third sub-surface131exceeds the fourth sub-surface133to form the protrusion14. The third sub-surface131, the fourth sub-surface133, and the fifth sub-surface135cooperatively define a groove15around the protrusion14. It can be understood that the third sub-surface131, the fourth sub-surface133, and the fifth sub-surface135are sequentially connected to one another. When the end cover assembly100is mounted to the energy-storage apparatus200, when the electrolyte is filled through the liquid-injection hole12, since the groove15is defined at the periphery of the protrusion14, when the electrolyte accidentally flows to the second surface13, the groove15allows the electrolyte to be retained in the groove15, so as to prevent the electrolyte from continuing to spread to the fifth sub-surface135, causing the waste of the electrolyte and corroding the top cover10.

Referring toFIG.15, optionally, the protrusion14has a linewidth S1in a range of 2.2 mm≤S1≤3.6 mm; and specifically, the linewidth S1of the protrusion14may be, but not limited to, 2.2 mm, 2.4 mm, 2.7 mm, 2.8 mm, 3.0 mm, 3.2 mm, 3.6 mm, etc. Before the sealing cap30is welded to the liquid-injection hole12, the liquid-injection hole12is plugged with a sealing plug (e.g., a rubber plug), the sealing cap30is then arranged on the first surface11, and the sealing cap30is welded. If the linewidth S1of the protrusion14is too large, the recessed space is too large, and after the liquid-injection hole12is plugged with the rubber plug, there is still a space for radial movement, reducing the sealing performance of the liquid-injection hole12. If the linewidth S1of the protrusion14is too small, the accommodating space provided for a convex cap at the top of the rubber plug of the liquid-injection hole12is insufficient, so that the sealing cap30is prone to protruding from the first surface11of the top cover10after the sealing cap30is welded. When the linewidth S1of the protrusion14is between 2.2 mm and 3.6 mm, it is possible to provide enough space for the convex cap at the top of the rubber plug of the liquid-injection hole12, so that the whole sealing cap30(i.e., an aluminum cover sheet of the liquid-injection hole12) after closing for sealing is flush with the first surface11of the top cover10, and it is also possible to avoid reduction of the sealing performance which is caused by the presence of a radial movement space due to an excessively large recessed space after the liquid-injection hole12is plugged with the rubber plug.

Optionally, the groove15has a linewidth S2in a range of 1.2 mm≤S2≤4.6 mm. Specifically, the linewidth S2of the groove15may be, but not limited to 1.2 mm, 1.5 mm, 1.7 mm, 2.2 mm, 2.4 mm, 2.7 mm, 2.8 mm, 3.0 mm, 3.2 mm, 3.6 mm, 3.8 mm, 4.0 mm, 4.2 mm, 4.6 mm, etc. If the linewidth S2of the groove15is too small, the width is not enough to well prevent the electrolyte from spreading to the outside of the groove15to cause the waste of the electrolyte. If the linewidth S2of the groove15is too large, the structural strength of the top cover10turning around the liquid-injection hole12will be reduced, which is likely to cause protruding deformation during subsequent use. When the linewidth S2of the groove15is 1.2 mm to 4.6 mm, the groove15may have a sufficient width such that the electrolyte will not spread to the outside of the groove15to cause the waste of the electrolyte, and it is also possible to prevent the protruding deformation during subsequent use due to the reduction of the structural strength of the top cover10turning around the liquid-injection hole12.

