END COVER ASSEMBLY, BATTERY, AND ENERGY STORAGE DEVICE

An end cover assembly includes a top cover unit, a pole, an upper plastic member, and a fixing member. The pole penetrates the top cover unit and includes a base portion and a connecting portion protruding from an end surface of the base portion. A part of the end surface of the base portion outside a coverage area of the connecting portion is formed as a step surface surrounding the connecting portion. The upper plastic member is at least partially sleeved on a peripheral side of the base portion. The upper plastic member is partially located at a side of the top cover unit. The fixing member is partially located at the other side of the top cover unit. A seam is formed between the fixing member and the connecting portion and surrounds the connecting portion, and the step surface abuts against the fixing member and cover the seam.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of priority under the Paris Convention to Chinese Patent Application No. 202310785692.4 filed on Jun. 29, 2023, which is incorporated herein by reference in its entirety.

FIELD

The present disclosure relates to the field of energy storage technologies, and in particular, to an end cover assembly, a battery, and an energy storage device.

BACKGROUND

A rechargeable battery, also known as a secondary battery or a storage battery, enables active materials to be activated for continued use through recharging after discharge, such that the rechargeable battery gradually becomes a main power source of an electric system due to its recyclable characteristic. The rechargeable battery generally includes an end cover assembly. However, during assembly of the end cover assembly, welding heat will damage other parts in the end cover assembly to cause partial failures, thereby affecting reliability of the whole end cover assembly.

SUMMARY

One technical problem to be solved by the present disclosure is how to improve reliability of an end cover assembly.

An end cover assembly includes a top cover unit, a pole, an upper plastic member, and a fixing member. The pole penetrates the top cover unit and includes a base portion and a connecting portion. The connecting portion protrudes from an end surface of the base portion in an axial direction of the base portion, and a part of the end surface of the base portion outside a coverage area of the connecting portion is formed as a step surface surrounding the connecting portion. The upper plastic member is at least partially sleeved on a peripheral side of the base portion. The upper plastic member is partially located at a side of the top cover unit in a thickness direction of the top cover unit. The fixing member is partially located at the other side of the top cover unit in the thickness direction of the top cover unit. A seam surrounding the connecting portion is defined between the fixing member and the connecting portion, and the step surface is configured to abut against the fixing member and cover the seam.

A battery includes the end cover assembly according to any one of the above. In this way, reliability of the battery can be improved.

An energy storage device includes at least one battery as described above.

DETAILED DESCRIPTION

In order to clarify the above-mentioned objects, features, and advantages of the present disclosure, specific implementations of the present disclosure are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are provided to facilitate full understanding of the present disclosure. However, the present disclosure can be implemented in many other ways different from those described herein, and similar improvements can be made by those skilled in the art without contradicting the intent of the present disclosure. Therefore, the present disclosure is not limited by specific embodiments disclosed below.

In the description of the present disclosure, it needs to be understood that, if terms such as “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “over”, “below”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “in”, “out”, “clockwise”, “counterclockwise”, “axial”, “radial”, and “circumferential” appear, orientation or positional relationship indicated by these terms is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the associated device or element must have a specific orientation, or be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present disclosure.

In addition, if terms such as “first” and “second” appear, the term “first” or “second” is only for descriptive purposes, rather than indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features associated with “first” or “second” can explicitly or implicitly include at least one of the features. In the description of the present disclosure, if a term “plurality of” appear, the term “plurality of” means at least two, unless otherwise specifically indicated.

In the present disclosure, unless otherwise clearly specified and limited, if terms such as “install”, “connect”, “connect to”, “fix” and the like appear, the terms may be understood in a broad sense. For example, unless otherwise clearly specified and limited, it may be a fixed connection or a detachable connection or connection as one piece; mechanical connection or electrical connection or communication; direct connection or indirect connection through an intermediate; internal communication of two components or the interaction relationship between two components. For those skilled in the art, the specific meaning of the above-mentioned terms in the present disclosure can be understood according to specific circumstances.

In the present disclosure, unless expressly stipulated and defined otherwise, if descriptions like the first feature “on” or “under” the second feature appear, the first feature “on” or “under” the second feature may mean that the first feature is in direct contact with the second feature, or the first and second features are in indirect contact through an intermediate. Moreover, the first feature “above” the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply mean that the level of the first feature is higher than that of the second feature. The first feature “below” the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply mean that the level of the first feature is smaller than that of the second feature.

It may be noted that if an element is referred to as being “fixed to” or “disposed on” another element, it may be directly on another element or intervening elements may also exist. If one element is considered to be “connected” to another element, it may be directly connected to another element or intervening elements may be present simultaneously. If present, terms “vertical”, “horizontal”, “upper”, “lower”, “left”, “right” and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementations.

