Battery monomer, battery device and power utilization device

Abstract

The utility model discloses a battery monomer, a battery device and a power utilization device, the battery monomer comprises an end cover and a steel shell, an electrode assembly is accommodated in the steel shell, the steel shell comprises an extension side wall, the extension direction of the extension side wall is consistent with the extension direction of an electrode slice in the electrode assembly, and the end part of the extension side wall is welded with the end cover to form a welding area; the thickness range of the extending side wall is 0.5-3 mm, the extending side wall comprises a reinforcing area and a main body area, the welding area, the reinforcing area and the main body area are sequentially connected in the extending direction of the extending side wall, the thickness of the reinforcing area is different from that of the main body area, and the thickness of at least part of the main body area is smaller than that of the reinforcing area. According to the technical scheme provided by the embodiment of the invention, the probability of cracking at the welding position between the end cover and the steel shell can be reduced.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and particularly to a battery cell, a battery device, and an electrical device. Background Art

[0002] A battery cell generally includes an end cap and a steel shell, wherein the electrode assembly is accommodated inside the steel shell. In the related art, the end cap and the steel shell are usually connected by welding. During the use of the battery cell, the welded joint between the end cap and the steel shell is prone to cracking. Summary of the Utility Model

[0003] The present application provides a battery cell, a battery device, and an electrical device, which can reduce the probability of cracking at the welded joint between the end cap and the steel shell.

[0004] The present application provides a battery cell. The battery cell includes an end cap and a steel shell, and an electrode assembly is accommodated inside the steel shell. The steel shell includes an extended side wall, and the extending direction of the extended side wall is consistent with the extending direction of the electrode plate in the electrode assembly. The end of the extended side wall is welded to the end cap to form a welding area. The thickness range of the extended side wall is 0.5-3 mm. The extended side wall includes a strengthening area and a main body area. The welding area, the strengthening area, and the main body area are sequentially connected along the extending direction of the extended side wall. The thickness of the strengthening area is different from the thickness of the main body area, and at least part of the thickness of the main body area is less than the thickness of the strengthening area.

[0005] In the technical solution provided by this application, the battery cell includes an end cap and a steel shell, and the electrode assembly is accommodated inside the steel shell. Here, the end cap is arranged at the open end of the steel shell to close the opening. The steel shell provides an accommodation space and protection for the electrode assembly. The steel shell includes an extended side wall, and the extending direction of the extended side wall is the same as that of the electrode sheet in the electrode assembly. The end of the extended side wall is welded to the end cap to form a welding area. Here, the steel shell is welded to the end cap through the end of the extended side wall, so that the end cap and the steel shell jointly enclose a sealed cavity for accommodating the electrode assembly. The thickness range of the extended side wall is 0.5 - 3 mm. In this way, it can not only prevent the extended side wall from affecting the structural strength of the steel shell due to too thin thickness, but also avoid the extended side wall from affecting the internal space of the steel shell due to too thick thickness. The extended side wall includes a strengthening area and a main body area. The welding area, the strengthening area, and the main body area are sequentially connected along the extending direction of the extended side wall. The thickness of the strengthening area is different from that of the main body area, and at least part of the thickness of the main body area is smaller than the thickness of the strengthening area. In this way, by increasing the thickness of the strengthening area on the extended side wall, the thermal insulation performance of the strengthening area can be improved, thereby reducing the influence of high temperature on the structure at the strengthening area and enhancing the toughness and strength at the strengthening area. Compared with the related art, during the welding process between the end cap and the steel shell, a thermally affected weak area is formed near the welding area on the steel shell. In the embodiment of this application, the extended side wall of the steel shell includes a strengthening area, and the strengthening area improves the thermal insulation performance by increasing the thickness, thereby avoiding the formation of a thermally affected weak area on the steel shell and enhancing the toughness and strength at the strengthening area. In this way, when the electrode assembly generates stress on the steel shell due to volume change, the deformation amount at the strengthening area becomes smaller, thereby reducing the probability of cracking at the welding area.

[0006] In some embodiments of this application, the inner wall surface of the strengthening area protrudes from the inner wall surface of the main body area, and / or the outer wall surface of the strengthening area protrudes from the outer wall surface of the main body area.

[0007] In some embodiments of this application, in the extending direction of the extended side wall, the size range of the strengthening area is 1 - 5 mm.

[0008] In some embodiments of this application, the main body area includes a normal part and a transition part. The normal part is connected to the strengthening area through the transition part, and the thickness of the transition part is less than or equal to the thickness of the strengthening area.

[0009] In some embodiments of this application, in the extending direction of the extended side wall, the thickness of the transition part gradually decreases, the thickness of the normal part is uniformly set, and the thickness of the normal part is equal to the minimum thickness of the transition part.

[0010] In some embodiments of this application, in the extending direction of the extended side wall, the thickness of the transition part is uniformly set, the thickness of the normal part gradually decreases, and the maximum thickness of the normal part is equal to the thickness of the transition part.

