Battery and energy storage equipment

Abstract

The utility model provides a battery and energy storage equipment, and relates to the technical field of energy storage, a shell of the battery comprises an upper cover, a side wall and a bottom wall, the side wall comprises a folded edge located at the end, close to the upper cover, of the side wall, the folded edge extends towards one side of an inner cavity of the shell, the upper cover and the folded edge are stacked, and the side wall is welded to the upper cover through the folded edge. The side wall of the battery is welded with the upper cover through the folded edge, so that when the battery is in thermal runaway, even if the side wall is deformed due to large acting force, the folded edge and the upper cover can still be kept in a laminated and attached state, and the direction of force borne by a welding pool formed by welding the folded edge and the upper cover is still consistent with the extending direction of the folded edge; therefore, a welding pool of the folded edge and the upper cover can be prevented from being subjected to shear stress, and the welding pool formed by welding the upper cover and the folded edge is prevented from cracking or breaking, so that the safety performance of the battery is improved, and the risk of combustion or explosion of the battery is reduced.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and more particularly to a battery and energy storage device. Background Technology

[0002] With the development of battery technology, the development of large-capacity batteries has received great attention. However, due to their large capacity, large-capacity batteries generate more gas during thermal runaway, and the battery casing expands relatively much. This greatly increases the probability of weld cracking on the battery casing cover. Cracks in the weld seam of the casing cover can lead to a large amount of electrolyte spraying in random directions and the core flying out, making the battery pack containing the battery at risk of arcing, fire, or even explosion. Utility Model Content

[0003] The embodiments of this application provide a battery and an energy storage device to solve the problem of weld cracking in the battery casing cover and improve the battery's safety performance.

[0004] In a first aspect, embodiments of this application provide a battery, which includes a casing and a battery cell housed within the casing. The casing includes a bottom wall, multiple side walls, and a top cover. The bottom wall and the top cover are opposite each other in the height direction of the battery, and are located at opposite ends of the multiple side walls in the height direction of the battery. For any one of the multiple side walls, the side wall includes a folded edge located at the top of the side wall in the height direction of the battery; that is, any one of the multiple side walls includes the aforementioned folded edge. The folded edge extends toward the side where the inner cavity of the casing is located, that is, the folded edge extends along the side wall toward the inner cavity of the casing. Here, the direction of the side wall toward the inner cavity of the casing refers to the direction in which the portion of the side wall without the folded edge faces the inner cavity of the casing. The projection of the folded edge and the top cover in the height direction of the battery overlaps, and the folded edge and the top cover are welded together.

[0005] In this embodiment, since the sidewall is welded to the top cover by a folded edge, and the folded edge extends toward the side where the inner cavity of the housing is located, that is, the extension direction of the folded edge is parallel to the top cover, and the projections of the folded edge and the top cover overlap in the height direction of the battery, the welding of the folded edge and the top cover can include the following two welding methods: the first is to weld the edge of the folded edge to the surface of the top cover away from the inner cavity of the housing, and the second is to weld the circumferential edge of the top cover to the surface of the folded edge away from the inner cavity of the housing. Both the first and second welding methods can effectively change the force on the weld seam when the battery is thermally runaway, so as to avoid the weld seam of the top cover and the folded edge from cracking.

[0006] Specifically, for the first welding method, since the edge of the folded edge is welded to the surface of the top cover away from the inner cavity of the casing, the weld pool formed by the folded edge and the top cover is arranged in a direction parallel to the top cover. When the battery experiences thermal runaway, the sidewall will deform first due to its thinness, and the deformation direction will be parallel to the top cover. Since the weld pool of the folded edge and the top cover is arranged in a direction parallel to the top cover, when the sidewall deforms, a tensile force will be applied to the folded edge in a direction parallel to the top cover. The folded edge will also apply a tensile force parallel to the top cover to the weld pool of the folded edge and the top cover. However, the tensile strength of the weld pool is usually large enough, so the weld between the top cover and the folded edge is basically impossible to be pulled apart. Therefore, when the battery experiences thermal runaway, the weld between the top cover and the folded edge can be prevented from cracking, thus improving the battery's safety performance. Furthermore, since the folded edge is located on the side of the top cover away from the inner cavity of the casing, the folded edge can also restrict the movement of the top cover along the height direction of the battery. When the top cover is subjected to an upward pushing force, it will drive the top cover and the folded edge to remain in a close fit. This can prevent the weld pool formed by the folded edge and the top cover from being subjected to shear stress, thereby preventing the weld pool formed by the folded edge and the top cover from cracking or breaking, improving the safety performance of the battery, and reducing the risk of the battery burning or exploding.

