Manufacturing method of explosion-proof grooved battery casing, battery casing and secondary battery

Abstract

This invention relates to a method for manufacturing a battery casing with explosion-proof grooves, the battery casing itself, and a secondary battery. The manufacturing method includes: taking a casing; etching multiple spaced first grooves on the outer and / or inner surface of the casing; etching a second groove between every two adjacent first grooves; connecting the multiple first grooves into a whole through the second grooves to form explosion-proof grooves, wherein the residual value of each second groove is less than the residual value of the first groove. In this invention, by etching multiple first and second grooves on the casing to form explosion-proof grooves, the tearing difficulty of each area of ​​the explosion-proof grooves can be adjusted through the second grooves, making the tearing difficulty of each area of ​​the explosion-proof grooves more similar, thus avoiding the situation where the area outside the explosion-proof grooves of the casing is torn open with a large gap or the explosion is insufficient in the event of an explosion.

Description

Technical Field

[0001] This invention belongs to the field of secondary battery technology, and relates to a method for manufacturing a battery casing with explosion-proof grooves, the battery casing, and a secondary battery. Background Technology

[0002] Currently, new energy vehicles and electric vehicles have become a new trend in the automotive industry; and secondary batteries, as the power source for pure electric vehicles, plug-in hybrid electric vehicles, and electric bicycles, are also widely used in the new energy field. Current secondary batteries are beginning to use lithium batteries encapsulated in thinner stainless steel shells to save material costs and reduce battery space. Explosion-proof markings formed by laser etching on the stainless steel shell serve as an integrated explosion-proof valve, replacing the explosion-proof valve welded to the shell. This simplifies the manufacturing process of the explosion-proof structure and makes the explosion-proof structure and shell a single unit, avoiding the impact of poor welding on the explosion-proof performance.

[0003] Furthermore, to prevent the area enclosed by the explosion-proof markings from tearing apart under high pressure during an explosion and causing secondary damage to surrounding components, the explosion-proof markings generally do not use a closed curve but instead leave a gap. Since the gap is of normal thickness and will not tear, this ensures that the area enclosed by the explosion-proof markings remains connected to the casing. However, because explosion-proof markings are generally curved, the gas pressure required for tearing at different points on the curve can vary significantly, making it difficult to accurately adjust the overall tearing gas pressure value of the explosion-proof markings. Since stainless steel casings are generally thin, if the overall tearing gas pressure value of the explosion-proof markings is too low, the area enclosed by the markings will generate a large outward impact force during an explosion, causing the casing to tear open a large gap from the notch and extend to the edge of the casing, thus damaging adjacent battery casings. If the overall tearing gas pressure value of the explosion-proof markings is too high, the explosion at the markings may be incomplete, potentially leading to a battery explosion and causing even greater danger. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is to provide a method for manufacturing a battery casing with explosion-proof grooves, a battery casing and a secondary battery.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for manufacturing a battery casing with explosion-proof grooves includes the following steps:

[0007] S101, Take a shell;

[0008] S102, A plurality of spaced first grooves are etched on the outer and / or inner surfaces of the housing;

[0009] S103. A second etch is formed between every two adjacent first etches, and multiple first etches are connected into a whole through the second etches to form an explosion-proof etch. The residual value of the second etch is less than the residual value of the first etch.

[0010] A method for manufacturing a battery casing with explosion-proof grooves includes the following steps:

[0011] S201. Take a shell;

[0012] S202, Etching a first groove in the shape of a continuous line on the outer surface and / or inner surface of the housing;

[0013] S203. Multiple second marks are formed by etching at intervals along the length direction of the first mark, thereby forming explosion-proof marks. The residual value of each of the second marks is less than the residual value of the first mark.

[0014] Furthermore, the shape of the explosion-proof groove is one or more combinations of circular arc, elliptical arc, spline curve and straight line segment, and the beginning and end of the explosion-proof groove are not connected.

