Secondary battery case and secondary battery

Abstract

The utility model relates to a secondary battery shell and a secondary battery, the secondary battery shell comprises a bottom and a side wall, the thickness of the bottom wall is H1, the side wall is connected with the bottom wall, an accommodating cavity for accommodating a naked battery cell is defined by the side wall and the bottom wall, the thickness of the side wall is H2, and the capacity of the accommodating cavity is L; wherein 0.85 mm < = H1 < = 2.5 mm, and 0.35 mm < = H2 < = 1.5 mm. According to the secondary battery shell provided by the invention, the containing cavity is defined by the bottom wall and the side wall, the thickness H1 of the bottom wall is set to be 0.85 mm-2. 5mm, and the thickness H2 of the side wall is set to be 0.35 mm-1. 5mm. By controlling the thickness of the bottom wall and the thickness of the side wall, it can be ensured that the secondary battery shell has enough structural strength, the undesirable phenomenon that the secondary battery shell cracks in the packaging and using process is prevented, and the service life of the secondary battery shell is prolonged. When the naked battery cell is accommodated in the accommodating cavity, the matching degree of the secondary battery shell and the naked battery cell is relatively high, and the safety performance of the secondary battery can be improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of batteries, in particular to a secondary battery shell and a secondary battery. BACKGROUND

[0002] Lithium ion batteries for large-scale applications have three types in terms of appearance classification, namely square aluminum shell, cylindrical and soft package. Since the square aluminum shell battery has better cost performance in many application scenarios, and the aluminum shell structure can better isolate the internal and external environment of the battery, the application of the aluminum shell in the battery packaging field is increasingly widespread.

[0003] At present, the aluminum shell structure for accommodating bare battery cells generally adopts punching or drawing forming, and the parameters of the aluminum shell depend on the production capacity, which is prone to poor matching with the bare battery cells and cracking. Practical new type content

[0004] Therefore, it is necessary to provide a secondary battery shell and a secondary battery in view of the problem that the existing aluminum shell structure has poor matching with the bare battery cells and is prone to cracking.

[0005] A secondary battery shell for accommodating a bare battery cell, the secondary battery shell comprising:

[0006] a bottom wall, the thickness of the bottom wall being H1;

[0007] a side wall connected with the bottom wall and surrounding the bottom wall to form a containing cavity for containing the bare battery cell, the thickness of the side wall being H2, and the capacity of the containing cavity being L;

[0008] wherein 0.85mm≤H1≤2.5mm and 0.35mm≤H2≤1.5mm.

[0009] In one of the embodiments, the relationship between the thickness H1 of the bottom wall and the capacity L of the containing cavity is 0.3269ln(H1)+0.943≤L≤0.3995ln(H1)+1.4825.

[0010] In one of the embodiments, the side wall comprises two large-face side walls spaced apart along a first direction and two small-face side walls spaced apart along a second direction, the two large-face side walls and the two small-face side walls being connected end to end, the surface size of the large-face side wall being larger than that of the small-face side wall, the thickness of the large-face side wall being H3, and the thickness of the small-face side wall being H4;

[0011] wherein 0.35mm≤H3≤1.05mm and 0.35mm≤H4≤1.5mm.

[0012] In one of the embodiments, the relationship between the thickness H3 of the large-face sidewall and the volume L of the accommodating cavity is: -0.0038H3 2 +0.0788H3+0.3021≤L≤-0.0043H3 2 +0.0888H3+0.5526.

[0013] In one of the embodiments, the relationship between the thickness H4 of the small-face sidewall and the volume L of the accommodating cavity is: 0.3884H4 0.4354 ≤L≤0.8413H4 0.2926 .

[0014] In one of the embodiments, the connection between the large-face sidewall and the adjacent small-face sidewall forms a first arc-shaped part, and the radius of the circular arc of the first arc-shaped part is R1, 1.5mm≤R1≤3mm.

[0015] In one of the embodiments, the sidewall is provided with a protrusion on the side away from the bottom wall, and the protrusion extends towards the inside of the accommodating cavity;

[0016] wherein the length of the protrusion extending towards the inside of the accommodating cavity is D, and 0.1mm≤D≤0.3mm.

