Battery shell and secondary battery

Abstract

The utility model relates to a battery shell and a secondary battery, the battery shell comprises a shell, and anti-explosion nicks are formed on the outer surface and / or the inner surface of the shell; the explosion-proof nicks comprise a plurality of first nicks arranged at intervals and a plurality of second nicks connected between every two adjacent first nicks, and the nick residual value of each second nick is smaller than the nick residual value of each first nick. According to the utility model, the plurality of first nicks and second nicks are arranged to form the explosion-proof nicks, and the tearing difficulty of each area of the explosion-proof nicks can be adjusted through the second nicks, so that the tearing difficulty of each area of the explosion-proof nicks is relatively close; and the conditions that the areas except the explosion-proof nicks of the shell are torn to form larger gaps and the explosion is insufficient during explosion are avoided.

Description

Technical Field

[0001] The utility model belongs to the technical field of secondary batteries and relates to a battery shell and a secondary battery. Background Art

[0002] At present, new energy vehicles and electric vehicles have become a new development trend in the automotive industry; and secondary batteries, as the power source of pure electric vehicles, plug-in hybrid vehicles and electric bicycles, are also widely used in the field of new energy. At present, secondary batteries begin to use lithium batteries encapsulated in thinner stainless steel shells to save material costs and reduce the space occupied by batteries, and the explosion-proof notches formed by laser etching on the stainless steel shell are used as integrated explosion-proof valves to replace the explosion-proof valves welded on the shell; thereby simplifying the manufacturing process of the explosion-proof structure, and making the explosion-proof structure and the shell as a whole, avoiding the impact of poor welding effect on the explosion-proof effect of the explosion-proof structure.

[0003] In addition, in order to avoid the area enclosed by the explosion-proof notch from being torn as a whole and blown away by high pressure during explosion, causing secondary damage to the surrounding devices, the explosion-proof notch generally does not use a closed curve, but leaves a gap; since the gap is of normal thickness and will not be torn, it can ensure that the area enclosed by the explosion-proof notch remains connected to the shell. However, since the explosion-proof notch is generally in the shape of a curve, there may be large differences in the air pressure values ​​required for tearing at different locations of the curve, making it difficult to accurately adjust the overall tearing air pressure value of the explosion-proof notch. Since the wall thickness of the stainless steel shell is generally thin, if the overall tearing air pressure value of the explosion-proof notch is small, the area enclosed by the explosion-proof notch will produce a large outward impact force during explosion, which will cause the shell to be torn from the notch to open a large gap and extend to the edge of the shell, thereby causing damage to the adjacent battery shell. If the overall tearing air pressure value of the explosion-proof notch is large, it will lead to insufficient explosion at the explosion-proof notch, which may cause the battery to explode and cause greater danger. Utility Model Content

[0004] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a battery housing and a secondary battery.

[0005] In order to achieve the above object, the utility model provides the following technical solutions:

[0006] A battery shell comprises a shell, wherein explosion-proof notches are formed on the outer surface and / or the inner surface of the shell; the explosion-proof notches comprise a plurality of first notches arranged at intervals and a plurality of second notches connected between every two adjacent first notches, wherein the notch residual value of each of the second notches is smaller than the notch residual value of the first notches.

[0007] A battery shell comprises a shell, wherein explosion-proof notches are formed on the outer surface and / or the inner surface of the shell; the explosion-proof notches comprise a first notch in the form of a continuous line and a plurality of second notches which are arranged at intervals along the length direction of the first notch and overlap therewith, wherein the notch residual value of the second notch is smaller than the notch residual value of the first notch.

[0008] Furthermore, the shape of the explosion-proof notch is a combination of one or more of a circular arc, an elliptical arc, a spline curve and a straight line segment, and the beginning and the end of the explosion-proof notch are not connected.

[0009] Furthermore, a first curvature radius threshold and a second curvature radius threshold are pre-set, and the first curvature radius threshold is greater than the second curvature radius threshold; the shape of the explosion-proof notch includes a curve with a curvature radius less than the second curvature radius threshold and a curve or a straight line segment with a curvature radius greater than the first curvature radius threshold, the straight line segment area in the explosion-proof notch or the curve area with a curvature radius greater than the first curvature radius threshold is a large curvature area, and the curve area in the explosion-proof notch with a curvature radius less than the second curvature radius threshold is a small curvature area.