[0015] Furthermore, a first radius of curvature threshold and a second radius of curvature threshold are preset, wherein the first radius of curvature threshold is greater than the second radius of curvature threshold; the shape of the explosion-proof groove includes curves with a radius of curvature less than the second radius of curvature threshold and curves or straight line segments with a radius of curvature greater than the first radius of curvature threshold. The straight line segment region or the curve region with a radius of curvature greater than the first radius of curvature threshold in the explosion-proof groove is a large curvature region, and the curve region with a radius of curvature less than the second radius of curvature threshold in the explosion-proof groove is a small curvature region.

[0016] 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; and / or

[0017] The residual value of the second groove in the region of high curvature is less than the residual value of the second groove in the region of low curvature.

[0018] Furthermore, the explosion-proof markings include a first curved marking and a second curved marking, as well as a connecting marking connecting the first curved marking and the second curved marking. The first curved marking and the second curved marking are not connected, thereby forming a gap between the first curved marking and the second curved marking. The shapes of the first curved marking and the second curved marking are curves with a maximum radius of curvature less than a second radius of curvature threshold, and the shape of the connecting marking is a straight line segment or a curve with a minimum radius of curvature greater than a first radius of curvature threshold.

[0019] Furthermore, the first and second curved grooves are in the shape of a circular arc, an elliptical arc, or a planar spiral, and the angle range of the first and second curved grooves is 180° to 270°; the connecting groove is in the shape of a straight line segment, a circular arc with a radius greater than a first radius of curvature threshold, or an elliptical arc with a minimum radius of curvature greater than a first radius of curvature threshold.

[0020] Furthermore, the shell is made of stainless steel with a thickness of 0.15mm to 0.3mm, the residual value of the first groove is 0.10mm to 0.15mm, and the residual value of the second groove is 0.03mm to 0.09mm. Both the first groove and the second groove are groove structures with a wider top and a narrower bottom, and the bottom width of the cross section is 0.03mm to 0.1mm.

[0021] A battery casing is manufactured using a method for producing a battery casing with explosion-proof grooves.

[0022] A secondary battery, including a battery casing.

[0023] In this invention, by setting multiple first and second notches in a shape similar to dashed lines, the first notches can increase the blocking effect during explosion, preventing the explosion energy from being incompletely absorbed after detonation at the explosion-proof notch, thus avoiding large gaps in other parts of the casing and damage to adjacent battery casings. By selecting the position, number, residual value, and length of the second notches, the tearing difficulty in areas with small curvature can be selectively reduced, making the tearing difficulty of each area of ​​the explosion-proof notch more similar and avoiding incomplete explosion. Attached Figure Description

[0024] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0025] Figure 1 This is a flowchart of an embodiment of the method for manufacturing an explosion-proof, grooved battery casing according to the present invention.

[0026] Figure 2 This is a schematic diagram of the shell structure.

[0027] Figure 3 A schematic diagram of the structure used to create the first notch.

[0028] Figure 4 This is a schematic diagram of the cross-section of the explosion-proof markings.

[0029] Figure 5 This is a schematic diagram of the structure of the battery casing after making explosion-proof grooves.

[0030] Figure 6 This is a schematic diagram of the overall structure of the explosion-proof grooves.

[0031] Figure 7 This is a schematic diagram of the structure of the first and second notches.

[0032] Figure 8a , Figure 8b , Figure 8c , Figure 8d and Figure 8e These are schematic diagrams of several different shapes of explosion-proof markings used during blasting tests.

[0033] Figure 9a for Figure 8a A diagram illustrating the notch formed after the explosion-proof grooves in the image are torn.

[0034] Figure 9b for Figure 7 A diagram illustrating the notch formed after the explosion-proof grooves in the design are torn.

[0035] Figure 10 This is a flowchart of another embodiment of the method for manufacturing an explosion-proof, etched battery casing according to the present invention.