[0017] In one of the embodiments, the protrusion comprises a transition part and a support part, the transition part is smoothly connected to the sidewall, the support part is connected to the transition part and extends into the inside of the accommodating cavity;

[0018] wherein the cross section of the transition part in the thickness direction of the sidewall is arc-shaped, or the transition part and the sidewall form an obtuse angle, and the transition part is inclined towards the side of the bottom wall.

[0019] In one of the embodiments, the protrusion is two, the two protrusions are opposite to each other and are located on the side of the sidewall towards the inside of the accommodating cavity.

[0020] A secondary battery, comprising:

[0021] The secondary battery shell according to any one of the above technical solutions;

[0022] A bare cell, which is accommodated in the accommodating cavity, and comprises a positive electrode sheet, a negative electrode sheet and an insulating film; and

[0023] A top cover, which is arranged on the secondary battery shell and can seal the open end of the secondary battery shell.

[0024] The bottom wall and the side wall form a containing cavity, the thickness H1 of the bottom wall is set to 0.85mm-2.5mm, and the thickness H2 of the side wall is set to 0.35mm-1.5mm. By controlling the thickness of the bottom wall and the side wall, the secondary battery shell has sufficient structural strength, and the cracking of the secondary battery shell during packaging and use is prevented. When the bare battery cell is contained in the containing cavity, the matching degree of the secondary battery shell and the bare battery cell is high, and the safety performance of the secondary battery is improved. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 A structure schematic view of the secondary battery shell provided in some embodiments.

[0026] Figure 2 A front view of the secondary battery shell provided in some embodiments.

[0027] Figure 3 A top view of the secondary battery shell provided in some embodiments.

[0028] Figure 4 A structure schematic view of the secondary battery shell provided in some embodiments. Figure 1 A local enlarged view of area A in the structure schematic view.

[0029] Figure 5 A structure schematic view of the secondary battery provided in some embodiments.

[0030] Figure 6 A trend chart of the containing cavity capacity changing with the thickness of the bottom wall provided in some embodiments.

[0031] Figure 7 A trend chart of the containing cavity capacity changing with the thickness of the large-face side wall provided in some embodiments.

[0032] Figure 8 A trend chart of the containing cavity capacity changing with the thickness of the small-face side wall provided in some embodiments.

[0033] Figure 9 A trend chart of the containing cavity capacity changing with the radius of the second arc-shaped part provided in some embodiments.

[0034] REFERENCE SIGNS:

[0035] 100, secondary battery shell;

[0036] 110, bottom wall; 120, side wall; 121, large-face side wall; 122, small-face side wall; 130, containing cavity; 140, first arc-shaped part; 150, second arc-shaped part; 160, protrusion; 161, transition part; 162, support part;

[0037] 200, secondary battery; 210, bare cell; 220, top cover. DETAILED DESCRIPTION

[0038] In order to make the above objectives, features and advantages of the present application more clear and easily understood, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced in a number of different ways without some of the specific details described herein, and it is understood that similar improvements and modifications can be made without departing from the spirit and scope of the present application. It is also understood that the present application will include all such improvements and modifications.

[0039] In the description of the present application, it should be understood that, if there are terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0040] In addition, if the terms "first", "second" appear, these terms are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implying the number of technical features indicated. Therefore, the features limited by "first", "second" can include at least one of the features explicitly or implicitly. In the description of the present application, if the term "multiple" appears, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0041] In the present application, unless otherwise specifically defined and limited, if the terms "mounting", "connecting", "connecting", "fixing" and the like appear, these terms should be interpreted broadly. For example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise specifically limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0042] In this application, unless otherwise clearly indicated and limited, if there is a description such as "on" or "under" or the like between a first feature and a second feature, it can mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, "over", "above", and "on" of the first feature to the second feature can be that the first feature is directly above or obliquely above the second feature, or only means that the horizontal height of the first feature is higher than that of the second feature. "Under", "below", and "under" of the first feature to the second feature can be that the first feature is directly below or obliquely below the second feature, or only means that the horizontal height of the first feature is less than that of the second feature.