[0010] Furthermore, the maximum length of the second notch in the large curvature region is greater than the maximum length of the second notch in the small curvature region.

[0011] Furthermore, the residual value of the second notch in the large curvature region is smaller than the residual value of the second notch in the small curvature region.

[0012] Furthermore, the explosion-proof notch includes a first curved notch, a second curved notch, and a connecting notch connecting the first curved notch and the second curved notch, wherein the first curved notch and the second curved notch are not connected to each other, thereby forming a gap between the first curved notch and the second curved notch; the shape of the first curved notch and the second curved notch is a curve whose maximum curvature radius is less than a second curvature radius threshold, and the shape of the connecting notch is a straight line segment or a curve whose minimum curvature radius is greater than the first curvature radius threshold.

[0013] Furthermore, the shapes of the first curved notch and the second curved notch are circular arcs, elliptical arcs or planar spirals, and the angle range of the first curved notch and the second curved notch is 180° to 270°; the shape of the connecting notch is a straight line segment, an arc with a radius greater than a first curvature radius threshold, or an elliptical arc with a minimum curvature radius greater than the first curvature radius threshold.

[0014] Furthermore, the shell is made of stainless steel material with a thickness of 0.15mm to 0.3mm, the residual value of the first notch is 0.10mm to 0.15mm; the residual value of the second notch is 0.03mm to 0.09mm; the first notch and the second notch are both groove structures with a wide upper part and a narrow lower part in cross section, and the bottom width of the cross section is 0.03mm to 0.1mm.

[0015] A secondary battery includes a battery casing.

[0016] In the utility model, by setting a plurality of first notches and a plurality of second notches in a shape similar to a dotted line, the first notches can increase the blocking effect during explosion, and avoid the explosion at the explosion-proof notches after the explosion cannot completely absorb the energy of the explosion, resulting in other parts of the shell being torn open with a large gap, thereby causing damage to the adjacent battery shell. By selecting the position, number, notch residual value and length of the second notches, the tearing difficulty of the small curvature area can be selectively reduced, so that the tearing difficulty of each area of ​​the explosion-proof notches is relatively close, and the situation of insufficient explosion can be avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0018] Figure 1 and Figure 2 The utility model is a schematic structural diagram of a battery housing according to an embodiment of the present invention.

[0019] Figure 3 Schematic diagram of the cross section of the explosion-proof notch.

[0020] Figure 4 It is a schematic diagram of the overall structure of the explosion-proof notch.

[0021] Figure 5 Schematic diagram of the structure of the first notch and the second notch.

[0022] Figure 6a , Figure 6b , Figure 6c , Figure 6d and Figure 6e They are schematic diagrams of the structures of several explosion-proof notches of different shapes used in blasting tests.

[0023] Figure 7a for Figure 6a Schematic diagram of the gap formed after the explosion-proof notch is torn.

[0024] Figure 7b for Figure 5Schematic diagram of the gap formed after the explosion-proof notch is torn.

[0025] The meanings of the symbols in the accompanying drawings are:

[0026] Shell - 100; wide side - 101; narrow side - 102; top cover - 111; bottom cover - 112; explosion-proof notch - 200; first curved notch - 201; second curved notch - 202; connecting notch - 203; notch - 204; notches - 205, 206; small curvature area - 207; large curvature area - 208; first notches - 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222; second notches - 251, 252, 253, 254, 255, 256, 257, 258, 259, 260, 261. DETAILED DESCRIPTION

[0027] The following describes the implementation of the present invention through specific examples. The illustrations provided in the following embodiments are only used to schematically illustrate the basic concept of the present invention. The following embodiments and features in the embodiments may be combined with each other without conflict.

[0028] Example 1

[0029] The utility model discloses a battery shell, please refer to Figure 1 and Figure 2 , is a schematic diagram of the structure of an embodiment of a battery shell of the utility model. A battery shell of this embodiment includes a shell 100, and an explosion-proof notch 200 is formed on the outer surface and / or inner surface of the shell 100 by etching, so that an integrated explosion-proof valve structure is formed by the explosion-proof notch 200.