[0007] For the second welding method, since the top cover is usually thicker than the sidewalls, the sidewalls typically deform more significantly during battery thermal runaway, while the top cover deforms less, or even negligibly. By placing the top cover on the surface of the folded edge facing away from the inner cavity of the casing, and welding the circumferential edge of the top cover to the surface of the folded edge facing away from the inner cavity of the casing, the weld pool between the folded edge and the top cover can be arranged parallel to the top cover. During battery thermal runaway, the sidewall deforms in a direction parallel to the top cover. Thus, when the sidewall deforms, it applies a tensile force parallel to the top cover to the folded edge. The folded edge applies a tensile force parallel to the top cover to the weld pool between the folded edge and the top cover. However, the tensile strength of the weld pool is usually high enough that the weld between the top cover and the folded edge is virtually impossible to pull apart. Therefore, during battery thermal runaway, cracking of the weld between the top cover and the folded edge can be avoided, improving battery safety performance.

[0008] In some embodiments, multiple sidewalls are sequentially connected to form a frame. The frame has a top opening and a bottom opening, with folded edges on the sidewalls forming the top opening. The bottom wall is located at the bottom of the frame to close the bottom opening. A top cover is located inside the frame, sealing the side of the folded edge facing the inner cavity of the housing to close the top opening. By placing the top cover inside the frame, with the folded edge located on the side of the top cover away from the inner cavity of the housing, and the top cover and the folded edge overlapping in the height direction, the top cover can seal the side of the folded edge facing the inner cavity of the housing to close the top opening of the frame. The folded edge can limit the top cover in the height direction of the battery, effectively preventing the top cover from detaching from the frame and preventing separation between the top cover and the sidewalls. Moreover, since the folded edge has a certain limiting effect on the top cover, it can effectively reduce or avoid the stress on the weld pool between the folded edge and the top cover in the height direction of the battery during thermal runaway, thereby reducing the risk of weld cracking between the top cover and the folded edge.

[0009] In some embodiments, the edge of the folded edge extending in the direction of extension is welded to the surface of the top cover away from the inner cavity of the housing to form a weld pool, and the arrangement direction of the weld pool and the folded edge is parallel to the top cover. Specifically, the sidewall also includes a sidewall body extending in the same direction as the height direction of the battery. The folded edge extends from the end of the sidewall body near the top cover in a direction away from the sidewall body, and the edge of the folded edge away from the sidewall body is welded to the surface of the top cover away from the inner cavity of the housing to form a weld pool. It can be understood that the extension direction of the folded edge is parallel to the direction of the top cover. In this embodiment, since the arrangement direction of the weld pool and the folded edge is parallel to the top cover, based on mechanical analysis, if cracking of the weld pool at the welding position of the top cover and the folded edge is to be caused, the angle formed between the folded edge and the top cover needs to be increased, causing the weld between the top cover and the folded edge to bend, that is, for the weld pool to bend. In this embodiment, when the battery experiences thermal runaway, since only the sidewall deforms, the angle between the folded edge of the sidewall and the main body of the sidewall increases relatively. This allows the top cover and the folded edge to remain relatively stationary, meaning that the weld between the top cover and the folded edge will not bend, and the weld pool will not bend either. Instead, the weld pool is only subjected to the tensile force of the folded edge in the direction parallel to the top cover. Due to the high tensile strength of the weld pool, cracking of the weld pool between the top cover and the folded edge is prevented, ensuring safety performance during battery thermal runaway.

[0010] In some embodiments, the battery also includes a support member located within the housing cavity and close to the sidewall, specifically in contact with the sidewall. Because the support member is in contact with the sidewall, underutilized space within the housing near the sidewall can be effectively utilized. One end of the support member along its length is located on the bottom wall, and the other end extends to the top cover. Supported between the bottom wall and the top cover by the support member, the top cover can be placed within the frame first, and its position defined by the support member, before the sidewall folds are processed. Because the top cover is limited by the support member, the processing of the sidewall folds can be more precise and convenient. For example, when forming the sidewall folds by rolling, the limitation by the support member prevents the folds from pressing against the top cover and consequently other components within the housing.

[0011] In some embodiments, multiple sidewalls are sequentially connected to form a frame, and the folded edges on the multiple sidewalls form the top opening of the frame. The top cover seals the side of the folded edge away from the inner cavity of the housing to close the top opening. The circumferential edge of the top cover is located on the surface of the folded edge away from the inner cavity of the housing. The circumferential edge of the top cover is welded to the surface of the folded edge away from the inner cavity of the housing to form a weld pool. The arrangement direction of the weld pool and the top cover is parallel to the top cover. In this embodiment, since the thickness of the top cover is usually relatively large, the deformation of the top cover is small when the battery experiences thermal runaway, and there is basically no relative bending between the top cover and the folded edge, that is, there is basically no angle between the top cover and the folded edge. In this embodiment, by welding the circumferential edge of the top cover to the surface of the folded edge away from the inner cavity of the housing, the weld pool formed by the top cover and the folded edge may be subjected to forces in two directions. One of the forces is that when the sidewall deforms, it will drive the folded edge to pull the weld pool in a direction parallel to the top cover, that is, the weld pool will be subjected to a tensile force parallel to the top cover. Another force is the thrust exerted by the gas on the top cover along the height direction of the battery during battery thermal runaway. As a result, the top cover will exert a tensile force on the battery in the height direction. However, the weld pool has a high tensile strength, which can prevent cracking when subjected to the forces in the above two directions, thereby improving the safety of the battery during thermal runaway.