[0043] It should be noted that if an element is referred to as being "fixed" or "set" on another element, it can be directly on the other element or there can be an intermediate element. If an element is considered to be "connected" to another element, it can be directly connected to the other element or there can be an intermediate element. If present, the terms "vertical", "horizontal", "up", "down", "left", "right", and similar expressions used in this application are only for illustrative purposes and do not represent the only implementation.

[0044] The technical solutions provided by the embodiments of the present application will be described below with reference to the accompanying drawings.

[0045] Reference Figures 1-5As shown, the application provides a secondary battery shell 100 for accommodating a bare battery cell 210. The secondary battery shell 100 comprises a bottom wall 110 and a side wall 120, the bottom wall 110 and the side wall 120 are connected, and the bottom wall 110 and the side wall 120 are surrounded to form a containing cavity 130 containing the bare battery cell 210. Exemplarily, the thickness of the bottom wall 110 is defined as H1, the thickness of the side wall 120 is defined as H2, and the capacity of the containing cavity 130 is defined as L. The capacity L of the containing cavity 130 is the sum of the hollow space size formed by the bottom wall 110 and the side wall 120, the volume of the side wall 120, and the volume of the bottom wall 110. Wherein, 0.85mm≤H1≤2.5mm, 0.35mm≤H2≤1.5mm. In a specific arrangement, the thickness H1 of the bottom wall 110 can be any one of 0.85mm, 0.92mm, 1.0mm, 1.08mm, 1.15mm, 1.22mm, 1.3mm, 1.38mm, 1.45mm, 1.52mm, 1.6mm, 1.68mm, 1.75mm, 1.82mm, 1.9mm, 1.98mm, 2.05mm, 2.12mm, 2.2mm, 2.28mm, 2.35mm, 2.42mm, 2.5mm, and the thickness H2 of the side wall 120 can be any one of 0.35mm, 0.42mm, 0.5mm, 0.58mm, 0.65mm, 0.72mm, 0.8mm, 0.88mm, 0.95mm, 1.02mm, 1.1mm, 1.18mm, 1.25mm, 1.32mm, 1.4mm, 1.45mm, 1.5mm. Of course, the thickness H1 of the bottom wall 110 and the thickness H2 of the side wall 120 are not limited to the specific values provided above, such as the thickness H1 of the bottom wall 110 can also be other values within the range of 0.85mm-2.5mm, and the thickness H2 of the side wall 120 can also be other values within the range of 0.35mm-1.5mm. The application does not limit the specific values of the thickness H1 of the bottom wall 110 and the thickness H2 of the side wall 120.

[0046] The above-mentioned secondary battery shell 100, the bottom wall 110 and the side wall 120 surround to form the containing cavity 130, and the thickness H1 of the bottom wall 110 is set to 0.85mm-2.5mm, and the thickness H2 of the side wall 120 is set to 0.35mm-1.5mm. By reasonably controlling the thickness of the bottom wall 110 and the side wall 120, the secondary battery shell 100 can have sufficient structural strength to prevent the secondary battery shell 100 from cracking during packaging and use. When the bare battery cell 210 is contained in the containing cavity 130, the matching degree of the secondary battery shell 100 and the bare battery cell 210 is high, and the adverse phenomenon of explosion of the secondary battery shell 100 due to excessive internal pressure can be avoided, and the safety performance of the secondary battery 200 is improved.

[0047] In one embodiment, see Figure 1 and Figure 2 As shown, the relationship between the thickness H1 of the bottom wall 110 and the capacity L of the accommodating cavity 130 is: 0.3269ln(H1)+0.943≤L≤0.3995ln(H1)+1.4825. Table 1 below illustrates the relationship between the capacity L of the accommodating cavity 130 and the thickness H1 of the bottom wall 110.