[0030] The housing 100 is preferably made of stainless steel, and generally a stainless steel material with a wall thickness in the range of 0.15 mm to 0.3 mm is selected to make the housing 100; in this embodiment, the wall thickness of the stainless steel housing 100 is 0.18 mm ± 0.005 mm. Of course, the housing 100 can also be made of aluminum alloy material. When aluminum alloy material is used, the wall thickness of the housing 100 will be much greater than the wall thickness of the housing 100 when stainless steel material is used.

[0031] The shell 100 is generally a rectangular parallelepiped in the shape of a thin sheet, including a top cover 111, a bottom cover 112 opposite to the top cover 111, two oppositely arranged wide sides 101 and two oppositely arranged narrow sides 102. The shell 100 of this shape can be used to produce blade batteries, square batteries, etc. Since the two wide sides 101 of the aforementioned batteries will be closely attached to the batteries adjacent to the two sides during the installation process, it will prevent the explosion-proof notch 200 from being torn, therefore, the explosion-proof notch 200 is generally not set on the two wide sides 101 of the shell 100. In addition, the top cover 111 of the shell 100 is provided with components such as electrodes, and there is less area for etching to form the explosion-proof notch 200, and generally the explosion-proof notch 200 is avoided to be set on the top cover 111. Therefore, it is generally selected to etch the explosion-proof notch 200 on one of the narrow sides 102 of the shell 100 or on the bottom cover 112 of the shell 100.

[0032] When the battery cells inside the battery are damaged and emit a large amount of heat and / or release gas, the pressure inside the shell 100 expands rapidly; when the shell 100 is provided with an explosion-proof notch 200, if the air pressure inside the shell 100 is too high, as the air pressure increases, the explosion-proof notch 200 will be torn open under the action of the high air pressure, so that the high-pressure gas inside the shell 100 is discharged from the torn part, thereby quickly reducing the air pressure inside the shell 100, preventing the battery from exploding, and ensuring the personal safety of the manufacturer and the user. The air pressure value at which the explosion-proof notch 200 is just completely torn open is the overall tearing air pressure value of the explosion-proof notch 200.

[0033] The explosion-proof notch 200 includes a plurality of first notches arranged at intervals and a plurality of second notches connected between every two adjacent first notches, so that each second notch forms a shape similar to a dotted line. Of course, when the head end and / or tail end of the explosion-proof notch 200 is a second notch, the second notch at the head end or tail end is only connected to an adjacent first notch. The notch residual values ​​of each of the first notches can generally be the same; the notch residual values ​​of each of the second notches can be the same or different, but the notch residual values ​​of each of the second notches are smaller than the notch residual values ​​of the first notches. The notch residual value of the first notch is generally in the range of 0.10mm to 0.15mm; the notch residual value of the second notch is generally in the range of 0.03mm to 0.09mm.

[0034] See also Figure 3, the explosion-proof notch 200 (i.e., the first notch and the second notch) is generally a groove structure with a wide upper section and a narrow lower section. In this embodiment, the cross-sections of the first notch and the second notch are both trapezoidal with a wide upper section and a narrow lower section. The overall tearing pressure value of the explosion-proof notch 200 is affected by multiple factors, the main influencing factors including the notch residual value t of the explosion-proof notch 200, the bottom width W of the cross-section of the explosion-proof notch 200, the angle a between the waist of the cross-section trapezoid and the vertical direction (i.e., the height of the trapezoid), the shape of the explosion-proof notch 200, the wall thickness T of the shell 100, and the material of the shell 100. The notch residual value of the explosion-proof notch 200 is defined as the remaining thickness of the shell 100 after thinning at the explosion-proof notch 200.