[0011] In some embodiments of the present application, in the extending direction of the extended sidewall, the thicknesses of the transition part and the ordinary part gradually decrease, and the minimum thickness on the transition part is equal to the maximum thickness on the ordinary part.

[0012] In some embodiments of the present application, the cross-section of the steel shell is rectangular, and at least two electrode sheets are stacked along the length direction of the steel shell. In the width direction of the steel shell, the extended sidewalls are arranged on opposite sides of the steel shell, and the width direction of the steel shell is perpendicular to the extending direction of the extended sidewalls.

[0013] In some embodiments of the present application, the cross-section of the steel shell is rectangular, and the electrode sheets are wound around the steel shell in the circumferential direction. The size of the electrode sheet in the length direction of the steel shell is greater than the size of the electrode sheet in the width direction of the steel shell. In the width direction of the steel shell, the extended sidewalls are arranged on opposite sides of the steel shell, and the length direction of the steel shell, the width direction of the steel shell, and the extending direction of the extended sidewalls are perpendicular to each other.

[0014] In some embodiments of the present application, the electrode assembly is disposed opposite to the main body area of the steel shell, and in the extending direction of the extended sidewall, the size of the electrode assembly is smaller than the size of the main body area.

[0015] In some embodiments of the present application, in the extending direction of the extended sidewall, there are two end caps. One of the two end caps is welded to the first end of the extended sidewall, and the other of the two end caps is welded to the second end of the extended sidewall to form two welding areas. The extended sidewall includes two reinforcing areas arranged at intervals, and the two reinforcing areas are respectively connected to the welding areas corresponding to the respective ends.

[0016] The second aspect of the present application provides a battery device, including a box body and the battery cell according to any one of the first aspect, and the battery cell is installed in the box body.

[0017] In the technical solution of the embodiment of the present application, since the battery device includes the battery cell of the first aspect, therefore, it has the same technical effect. That is, the probability of cracking at the welding joint between the end cap and the steel shell can be reduced.

[0018] The third aspect of the present application provides an electrical device, including an electrical appliance and the battery device of the second aspect, and the battery device is electrically connected to the electrical appliance.

[0019] In the technical solution of the embodiment of the present application, since the battery device includes the battery device of the second aspect, and the battery device further includes the battery cell of the first aspect, therefore, it has the same technical effect. That is, the probability of cracking at the welding joint between the end cap and the steel shell can be reduced. Description of the Drawings

[0020] Upon reading the following detailed description of the preferred embodiments, various other advantages and benefits will become apparent to those of ordinary skill in the art. The drawings are only for the purpose of illustrating the preferred embodiments and are not considered to be a limitation of the present application. Moreover, in all the drawings, the same reference numerals are used to denote the same components. In the drawings:

[0021] Figure 1 Schematic structural diagram of a battery cell provided by an embodiment of the present application (first example);

[0022] Figure 2 is Figure 1 Cross-sectional view taken along line A-A in;

[0023] Figure 3 is Figure 2 Enlarged view at B in;

[0024] Figure 4 Schematic structural diagram of an extended side wall (first example);

[0025] Figure 5 Schematic structural diagram of an extended side wall (second example);

[0026] Figure 6 Schematic structural diagram of a battery cell provided by an embodiment of the present application (first example);

[0027] Figure 7 is Figure 6 Side view (first perspective) of;

[0028] Figure 8 is Figure 7 Cross-sectional view taken along line C-C in;

[0029] Figure 9 is Figure 8 Enlarged view at D in;

[0030] Figure 10 is Figure 8 Enlarged view at E in;

[0031] Figure 11 is Figure 6 Side view (second perspective) of;

[0032] Figure 12 is Figure 11 Enlarged view at F in.

[0033] Explanation of reference numerals:

[0034] 1 - End cap; 11 - Flange; 2 - Steel shell; 21 - Extended side wall; 211 - Reinforcement area; 212 - Main body area; 2121 - Transition part; 2122 - Ordinary part; 3 - Electrode assembly; 4 - Welding area. Detailed implementation manners

[0035] The embodiments of the technical solutions of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solutions of the present application more clearly, so they are only examples and cannot be used to limit the protection scope of the present application.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and the above accompanying drawings are intended to cover non-exclusive inclusion.

[0037] In the description of the embodiments of the present application, technical terms such as "first", "second", "third", etc. are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present application, "a plurality of" means two or more unless otherwise specifically defined.

[0038] Referring to "embodiments" herein means that the specific features, structures or characteristics described in connection with the embodiments may be included in at least one embodiment of the present application. The phrase does not necessarily refer to the same embodiment at each occurrence in the specification, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0039] In the description of the embodiments of the present application, the term "and / or" is only a description of the associated relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0040] In the description of the embodiments of the present application, the orientation or positional relationship indicated by technical terms such as "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed, operated or used in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0041] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", "connection", "fixation" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can also be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and can be the connection inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific situations.