[0048] Table 1

[0049]

[0050]

[0051] Thus, the variation trend of the capacity L of the accommodating cavity 130 with the thickness H1 of the bottom wall 110 is as follows: Figure 6 As shown, the capacity L of the accommodating cavity 130 is reasonably designed according to the thickness H1 of the bottom wall 110 to ensure that the bottom wall 110 can withstand the weight compression and volume bearing of the bare cell 210 inside the accommodating cavity 130, so that the secondary battery casing 100 has sufficient structural strength and prevents the secondary battery casing 100 from cracking during packaging and use.

[0052] For example, when accommodating a large-sized bare cell 210, since the capacity L of the accommodating cavity 130 needs to be set to be large, the thickness H1 of the bottom wall 110 can be set to be large to avoid the bottom wall 110 cracking due to the excessive size and weight of the bare cell 210. Conversely, when accommodating a small-sized bare cell 210, since the capacity L of the accommodating cavity 130 needs to be set to be small, the thickness H1 of the bottom wall 110 can be set to be small. While ensuring that the bottom wall 110 has sufficient structural strength, the miniaturization and lightweight design of the secondary battery casing 100 can be achieved, reducing the molding cost of the secondary battery casing 100.

[0053] In one embodiment, see Figures 1-3 As shown, the sidewall 120 includes a first direction ( Figure 1 The two large sidewalls 121, spaced apart in the X direction (as shown), and along the second direction (as shown) Figure 1 Two small sidewalls 122 are spaced apart (as shown in the Y direction), and two large sidewalls 121 are connected end-to-end to the two small sidewalls 122, with the surface dimensions of the large sidewalls 121 being larger than the surface dimensions of the small sidewalls 122. For example, the two large sidewalls 121 are arranged along... Figure 1 As shown, the two small sidewalls 122 are spaced apart in the X direction. Figure 1The Y direction interval is shown, and the two sides of the large side wall 121 are respectively adjacent to two small side walls 122, and the two sides of the small side wall 122 are respectively adjacent to two large side walls 121. As defined, the thickness of the large side wall 121 is H3, and the thickness of the small side wall 122 is H4, wherein 0.35mm≤H3≤1.05mm, 0.35mm≤H4≤1.5mm. In the specific setting, the thickness H3 of the large side wall 121 can be any one of 0.35mm, 0.42mm, 0.5mm, 0.58mm, 0.65mm, 0.72mm, 0.8mm, 0.88mm, 0.95mm, 1.05mm, and the thickness H4 of the small side wall 122 can be any one of 0.35mm, 0.42mm, 0.5mm, 0.58mm, 0.65mm, 0.72mm, 0.8mm, 0.88mm, 0.95mm, 1.02mm, 1.1mm, 1.18mm, 1.25mm, 1.32mm, 1.4mm, 1.48mm, 1.5mm. Of course, the thickness H3 of the large side wall 121 and the thickness H4 of the small side wall 122 are not limited to the specific values provided above, such as the thickness H3 of the large side wall 121 which can also be other values within the range of 0.35mm-1.05mm, and the thickness H4 of the small side wall 122 which can also be other values within the range of 0.35mm-1.5mm. The specific values of the thickness H3 of the large side wall 121 and the thickness H4 of the small side wall 122 are not limited in the present application.

[0054] The secondary battery shell 100 described above sets the thickness H3 of the large side wall 121 to 0.35mm-1.05mm and the thickness H4 of the small side wall 122 to 0.35mm-1.5mm. By reasonably controlling the thickness of the large side wall 121 and the small side wall 122, the secondary battery shell 100 can have sufficient structural strength to prevent cracking of the secondary battery shell 100 during packaging and use. When the bare cell 210 is accommodated in the accommodation cavity 130, the matching degree of the secondary battery shell 100 and the bare cell 210 is high, and the adverse phenomenon of explosion of the secondary battery shell 100 due to excessive internal pressure can be avoided, thereby improving the safety performance of the secondary battery 200.

[0055] Specifically, referring to Figures 1-3 As shown, the relationship between the thickness H3 of the large side wall 121 and the capacity L of the accommodation cavity 130 is: -0.0038H3 2 +0.0788H3+0.3021≤L≤-0.0043H3 2 +0.0888H3+0.5526. Table 2 below illustrates the relationship between the capacity L of the accommodation cavity 130 and the thickness H3 of the large side wall 121.