[0012] In some embodiments, the battery further includes a support member located within the inner cavity of the housing and conforming to the side wall. One end of the support member is positioned on the bottom wall along its length, and the other end extends to the folded edge. In this embodiment, the support member is located between the bottom wall and the folded edge, and can be used to support the folded edge. Specifically, when processing the folded edge on the side wall, the support of the support member facilitates the processing of the folded edge. For example, when processing the folded edge by rolling, the support of the support member makes it easier to form the folded edge accurately. After the folded edge processing is completed, the top cover can be welded to the folded edge to achieve housing encapsulation.

[0013] In some embodiments, the support member, top cover, and folded edge project overlapping in the height direction of the battery. Because the support member, top cover, and folded edge project overlapping in the height direction of the battery, the folded edge and top cover can avoid excessive deformation when subjected to forces in the height direction of the battery through the support member, ensuring the assembly accuracy of the top cover and folded edge, and reducing the processing difficulty of the battery casing.

[0014] In some embodiments, there are four supports, located at the four corners of the housing cavity. Since the space at the four corners of the housing cavity is often not fully utilized, setting the number of supports to four not only provides sufficient support for the top cover or folded edge, but also effectively utilizes the space at the four corners of the housing cavity, reducing the impact on the layout of the battery housing structure.

[0015] In some embodiments, the sidewalls and bottom wall can be integrally formed, for example, by die casting. In other embodiments, they can also be connected by bending sheet metal.

[0016] In some embodiments, the battery also includes an explosion-proof valve located on the top cover. Because of the explosion-proof valve on the top cover, pressure can be released promptly in the event of thermal runaway, preventing the battery from burning and exploding. In this embodiment, by preventing cracking of the weld between the top cover and the side wall, the explosion-proof valve can more effectively achieve its purpose of reasonable pressure release, effectively preventing the uncontrolled leakage of electrolyte and other substances inside the battery, thereby improving the battery's safety performance during thermal runaway.

[0017] In some embodiments, the thickness of the top cover is greater than the thickness of the sidewalls. This is because the battery casing needs to be designed with strength and safety in mind. The top cover, as a crucial component of the battery, plays a vital role in sealing and protecting the internal cells. To ensure that the battery does not leak or explode due to external pressure or internal gas expansion during use, the top cover typically needs to have higher strength and better sealing performance. Therefore, the thickness of the top cover usually needs to be greater than the sidewalls to provide additional protection. Secondly, from a structural mechanics perspective, the top cover needs to withstand more stress concentration. Therefore, increasing the thickness of the top cover helps to mitigate stress concentration, improving battery safety and lifespan.

[0018] Secondly, embodiments of this application provide an energy storage device, including a housing and a battery as described in any of the first aspects above, wherein the battery is disposed within the housing.

[0019] In some embodiments, the energy storage device may be a battery pack, an energy storage cabinet, or a vehicle powered by electricity. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0021] Figure 1 This is a simplified diagram of a battery casing in the related art;

[0022] Figure 2 This is a schematic diagram of the structure of a battery pack provided in an embodiment of this application;

[0023] Figure 3 This is a schematic diagram of the structure of a battery provided in an embodiment of this application;

[0024] Figure 4 for Figure 3 A schematic diagram showing the welding between the top cover and the side wall of the battery.

[0025] Figure 5 for Figure 3 An exploded view of the battery in the embodiment;

[0026] Figure 6 A schematic diagram of the welding between the top cover and the side wall of another battery provided in an embodiment of this application;

[0027] Figure 7 This is a schematic diagram of the welding between the top cover and the side wall of another battery provided in an embodiment of this application.

[0028] Explanation of reference numerals in the attached figures:

[0029] 1. Battery pack; 2. Casing; 3. Battery;

[0030] 10. Shell; 101. Shell cavity; 11. Side wall; 111. Side wall body; 112. Folded edge; 113. Second folded edge; 12. Top cover; 13. Bottom wall; 14. Frame; 141. Top opening; 142. Bottom opening;

[0031] 20. Battery cells;

[0032] 31. Positive terminal; 32. Negative terminal; 33. Explosion-proof valve;

[0033] 40. Support components;

[0034] a. Welding pool. Detailed Implementation

[0035] The following section will first explain some of the terms used in the embodiments of this application.

[0036] The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0037] In this specification, the terms "vertical" and "parallel" are explained.

[0038] Perpendicularity: The perpendicularity defined in this application is not limited to an absolute perpendicular intersection (with an included angle of 90 degrees). It is permissible for non-absolute perpendicular intersections caused by factors such as assembly tolerances, design tolerances, and structural flatness. It is permissible for errors within a small angular range, such as an assembly error range of 80 to 100 degrees, which can all be understood as a perpendicular relationship.