[0042] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, the technical term "contact" should be understood in a broad sense. It can be direct contact or contact through an intermediate medium layer. It can be contact where there is basically no interaction force between the two in contact, or contact where there is an interaction force between the two in contact.

[0043] Next, the present application will be described in detail.

[0044] In the embodiments of the present application, for the convenience of describing directions, refer to Figures 1 to 12 which are all marked with directions. Among them, the first direction is the extending direction of the extending side wall 21, that is, the height direction of the steel shell 2; the second direction is the width direction of the steel shell 2; the third direction is the length direction of the steel shell 2. It should be noted that the direction markings are only used to describe the present application, but not to limit the scope of the present application.

[0045] Battery cells are more and more widely used in life and industry. Battery cells are not only used in energy storage power systems such as hydropower, thermal power, wind power, and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in many fields such as aerospace. With the continuous expansion of the application fields of battery cells, the market demand for them is also constantly increasing.

[0046] A battery cell usually includes an end cap and a steel shell. Among them, the electrode assembly is accommodated inside the steel shell. In the related art, the end cap and the steel shell are usually connected by welding to construct a sealed cavity for accommodating the electrode assembly and the electrolyte.

[0047] The inventors of the present application have noticed that during the welding process of the end cap and the steel shell, the temperature near the welding area on the steel shell will exceed the melting point of the steel, causing the material in this area to melt and re-solidify. The re-solidification process will lead to grain coarsening, thereby forming a heat-affected weak zone on the steel shell, and the toughness and strength in the heat-affected weak zone will both decrease. During the cyclic use of the electrode assembly, the volume of the electrode assembly will expand and contract, and this repeated volume change will generate stress on the steel shell, and the stress will cause a large deformation in the heat-affected weak zone on the steel shell, resulting in the welding joint between the end cap and the steel shell being prone to cracking, and the electrolyte in the battery cell being likely to leak from the crack, thus affecting the service life of the battery cell.

[0048] The inventors of the present application have found through research that increasing the thickness of the material near the welding area on the steel shell can improve the thermal insulation performance of this area, thereby reducing the impact of high temperature on the structure of this area.

[0049] Based on such a design concept, referring to Figure 1 、 Figure 2 and Figure 3 ,the inventors of the present application have designed a battery cell, which includes an end cap 1 and a steel shell 2. An electrode assembly 3 is accommodated inside the steel shell 2. The steel shell 2 includes an extended side wall 21. The extending direction of the extended side wall 21 is the same as the extending direction of the electrode plate in the electrode assembly 3. The end of the extended side wall 21 is welded to the end cap 1 to form a welding area 4. The thickness range of the extended side wall 21 is 0.5 - 3 mm. The extended side wall 21 includes a strengthening area 211 and a main body area 212. The welding area 4, the strengthening area 211 and the main body area 212 are connected in sequence along the extending direction of the extended side wall 21. The thickness of the strengthening area 211 is different from the thickness of the main body area 212, and at least part of the thickness of the main body area 212 is less than the thickness of the strengthening area 211.

[0050] In the embodiment of the present application, in the extending direction of the extended side wall 21, the thickness of the main body area 212 can be set uniformly or non-uniformly, and the embodiment of the present application does not limit this.

[0051] In the embodiments of the present application, the function of the strengthening region 211 is to enhance the toughness and strength of the steel shell 2 near the welding region 4. Therefore, the thickness of the strengthening region 211 has multiple possibilities. For example, the thickness of the strengthening region 211 can be 0.5 mm, or 1 mm, or 2 mm. The thickness of the main body region 212 is different from that of the strengthening region 211, and at least part of the thickness of the main body region 212 is less than that of the strengthening region 211. Therefore, when the thickness of the strengthening region 211 is determined, the thickness of the main body region 212 has multiple possibilities. For example, when the thickness of the strengthening region 211 is 2 mm, when the thickness of the main body region 212 is uniformly set, the thickness of the main body region 212 can be 1 mm, or 1.5 mm; when the thickness of the main body region 212 is non-uniformly set, the maximum thickness of the main body region 212 can be 3 mm, and the minimum thickness can be 1 mm, or the maximum thickness of the main body region 212 can be 2 mm, and the minimum thickness can be 0.5 mm, or the maximum thickness of the main body region 212 can be 1 mm, and the minimum thickness can be 0.8 mm. The embodiments of the present application do not limit this.