[0056] Table 2

[0057]

[0058] Thus, the variation trend of the capacity L of the accommodating cavity 130 with the thickness H3 of the large-surface sidewall 121 is as follows: Figure 7 As shown, the capacity L of the accommodating cavity 130 is reasonably designed according to the thickness H3 of the large side wall 121 to ensure that the large side wall 121 can withstand the side compression of the bare cell 210 inside the accommodating cavity 130, so that the secondary battery casing 100 has sufficient structural strength and prevents the secondary battery casing 100 from cracking during packaging and use.

[0059] For example, when accommodating a large-sized bare cell 210, since the capacity L of the accommodating cavity 130 needs to be set to be large, the thickness H3 of the large sidewall 121 can be set to be large to avoid the undesirable phenomenon of the large sidewall 121 being severely compressed and cracked due to the excessive size of the bare cell 210. Conversely, when accommodating a small-sized bare cell 210, since the capacity L of the accommodating cavity 130 needs to be set to be small, the thickness H3 of the large sidewall 121 can be set to be small. On the basis of ensuring that the large sidewall 121 has sufficient structural strength, the miniaturization and lightweight design of the secondary battery casing 100 can be achieved, thereby reducing the molding cost of the secondary battery casing 100.

[0060] Similarly, see Figures 1-3 As shown, the relationship between the thickness H4 of the small sidewall 122 and the capacity L of the accommodating cavity 130 is: 0.3884H4 0.4354 ≤L≤0.8413H4 0.2926 The following Table 3 illustrates the relationship between the capacity L of the accommodating cavity 130 and the thickness H4 of the small sidewall 122.

[0061] Table 3

[0062]

[0063] Thus, the variation trend of the capacity L of the accommodating cavity 130 with the thickness H4 of the small sidewall 122 is as follows: Figure 8 As shown, the capacity L of the accommodating cavity 130 is reasonably designed according to the thickness H4 of the small sidewall 122 to ensure that the small sidewall 122 can withstand the side compression of the bare cell 210 inside the accommodating cavity 130, so that the secondary battery casing 100 has sufficient structural strength and prevents the secondary battery casing 100 from cracking during packaging and use.

[0064] Exemplarily, as in the accommodation of the large size specification bare electric core 210, since the capacity L of the accommodation cavity 130 needs to be set to be large, the thickness H4 of the small side wall 122 can be set to be large, so as to avoid the cracking of the small side wall 122 due to the large size of the bare electric core 210. Conversely, as in the accommodation of the small size specification bare electric core 210, since the capacity L of the accommodation cavity 130 needs to be set to be small, the thickness H4 of the small side wall 122 can be set to be small, so as to realize the miniaturization and lightweight design of the secondary battery shell 100 on the basis of ensuring the structural strength of the small side wall 122, and reduce the forming cost of the secondary battery shell 100.

[0065] In an embodiment, referring to FIG. 1, Figures 1-3 As shown in the figure, the connection between the large side wall 121 and the adjacent small side wall 122 forms a first arc-shaped part 140, and the radius of the circular arc of the first arc-shaped part 140 is R1, and 1.5mm≤R1≤3mm. In a specific setting, the radius R1 of the circular arc of the first arc-shaped part 140 can be any one of 1.5mm, 1.62mm, 1.75mm, 1.88mm, 2mm, 2.12mm, 2.25mm, 2.38mm, 2.5mm, 2.62mm, 2.75mm, 2.88mm, and 3mm. Of course, the radius R1 of the circular arc of the first arc-shaped part 140 is not limited to the specific values provided above, and the radius R1 of the circular arc of the first arc-shaped part 140 can also be other values within the range of 1.5mm to 3mm. The specific value of the radius R1 of the circular arc of the first arc-shaped part 140 is not limited in the present application. It should be noted that in the present embodiment, the first arc-shaped part 140 is a circular arc surface formed on one side of the outside of the secondary battery shell 100.