[0039] Parallelism: The parallelism defined in this application is not limited to absolute parallelism. This definition of parallelism can be understood as basic parallelism, allowing for situations where the parallelism is not absolute due to factors such as assembly tolerances, design tolerances, and structural flatness. These situations may lead to the sliding mating part and the first door panel not being absolutely parallel, but this application also defines such situations as parallelism.

[0040] Modern society is filled with a vast array of devices that rely on electricity, from small household appliances to large data centers and factory production lines. Electricity supply is a crucial factor in maintaining the normal operation of modern society. Therefore, energy storage devices have developed rapidly and are widely used. These devices include battery packs, energy storage cabinets using battery packs, uninterruptible power supply (UPS) cabinets, and even vehicles using battery packs. Energy storage devices can be used to store electrical energy and supply power to equipment that requires electricity. Applications include site energy, photovoltaics, residential energy storage, industrial and commercial energy storage, and large-scale ground-mounted power plant energy storage.

[0041] Energy storage devices typically consist of multiple batteries. If one battery experiences thermal runaway and subsequently catches fire or explodes, it can cause other batteries to catch fire or explode as well. For example... Figure 1 This is a simplified diagram of a battery casing 10 in the related art, with reference to... Figure 1The battery casing 10 includes a side wall 11 and a top cover 12. The side wall 11 and the top cover 12 are arranged vertically. The edge of the side wall 11 facing the top cover 12 is welded to the edge of the top cover 12 to form a weld pool a. However, as the battery capacity increases, a large amount of gas will be generated when the battery runs away from thermal control. This will cause the side wall 11 of the casing 10 to be pushed outward perpendicular to the side wall 11, causing the side wall 11 of the casing 10 to deform. The direction of the deformation of the side wall 11 is perpendicular to the side wall 11, that is, parallel to the top cover 12. After the side wall 11 is subjected to thrust, the weld pool a at the welding position between the top cover 12 and the side wall 11 is subjected not only to normal stress in the first direction, but also to shear stress in the second direction, and even bending stress due to the bending of the side wall 11. When subjected to these forces, the probability of the weld pool a between the top cover 12 and the side wall 11 breaking or cracking increases significantly. Cracking of the weld between the top cover 12 and the side wall 11 will cause a large amount of electrolyte to spray out in random directions and the core to fly out. This will not only cause thermal runaway of other batteries, but also easily cause other batteries to arc and catch fire or even explode, which greatly reduces the safety performance of the energy storage device.

[0042] In view of this, refer to Figure 2 This application provides an energy storage device with a long service life and a good user experience, for example, an energy storage device as... Figure 1 Taking the battery pack 1 in the embodiment as an example, the battery pack 1 includes a shell 2 and a plurality of batteries 3 disposed inside the shell 2. The plurality of batteries 3 are arranged inside the shell 2 to store electrical energy or release electrical energy.

[0043] In order to reduce the probability of battery pack 1 burning or exploding and improve the safety performance of battery pack 1, this embodiment reduces the probability of weld cracking of battery 3 in battery pack 1, thereby reducing the risk of arcing of battery 3, and thus reducing the probability of battery pack 1 burning or exploding, thereby improving the safety performance of battery pack 1.

[0044] Figure 3 This is a schematic diagram of the structure of a battery 3 provided in an embodiment of this application. The inner cavity 101 of the casing, the battery cell 20, etc., mentioned in this embodiment can all be referred to... Figure 5 , Figure 3 Not shown.

[0045] Reference Figure 3 The battery 3 includes a casing 10 and a battery cell 20 housed within the casing 10 (e.g., ...). Figure 5The housing 10 includes a bottom wall 13, a top cover 12, and multiple side walls 11, with the top cover 12 and bottom wall 13 located at opposite ends of the side walls 11. Specifically, the multiple side walls 11 enclose a frame 14, with the top cover 12 located at the top of the frame 14 and used to close the top opening 141 of the frame 14, and the bottom wall 13 located at the bottom of the frame 14 and used to close the bottom opening 142 of the frame 14. The top cover 12, the frame 14, and the bottom wall 13 together form an inner cavity 101 for housing the battery cell 20 (e.g., ...). Figure 5 For ease of description, the direction in which the top cover 12 and the bottom wall 13 face each other is defined as the height direction of the battery 3, which is also the Z direction in the attached figure. The Z direction in the following text also represents the height direction of the battery 3.

[0046] In some embodiments, the multiple sidewalls 11 and the bottom wall 13 are integrally formed, such as by die casting, to reduce welding points and improve the toughness of the connections between the multiple sidewalls 11 and between the multiple sidewalls 11 and the bottom wall 13, thereby reducing the risk of cracking or breakage at the connections between the multiple sidewalls 11 and between the multiple sidewalls 11 and the bottom wall 13.

[0047] The top cover 12 is provided with a positive terminal 31 and a negative terminal 32, which are used to connect to the battery cell 20.