Referring toFIG.1andFIG.2, an end cover assembly10provided in an embodiment of the present disclosure is applied to a battery20(as shown inFIG.9). The battery20is applied to an energy storage device30. The energy storage device30can be used to store energy. The energy storage device30includes at least one battery20. The end cover assembly10includes a top cover unit100, an upper plastic member200, a fixing member300, and a pole400. The top cover unit100may serve as a bearing carrier, so that each of the upper plastic member200and the fixing member300is arranged on the top cover unit100, and the pole400is sleeved in the upper plastic member200and is connected to the fixing member300through welding. Moreover, the pole400penetrates the top cover unit100.

Referring toFIG.1,FIG.2, andFIG.3, in some embodiments, the top cover unit100includes a cover plate110and a lower plastic member120. The cover plate110and the lower plastic member120are stacked on each other. The cover plate110may be made of an aluminum material. Obviously, the lower plastic member120is made of a plastic material. The cover plate110has a first counter bore111and a through hole112defined thereon. The first counter bore111and the through hole112are coaxially arranged and in communication with each other. An aperture of the first counter bore111is greater than an aperture of the through hole112. The first counter bore111is formed by recessing a surface of the cover plate110away from the lower plastic member120in a thickness direction of the cover plate110by a set depth. The through hole112is formed by recessing a middle part of a bottom wall surface of the first counter bore111and extends to a surface of the cover plate110close to the lower plastic member120in the thickness direction of the cover plate110, such that the through hole112has an opening defined on the surface, i.e., the through hole112plays a role in penetrating the cover plate110.

Referring toFIG.1,FIG.2, andFIG.4, in some embodiments, the lower plastic member120has a second counter bore121and a mounting hole122defined therein. Both the second counter bore121and the mounting hole122are coaxially arranged and in communication with each other. An aperture of the second counter bore121is greater than an aperture of the mounting hole122. The second counter bore121is formed by recessing a surface of the lower plastic member120away from the cover plate110in a thickness direction of the lower plastic member120by a set depth. The mounting hole122is formed by recessing a middle part of a bottom wall surface of the second counter bore121and extends to a surface of the lower plastic member120close to the cover plate110in the thickness direction of the lower plastic member120, so that the mounting hole122has an opening formed on the surface, i.e., the mounting hole122plays a role in penetrating the lower plastic member120.

Referring toFIG.7andFIG.8, when the cover plate110and the lower plastic member120are stacked on each other, the first counter bore111, the through hole112, the mounting hole122, and the second counter bore121are sequentially arranged in a thickness direction of the entire end cover assembly10, and the first counter bore111, the through hole112, the mounting hole122, and the second counter bore121are in communication with each other, such that the pole400can pass through the first counter bore111, the through hole112, the mounting hole122, and the second counter bore121simultaneously.

Referring toFIG.2andFIG.5, in some embodiments, the upper plastic member200is made of a plastic material and includes a base ring210, an outer sleeve220, and an inner sleeve230. The base ring210may be of an annular structure and is horizontally disposed. Each of the outer sleeve220and the inner sleeve230may be of a cylindrical structure and vertically arranged. The inner sleeve230and the outer sleeve220are arranged at two opposite sides of the base ring210in a thickness direction of the base ring210, and the outer sleeve220is connected to a peripheral side of the base ring210, so that the outer sleeve220surrounds the base ring210and extends towards a side in the thickness direction of the base ring210by a set length. Obviously, the outer sleeve220protrudes from the base ring210by a set length. The inner sleeve230is connected to the peripheral side of the base ring210, so that the base ring210is arranged surrounding the inner sleeve230, and the inner sleeve230extends towards the other side in the thickness direction of the base ring210by a set length. Obviously, the inner sleeve230also protrudes from the base ring210by a set length.