[0052] In the technical solution provided by the embodiment of the present application, the battery cell includes an end cap 1 and a steel shell 2, and an electrode assembly 3 is accommodated inside the steel shell 2. Here, the end cap 1 is disposed at the open end of the steel shell 2 to close the open end. The steel shell 2 provides an accommodation space and protection for the electrode assembly 3. The steel shell 2 includes an extended side wall 21, and the extending direction of the extended side wall 21 is the same as the extending direction of the electrode plate in the electrode assembly 3. The end of the extended side wall 21 is welded to the end cap 1 to form a welding area 4. Here, the steel shell 2 is welded to the end cap 1 through the end of the extended side wall 21, so that the end cap 1 and the steel shell 2 jointly enclose a sealed cavity for accommodating the electrode assembly 3. The thickness range of the extended side wall 21 is 0.5-3 mm. In this way, it is possible to avoid the influence of the too thin thickness of the extended side wall 21 on the structural strength of the steel shell 2, and it is also possible to avoid the influence of the too thick thickness of the extended side wall 21 on the internal space of the steel shell 2. The extended side wall 21 includes a strengthening area 211 and a main body area 212. The welding area 4, the strengthening area 211, and the main body area 212 are sequentially connected along the extending direction of the extended side wall 21. The thickness of the strengthening area 211 is different from the thickness of the main body area 212, and at least part of the thickness of the main body area 212 is less than the thickness of the strengthening area 211. In this way, by increasing the thickness of the strengthening area 211 on the extended side wall 21, the thermal insulation performance of the strengthening area 211 can be improved, thereby reducing the influence of high temperature on the structure at the strengthening area 211 and improving the toughness and strength at the strengthening area 211. Compared with the related art, during the welding process of the end cap 1 and the steel shell 2, a thermally affected weak area is formed at the area of the steel shell 2 close to the welding area 4. In the embodiment of the present application, the extended side wall of the steel shell 2 includes a strengthening area 211, and the strengthening area 211 improves the thermal insulation performance by increasing the thickness, thereby avoiding the formation of a thermally affected weak area on the steel shell 2 and improving the toughness and strength at the strengthening area 211. In this way, when the electrode assembly 3 generates stress on the steel shell 2 due to volume change, the deformation amount at the strengthening area 211 becomes smaller, thereby reducing the probability of cracking of the welding area 4.

[0053] In the embodiment of the present application, the inner wall surface of the strengthening area 211 protrudes from the inner wall surface of the main body area 212, and / or, the outer wall surface of the strengthening area 211 protrudes from the outer wall surface of the main body area 212.

[0054] It should be noted that in the embodiment of the present application, the inner wall surfaces of the strengthening area 211 and the main body area 212 refer to the sides of the strengthening area 211 and the main body area 212 facing the inside of the steel shell 2, and the outer wall surfaces of the strengthening area 211 and the main body area 212 refer to the sides of the strengthening area 211 and the main body area 212 facing away from the inside of the steel shell 2.

[0055] In the embodiment of the present application, with reference to Figure 3, the inner wall surface of the strengthening area 211 can protrude from the inner wall surface of the main body area 212, and the outer wall surface of the strengthening area 211 can be flush with the outer wall surface of the main body area 212. In this way, when assembling the battery cell components, adjacent battery cells can be closely arranged, avoiding the formation of gaps between the main body areas 212 of adjacent battery cells, thereby affecting the energy density of the battery cell components. Refer to Figure 11 and Figure 12 , the outer wall surface of the strengthening area 211 can protrude from the inner wall surface of the main body area 212, and the inner wall surface of the strengthening area 211 can be flush with the inner wall surface of the main body area 212. Here, the inner wall surface of the strengthening area 211 is located at the open end of the steel shell 2, and the electrode assembly 3 needs to be inserted into the steel shell 2 through the open end. The inner wall surface of the strengthening area 211 being flush with the inner wall surface of the main body area 212 can increase the size of the open end, making it easier for the electrode assembly 3 to be inserted into the steel shell 2, thereby improving the production efficiency of the battery cell. In addition, the inner wall surface of the strengthening area 211 being flush with the inner wall surface of the main body area 212 can also increase the internal space of the steel shell 2, thereby providing a larger accommodation space for the electrode assembly 3 and the electrolyte. The inner wall surface of the strengthening area 211 can protrude from the inner wall surface of the main body area 212, and the outer wall surface of the strengthening area 211 can also protrude from the outer wall surface of the main body area 212. In this way, on the one hand, the protrusion amount of the inner wall surface of the strengthening area 211 can be reduced, thereby reducing the impact on the installation of the electrode assembly 3; on the other hand, the protrusion amount of the outer wall surface of the strengthening area 211 can be reduced. In this way, when assembling the battery cell components, the gap between the main body areas 212 of adjacent battery cells is small. When there is a buffer pad arranged between adjacent battery cells, due to the relatively thin thickness of the buffer pad, the buffer pad can be arranged between the main body areas 212 of adjacent battery cells, making good use of the gap between the main body areas 212 of adjacent battery cells, thereby reducing the occupied space of the battery cell components.

[0056] In the embodiment of the present application, in the extending direction of the extending side wall 21, the size range of the strengthening area 211 is 1-5 mm. In this way, the strengthening area 211 can not only improve the toughness and strength of the extending side wall 21 near the welding area 4, but also avoid increasing the occupied space and weight of the steel shell 2 due to the too large size of the strengthening area 211.