[0048] The top cover 12 is also equipped with an explosion-proof valve 33. With the setting of the explosion-proof valve 33, when the battery 3 experiences thermal runaway, the pressure can be released in time through the explosion-proof valve 33 to prevent the air pressure inside the housing 10 from being too high, thereby reducing the problem of the weld between the top cover 12 and the side wall 11 cracking due to excessive air pressure inside the housing 10.

[0049] Reference Figure 3 In some embodiments, for any one of the plurality of sidewalls 11, each sidewall 11 includes a flange 112 located at the top of the sidewall 11, that is, the flange 112 is located at the end of the sidewall 11 facing the top cover 12. The flange 112 extends toward the side of the housing cavity 101, that is, the direction in which the flange 112 extends is the direction in which the sidewall 11 faces the housing cavity 101.

[0050] Specifically, for each of the multiple sidewalls 11, a sidewall 11 includes a sidewall body 111 and a flange 112. The extension direction of the body is consistent with the height direction of the battery 3, that is, the body is approximately perpendicular to the bottom wall 13 or the top cover 12. The direction of the sidewall 11 toward the inner cavity 101 of the housing is also the direction of the body toward the inner cavity 101 of the housing, that is, the direction perpendicular to the sidewall body 111 and away from the sidewall body 111. In other words, the flange 112 is formed by extending from the top edge of the sidewall body 111 toward a direction away from the sidewall body 111. Since the flange 112 is formed by bending the sidewall 11 and is part of the sidewall 11, the connection between the sidewall body 111 and the flange 112 has strong toughness. When the sidewall body 111 or the flange 112 is subjected to a large thrust, the included angle between the sidewall body 111 and the flange 112 may become larger, but it can still prevent the connection between the sidewall body 111 and the flange 112 from cracking or breaking.

[0051] Reference Figure 3 The top cover 12 and the folded edge 112 are stacked on the height Z direction of the battery 3, and the folded edge 112 is located on the outside of the top cover 12, that is, on the side of the top cover 12 away from the inner cavity 101 of the housing. Specifically, the top opening 141 of the frame 14 is formed by the folded edges 112 on multiple side walls 11, and the top opening 141 of the frame 14 can be closed by the cooperation of the top cover 12 and the folded edge 112. Since the folded edge 112 is located on the side of the top cover 12 away from the inner cavity 101 of the housing, the movement of the top cover 12 can be restricted in the height direction of the battery 3 by the folded edge 112, so as to prevent the top cover 12 from separating from the side wall 11 and improve the stability of the connection between the top cover 12 and the side wall 11.

[0052] Figure 4 for Figure 3 A schematic diagram of the welding between the top cover 12 and the side wall 11 of the middle battery 3.

[0053] Reference Figure 4In some embodiments, the top cover 12 and the folded edge 112 are welded. Specifically, the edge of the folded edge 112 away from the side wall body 111 is welded to the surface of the top cover 12 away from the inner cavity 101 of the housing, forming a weld pool a. The weld pool a is located at the edge of the folded edge 112 away from the side wall body 111, and the arrangement direction of the weld pool a and the folded edge 112 is parallel to the top cover 12. In this embodiment, when the battery 3 experiences thermal runaway and releases a large amount of gas inside the casing 10, the upper cover 12, being relatively thick, undergoes less deformation and has a smaller impact on the stress on the weld pool a. However, the side wall 11, being relatively thin, undergoes greater deformation due to the impact of the gas. The direction of the deformation of the side wall 11 is perpendicular to the side wall 11 and away from the inner cavity 101 of the casing. Since the folded edge 112 is formed by bending the side wall 11, the connection between the folded edge 112 and the side wall body 111 has greater toughness. After the side wall 11 deforms, the included angle between the side wall body 111 and the folded edge 112 will increase, without cracking or breaking. When the side wall 11 deforms, it will cause the flange 112 to pull the weld pool a along the extension direction of the flange 112, that is, to pull the weld pool a along the direction parallel to the upper cover 12. In other words, the weld pool a formed by welding the upper cover 12 and the flange 112 is still only subjected to normal stress parallel to the upper cover 12 when the side wall 11 deforms. Figure 4 In the X direction, it will not be subjected to shear stress that is more damaging to the weld pool a. Therefore, even if the side wall 11 deforms when the battery 3 experiences thermal runaway, the weld between the top cover 12 and the folded edge 112 will not crack or break. This will prevent electrolyte and other impurities from spraying out from the non-explosion-proof valve 33, thereby reducing the impact on other batteries 3, reducing the risk of battery 3 burning and exploding, and improving the safety performance of battery 3.

[0054] Even in certain special scenarios, the top cover 12 is relatively thin and deforms. Since the folded edge 112 is located on the side of the top cover 12 away from the inner cavity 101 of the housing, and the force on the top cover 12 is perpendicular to the top cover 12 and away from the inner cavity 101 of the housing, the top cover 12 will still be in close contact with the folded edge 112 even if it deforms. The weld pool a formed by welding the top cover 12 and the folded edge 112 can only be subjected to normal stress consistent with the extension direction of the top cover 12 (the extension direction of the folded edge 112), which will not cause the weld pool a to crack or break. The connection stability between the top cover 12 and the side wall 11 can still be guaranteed, and the safety of the battery 3 can be improved. It is understandable that when the upper cover 12 and the folded edge 112 are no longer in contact, the weld pool a formed by the welding of the upper cover 12 and the folded edge 112 will be subjected to shear stress. Since the upper cover 12 and the folded edge 112 can always be kept in contact in this embodiment, the weld pool a formed by the welding of the upper cover 12 and the folded edge 112 can be prevented from being subjected to shear stress.