[0035] If the residual value t of the explosion-proof notch 200 is small, the overall tearing pressure value of the explosion-proof notch 200 is small; when the explosion-proof notch 200 explodes due to battery damage, the blocking force at the explosion-proof notch 200 is small, which may easily lead to the explosion-proof notch 200 completely exploding, and the enclosed part of the explosion-proof notch 200 will tear other parts of the shell 100 into a large gap under the influence of the huge impact force, thereby causing damage to the adjacent battery shell 100. If the residual value t of the notch is large, when the internal pressure of the battery reaches the upper limit pressure, the explosion-proof notch 200 may not be completely torn open; as a result, the pressure relief port formed at the explosion-proof notch 200 is relatively small, and the gas inside the battery cannot be discharged in time, which may cause the battery to over-expand and cause an explosion. However, since there are many factors that affect the overall tearing pressure value of the explosion-proof notch 200, when the residual values ​​of the notches at various locations of the explosion-proof notch 200 are the same, or the residual values ​​of the notches at various locations in several large component areas of the explosion-proof notch 200 are the same, it is difficult to reduce the influence of other factors on the overall tearing pressure value of the explosion-proof notch 200, and ensure that the explosion-proof notch 200 can be completely torn open without causing other parts of the shell 100 to be torn open with larger gaps.

[0036] In this embodiment, by setting the first and second notches with different notch residual values, the tearing difficulty of the explosion-proof notch 200 can be improved as a whole by increasing the notch residual value at the first notch, and then the tearing difficulty of the explosion-proof notch 200 can be adjusted by setting the second notch. By selecting the position, number, notch residual value and length of the second notch, the tearing difficulty of the explosion-proof notch 200 can be adjusted, making the adjustment of the tearing difficulty of the explosion-proof notch 200 more convenient and accurate, so that the tearing difficulty can be selectively reduced in various areas of the explosion-proof notch 200. For example, a longer second notch is generally set in an area of ​​the explosion-proof notch 200 where the tearing difficulty is large, and the notch residual value of the second notch in the area can be appropriately reduced, so that the tearing difficulty of the area on the explosion-proof notch 200 that was originally difficult to tear decreases more, and the tearing difficulty of each area of ​​the explosion-proof notch 200 becomes relatively close after adjustment. This facilitates controlling the overall tearing pressure value of the explosion-proof notch 200 so that the overall tearing pressure value of the explosion-proof notch 200 can satisfy the requirement of completely tearing the explosion-proof notch 200 without tearing other parts of the shell 100 into larger gaps.

[0037] The lower base width W of the cross section of the first notch and the second notch can be the same, generally 0.03 mm to 0.1 mm. In this embodiment, the lower base width W of the cross section of the first notch and the second notch is 0.08 mm. The value of the angle a between the waist of the trapezoid of the cross section of the first notch and the second notch and the height of the trapezoid is generally in the range of 25° to 45°.

[0038] Under the same conditions, the smaller the radius of curvature of the explosion-proof notch 200 curve, the more difficult it is to tear. Therefore, whether the area is easy to tear can be judged according to the radius of curvature of the curve of each area of ​​the explosion-proof notch 200, so as to roughly determine the setting length of the second notch. For example, a first curvature radius threshold and a second curvature radius threshold can be pre-set, and the first curvature radius threshold is greater than the second curvature radius threshold. The first curvature radius threshold is generally greater than the width of the narrow side 102 or the bottom cover 112 of the shell 100 where the explosion-proof notch 200 is located (i.e., the width of the bottom cover 112 along the curvature radius of the shell 100). Figure 1 or Figure 2 The second curvature radius threshold is generally smaller than half of the width of the narrow side surface 102 of the shell 100 or the bottom cover 112 where the explosion-proof notch 200 is located.

[0039] The shape of the explosion-proof notch 200 includes a curve with a curvature radius less than the second curvature radius threshold and a curve or straight line segment with a curvature radius greater than the first curvature radius threshold. The straight line segment area or the curve area with a curvature radius greater than the first curvature radius threshold in the explosion-proof notch 200 is a large curvature area 208, that is, an area that is easy to tear (an area with low tearing difficulty). The curve area with a curvature radius less than the second curvature radius threshold in the explosion-proof notch 200 is a small curvature area 207, that is, an area that is not easy to tear (an area with high tearing difficulty). When setting the second notch, the maximum length of the second notch in the large curvature area 208 (that is, the length of the longest second notch in the area) can be made greater than the maximum length of the second notch in the small curvature area 207, so that the tearing difficulty of the area that is not easy to tear is reduced more. Alternatively, the notch residual value of the second notch in the large curvature area 208 can be made less than the notch residual value of the second notch in the small curvature area 207, which can also reduce the tearing difficulty of the area that was originally not easy to tear. Of course, the maximum length of the second notch in the large curvature region 208 can be greater than the maximum length of the second notch in the small curvature region 207 , and the notch residual value of the second notch in the large curvature region 208 can be less than the notch residual value of the second notch in the small curvature region 207 .