[0057] It should be noted that in the embodiment of the present application, in the extending direction of the extending side wall 21, there are various possibilities for the size of the strengthening area 211. For example, refer to Figure 3 , the size L of the strengthening area 211 can be 1 mm, can also be 3 mm, or can also be 5 mm. The embodiment of the present application does not limit this.

[0058] Refer to Figure 3, in the embodiments of the present application, the main body region 212 includes a general part 2122 and a transition part 2121. The general part 2122 is connected to the strengthening region 211 through the transition part 2121, and the thickness of the transition part 2121 is less than or equal to the thickness of the strengthening region 211. Here, the transition part 2121 can reduce the stress concentration caused by the thickness change between the general part 2122 and the strengthening region 211, thereby improving the structural strength of the extended sidewall 21.

[0059] In the embodiments of the present application, the transition part 2121 and the general part 2122 are usually integrally connected. And in the extending direction of the extended sidewall 21, the thickness of the transition part 2121 can be set uniformly or non-uniformly, and the thickness of the general part 2122 can be set uniformly or non-uniformly. The embodiments of the present application do not limit this. It should be noted that in the case where the thickness of the transition part 2121 is non-uniformly set, the maximum thickness on the transition part 2121 needs to be less than or equal to the thickness of the strengthening region 211.

[0060] In the embodiments of the present application, in the extending direction of the extended sidewall 21, the size range of the transition part 2121 is 1-3 mm. In this way, the transition part 2121 can not only reduce the stress concentration caused by the thickness change between the general part 2122 and the strengthening region 211, but also avoid increasing the occupied space and weight of the steel shell 2 due to the too large size of the strengthening region 211.

[0061] It should be noted that in the embodiments of the present application, in the extending direction of the extended sidewall 21, there are various possibilities for the size of the transition part 2121. For example, referring to Figure 3 , the size N of the transition part 2121 can be 1 mm, can also be 2 mm, or can also be 3 mm. The embodiments of the present application do not limit this.

[0062] Referring to Figure 3 , in the embodiments of the present application, in the extending direction of the extended sidewall 21, the thickness of the transition part 2121 gradually decreases, the thickness of the general part 2122 is set uniformly, and the thickness of the general part 2122 is equal to the minimum thickness of the transition part 2121. Here, the gradually decreasing thickness of the transition part 2121 can improve the stress distribution when the transition part 2121 is stressed through a gradually changing thickness design, reduce stress concentration, and thus enhance the structural strength of the extended sidewall 21. The thickness of the general part 2122 is set uniformly, so that the manufacturing process of the general part 2122 can be simplified and the production complexity can be reduced. The thickness of the general part 2122 is equal to the minimum thickness of the transition part 2121, so that the thickness change at the connection between the general part 2122 and the transition part 2121 can be avoided, and thus the stress concentration caused by the thickness change at the connection between the general part 2122 and the transition part 2121 can be reduced.

[0063] Reference Figure 4 In the embodiment of the present application, in the extending direction of the extended side wall 21, the thickness of the transition portion 2121 is uniformly set, the thickness of the common portion 2122 gradually decreases, and the maximum thickness on the common portion 2122 is equal to the thickness of the transition portion 2121. Here, the uniform setting of the thickness of the transition portion 2121 can simplify the manufacturing process of the transition portion 2121 and reduce production complexity. The thickness of the common portion 2122 gradually decreases, so that the stress distribution when the common portion 2122 is stressed can be improved through the gradient thickness design, stress concentration can be reduced, and thus the structural strength of the extended side wall 21 can be enhanced. The maximum thickness on the common portion 2122 is equal to the thickness of the transition portion 2121, so that the thickness change at the connection between the common portion 2122 and the transition portion 2121 can be avoided, and thus the stress concentration caused by the thickness change at the connection between the common portion 2122 and the transition portion 2121 can be reduced.

[0064] Reference Figure 5 In the embodiment of the present application, in the extending direction of the extended side wall 21, the thicknesses of the transition portion 2121 and the common portion 2122 gradually decrease, and the minimum thickness on the transition portion 2121 is equal to the maximum thickness on the common portion 2122. Here, the gradual decrease in the thicknesses of the transition portion 2121 and the common portion 2122 can improve the stress distribution when the main body region 212 is stressed through the gradient thickness design, reduce stress concentration, and thus enhance the structural strength of the extended side wall 21. The minimum thickness on the transition portion 2121 is equal to the maximum thickness on the common portion 2122, so that the thickness change at the connection between the common portion 2122 and the transition portion 2121 can be avoided, and thus the stress concentration caused by the thickness change at the connection between the common portion 2122 and the transition portion 2121 can be reduced.