[0055] In addition, since the folded edge 112 of the side wall 11 is located on the side of the top cover 12 away from the inner cavity 101 of the housing, when the battery 3 thermally runs away, the folded edge 112 can restrict the top cover 12 from moving upward when it is subjected to an outward impact. Since the folded edge 112 can offset a large part of the force that restricts the upward movement of the top cover 12, the weld pool a will basically no longer be subjected to stress in the Z direction, thereby reducing the risk of cracking or breaking of the weld pool a.

[0056] Reference Figure 4 In some embodiments, the battery 3 further includes a support member 40, which is located within the inner cavity 101 of the housing and fits against the side wall 11. One end of the support member 40 in the longitudinal direction is located on the bottom wall 13, and the other end of the support member 40 in the longitudinal direction extends to the top cover 12. By positioning the support member 40 between the bottom wall 13 and the top cover 12, the top cover 12 can be supported by the support member 40, thereby allowing for precise control of the space within the inner cavity 101 of the housing. In addition, by supporting the top cover 12 by the support member 40, the formation of the top folded edge 112 of the side wall 11 can be facilitated. For example, during bending, the support member 40 supports the top cover 12, and the top cover 12 can in turn support the folded edge 112, thus facilitating the processing of the folded edge 112. For example, during the rolling edge process, the support of the top cover 12 on the folded edge 112 facilitates the rolling edge process. In addition, since the support member 40 is supported between the upper cover 12 and the bottom wall 13, when the battery 3 experiences thermal runaway, the deformation of the side wall 11 can be reduced under the support of the support member 40, thereby reducing the tensile force on the folded edge 112 in the X direction, reducing the magnitude of the normal stress in the X direction of the weld pool a formed by welding the folded edge 112 and the upper cover 12, and thus reducing the risk of cracking of the weld pool a formed by welding the folded edge 112 and the upper cover 12.

[0057] Reference Figure 4 In some embodiments, the support member 40, the top cover 12 and the folded edge 112 overlap in the Z direction. Under the support of the support member 40, the top cover 12 and the folded edge 112 can be kept in a close fit when the battery 3 experiences thermal runaway. This reduces the risk of shear stress on the weld pool a at the welding position of the top cover 12 and the folded edge 112, thereby improving the connection stability of the top cover 12 and the folded edge 112.

[0058] Reference Figure 4In some embodiments, the thickness L1 of the top cover 12 is greater than the thickness L2 of the side wall 11. Since the casing 10 of the battery 3 needs to consider both strength and safety in its design, the top cover 12, as an important component of the battery 3, plays a crucial role in sealing and protecting the internal battery cells 20. To ensure that the battery 3 does not leak or explode due to external pressure or internal gas expansion during use, the top cover 12 typically needs to have higher strength and better sealing performance. Therefore, the thickness L1 of the top cover 12 usually needs to be larger than the thickness L2 of the side wall 11 to provide additional protection. Secondly, from a structural mechanics perspective, the top cover 12 needs to withstand more stress concentration. Therefore, increasing the thickness L1 of the top cover 12 is beneficial for mitigating stress concentration and improving the safety and lifespan of the battery 3.

[0059] Figure 5 for Figure 3 An exploded view of battery 3 in the embodiment.

[0060] Reference Figure 5 In some embodiments, there are four support members 40, which are located at the four corners of the inner cavity 101 of the housing. For the battery 3 with a square housing 10, by providing support members 40 at the four corners of the inner cavity 101 of the housing, the four corners of the top cover 12 can be supported by the four support members 40, thereby ensuring the stability of the top cover 12 when it is subjected to pressure from the folded edges 112 of the multiple side walls 11.

[0061] In addition, since the four corners of the inner cavity 101 of the housing are usually not fully utilized, the four support members 40 are set at the four corners of the inner cavity 101 of the housing. This can make full use of the space at the four corners of the inner cavity 101 of the housing. Not only will it not affect the layout of other components (such as the battery cell 20) in the inner cavity 101 of the housing, but on the contrary, the four support members 40 can also provide support for the battery cell 20 and the like, thereby improving the stability of the battery cell 20 relative to the housing 10.

[0062] Reference Figure 5 In some embodiments, the support member 40 has a columnar structure, specifically a cylindrical structure, a square columnar structure, or a columnar structure of other shapes.

[0063] It is understandable that the four columnar support members 40 can also be replaced by two plate-shaped support members 40.