Referring toFIG.5,FIG.7, andFIG.8, during mounting of the upper plastic member200, the inner sleeve230may penetrate the through hole112, and the inner sleeve230may form an interference fit relationship with the through hole112. The base ring210is at least partially accommodated in the first counter bore111and abuts against a non-recessed edge part of the bottom wall surface of the first counter bore111, i.e., the base ring210is stacked on the bottom wall surface of the first counter bore111, so that the bottom wall surface of the first counter bore111achieves a good position-limiting effect on the entire upper plastic member200in a vertical direction to. Moreover, a side wall surface of the first counter bore111can also play a good position-limiting effect on the upper plastic member200in a horizontal direction. In this way, mounting efficiency and mounting precision of the upper plastic member200are improved. It can be understood that the vertical direction may also be understood as the thickness direction of the entire end cover assembly10. When the inner sleeve230is engaged with the through hole112, a free end of the inner sleeve230may also extend in the mounting hole122of the lower plastic member120. In addition, the aperture of the mounting hole122is greater than an outer diameter of the inner sleeve230, so that there will be a large distance between the inner sleeve230and a side wall surface of the mounting hole122. Obviously, after the upper plastic member200is mounted, the outer sleeve220may be at least partially located outside the first counter bore111. A part of the outer sleeve220located outside the first counter bore111can be understood as that a part of the outer sleeve220is located at a side of top cover unit100in a thickness direction of the top cover unit100. In some embodiments, an end of the inner sleeve230away from the base ring210is a free end. The free end has an outer chamfer231located thereon, and the outer chamfer231may be an externally outer chamfer. An angle of the outer chamfer231ranges from 10 degrees to 45 degrees. For example, a specific value of an angle of the outer chamfer231may be 10 degrees, 35 degrees, or 45 degrees. By providing the outer chamfer231, on the one hand, during an engagement between the inner sleeve230and the through hole112, the outer chamfer231can play a good guiding role, which enables the inner sleeve230to smoothly penetrate the through hole112to be engaged with the through hole112. In this way, assembly difficulty of the upper plastic member200can be lowered, thereby improving assembly efficiency of the upper plastic member200on the cover plate110. On the other hand, a scraping force generated between the inner sleeve230and the cover plate110during assembly of the inner sleeve230can be reduced, so that the inner sleeve230is prevented from generating excessive plastic debris under the action of the scraping force, thereby preventing the debris from affecting normal use functions of the end cover assembly10and the battery20. Moreover, an influence of the inner sleeve230on a structural strength due to scraping is also avoided.

Referring toFIG.5,FIG.7, andFIG.8, in some embodiments, the fixing member300may also be of a ring-shaped structure and made of a metal material. The fixing member300is at least partially accommodated in the second counter bore121of the lower plastic member120, such that a part of the fixing member300is located at the other side of the top cover unit100opposite to the upper plastic member200in the thickness direction of the top cover unit100, and the fixing member300abuts against a non-recessed edge part of the bottom wall surface of the second counter bore121, i.e., the fixing member300is stacked on the bottom wall surface of the second counter bore121, so that the bottom wall of the second counter bore121has a good position-limiting effect on the entire fixing member300in the vertical direction, and a side wall surface of the second counter bore121may also play a good position-limiting effect on the fixing member300in the horizontal direction. In this way, mounting efficiency and mounting precision of the fixing member300are improved. After the fixing member300is accommodated in the second counter bore121, a part of the lower plastic member120is flanked by the fixing member300and the cover plate110, so that the fixing member300and the cover plate110achieve a partially covering effect on two opposite ends of the mounting hole122of the lower plastic member120.

Referring toFIG.6,FIG.7, andFIG.8, in some embodiments, the pole400includes a base portion410and a connecting portion420. Both the base portion410and the connecting portion420are coaxially arranged. A cross section of the connecting portion420is smaller than a cross-sectional size of the base portion410. The connecting portion420protrudes from an end surface of the base portion410in an axial direction of the base portion410. An edge part of the end surface is uncovered by the connecting portion420, i.e., the edge part of the end surface is located outside a covering range of the connecting portion420, so that the edge part of the end surface forms a step surface411arranged to surround the connecting portion420. The upper plastic member200is sleeved on a peripheral side of the base portion410. The fixing member300is sleeved outside the connecting portion420. Moreover, the fixing member300abuts against the step surface411.

The base portion410includes a first section412and a second section413, the first section412and the second section413are coaxially arranged. A cross section of the first section412perpendicular to an axial direction of the pole400is greater than a cross section of the second section413perpendicular to the axial direction of the pole400. The second section413has an end connected to the first section412and another end connected to the connecting portion420, so that the second section413is connected between the first section412and the connecting portion420, and the step surface411is located on the second section413. After the pole400is assembled with the upper plastic member200, the outer sleeve220of the upper plastic member200is sleeved on the first section412, the inner sleeve230of the upper plastic member200is sleeved on the second section413, and the base ring210of the upper plastic member200is stacked on the first section412in a thickness direction of the end cover assembly10. Therefore, the base ring210has a good position-limiting effect on the pole400in the vertical direction, and each of the inner sleeve230and the outer sleeve220has a good position-limiting effect on the pole400in the horizontal direction. In this way, assembly efficiency and assembly precision between the pole400and the upper plastic member200can be improved. After the assembly between the upper plastic member200and the pole400is completed, the base ring210of the upper plastic member200is flanked by the cover110and the first section412of the pole400.