Referring toFIG.3,FIG.16, andFIG.17, in some embodiments, the energy-storage apparatus200further includes an electrode assembly210. The top cover10further has a second surface13away from the first surface11, and the liquid-injection hole12further extends through the second surface13. The top cover10further defines a first accommodating recess16from the second surface13, a second accommodating recess17recessed from a bottom wall of the first accommodating recess16, and a first through hole18extending through both a bottom wall of the second accommodating recess17and the first surface11. The first accommodating recess16, the second accommodating recess17, and the first through hole18are in communication with one another, and the first through hole18is spaced apart from the liquid-injection hole12. The end cover assembly100further includes a lower plastic member50and a pole70. The lower plastic member50is arranged on the second surface13of the top cover10. The lower plastic member50includes a body portion51, a first abutting portion52protruding from the surface of the body portion51facing the top cover10, and a second abutting portion53protruding from the surface of the first abutting portion52facing the top cover10. The first abutting portion52is located in the first accommodating recess16and abuts against the bottom wall of the first accommodating recess16and a side wall of the first accommodating recess16. The second abutting portion53is located in the second accommodating recess17and abuts against the bottom wall of the second accommodating recess17and a side wall of the second accommodating recess17. The lower plastic member50further defines a second through hole54sequentially extending through the body portion51, the first abutting portion52, and the second abutting portion53. The second through hole54is defined corresponding to the first through hole18. The pole70has one part located on the side of the lower plastic member50away from the top cover10, and another part sequentially extending through the second through hole54and the first through hole18and insulated from the top cover10, and the pole70is configured to be electrically connected to the electrode assembly210. By means of the interference fit between the first abutting portion52and the first accommodating recess16and the interference fit between the second abutting portion53and the second accommodating recess17, it is possible to improve the sealing performance of a fitting surface between the lower plastic member50and the top cover10to prevent the electrolyte from flowing to a through hole of the pole70through the gap between the lower plastic member50and the top cover10, which can improve the sealing performance of the end cover assembly100and thus prolong the service life of the energy-storage apparatus.

Referring toFIG.18andFIG.19, in some embodiments, the end cover assembly100further includes a lower plastic member50. The lower plastic member50is disposed at the side of the top cover10away from the first surface11. The lower plastic member50includes a first plastic sub-member55, a second plastic sub-member56, a third plastic sub-member57, and a fourth plastic sub-member58. The first plastic sub-member55and the second plastic sub-member56are arranged at an interval in a first direction on the surface of the top cover10away from the first surface11(as shown by arrow A inFIG.18). The first plastic sub-member55defines a leakage hole551at a position of first plastic sub-member55close to the second plastic sub-member56, and the leakage hole551is in communication with the liquid-injection hole12. The first plastic sub-member55has a first peripheral side wall552and a second peripheral side wall553that are connected end-to-end and define the leakage hole551. The first peripheral side wall552is a cambered surface, the second peripheral side wall553is a flat surface, and the second peripheral side wall553is closer to the second plastic sub-member56than the first peripheral side wall552. The third plastic sub-member57and the fourth plastic sub-member58are arranged at an interval in a second direction (as shown by arrow B inFIG.18). The third plastic sub-member57is connected to both the first plastic sub-member55and the second plastic sub-member56in a snap-fit manner, and the fourth plastic sub-member58is connected to both the first plastic sub-member55and the second plastic sub-member56in a snap-fit manner. The third plastic sub-member57and the fourth plastic sub-member58are both partially located between the first plastic sub-member55and the second plastic sub-member56, where the first direction is perpendicular to the second direction. Since the leakage hole551is at a position next to an explosion-proof hole of the top cover10, providing the flat second peripheral side wall553at the position of the side wall of the leakage hole551can reduce the length of the first plastic sub-member55in the first direction, so as to better provide avoidance for the third plastic sub-member57and the fourth plastic sub-member58, so that the flow channel formed by the part of the top cover10corresponding to the explosion-proof hole and the lower plastic member50may be symmetrical, and thus the airflow pressure exerted on an explosion-proof sheet arranged on the explosion-proof hole can be more uniform.

In a specific embodiment, the second peripheral side wall553is parallel to the surface of the first plastic sub-member55facing the second plastic sub-member56. In another specific embodiment, the second peripheral side wall553, the surface of the first plastic sub-member55facing the second plastic sub-member56, and the surface of the second plastic sub-member56facing the first plastic sub-member55are parallel to one another. In this way, the first plastic sub-member55and the second plastic sub-member56each have more regular appearance, which can better provide avoidance for the third plastic sub-member57and the fourth plastic sub-member58. In addition, since the first plastic sub-member55and the second plastic sub-member56are equal in length in the first direction, the third plastic sub-member57and the fourth plastic sub-member58can be made symmetrical in the second direction, so that during assembly, the third plastic sub-member57and the fourth plastic sub-member58can be assembled interchangeably, reducing the assembly accuracy.