[0036] The meanings of the labels in the attached diagram are as follows:

[0037] Shell - 100; Wide side - 101; Narrow side - 102; Top cover - 111; Bottom cover - 112; Explosion-proof groove - 200; First curve groove - 201; Second curve groove - 202; Connection groove - 203; Notch - 204; Gap - 205, 206; Small curvature area - 207; Large curvature area - 208; First groove - 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222; Second groove - 251, 252, 253, 254, 255, 256, 257, 258, 259, 260, 261. Detailed Implementation

[0038] The following specific examples illustrate the implementation of the present invention. The illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0039] Example 1

[0040] This invention discloses a method for manufacturing a battery casing with explosion-proof grooves. Please refer to [link / reference]. Figure 1 This is a flowchart illustrating an embodiment of the method for manufacturing an explosion-proof, grooved battery casing according to the present invention. The method for manufacturing the explosion-proof, grooved battery casing in this embodiment includes the following steps:

[0041] S101, Take a housing 100. Please refer to [link / reference]. Figure 2 The housing 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 side panels 101, and two oppositely arranged narrow side panels 102. This type of housing 100 can be used to produce batteries such as blade batteries and prismatic batteries. The housing 100 is preferably made of stainless steel, generally with a wall thickness in the range of 0.15mm to 0.3mm; in this embodiment, the wall thickness of the stainless steel housing 100 is 0.18mm ± 0.005mm. Of course, the housing 100 can also be made of aluminum alloy; when aluminum alloy is used, the wall thickness of the housing 100 will be much greater than that when stainless steel is used.

[0042] S102, please refer to Figure 3 Multiple spaced first grooves are etched onto the outer and / or inner surfaces of the housing 100. The residual value of each of the multiple first grooves can be the same, allowing all first grooves to be formed in a single etching operation. The residual value of the first grooves is generally in the range of 0.10 mm to 0.15 mm. Since the two wide sides 101 of blade batteries, prismatic batteries, etc., are tightly fitted to adjacent batteries during installation, preventing the explosion-proof grooves 200 from being torn open, the explosion-proof grooves 200 are generally not provided on the two wide sides 101 of the housing 100. Furthermore, the top cover 111 of the housing 100 has electrodes and other components, leaving limited area for etching to form the explosion-proof grooves 200; therefore, the explosion-proof grooves 200 are generally avoided on the top cover 111. Therefore, the explosion-proof grooves 200 are typically etched onto one of the narrow sides 102 of the housing 100 or onto the bottom cover 112 of the housing 100. That is, the first etch mark in this step is usually etched on one of the narrow sides 102 of the housing 100 or on the bottom cover 112 of the housing 100.

[0043] Please see Figure 4 The explosion-proof notch 200 (i.e., the first notch and the second notch) is generally a groove structure with a wider top and narrower bottom. In this embodiment, both the first and second notches have trapezoidal cross-sections with a wider top and narrower bottom. The overall tear pressure value of the explosion-proof notch 200 is affected by multiple factors, the main influencing factors including the residual value t of the explosion-proof notch 200, the width W of the lower base of the cross-section of the explosion-proof notch 200, the angle α between the waist of the trapezoidal cross-section 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 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.

[0044] S103, please refer to Figure 5 A second etch is formed between every two adjacent first etch marks, resulting in a dotted-line-like shape for each second etch. When the first and / or last end of the explosion-proof etch mark 200 is a second etch, it connects only to one adjacent first etch mark. Multiple first etch marks spaced apart are connected into a single unit by these second etches, forming the explosion-proof etch mark 200. The residual value of each second etch is less than the residual value of the first etch. The residual values ​​of the multiple second etches can be the same or different. When all the residual values ​​of the second etches are the same, all second etches can be formed by a single etching operation. When the residual values ​​of the second etches are not completely identical, all second etches can be formed by multiple etching operations. The residual value of the second etch is generally in the range of 0.03 mm to 0.09 mm.