[0040] The overall shape of the explosion-proof notch 200 can be a combination of one or more of a circular arc, an elliptical arc, a spline curve, and a straight line segment, and the head and tail ends of the explosion-proof notch 200 are not connected. Since the shape of the explosion-proof notch 200 is a closed curve, when the battery cell heats up and the gas inside the shell 100 expands, causing the explosion-proof notch 200 to be torn, the area enclosed by the explosion-proof notch 200 will often be torn as a whole and blown away by high voltage, which can easily cause secondary damage to other battery cells or water cooling plates and surrounding connecting circuits. Therefore, the explosion-proof notch 200 adopts a non-closed shape with a non-connected head and tail, which can avoid secondary damage to the battery when the battery cell heats up.

[0041] For example, the explosion-proof notch 200 may include a first curved notch 201 and a second curved notch 202 symmetrically arranged and a connecting notch 203 connecting the first curved notch 201 and the second curved notch 202, wherein the first curved notch 201 and the second curved notch 202 are not connected, so that a gap 204 is formed between the first curved notch 201 and the second curved notch 202. The shape of the first curved notch 201 and the second curved notch 202 is a curve whose maximum curvature radius is less than a second curvature radius threshold (i.e., the first curved notch 201 and the second curved notch 202 are large curvature regions 208). The shape of the connecting notch 203 is a straight line segment or a curve whose minimum curvature radius is greater than the first curvature radius threshold (i.e., the connecting notch 203 is a small curvature region 207). The shape of the first curved notch 201 and the second curved notch 202 is generally a circular arc, an elliptical arc or a plane spiral line, and the angle range of the first curved notch 201 and the second curved notch 202 is generally 180° to 270°. The shape of the connecting notch 203 is generally a straight line segment, an arc with a radius greater than a first curvature radius threshold, or an elliptical arc with a minimum curvature radius greater than the first curvature radius threshold.

[0042] See also Figure 4 and Figure 5In this embodiment, the explosion-proof notch 200 is provided on the bottom cover 112 of the housing 100, and the width of the bottom cover 112 is 32 mm. The shape of the connecting notch 203 is a straight line segment, and the shape of the first curved notch 201 and the second curved notch 202 is an arc with a diameter of 15 mm and an angle of 240° (i.e., an arc with an angle of 60° added to a semicircular arc). In the first curved score 201 region, the first score 211, the second score 251, the first score 212, the second score 252, the first score 213, the second score 253, the first score 214, the second score 254, the first score 215, the second score 255, the first score 216 and the second score 256 are arranged at intervals, in the connecting score 203 region, the first score 217, the second score 257, the first score 218, the second score 258, the first score 219, the second score 259, the first score 220 and the second score 260 are arranged at intervals, and in the second curved score 202 region, the first score 221, the second score 261 and the first score 222 are arranged at intervals. The score residual value of each of the first scores is 0.13 mm, and the score residual value of each of the second scores is about 0.08 mm. By setting the angle of the first curved notch 201 and the second curved notch 202 to be greater than 180°, the leading end and the trailing end of the explosion-proof notch 200 (i.e., one end of the first curved notch 201 where the first notch 211 is set and one end of the second curved notch 202 where the first notch 222 is set) are concave inward, so that when the explosion-proof notch 200 explodes, part of the impact force can be converted into an inward tearing force, thereby offsetting part of the outward tearing force and reducing the size of the notch formed by the tearing.