[0065] In the embodiment of the present application, the function of the steel shell 2 is to provide an accommodation space and protection for the electrode assembly 3. Therefore, the shape of the steel shell 2 has various possibilities. For example, the cross-section of the steel shell 2 can be circular or rectangular, and the embodiment of the present application does not limit this. When the cross-section of the steel shell 2 is circular, the extended side wall 21 can be arranged around the circumference of the steel shell 2.

[0066] In the embodiment of the present application, the arrangement methods of the electrode sheets in the steel shell 2 generally include two methods: stacking and winding. When the electrode sheets are arranged in a stacking manner, the positive and negative electrode sheets and the separator are alternately stacked to form a layered structure similar to a book page, and each layer is separated by the separator, and finally the electrode assembly 3 is formed through pressing and bonding. When the electrode sheets are arranged in a winding manner, the positive and negative electrode sheets and the separator are laminated in a certain order and then wound around a winding axis to form a cylindrical or elliptical structure.

[0067] In the embodiment of the present application, the cross-section of the steel shell 2 is rectangular, and at least two electrode sheets are stacked along the width direction of the steel shell 2. In the width direction of the steel shell 2, the extended side walls 21 are arranged on the opposite sides of the steel shell 2, and the width direction of the steel shell 2 is perpendicular to the extending direction of the extended side walls 21.

[0068] In the embodiment of the present application, in the length direction of the steel shell 2, there are various possibilities for the thickness design of the strengthening area 211. For example, in the length direction of the steel shell 2, the thickness of the strengthening area 211 can be uniformly set, or can be designed to gradually decrease from the middle to both sides. The embodiment of the present application does not limit this.

[0069] In the embodiment of the present application, the cross-section of the steel shell 2 being rectangular enables the battery cells to be arranged compactly. Especially when designing the battery device, the space can be effectively utilized to improve the overall energy density; at least two electrode sheets are stacked along the length direction of the steel shell 2. Since the stacked electrode sheets do not include the "C corner" in the winding process, the stacked electrode sheets can make more effective use of the internal space of the steel shell 2, enabling the steel shell 2 to accommodate more active materials within the same volume, thereby improving the energy density; in the width direction of the steel shell 2, the extended side walls 21 are arranged on the opposite sides of the steel shell 2, and the width direction of the steel shell 2 is perpendicular to the extending direction of the extended side walls 21. Here, the volume change of the electrode assembly 3 is mainly concentrated in the stacking direction of the electrode sheets, that is, the width direction of the steel shell 2. Therefore, the extended side walls 21 are arranged in this way to specifically optimize the structural strength of the steel shell 2. Of course, the electrode assembly 3 also has volume changes in the length direction of the steel shell 2, and the extended side walls 21 can also be arranged on the opposite sides in the length direction of the steel shell 2, that is, the extended side walls 21 are arranged to surround in the circumferential direction of the steel shell 2.

[0070] In the embodiment of the present application, the cross-section of the steel shell 2 is rectangular, the electrode sheets are wound along the circumferential direction of the steel shell 2, the size of the electrode sheets in the length direction of the steel shell 2 is larger than the size of the electrode sheets in the width direction of the steel shell 2, and in the width direction of the steel shell 2, the extended side walls 21 are arranged on the opposite sides of the steel shell 2, and the length direction of the steel shell 2, the width direction of the steel shell 2 and the extending direction of the extended side walls 21 are perpendicular to each other.

[0071] In the embodiments of the present application, the cross-section of the steel shell 2 is rectangular, which enables the battery cells to be arranged compactly. Especially when designing the battery device, the space can be effectively utilized to improve the overall energy density. The electrode sheet is wound around the circumference of the steel shell 2. In this way, the structure of the electrode assembly 3 is relatively simple, facilitating the processing and manufacturing of the electrode sheet. When the electrode sheet is wound in the steel shell 2, the shape of the cross-section of the electrode sheet is usually oval. Therefore, the dimension of the electrode sheet in the length direction of the steel shell 2 is greater than the dimension of the electrode sheet in the width direction of the steel shell 2. In the width direction of the steel shell 2, the extended side walls 21 are arranged on the opposite sides of the steel shell 2. Here, the volume change of the electrode assembly 3 is mainly concentrated in the width direction of the steel shell 2. Therefore, setting the extended side walls 21 in this way can specifically optimize the structural strength of the steel shell 2. Of course, there is also volume change of the electrode assembly 3 in the width direction of the steel shell 2, and the extended side walls 21 can also be arranged on the opposite sides in the width direction of the steel shell 2, that is, the extended side walls 21 are arranged in a circumferential manner around the steel shell 2.