[0045] When the battery cells inside the battery are damaged and emit a large amount of heat and / or release gas, the pressure inside the casing 100 expands rapidly. When explosion-proof grooves 200 are provided on the casing 100, if the air pressure inside the casing 100 is too high, the explosion-proof grooves 200 will be torn open under the high pressure, allowing the high-pressure gas inside the casing 100 to escape from the torn opening. This quickly reduces the air pressure inside the casing 100, preventing the battery from exploding and ensuring the safety of the manufacturer and the user. The air pressure value at which the explosion-proof grooves 200 are just completely torn open is the overall tear pressure value of the explosion-proof grooves 200.

[0046] If the residual value t of the explosion-proof notch 200 is small, the overall tear pressure value of the explosion-proof notch 200 will be small. When cell damage causes the explosion-proof notch 200 to burst open, the resistance at the notch 200 will be small, making it easy for the notch 200 to completely burst open. Under the influence of the huge impact, the enclosed part of the notch 200 will tear large gaps in other parts of the casing 100, thereby damaging adjacent battery casings 100. If the residual value t is large, the explosion-proof notch 200 may not be able to completely tear open when the internal pressure of the battery reaches the upper limit. This will result in a small pressure relief port formed at the explosion-proof notch 200, which cannot release the gas inside the battery in time, potentially leading to excessive battery expansion and an explosion. However, since there are many factors affecting the overall tear pressure value of the explosion-proof notch 200, when the residual value of the notch is the same everywhere, or when the residual value of the notch is the same in several large component areas of the explosion-proof notch 200, it is difficult to reduce the influence of other factors on the overall tear pressure value of the explosion-proof notch 200, so as to ensure that the explosion-proof notch 200 can be completely torn open without causing large gaps to be torn in other parts of the housing 100.

[0047] In this embodiment, by etching to form a first and a second etchant with different residual values, the tearing difficulty of the explosion-proof etchant 200 can be increased overall by increasing the residual value at the first etchant. Then, the tearing difficulty can be adjusted by setting the second etchant. The tearing difficulty of the explosion-proof etchant 200 can be adjusted by selecting the position, number, residual value, and length of the second etchant, making the adjustment more convenient and precise. This allows for selective reduction of tearing difficulty in different areas of the explosion-proof etchant 200. For example, a longer second etchant is typically set in areas of high tearing difficulty, and the residual value of the second etchant in that area can be appropriately reduced. This results in a greater reduction in tearing difficulty in areas of the explosion-proof etchant 200 that were originally difficult to tear, making the tearing difficulty in different areas of the explosion-proof etchant 200 more similar after adjustment. This facilitates the control of the overall tear pressure value of the explosion-proof notch 200, ensuring that the overall tear pressure value of the explosion-proof notch 200 meets the requirement that the explosion-proof notch 200 can be completely torn open without causing large gaps to be torn in other parts of the housing 100.

[0048] The width W of the lower base of the cross-sections of the first and second notches can be the same, generally 0.03mm to 0.1mm. In this embodiment, the width W of the lower base of the cross-sections of the first and second notches is 0.08mm. The angle α between the waist and the height of the trapezoid of the cross-sections of the first and second notches is generally in the range of 25° to 45°.

[0049] Because, under the same conditions, areas with smaller radii of curvature of the explosion-proof notch 200 curve are more difficult to tear, the ease of tearing of an area can be determined based on the radii of curvature of the curve in each region of the explosion-proof notch 200, thus roughly determining the length of the second notch. For example, a first radius of curvature threshold and a second radius of curvature threshold can be preset, where the first radius of curvature threshold is greater than the second radius of curvature threshold. The first radius of curvature threshold is generally greater than the width of the narrow side 102 or bottom cover 112 of the housing 100 where the explosion-proof notch 200 is located (i.e., along...). Figure 1 or Figure 2 The length in the y-axis direction), the second radius of curvature threshold is generally less than half the width of the narrow side 102 or bottom cover 112 of the housing 100 where the explosion-proof notch 200 is located.