[0066] In this way, the radius R1 of the circular arc of the first arc-shaped part 140 is set to be 1.5mm to 3mm, the radius of the circular arc of the first arc-shaped part 140 is reasonably controlled, the space utilization of the secondary battery shell 100 is optimized, the structural strength of the large side wall 121 and the small side wall 122 in the connection process is improved, the large side wall 121 and the small side wall 122 are smoothly transitioned, the stress concentration phenomenon is not easy to occur in the connection part of the large side wall 121 and the small side wall 122 in the pressure process, and the cracking phenomenon of the secondary battery shell 100 due to the extrusion of the bare electric core 210 is avoided.

[0067] In an embodiment, referring to FIG. 1, Figure 1 and Figure 2As shown, the second arc-shaped portion 150 is formed at the joint of the bottom wall 110 and the side wall 120, and the radius of the arc of the second arc-shaped portion 150 is R2, 0.8mm≤R2≤3mm. In a specific setting, the radius of the arc of the second arc-shaped portion 150 can be any one of 0.8mm, 0.88mm, 0.95mm, 1.02mm, 1.1mm, 1.18mm, 1.25mm, 1.32mm, 1.4mm, 1.5mm, 1.58mm, 1.65mm, 1.75mm, 1.82mm, 1.9mm, 2mm, 2.08mm, 2.15mm, 2.25mm, 2.32mm, 2.4mm, 2.5mm, 2.58mm, 2.65mm, 2.75mm, 2.82mm, 2.9mm, 3mm. Of course, the radius of the arc of the second arc-shaped portion 150 is not limited to the specific values provided above, such as the radius of the arc of the second arc-shaped portion 150 can also be other values within the range of 0.8mm-3mm, and the specific value of the radius of the arc of the second arc-shaped portion 150 is not limited in the present application. It should be noted that in the present embodiment, the second arc-shaped portion 150 is a circular arc surface formed on the outer side of the secondary battery shell 100.

[0068] Therefore, by setting the radius of the arc of the second arc-shaped portion 150 to 0.8mm-3mm, and by reasonably controlling the radius of the arc of the second arc-shaped portion 150, the space utilization of the secondary battery shell 100 is optimized, the structural strength of the joint of the bottom wall 110 and the side wall 120 is improved, the smooth transition between the bottom wall 110 and the side wall 120 is achieved, and the stress concentration phenomenon at the joint of the bottom wall 110 and the side wall 120 during the pressing process is avoided, thereby avoiding the cracking of the secondary battery shell 100 due to the extrusion of the bare cell 210.

[0069] Further, referring to Figure 1 and Figure 2 As shown, the relationship between the radius of the arc of the second arc-shaped portion 150 R2 and the capacity L of the accommodation cavity 130 is: -0.0099R2 3 +0.0653R2 2 +0.2297R2+0.7564≤L≤-0.0114R2 3 +0.0752R2 2 +0.2643R2+1.0842. Table 4 below illustrates the relationship between the capacity L of the accommodation cavity 130 and the radius of the arc of the second arc-shaped portion 150 R2.

[0070] Table 4

[0071]

[0072] Therefore, the capacity L of the accommodating cavity 130 changes with the radius R2 of the second arc-shaped portion 150 as shown in the following table: Figure 9 As shown in the table, the capacity L of the accommodating cavity 130 is designed according to the radius R2 of the second arc-shaped portion 150 of the bottom wall 110, so as to ensure that the connection between the bottom wall 110 and the side wall 120 can withstand the weight extrusion and volume bearing of the bare battery cell 210 in the accommodating cavity 130, that is, the secondary battery shell 100 has sufficient structural strength to prevent cracking of the secondary battery shell 100 during packaging and use.