Also referring toFIG.20, in some embodiments, the top cover10further has a second surface13away from the first surface11, and defines an explosion-proof hole19extending through the first surface11and the second surface13, the explosion-proof hole19is spaced apart from the liquid-injection hole12. The end cover assembly100further includes an explosion-proof sheet21. The explosion-proof sheet21seals the explosion-proof hole19and is connected to the top cover10. The first plastic sub-member55further defines a vent channel554in communication with the leakage hole551. The vent channel554extends through both the surface of the first plastic sub-member55facing the second plastic sub-member56and the surface of the first plastic sub-member55facing the top cover10, and the vent channel554is in communication with the side of the explosion-proof sheet21facing the first plastic sub-member55. A gas chamber is enclosed by the explosion-proof sheet21, the top cover10and the lower plastic member50, and the vent channel554is in communication with the gas chamber, such that the gas in the energy-storage apparatus200can pass through the leakage hole551and the vent channel554to reach the gas chamber on the side of the explosion-proof sheet21facing the lower plastic member. By means of defining the vent channel554in communication with the leakage hole551and allowing the vent channel554to extend through both the surface of the first plastic sub-member55facing the second plastic sub-member56and the surface of the first plastic sub-member55facing the top cover10, an air flow channel by which the leakage hole551of the lower plastic member50is in communication with the gas chamber below the explosion-proof sheet21can be defined, increasing the number of channels for gas accumulation.

Optionally, the explosion-proof sheet21is provided with scorings (not shown), such that when the internal pressure of the energy-storage apparatus200increases to reach a certain value, a fracture will occur for blasting to release pressure of the energy-storage apparatus200.

In some embodiments, the end cover assembly100in the embodiment of the present disclosure further includes a protective sheet23. The protective sheet23is arranged on the side of the explosion-proof sheet21away from the lower plastic member50(i.e., the side of the first surface11of the top cover10) to seal the explosion-proof hole19and protect the explosion-proof sheet21, so as to prevent the electrolyte inside the energy-storage apparatus200from overflowing caused by foreign objects hitting the explosion-proof sheet21and damaging the explosion-proof sheet21.

In some embodiments, the end cover assembly100in the embodiments of the present disclosure further includes a top patch (not shown). The top patch is arranged on the first surface11of the top cover10and the sealing cap30.

Referring toFIG.18andFIG.19, in some embodiments, the end cover assembly100in the embodiments of the present disclosure further includes a positive-electrode metal pressing block41and a negative-electrode metal pressing block43. The positive-electrode metal pressing block41and the negative-electrode metal pressing block43are arranged at an interval on the side of the first surface11of the top cover10and are respectively insulated from the top cover10, the positive-electrode metal pressing block41is electrically connected to the positive-electrode adapter sheet231, and the negative-electrode metal pressing block43is electrically connected to the negative-electrode adapter sheet233. The positive-electrode metal pressing block41and the negative-electrode metal pressing block43cooperate to achieve electrical connection or conduction between the energy-storage apparatus200and the external electricity-consumption device or a further energy-storage apparatus200.

In some embodiments, the end cover assembly100in the embodiments of the present disclosure further includes a positive-electrode upper plastic member61and a negative-electrode upper plastic member63. The positive-electrode upper plastic member61is at least partially located between the positive-electrode metal pressing block41and the top cover10to insulate the positive-electrode metal pressing block41from the top cover10. The negative-electrode upper plastic member63is at least partially located between the negative-electrode metal pressing block43and the top cover10to insulate the negative-electrode metal pressing block43from the top cover10.

Optionally, the positive-electrode upper plastic member61may be, but not limited to, an insulating component such as a resin or rubber. The negative-electrode upper plastic member63may be, but not limited to, an insulating component such as a resin or rubber.