[0050] The explosion-proof notch 200 includes curves with a radius of curvature smaller than a second radius of curvature threshold and curves or straight line segments with a radius of curvature larger than a first radius of curvature threshold. The straight line segment region or the curve region with a radius of curvature larger than the first radius of curvature threshold in the explosion-proof notch 200 is a large curvature region 208, i.e., an area that is easy to tear (area with low tearing difficulty). The curve region with a radius of curvature smaller than the second radius of curvature threshold in the explosion-proof notch 200 is a small curvature region 207, i.e., an area that is not easy to tear (area with high tearing difficulty). When setting the second notch, the maximum length of the second notch in the large curvature region 208 (i.e., the length of the longest second notch in this region) can be greater than the maximum length of the second notch in the small curvature region 207, thereby further reducing the tearing difficulty in areas that are not easy to tear. Alternatively, the residual value of the second notch in the large curvature region 208 can be less than the residual value of the second notch in the small curvature region 207, which similarly reduces the tearing difficulty in areas that were originally not easy to tear. Of course, the maximum length of the second groove in the large curvature region 208 can also be greater than the maximum length of the second groove in the small curvature region 207, and the groove residual value of the second groove in the large curvature region 208 can be less than the groove residual value of the second groove in the small curvature region 207.

[0051] The overall shape of the explosion-proof etchant 200 formed by the connection of the first and second etchants can be one or more combinations of circular arcs, elliptical arcs, spline curves, and straight line segments, and the beginning and end of the explosion-proof etchant 200 are not connected. Since the explosion-proof etchant 200 is a closed curve, when the cell heats up and the gas inside the casing 100 expands, causing the explosion-proof etchant 200 to tear, the area enclosed by the explosion-proof etchant 200 often tears completely and is blown away by high pressure, easily causing secondary damage to other cells, water-cooling plates, and surrounding circuits. Therefore, the explosion-proof etchant 200 adopts a non-closed shape where the beginning and end are not connected, which can avoid secondary damage to the battery when the cell heats up.

[0052] For example, the explosion-proof notch 200 may include a symmetrically arranged first curved notch 201 and second curved notch 202, and a connecting notch 203 connecting the first curved notch 201 and the second curved notch 202. The first curved notch 201 and the second curved notch 202 are not connected, thereby forming a gap 204 between the first curved notch 201 and the second curved notch 202. The first curved notch 201 and the second curved notch 202 are curves with a maximum radius of curvature less than a second radius of curvature threshold (i.e., the first curved notch 201 and the second curved notch 202 are large curvature regions 208). The connecting notch 203 is a straight line segment or a curve with a minimum radius of curvature greater than a first radius of curvature threshold (i.e., the connecting notch 203 is a small curvature region 207). The first curved notch 201 and the second curved notch 202 are generally circular arcs, elliptical arcs, or planar spirals, 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 groove 203 is generally a straight line segment, an arc with a radius greater than the first radius of curvature threshold, or an elliptical arc with a minimum radius of curvature greater than the first radius of curvature threshold.

[0053] Please see Figure 6 and Figure 7In this embodiment, the explosion-proof groove 200 is provided on the bottom cover 112 of the housing 100, and the bottom cover 112 has a width of 32mm. The connecting groove 203 is a straight line segment, and the first curved groove 201 and the second curved groove 202 are arcs with a diameter of 15mm and an angle of 240° (that is, an arc with an added 60° on the basis of a semi-circular arc). In the area of ​​the first curved groove 201, first grooves 211, 251, 212, 252, 213, 253, 214, 254, 215, 255, 216, and 256 are spaced apart. In the area of ​​the connecting groove 203, first grooves 217, 257, 218, 258, 219, 259, 220, and 260 are spaced apart. In the area of ​​the second curved groove 202, first grooves 221, 261, and 222 are spaced apart. The residual value of each first groove is 0.13 mm, and the residual value of each second groove is approximately 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 beginning and end of the explosion-proof notch 200 (i.e., the end of the first curved notch 201 where the first notch 211 is located and the end of the second curved notch 202 where the first notch 222 is located) are concave inward. This allows a portion of the impact force to be converted into an inward tearing force when the explosion-proof notch 200 explodes, thereby offsetting a portion of the outward tearing force and reducing the size of the notch formed by the tear.