[0064] In some embodiments, the support member 40 is integrally formed with the housing 10; in other embodiments, the support member 40 and the housing 10 may be bonded or welded together.

[0065] Reference Figure 5In some embodiments, the battery cell 20 is a wound core. It is understood that in other embodiments, the battery cell 20 may also be a stacked structure.

[0066] Figure 6 This is a schematic diagram of the welding between the top cover 12 and the side wall 11 of another battery provided in an embodiment of this application. Figure 6 Compared to the example Figure 4 The main difference in the embodiments is that the relative positions of the top cover 12 and the folded edge 112 are different. Figure 4 The top cover 12 is located below the folded edge 112. Figure 6 The folded edge 112 is located below the top cover 12.

[0067] Reference Figure 6 In some embodiments, the folded edge 112 is located on the side of the upper cover 12 closest to the inner cavity 101 of the housing. To facilitate welding of the upper cover 12 and the folded edge 112, the overall area of ​​the upper cover 12 is smaller than the area enclosed by the outermost edge of the folded edge 112. That is, when the upper cover 12 is placed on the folded edge 112, the circumferential edge of the upper cover 12 is located on the surface of the folded edge 112 away from the inner cavity 101 of the housing, and the circumferential edge of the upper cover 12 is welded to the surface of the folded edge 112 away from the inner cavity 101 of the housing, forming a weld pool a. In this embodiment, during battery thermal runaway, the sidewall 11 deforms, and the direction of deformation is the X direction (same as above). Figure 4 In the embodiment, that is, the extension direction of the folded edge 112 and the upper cover 12, the side wall 11 drives the folded edge 112 to pull the upper cover 12 and the weld pool a formed by welding the folded edge 112 in the X direction, so the weld pool a formed by welding the upper cover 12 and the folded edge 112 will be subjected to normal stress in the X direction. In addition, since the upper cover 12 will be subjected to thrust in the Z direction, the upper cover 12 will apply a normal stress in the Z direction to the weld pool a formed by welding the upper cover 12 and the folded edge 112. However, since the upper cover 12 and the folded edge 112 are stacked, when the side wall body 111 deforms, the angle between the side wall body 111 and the folded edge 112 will increase, so as to ensure that the folded edge 112 and the upper cover 12 can always maintain a parallel and close state. Therefore, when the battery undergoes thermal runaway and the side wall 11 deforms, the weld pool a formed by welding the upper cover 12 and the folded edge 112 can still avoid being subjected to shear stress. When the weld pool a formed by welding the top cover 12 and the folded edge 112 is subjected to only normal stress and not shear stress, the risk of breakage or cracking at the welding position of the top cover 12 and the folded edge 112 can be effectively reduced, the risk of battery combustion or explosion can be reduced, and the safety performance of the battery can be effectively improved.

[0068] Reference Figure 6In some embodiments, one end of the support member 40 extends to the bottom wall 13 along its length, and the other end extends to the folded edge 112. By limiting this end with the support member 40, the length of the folded edge 112 in the extension direction can be precisely controlled. Moreover, the support of the support member 40 facilitates the processing of the folded edge 112 and reduces its processing difficulty. In addition, since the support member 40 supports the folded edge 112 and the bottom wall 13, it can effectively reduce the deformation of the side wall 11, thereby reducing the tensile force on the folded edge 112 in the X direction, reducing the magnitude of the normal stress in the X direction of the weld pool a formed by welding the folded edge 112 and the top cover 12, and thus reducing the risk of cracking of the weld pool a formed by welding the folded edge 112 and the top cover 12.

[0069] It should be noted that, Figure 6 In the embodiment, the thickness L1 of the top cover 12 is greater than the thickness L2 of the side wall 11. The strength of the top cover 12 is high enough to minimize the deformation of the top cover 12, so that the top cover 12 and the folded edge 112 fit together as closely as possible, thereby reducing the shear stress on the weld pool a at the welding position of the top cover 12 and the folded edge 112.

[0070] Figure 7 This is a schematic diagram of the welding between the top cover 12 and the side wall 11 of another battery provided in an embodiment of this application. Figure 7 The solution in the embodiments is compared to Figure 4 The main difference lies in the connection method between the bottom wall 13 and the side wall 11. Figure 4 The bottom wall 13 and the plurality of side walls 11 in the embodiment can be a one-piece molded design. Figure 7 In the embodiment, the bottom wall 13 and the multiple side walls 11 are connected by welding.

[0071] To prevent cracking or breakage at the welded joint between the bottom wall 13 and the side wall 11, refer to Figure 7 In some embodiments, for each of the plurality of sidewalls 11, the plurality of sidewalls 11 include a folded edge located at the bottom of the sidewall 11. In order to distinguish it from the folded edge 112 at the top of the sidewall 11 mentioned above, the folded edge at the bottom of the sidewall 11 is defined as the second folded edge 113. The second folded edge 113 is located at the end of the sidewall 11 near the bottom wall 13. Specifically, the second folded edge 113 is located at the end of the sidewall body 111 near the bottom wall 13. The second folded edge 113 extends from the edge of the sidewall body 111 considering the bottom wall 13 toward the side of the housing cavity 101. The extension direction of the second folded edge 113 is the same as the extension direction of the folded edge 112 located at the top of the sidewall 11 mentioned above.