In response to the fixing member300being sleeved on a peripheral side of the connecting portion420, an annular seam310is defined between the fixing member300and the connecting portion420. Obviously, the seam310surrounds the connecting portion420. In response to the fixing member300being needed to be welded and connected to the connecting portion420, laser welding can be used to perform the welding connection. The laser is irradiated into the seam310, so that a part of the fixing member300and the connecting portion420close to the seam310generates a molten liquid, and the molten liquid is solidified to form a welding layer after cooling. Therefore, the fixing member300and the connecting portion420are made welded to each other. Given that the fixing member300abuts against the step surface411of the pole400, mounting precision of the fixing member300can be improved, and a precision requirement of the fixing member300for a welding fixture during welding can be lowered.

For the end cover assembly10in the above embodiments, given that the cross section of the second section413is greater than the cross section of the connecting portion420, the second section413has a step surface411arranged to surround the connecting portion420, and the step surface411abuts against the fixing member300and achieves a covering effect on the seam310. Given that the inner sleeve230of the upper plastic member200is sleeved on a peripheral side of the second section413, the fixing member300is sleeved on the peripheral side of the connecting portion420, and the step surface411plays a covering effect on the seam310. During welding by using the laser, the laser will be irradiated onto the step surface411through the seam310. Moreover, under the shielding effect of the step surface411, the laser cannot irradiate the inner sleeve230, thereby preventing the occurrence of functional failures of the local part of the inner sleeve230due to burning, preventing the normal function of the end cover assembly10from being weakened, and finally improving the reliability of the whole end cover assembly10. In other embodiments of the present disclosure, because of the occurrence of a distance between the inner sleeve230and the seam310between the fixing member300and the connecting portion420in the horizontal direction, a predetermined dislocation is maintained between the inner sleeve230and the seam310between the fixing member300and the connecting portion420, which effectively prevents the inner sleeve230from being located directly above the seam310, and further prevents the laser from irradiating onto the inner sleeve230.

Referring toFIG.6,FIG.7, andFIG.8, in some embodiments, the pole400further includes a boss portion430. The boss portion430and the connecting portion420are coaxially arranged. A size of a cross-section of the boss portion430is smaller than a size of a cross-section of the connecting portion420. The above cross sections are both cross sections perpendicular to the axial direction of the pole400. The boss portion430protrudes from an end surface of the connecting portion420away from the base portion410. Obviously, the boss portion430and the connecting portion420are connected to form a stepped structure. A connector is welded to an end surface of the boss portion430away from the connecting portion420. End surfaces of each of the connecting portion420and the fixing member300close to the boss portion430are flush with each other, so that the molten liquid during laser welding covers edge parts of the two end surfaces close to the seam310simultaneously, thereby enhancing a connection strength between the connecting portion420and the fixing member300.

For the end cover assembly10in the above embodiments, by arranging the boss portion430protruding from the end surface of the connecting portion420, the connector is effectively prevented from being welded onto the end surface of the connecting portion420, so that a welding position of the connector is transferred to the end surface of the boss portion430from the end surface of the connecting portion420. Therefore, the connector located on the end surface of the boss portion430keeps a predetermined distance from a protrusion of the welding layer on the end surface of the connecting portion420, thereby preventing the protrusion of the welding layer from forming a jacking effect on the connector, i.e., eliminating interference generated by the protrusion of the welding layer, and ensuring that the connector is always tightly attached to the protruding end surface. Therefore, during the welding of the connector and the boss portion430, given that the connector is always tightly attached to the protruding end surface, the width of fusion and the depth of fusion of the welding of the connector are effectively improved, thereby improving the connection strength between the connector and the boss portion430after the welding between the connector and the boss portion430, and making an improvement in the contact area of the connector and the boss portion430to enhance the overcurrent capacity. In response to the end cover assembly10being applied to the battery20, heat gathered by the battery20during charging and discharging can be effectively reduced.