[0054] In this embodiment, the explosion-proof markings 200 are formed by laser etching; wherein, the first marking and the second marking are formed by two separate laser etching processes. First, a first laser etching process is used to form a total of 12 first markings: first marking 211, first marking 212, first marking 213, first marking 214, first marking 215, first marking 216, first marking 217, first marking 218, first marking 219, first marking 220, first marking 221, and first marking 222. Then, a second laser etching process is used to form 11 second etchables between the 12 first etchables: second etchables 251, 252, 253, 254, 255, 256, 257, 258, 259, 260, and 261. This connects the 12 first etchables and the 11 second etchables into a single unit. The shape of the explosion-proof etchable 200 formed after the two laser etching processes is shown in the image. Figure 7 Of course, if the residual values ​​of the various second etch marks are inconsistent, the number of laser etching passes can be increased. It should be noted that... Figure 7The thicker lines of the second notch are only for easy differentiation between the first and second notches in the diagram, and do not represent the actual cross-sectional width of the first and second notches.

[0055] Among them, the second etchants 257, 258, 259, and 260, located in the area of ​​the connecting etchant 203 that is relatively easy to tear, are shorter and their lengths are basically the same. In the areas of the first curved etchant 201 and the second curved etchant 202 that are not easy to tear, the longest second etchants are the second etchant 254 and the second etchant 261, respectively. The lengths of the second etchants 254 and the second etchant 261 are much greater than the lengths of the second etchants 257, 258, 259, and 260. That is, the second etchants 254 and the second etchant 261 are easier to tear, thus making the tearing difficulty in the areas of the first curved etchant 201 and the second curved etchant 202 more reduced than that in the area of ​​the connecting etchant 203 after setting each second etchant.

[0056] Please see Figure 8a , Figure 8b , Figure 8c , Figure 8d and Figure 8e These are several different shapes of explosion-proof notches 200 used during the blasting test of this application. During the blasting process, Figure 8a , Figure 8b and Figure 8c The explosion-proof scoring 200 all tear a large notch 205 on the housing 100, extending to the junction of the side of the housing 100. Please refer to [link / reference]. Figure 9a That is Figure 8a The diagram shows how the explosion-proof notch 200 is torn to form a notch 205. The dotted line in the diagram represents the tear path. Figure 8d and Figure 8e Due to significant differences in tearing difficulty across different areas, the explosion-proof notch 200 resulted in insufficient bursting (i.e., the explosion-proof notch 200 failed to fully burst open). However, the explosion-proof notch 200 used in this embodiment (i.e....) Figure 5 When the explosion-proof notch 200 is subjected to a burst test, the notch 200 can be completely opened each time, and the notch 206 torn outside the explosion-proof notch 200 of the casing 100 is very small. Please refer to Figure 9b That is Figure 5 A schematic diagram showing the notch 206 formed after the explosion-proof notch 200 is torn (the dotted line in the diagram represents the tear path); from Figure 9b It can be seen that the notch 206 is still a considerable distance from the junction of the side of the casing 100, and will not cause damage to the adjacent battery casing 100.

[0057] In this embodiment, 12 first notches and 11 second notches are arranged in a dotted-line shape and connected sequentially to form explosion-proof notches 200. Because the residual value of the first notches is relatively large, they can increase the blocking effect during explosion, preventing the explosion energy from being completely absorbed after the explosion occurs at the explosion-proof notch 200, thus avoiding large gaps in other parts of the casing 100 and damage to adjacent battery casings 100. Because the residual value of the second notches is relatively small, by selecting the position, number, residual value, and length of the second notches, the tearing difficulty of the explosion-proof notches 200 in the small curvature area 207 can be selectively reduced, making the tearing difficulty of each area of ​​the explosion-proof notches 200 more similar and avoiding incomplete explosion.