[0072] Multiple second flanges 113 form a bottom opening 142 of the frame 14. The bottom wall 13 is located on the side of the multiple second flanges 113 closest to the inner cavity 101 of the housing, and closes the bottom opening 142 of the frame 14. The edges of the second flanges 113 away from the sidewall body 111 are welded to the surface of the bottom wall 13 opposite to the inner cavity 101 of the housing, forming a weld pool a. Figure 4 The principle behind the welded joints of the folded edge 112 and the top cover 12 in this embodiment being less prone to cracking is the same. In this embodiment, since the second bend is part of the side wall 11 and is formed by bending from the bottom of the side wall 11, when the battery experiences thermal runaway and the side wall 11 deforms, the angle between the second folded edge 113 and the side wall body 111 will increase. This will cause the second folded edge 113 to exert a tensile force in the same direction as the extension of the second folded edge 113 on the weld pool a formed by welding the second folded edge 113 and the bottom wall 13, i.e., a normal stress in the X direction. Apart from this, the weld pool a formed by welding the second folded edge 113 and the bottom wall 13 will not be subjected to other forces, including shear stress. Therefore, when the battery experiences thermal runaway, the weld pool a formed by welding the bottom wall 13 and the second folded edge 113 can be effectively prevented from cracking or breaking, thus improving the battery's safety performance.

[0073] Furthermore, since the second fold 113 is located on the outside of the bottom wall 13, when the battery experiences thermal runaway, the bottom wall 13 is subjected to a thrust in the Z direction, which will cause the bottom wall 13 and the second fold 113 to fit tightly together. This can effectively prevent the weld pool a formed by the welding of the bottom wall 13 and the second fold 113 from being subjected to shear stress, thereby effectively improving the safety of the battery.

[0074] Reference Figure 7 In some embodiments, one end of the support member 40 extends to the bottom wall 13 in the length direction, and the other end of the support member 40 extends to the top cover 12. Through the supporting effect of the support member 40, the bottom wall 13 and the second folded edge 113 can also be tightly fitted together to avoid the weld pool a formed by welding the bottom wall 13 and the second folded edge 113 being subjected to shear stress, thereby improving the safety of the battery.

[0075] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A battery, characterized in that, The battery includes a casing and battery cells housed within the casing. The housing includes a bottom wall, multiple side walls, and a top cover. The bottom wall and the top cover are located at opposite ends of the multiple side walls in the height direction of the battery. For any of the multiple side walls, the side wall includes a folded edge located at the top of the side wall in the height direction of the battery. The folded edge extends toward the side where the inner cavity of the housing is located. The folded edge overlaps with the projection of the top cover in the height direction of the battery. The folded edge and the top cover are welded together.

2. The battery according to claim 1, characterized in that, The plurality of sidewalls are connected in sequence to form a frame, and the folded edges on the plurality of sidewalls form the top opening of the frame. The top cover is located inside the frame and covers the side of the folded edge facing the inner cavity of the housing to close the top opening.

3. The battery according to claim 2, characterized in that, The sidewall also includes a sidewall body extending in the same direction as the height of the battery. The folded edge extends from one end of the sidewall body near the top cover toward a direction away from the sidewall body. The edge of the folded edge away from the sidewall body is welded to the surface of the top cover away from the inner cavity of the housing to form a weld pool.

4. The battery according to claim 2 or 3, characterized in that, The battery also includes a support member located inside the housing cavity and attached to the side wall. One end of the support member in the length direction is located on the bottom wall, and the other end of the support member in the length direction extends to the top cover.

5. The battery according to claim 1, characterized in that, The multiple sidewalls are connected in sequence to form a frame. The folded edges on the multiple sidewalls form the top opening of the frame. The top cover covers the side of the folded edge that is away from the inner cavity of the housing to close the top opening. The circumferential edge of the top cover is located on the surface of the folded edge that is away from the inner cavity of the housing. The circumferential edge of the top cover is welded to the surface of the folded edge that is away from the inner cavity of the housing.

6. The battery according to claim 5, characterized in that, The battery also includes a support member located inside the housing cavity and close to the side wall. One end of the support member in the length direction is located on the bottom wall, and the other end of the support member in the length direction extends to the folded edge.

7. The battery according to claim 4 or 6, characterized in that, In the height direction of the battery, the support member, the top cover, and the folded edge project overlapping.

8. The battery according to claim 7, characterized in that, The number of the support members is four, and the four support members are respectively located at the four corners of the inner cavity of the housing.

9. The battery according to claim 1, characterized in that, The battery also includes an explosion-proof valve disposed on the top cover, the thickness of which is greater than the thickness of the side wall.

10. An energy storage device, characterized in that, It includes a housing and a battery as described in any one of claims 1-9, wherein the battery is disposed within the housing.

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