Referring toFIG.6,FIG.7, andFIG.8, in some embodiments, a length of the boss portion430ranges from 0.1 mm to 1 mm, and the length of the boss portion430can be understood as a protruding height of the boss portion430relative to the connecting portion420. For example, the specific value of the length of the boss portion430may be 0.1 mm, 0.5 mm, 1 mm, or the like, so that a reasonable distance is maintained between the connector attached to the end surface of the boss portion430and the protrusion of the welding layer, thereby effectively eliminating jacking and interference effects of the protrusion of the welding layer on the connector. A size of the cross-section of the boss portion430gradually decreases from an end of the boss portion430close to the connecting portion420to an end of the boss portion430away from the connecting portion420, so that the boss portion430has a predetermined degree of taper. By enabling the boss portion430to have a predetermined degree of taper, on the one hand, demolding of the formed pole400in the mold is facilitated, and the boss portion430is prevented from forming scratches under the action of the scraping force of the mold; and on the other hand, the pole400has a large contact area with a punch of the mold during forming, which can lower abrasion of the punch, further improving consistency of the pole400product produced by the mold, and finally improving the quality of the pole400.

For example, the boss portion430may be in a circular truncated cone shape. Obviously, an end of the circular-truncated cone-shaped boss portion430with the largest cross-sectional size is directly connected to the connecting portion420, and the connector is welded to an end of the circular-truncated cone-shaped boss portion430having the smallest cross-sectional size. An angle α between a generatrix of the circular-truncated cone-shaped boss portion430and a central axis of the boss portion430ranges from 5 degrees to 45 degrees. For example, a specific value of the angle α may be 5 degrees, 35 degrees, or 45 degrees. The generatrix can be understood as an intersection line between a longitudinal section of the central axis of the boss portion430and an outer side surface of the boss portion430.

Referring toFIG.6,FIG.7, andFIG.8, in some embodiments, the end cover assembly10further includes a sealing member500. The sealing member500is at least partially accommodated in the mounting hole122of the lower plastic member120. The sealing member500surrounds the inner sleeve230of the upper plastic member200and abuts against the cover plate110and the fixing member300. By providing the sealing member500, a sealing capability of the end cover assembly10can be improved. Therefore, external liquid and dust are prevented from invading the battery20through the cover plate110assembly, and an electrolyte in the battery20is also prevented from leaking from the end cover assembly10.

Given that the occurrence of the step surface411between the base portion410and the connecting portion420, in response to the fixing member300abutting against the step surface411, a size of the sealing member500after compression is constant. In an exemplary embodiment of the present disclosure, a distance between the first section412and the fixing member300is denoted as a first size, a thickness size of base ring210of the upper plastic member200is denoted as a second size, and a thickness size of a part where the cover plate110stacks on the base ring210is denoted as a third size. The first size, the second size, and the third size form a size chain. Therefore, the size of the compressed sealing member500is equal to a value that the first size minus the second size and the third size concurrently. Therefore, the size of the compressed sealing member500is only related to the three sizes including the first size, the second size, and the third size, thereby eliminating the influence of other sizes, and reducing the number of sizes involved in the size chain, which can also be understood as lowering influence factors of the size of the compressed sealing member500. Meanwhile, given that the cover plate110, the upper plastic member200, and the pole400are each formed through molds, precision of each of the first size, the second size, and the third size can be ensured.

Therefore, by reducing the total number of sizes involved in the size chain that affect the size of the compressed sealing member500and ensuring machining precision of each size involved in the size chain, the dependence on the clamp can be reduced or even eliminated, so that the size of the compressed sealing member500is kept constant, i.e., stability and consistency of a compression amount of the sealing member500are improved, which further ensures the sealing performance of the sealing member500, thereby enabling sealing reliability of the end cover assembly10to be improved.

Referring toFIG.9,FIG.10, andFIG.11, the present disclosure further provides a battery20, an energy storage device30, and an electric system40. The battery20includes a box body21, a battery cell, and the end cover assembly10described above. The battery cell is accommodated in the box body21, and the end cover assembly10is covered on the box body21. By providing the end cover assembly10, reliability of the battery20during operation can be improved. The energy storage device30includes at least one battery20. For example, the energy storage device30includes multiple batteries20, so that the energy storage device30can be used to store energy. The electric system40includes the above energy storage device30. The energy storage device30may be, for example, a battery pack, a battery cluster, an energy storage cabinet, and the like. The electric system40includes a load and the energy storage device30. The energy storage device30stores power for the load. The electric system40may be, for example, an electric vehicle or the like.

The technical features of the above embodiments can be combined arbitrarily. In order to make the description simple, not every possible combination of the technical features in the above embodiments is described. However, as long as there is no conflict between the combinations of the technical features, any combination of the technical features may be considered as falling in the scope of this specification.

The above embodiments illustrate merely some implementations of the present disclosure. Although description of the above embodiments is specific and detailed, the description may not be construed as limitations on the scope of the present disclosure. It may be pointed out that, various modifications and improvements can be made by those skilled in the art without departing from the concept of the embodiments of the present disclosure, and shall fall within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be as defined by the claims as attached.