[0073] In an embodiment, as shown in Figure 1 , Figure 2 and Figure 4 , the side wall 120 is provided with a protrusion 160 away from the bottom wall 110, the protrusion 160 extends towards the inside of the accommodating cavity 130, the protrusion 160 is used for the resting bearing of the top cover 220, and when the top cover 220 is carried on the protrusion 160, the top cover 220 can seal the accommodating cavity 130. As in the present embodiment, the protrusion 160 is opened on the side of the side wall 120 close to the opening end of the accommodating cavity 130. The length of the protrusion 160 extending towards the inside of the accommodating cavity 130 is D, and 0.1mm≤D≤0.3mm. In specific setting, the length D of the protrusion 160 extending towards the inside of the accommodating cavity 130 can be any one of 0.1mm, 0.12mm, 0.15mm, 0.18mm, 0.2mm, 0.22mm, 0.25mm, 0.28mm, 0.3mm. Of course, the length D of the protrusion 160 extending towards the inside of the accommodating cavity 130 is not limited to the specific values provided above, such as the length D of the protrusion 160 extending towards the inside of the accommodating cavity 130 can also be other values within the range of 0.1mm-0.3mm. The specific value of the length D of the protrusion 160 extending towards the inside of the accommodating cavity 130 is not limited in the present application.

[0074] Therefore, the length D of the protrusion 160 extending towards the inside of the accommodating cavity 130 is set to 0.1mm-0.3mm, and the extension length of the protrusion 160 is reasonably controlled, so as to improve the bearing stability of the top cover 220 on the boss when the top cover 220 is carried on the protrusion 160, and the protrusion 160 will not cause adverse effects on the setting of the bare battery cell 210 in the accommodating cavity 130 due to the excessive extension length.

[0075] Specifically, as shown in Figure 1 , Figure 2 and Figure 4As shown, the protrusion 160 comprises a transition portion 161 and a supporting portion 162, the transition portion 161 is smoothly connected to the side wall 120, and the supporting portion 162 is connected to the transition portion 161, that is to say, two sides of the transition portion 161 are respectively connected to the side wall 120 and the supporting portion 162, and the supporting portion 162 extends into the accommodating cavity 130 to support the top cover 220. Wherein, the transition portion 161 is arc-shaped in the thickness direction of the side wall 120, or the transition portion 161 and the side wall 120 form an obtuse angle, and the transition portion 161 is inclined toward the bottom wall 110. No matter which way the transition portion 161 adopts, it can be smoothly connected to the side wall 120 to improve the structural strength of the supporting portion 162 connected to the side wall 120, and the transition portion 161 is gradually expanded toward the opening end of the accommodating cavity 130, which is convenient for the top cover 220 to enter the accommodating cavity 130 through the opening end.

[0076] Further, referring to Figure 1 , Figure 2 , Figure 4 and Figure 5 , the protrusion 160 is two, the two protrusions 160 are opposite, and the two protrusions 160 are located on the side of the side wall 120 toward the inside of the accommodating cavity 130. In this way, the two protrusions 160 can respectively bear the opposite sides of the top cover 220. On the one hand, it can improve the bearing stability of the top cover 220 on the protrusion 160, and on the other hand, setting the protrusion 160 to be less can simplify the molding cost of the secondary battery shell 100, and avoid that the protrusion 160 will occupy too much internal space of the secondary battery shell 100, and the protrusion 160 will not cause too much interference to the setting of the bare cell 210 in the accommodating cavity 130.

[0077] In addition, referring to Figure 1 , Figure 2 and Figure 5As shown, the application also provides a secondary battery 200, which comprises the secondary battery shell 100, the bare battery cell 210 and the top cover 220 according to the technical solutions described above. The bare battery cell 210 is accommodated in the accommodation cavity 130, and the bare battery cell 210 comprises a positive electrode sheet, a negative electrode sheet and an insulating film. Exemplarily, the bare battery cell 210 is the core component of the energy storage and function of the secondary battery 200, and the bare battery cell 210 is usually formed by winding or stacking the positive electrode sheet and the negative electrode sheet, and the insulating film is arranged between the positive electrode sheet and the negative electrode sheet, and the positive electrode sheet and the negative electrode sheet are respectively provided with a tab. In the charging and discharging process of the secondary battery 200, the positive electrode sheet and the negative electrode sheet can have corresponding chemical reactions to realize the charging and discharging function, and form a current loop through the tab, the pole and the external device circuit connection. The top cover 220 is arranged on the secondary battery shell 100 by welding, bonding, hot melting and the like, and the top cover 220 can seal the open end of the secondary battery shell 100. When the top cover 220 is arranged at the open end of the secondary battery shell 100, the top cover 220 can protect the bare battery cell 210.