[0043] The explosion-proof notch 200 is generally formed by laser etching, and the first notch and the second notch can be formed by two or multiple laser etchings, respectively. For example, the first notch 211, the first notch 212, the first notch 213, the first notch 214, the first notch 215, the first notch 216, the first notch 217, the first notch 218, the first notch 219, the first notch 220, the first notch 221 and the first notch 222, a total of 12 first notches, can be formed by the first laser etching. Then, a second laser etching is performed to form a total of 11 second notches, namely, second notches 251, 252, 253, 254, 255, 256, 257, 258, 259, 260, and 261, between the 12 first notches, so that the 12 first notches and the 11 second notches are connected to form a whole. The shape of the explosion-proof notch 200 formed after two laser etchings is shown in FIG. Figure 5 Of course, when the residual values ​​of the second marks are inconsistent, the number of laser etchings can be increased. Figure 5The thicker line of the second notch is just to facilitate the distinction between the first notch and the second notch in the figure, and does not represent the actual cross-sectional width of the first notch and the second notch.

[0044] Among them, the lengths of the second notches 257, 258, 259 and 260 located in the connecting notch 203 region which is relatively easy to tear are relatively short and are basically close in length. In the first curved notch 201 and the second curved notch 202 region which is not easy to tear, the longest second notches are the second notches 254 and the second notch 261 respectively, and the lengths of the second notches 254 and the second notch 261 are much longer than the lengths of the second notches 257, 258, 259 and the second notch 260, that is, the second notches 254 and the second notch 261 are easier to tear, so that the tearing difficulty of the first curved notch 201 region and the second curved notch 202 region after the second notches are set is reduced more than that of the connecting notch 203 region.

[0045] See also Figure 6a , Figure 6b , Figure 6c , Figure 6d and Figure 6e , respectively, are several different shapes of explosion-proof notches 200 used in the blasting test of this application. During the blasting process, Figure 6a , Figure 6b and Figure 6c The explosion-proof notches 200 tear a large notch 205 extending to the side junction of the shell 100 on the shell 100, see Figure 7a , that is Figure 6a FIG. 2 is a schematic diagram of a notch 205 formed after the explosion-proof notch 200 is torn, wherein the dotted line portion in the figure is the tearing path. Figure 6d and Figure 6e Due to the large difference in tearing difficulty of each area of ​​the explosion-proof notch 200, insufficient explosion (i.e., the explosion-proof notch 200 failed to explode completely) occurred. Figure 5 When the explosion test is performed on the explosion-proof notch 200 in the shell 100, the explosion-proof notch 200 can be completely exploded each time, and the notch 206 torn in the area outside the explosion-proof notch 200 of the shell 100 is very small. Figure 7b , that is Figure 5 Schematic diagram of the explosion-proof notch 200 in the figure formed by tearing the notch 206 (the dotted line in the figure is the tearing path); Figure 7b It can be seen that the notch 206 is still far away from the junction of the side surface of the housing 100 and will not cause damage to the adjacent battery housing 100 .

[0046] In this embodiment, by setting 12 first notches and 11 second notches into a shape similar to a dotted line and connecting them in sequence to form an explosion-proof notch 200, since the notch residual value of the first notch is relatively large, the first notch can increase the blocking effect during explosion, and avoid the explosion energy not being fully absorbed after the explosion at the explosion-proof notch 200, resulting in other parts of the shell 100 also being torn open with a large notch, thereby causing damage to the adjacent battery shell 100. Since the notch residual value of the second notch is relatively small, by selecting the position, number, notch residual value and length of the second notch, the tearing difficulty of the explosion-proof notch 200 at the small curvature area 207 can be selectively reduced, so that the tearing difficulty of each area of ​​the explosion-proof notch 200 is relatively close, and the situation of insufficient explosion is avoided.

[0047] Example 2

[0048] The difference between this embodiment and embodiment 1 is that the explosion-proof notch 200 of this embodiment includes a first notch in the form of a continuous line and a plurality of second notches arranged in a dotted line along the length direction of the first notch and overlapping thereon; that is, the overall shape of the first notch is the same as that of the explosion-proof notch 200, and each second notch is formed by further reducing the residual value of the notch in a partial area of ​​the first notch. The method for forming the explosion-proof notch 200 in this embodiment is as follows:

[0049] First, laser etching is performed for the first time according to the shape and residual value of the first notch to obtain the first notch. In this embodiment, the etching depth of each part of the first notch obtained by the first laser etching is 0.05 mm. After the first laser etching is completed, the shape of the first notch formed can be seen in FIG. Figure 4 .