[0072] Referring to Figure 2 , in the embodiments of the present application, the electrode assembly 3 is disposed opposite to the main body area 212 of the steel shell 2, and in the extending direction of the extended side wall 21, the dimension of the electrode assembly 3 is smaller than the dimension of the main body area 212. In this way, when the electrode assembly 3 is disposed inside the steel shell 2, the electrode assembly 3 can be disposed corresponding to the main body area 212 on the steel shell 2, and the strengthening area 211 on the steel shell 2 can avoid the electrode assembly 3. When stress is generated on the steel shell 2 due to the volume change of the electrode assembly 3, the stress can be transmitted to the strengthening area 211 through the main body area 212. Since the stress will attenuate during the transmission process, the stress at the strengthening area 211 can be reduced, thereby further reducing the probability of cracking at the welding area 4.

[0073] In the embodiments of the present application, the number of end caps 1 depends on the number of openings on the steel shell 2. Therefore, the number of end caps 1 has various possibilities. For example, referring to Figure 1 , when the number of openings on the steel shell 2 is one, the number of end caps 1 is also one. Referring to Figure 6 , Figure 7 and Figure 8 , when the number of openings on the steel shell 2 is two, the number of end caps 1 is also two. The embodiments of the present application do not limit this.

[0074] Referring to Figure 6 , Figure 7 and Figure 8 , in the embodiments of the present application, in the extending direction of the extended side wall 21, two end caps 1 are provided. Referring to Figure 9 and Figure 10, one of the two end caps 1 is welded to the first end of the extended side wall 21, and the other of the two end caps 1 is welded to the second end of the extended side wall 21 to form two welding zones 4. The extended side wall 21 includes two reinforcing zones 211 arranged at intervals, and the two reinforcing zones 211 are respectively connected to the welding zones 4 at the corresponding ends. In this way, openings are formed on both sides of the steel shell 2 in the extending direction of the extended side wall 21, which is beneficial to the loading and fixing of the electrode assembly 3, thereby improving the production efficiency of the battery cell.

[0075] Referring to Figure 9 and Figure 10 , in the embodiment of the present application, in the extending direction of the extended side wall 21, the size of the end cap 1 is smaller than that of the reinforcing zone 211. In this way, when the steel shell 2 and the end cap 1 are welded, the reinforcing zone 211 can have sufficient strength for local strengthening.

[0076] In the embodiment of the present application, there are various welding methods between the cover plate and the steel shell 2. For example, it can be butt welding between the cover plate and the steel shell 2; or, referring to Figure 3 , Figure 9 and Figure 10 , a flange 11 is designed on the circumference of the cover plate, and the cover plate is lapped on the end of the steel shell 2 through the flange 11, and the cover plate and the steel shell 2 are connected by side welding.

[0077] In the embodiment of the present application, the battery cell can be a lithium-ion battery, a sodium-ion battery, a sodium-lithium-ion battery, a lithium-metal battery, a sodium-metal battery, a lithium-sulfur battery, a magnesium-ion battery, a nickel-metal hydride battery, a nickel-cadmium battery, a lead-acid battery, etc., and the embodiment of the present application does not limit this.

[0078] In the embodiment of the present application, the battery cell can be a secondary battery, and a secondary battery refers to a battery cell that can activate the active material and continue to be used by charging after discharging the battery cell.

[0079] On this basis, the embodiment of the present application further provides a battery device, and the battery device further includes a box body and a battery cell, and the battery cell is installed in the box body.

[0080] In the embodiment of the present application, the battery device (Battery Apparatus) may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly (Battery Cell Assembly) may include a plurality of battery cells, and the plurality of battery cells are connected in series, parallel or in a hybrid connection through a busbar component.

[0081] In some embodiments, a battery cell assembly is typically formed by arranging a plurality of battery cells; as an example, the battery cell assembly can be a battery module, which is formed by arranging and fixing a plurality of battery cells into an independent module. As an example, the battery module can be formed by bundling a plurality of battery cells with cable ties.

[0082] In some embodiments, the battery device can be a battery pack, which includes a box body and one or more battery cell assemblies, and the battery cell assemblies are accommodated in the box body. The battery cell assembly can also be a battery module, and the battery cell assembly can be accommodated in the box body by fixing the battery module in the box body.

[0083] In some embodiments, the battery cell assembly can also be accommodated in the box body by directly fixing a plurality of battery cells to the box body.

[0084] In some embodiments, the box body can include a first box body and a second box body. The first box body and the second box body are snapped together so that a closed space is formed inside the box body to accommodate the battery cell assembly. Here, "closed" means covered or closed, which can be sealed or non-sealed. The first box body can be a top cover or a bottom plate.

[0085] In some embodiments, the box body can also include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are respectively connected to the frame so that a closed space is formed inside the box body to accommodate the battery cell assembly.

[0086] In some embodiments, the box body can also be part of the chassis structure of a vehicle. For example, the top cover of the box body can become at least part of the floor of the vehicle, or the frame of the box body can become at least part of the cross beam and longitudinal beam of the vehicle.

[0087] For the battery device provided by the embodiments of the present application, since it includes the battery cells of the embodiments of the present application, the battery device also has the same technical effects. That is, the probability of cracking at the welding joint between the end cover 1 and the steel shell 2 can be reduced.