In some embodiments, the end cover assembly100in the embodiments of the present disclosure further includes a positive pole71and a negative pole73. The positive pole71sequentially penetrates through the lower plastic member50, the top cover10, the positive-electrode upper plastic member61, and the positive-electrode metal pressing block41and is welded to the positive-electrode metal pressing block41, and the end of the positive pole71away from the metal pressing block is welded to the positive-electrode adapter sheet231to achieve electrical connection between the positive-electrode metal pressing block41and a positive-electrode sheet. The negative pole73sequentially penetrates through the lower plastic member50, the top cover10, the negative-electrode upper plastic member63, and the negative-electrode metal pressing block43and is welded to the negative-electrode metal pressing block43, and the end of the negative pole73away from the metal pressing block is welded to the negative-electrode adapter sheet233to achieve electrical connection between the negative-electrode metal pressing block43and a negative-electrode sheet.

Optionally, the positive pole71and the negative pole73each include a flange portion (not shown) and a boss (not shown) protruding from a surface of the flange portion. The flange portion is located between the lower plastic member50and the positive-electrode adapter sheet231/negative-electrode adapter sheet233and is welded to the positive-electrode adapter sheet231/negative-electrode adapter sheet233. The boss sequentially penetrates through the lower plastic member50, the top cover10, the positive-electrode upper plastic member61/negative-electrode upper plastic member63, and the positive-electrode metal pressing block41/negative-electrode metal pressing block43, such that the positive-electrode metal pressing block41is electrically connected to the positive-electrode adapter sheet231by means of the positive pole71, and the negative-electrode metal pressing block43is electrically connected to the negative-electrode adapter sheet233by means of the negative pole73.

Optionally, the flange portion is arranged on the side of the lower plastic member50away from the top cover, and the boss penetrates through the first through hole18and the second through hole54; and the boss has a central axis, and the pole70is rotationally symmetrical about the central axis. In this way, there is no need to distinguish left and right directions during assembly of the pole70, and the assembly can be completed by insertion after direct alignment of the long side, reducing the assembly requirement of the pole70.

In some embodiments, the end cover assembly100in the embodiments of the present disclosure further includes a sealing ring80, the boss of the positive pole71and the boss of the negative pole73are each sleeved with the sealing ring80, and the sealing ring80is configured to insulate the positive pole71/negative pole73from the top cover10and seal the gap between the positive pole71/negative pole73and the top cover10.

In some embodiments, the end cover assembly100in the embodiments of the present disclosure further includes a sealing pin90. The sealing pin90penetrates through the liquid-injection hole12for sealing the liquid-injection hole12. After the energy-storage apparatus200is assembled and filled with the electrolyte, the sealing pin90is firstly arranged in the liquid-injection hole12, the sealing cap30is then arranged on the first surface11of the top cover10and the sealing pin90, and the sealing cap30is welded to the top cover10.

Optionally, the sealing pin90may be, but not limited to, an insulating component such as a resin or rubber.

The terms of “embodiment” and “implementation” mentioned in the present disclosure means that the specific features, structures, or characteristics described with reference to the embodiments may be encompassed in at least one embodiment of the present disclosure. The phrase at various locations in the specification does not necessarily refer to the same embodiment, or an independent or alternative embodiment exclusive of another embodiment. Those skilled in the art should understand explicitly and implicitly that the embodiments described in the present disclosure may be combined with other embodiments. In addition, it should also be understood that the features, structures or characteristics described in the embodiments of the present disclosure may be combined as desired to obtain embodiments without departing from the spirit and scope of the technical solution of the present disclosure if there is no contradiction between the embodiments.

Finally, it should be noted that the above implementations are merely used for illustrating rather than limiting the technical solutions of the present disclosure; and although the present disclosure has been described in detail with reference to the preferred implementations, those skilled in the art should understand that modifications or equivalent substitutions may be made to the technical solutions of the present disclosure without departing from the spirit and scope of the technical solutions of the present disclosure.