[0050] Then, according to the position and residual value of each second mark, a second laser etching is performed on the first mark to form each second mark. The second laser etching generally continues to etch down 0.05mm based on the first laser etching, that is, the total etching depth at the position of the second mark after two laser etchings is about 0.10mm. Figure 5 , a total of 11 second notches are formed by the second laser etching, namely, second notches 251, 252, 253, 254, 255, 256, 257, 258, 259, 260, and 261. In this embodiment, since the first notches are formed by laser etching along a continuous path, the control process of laser etching when forming the first notches is simplified.

[0051] The utility model also discloses a secondary battery, which can be a power battery or an energy storage battery, and the shell of the secondary battery can adopt a battery shell of any of the above embodiments. Of course, the secondary battery also includes a battery cell contained in the battery shell and other structures necessary for conventional secondary batteries, which are all existing technologies and will not be described in detail here.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the utility model.

Claims

1. A battery housing, characterized in that: It includes a shell, and explosion-proof notches are formed on the outer surface and / or the inner surface of the shell; the explosion-proof notches include a plurality of first notches arranged at intervals and a plurality of second notches connected between every two adjacent first notches, and the notch residual value of each second notch is smaller than the notch residual value of the first notch.

2. A battery housing, characterized in that: It includes a shell, and explosion-proof notches are formed on the outer surface and / or the inner surface of the shell; the explosion-proof notches include a first notch in the form of a continuous line and a plurality of second notches that are spaced apart along the length direction of the first notch and overlap therewith, and the notch residual value of the second notch is smaller than the notch residual value of the first notch.

3. A battery casing according to claim 1 or 2, characterized in that: The shape of the explosion-proof notch is a combination of one or more of a circular arc, an elliptical arc, a spline curve and a straight line segment, and the head end and the tail end of the explosion-proof notch are not connected.

4. A battery casing according to claim 3, characterized in that: A first curvature radius threshold and a second curvature radius threshold are preset, and the first curvature radius threshold is greater than the second curvature radius threshold; the shape of the explosion-proof notch includes a curve with a curvature radius less than the second curvature radius threshold and a curve or a straight line segment with a curvature radius greater than the first curvature radius threshold, the straight line segment area in the explosion-proof notch or the curve area with a curvature radius greater than the first curvature radius threshold is a large curvature area, and the curve area in the explosion-proof notch with a curvature radius less than the second curvature radius threshold is a small curvature area.

5. A battery casing according to claim 4, characterized in that: The maximum length of the second notch in the large curvature region is greater than the maximum length of the second notch in the small curvature region.

6. A battery casing according to claim 4, characterized in that: The score residual value of the second score in the large curvature region is smaller than the score residual value of the second score in the small curvature region.

7. A battery casing according to claim 4, characterized in that: The explosion-proof notch includes a first curved notch, a second curved notch, and a connecting notch connecting the first curved notch and the second curved notch, wherein the first curved notch and the second curved notch are not connected to each other, thereby forming a gap between the first curved notch and the second curved notch; the first curved notch and the second curved notch are in the shape of a curve whose maximum curvature radius is less than a second curvature radius threshold, and the connecting notch is in the shape of a straight line segment or a curve whose minimum curvature radius is greater than the first curvature radius threshold.

8. A battery casing according to claim 7, characterized in that: The shapes of the first curved notch and the second curved notch are circular arcs, elliptical arcs or planar spirals, and the angle range of the first curved notch and the second curved notch is 180° to 270°; the shape of the connecting notch is a straight line segment, an arc with a radius greater than a first curvature radius threshold, or an elliptical arc with a minimum curvature radius greater than the first curvature radius threshold.

9. A battery casing according to claim 1 or 2, characterized in that: The shell is made of stainless steel material with a thickness of 0.15mm to 0.3mm, the residual value of the first notch is 0.10mm to 0.15mm; the residual value of the second notch is 0.03mm to 0.09mm; the first notch and the second notch are both groove structures with a wide upper part and a narrow lower part in cross section, and the bottom width of the cross section is 0.03mm to 0.1mm.

10. A secondary battery, characterized in that: The invention comprises a battery casing as claimed in any one of claims 1 to 9.

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