[0078] The secondary battery 200 described above can ensure that the secondary battery shell 100 has sufficient structural strength by controlling the thickness of the bottom wall 110 and the side wall 120, so that when the bare battery cell 210 is accommodated in the secondary battery shell 100, the secondary battery shell 100 can avoid the undesirable phenomenon of cracking, and the matching degree of the secondary battery shell 100 and the bare battery cell 210 is high, which can improve the safety performance of the secondary battery 200.

[0079] The technical features of the above-described embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described, but as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present application.

[0080] The above-described embodiments only express several implementation manners of the application, and the description is more specific and detailed, but it should not be understood as a limitation on the patent scope of the application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the application, a number of modifications and improvements can be made, which are all within the protection scope of the application. Therefore, the patent protection scope of the application should be subject to the appended claims.

Claims

1. A secondary battery case for housing a bare cell, characterized by comprising: The secondary battery shell comprises: a bottom wall, the thickness of the bottom wall being H1; a side wall, the side wall being connected with the bottom wall and surrounding the bottom wall to form a receiving cavity for receiving the bare battery cell, the thickness of the side wall being H2, and the capacity of the receiving cavity being L; wherein 0.85mm≤H1≤2.5mm and 0.35mm≤H2≤1.5mm.

2. The secondary battery case according to claim 1, wherein The relationship between the thickness H1 of the bottom wall and the capacity L of the receiving cavity is 0.3269ln(H1)+0.943≤L≤0.3995ln(H1)+1.4825.

3. The secondary battery case according to claim 1, wherein The side wall comprises two large-face side walls spaced apart along a first direction and two small-face side walls spaced apart along a second direction, the two large-face side walls and the two small-face side walls being connected end to end, the surface size of the large-face side wall being larger than that of the small-face side wall, the thickness of the large-face side wall being H3, and the thickness of the small-face side wall being H4; wherein 0.35mm≤H3≤1.05mm and 0.35mm≤H4≤1.5mm.

4. The secondary battery case according to claim 3, characterized by the relationship between the thickness H3 of the large surface side wall and the capacity L of the accommodating cavity is: -0.0038H3 2 +0.0788H3+0.3021≤L≤-0.0043H3 2 +0.0888H3+0.5526.

5. The secondary battery case according to claim 3, wherein The relationship between the thickness H4 of the facet side wall and the volume L of the accommodating cavity is: 0.3884H4 0.4354 ≤L≤0.8413H4 0.2926 .

6. The secondary battery case according to claim 3, wherein A first arc-shaped portion is formed at the connection between the large-face side wall and the adjacent small-face side wall, the radius of the first arc-shaped portion being R1, and 1.5mm≤R1≤3mm.

7. The secondary battery case according to claim 1, wherein The side wall is provided with a protrusion on the side away from the bottom wall, the protrusion extending towards the inside of the receiving cavity; wherein the length of the protrusion extending towards the inside of the receiving cavity is D, and 0.1mm≤D≤0.3mm.

8. The secondary battery case according to claim 7, wherein The protrusion comprises a transition portion and a support portion, the transition portion being smoothly connected to the side wall, and the support portion being connected to the transition portion and extending into the inside of the receiving cavity; wherein the cross section of the transition portion in the thickness direction of the side wall is arc-shaped, or the transition portion and the side wall form an obtuse angle, and the transition portion is inclined towards the side of the bottom wall.

9. The secondary battery case according to claim 7, wherein The protrusion is two, the two protrusions being opposite and located on the side of the side wall towards the inside of the receiving cavity.

10. A secondary battery characterized by comprising: The secondary battery comprises: the secondary battery shell according to any one of claims 1-9; a bare battery cell, the bare battery cell being received in the receiving cavity, the bare battery cell comprising a positive electrode sheet, a negative electrode sheet and an insulation film; and a top cover, the top cover being arranged on the secondary battery shell and capable of sealing the open end of the secondary battery shell.

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