[0088] In addition, the embodiments of the present application also provide an electrical device, which includes an electrical appliance and a battery device, and the battery device is electrically connected to the electrical appliance.

[0089] In the embodiments of the present application, the electrical device can be, but is not limited to, a mobile phone, a tablet computer, a laptop computer, an electric toy, an electric tool, a battery car, an electric vehicle, a ship, a spacecraft, etc. Among them, the electric toy can include a fixed or mobile electric toy, for example, a game console, an electric vehicle toy, an electric ship toy, an electric aircraft toy, etc., and the spacecraft can include an airplane, a rocket, a space shuttle, a spaceship, etc.

[0090] In the embodiments of the present application, the electrical device may be an electric vehicle, and the electrical appliance may be a drive motor, a control component, an in-vehicle air conditioner, an in-vehicle entertainment system, etc. in the electric vehicle. The battery device may be arranged at the bottom side of the vehicle body.

[0091] Since the electrical equipment provided by the embodiments of the present application includes the battery device of the embodiments of the present application, and the battery device further includes battery cells, the electrical equipment also has the same technical effects. That is, the probability of cracking at the welding joint between the end cover 1 and the steel shell 2 can be reduced.

[0092] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be covered by the scope of the specification of the present application. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way.

Claims

1. A battery cell, characterized in that, Comprising: End cap; Steel shell, which internally houses an electrode assembly. The steel shell includes an extended side wall, and the extending direction of the extended side wall is consistent with the extending direction of the electrode sheets in the electrode assembly. The end of the extended side wall is welded to the end cap to form a welding area. The thickness range of the extended side wall is 0.5 - 3 mm. The extended side wall includes a strengthening area and a main body area. The welding area, the strengthening area, and the main body area are sequentially connected along the extending direction of the extended side wall. The thickness of the strengthening area is different from that of the main body area, and at least part of the thickness of the main body area is less than the thickness of the strengthening area.

2. The battery cell according to claim 1, wherein The inner wall surface of the strengthening area protrudes from the inner wall surface of the main body area, and / or the outer wall surface of the strengthening area protrudes from the outer wall surface of the main body area.

3. The battery cell according to claim 1, wherein, In the extending direction of the extended side wall, the size range of the strengthening area is 1 - 5 mm.

4. The battery cell according to claim 1, wherein The main body area includes a normal part and a transition part. The normal part is connected to the strengthening area through the transition part, and the thickness of the transition part is less than or equal to the thickness of the strengthening area.

5. The battery cell according to claim 4, characterized in that, In the extending direction of the extended side wall, the thickness of the transition part gradually decreases, the thickness of the normal part is uniformly set, and the thickness of the normal part is equal to the minimum thickness of the transition part.

6. The battery cell according to claim 4, characterized in that, In the extending direction of the extended side wall, the thickness of the transition part is uniformly set, the thickness of the normal part gradually decreases, and the maximum thickness of the normal part is equal to the thickness of the transition part.

7. The battery cell according to claim 4, characterized in that, In the extending direction of the extended side wall, the thicknesses of the transition part and the normal part gradually decrease, and the minimum thickness of the transition part is equal to the maximum thickness of the normal part.

8. The battery cell according to any one of claims 1-7, characterized in that, The cross-section of the steel shell is rectangular. At least two electrode sheets are stacked along the length direction of the steel shell. In the width direction of the steel shell, the extended side walls are arranged on opposite sides of the steel shell, and the width direction of the steel shell is perpendicular to the extending direction of the extended side wall.

9. The battery cell according to any one of claims 1-7, characterized in that, The cross-section of the steel shell is rectangular. The electrode sheets are wound circumferentially along the steel shell. The size of the electrode sheet in the length direction of the steel shell is greater than the size of the electrode sheet in the width direction of the steel shell. In the width direction of the steel shell, the extended side walls are arranged on opposite sides of the steel shell, and the length direction of the steel shell, the width direction of the steel shell, and the extending direction of the extended side wall are perpendicular to each other.

10. The battery cell according to any one of claims 1-7, characterized in that, The electrode assembly is oppositely arranged with the main body area of the steel shell, and in the extending direction of the extended side wall, the size of the electrode assembly is smaller than the size of the main body area.

11. The battery cell according to any one of claims 1-7, characterized in that, In the extending direction of the extended side wall, there are two end caps. One of the two end caps is welded to the first end of the extended side wall, and the other of the two end caps is welded to the second end of the extended side wall to form two welding areas. The extended side wall includes two spaced strengthening areas, and the two strengthening areas are respectively connected to the welding areas at the corresponding ends.

12. A battery device, characterized in that, Comprising: Box body; The battery cell according to any one of claims 1-11, wherein the battery cell is installed in the box body.

13. An electrical device, characterized in that, Comprising: An electrical appliance; The battery device according to claim 12, wherein the battery device is electrically connected to the electrical appliance.

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