[0058] Example 2

[0059] Please see Figure 10 This is a flowchart illustrating another embodiment of the method for manufacturing a battery casing with explosion-proof grooves according to the present invention. The method for manufacturing a battery casing with explosion-proof grooves in this embodiment includes the following steps:

[0060] S201. Take a housing 100. The shape and material of the housing 100 can be the same as the housing 100 in Example 1.

[0061] S202. A continuous linear first groove is formed on the outer and / or inner surface of the housing 100 by a single laser etching; the shape of the first groove is shown in [reference]. Figure 6 The etching depth at each point of the first etch mark is 0.05 mm, meaning the residual etching value at each point of the first etch mark is 0.13 mm.

[0062] S203. Multiple second etchables overlapping the first etchable are formed by laser etching along the length of the first etchable, creating explosion-proof etchables 200. This ensures that the residual value of each of the second etchables is less than that of the first etchable. In this embodiment, 11 second etchables (251, 252, 253, 254, 255, 256, 257, 258, 259, 260, and 261) are formed through a second laser etching. During this step, the laser etching typically continues downwards by 0.05 mm from the first laser etching. Therefore, the total etching depth at the location of the second etchable after two laser etchings is generally around 0.10 mm, with a residual etching value of approximately 0.08 mm.

[0063] The difference between this embodiment and Embodiment 1 lies only in that: the explosion-proof marking 200 in this embodiment includes a continuous linear first marking and multiple second markings spaced at intervals along the length of the first marking and overlapping thereon; that is, the overall shape of the first marking is the same as that of the explosion-proof marking 200, and each second marking is formed by further reducing the marking residual value in a portion of the first marking. In this embodiment, since the first marking is formed by laser etching along a continuous path, the control process of laser etching when forming the first marking is simplified.

[0064] This invention also discloses a secondary battery, which can be a power battery or an energy storage battery. The casing of the secondary battery can adopt the battery casing of any of the above embodiments. Of course, the secondary battery also includes the battery cells housed in the battery casing and other structures necessary for conventional secondary batteries, which are prior art and will not be described in detail here.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for manufacturing a battery casing with explosion-proof grooves, characterized in that, Includes the following steps: S101, Take a shell; S102, Multiple spaced first grooves are formed on the outer and / or inner surfaces of the housing by laser etching; S103. A second groove is formed between every two adjacent first grooves by laser etching. Multiple first grooves are connected into a whole by the second grooves to form an explosion-proof groove. The groove residual value of the second groove is less than the groove residual value of the first groove. A first radius of curvature threshold and a second radius of curvature threshold are preset, wherein the first radius of curvature threshold is greater than the second radius of curvature threshold; the explosion-proof markings include symmetrically arranged first and second curved markings and connecting markings connecting the first and second curved markings, wherein one end of the first curved marking is connected to the first end of the connecting marking, and one end of the second curved marking is connected to the second end of the connecting marking; the first and second curved markings are not connected, thereby forming a gap between the first and second curved markings. The first and second curved grooves are circular arcs, elliptical arcs, or planar spirals, and the maximum radius of curvature of the first and second curved grooves is less than the second radius of curvature threshold; the angle range of the first and second curved grooves is 240° to 270°, so that the beginning and end of the explosion-proof grooves are concave inward. The shape of the connecting groove is a straight line segment, an arc with a radius greater than the first radius of curvature threshold, or an elliptical arc with a minimum radius of curvature greater than the first radius of curvature threshold. The shape of the explosion-proof markings includes curves with a radius of curvature less than a second radius of curvature threshold and curves or straight line segments with a radius of curvature greater than a first radius of curvature threshold. The straight line segment region or the curve region with a radius of curvature greater than the first radius of curvature threshold in the explosion-proof markings is a large curvature region, and the curve region with a radius of curvature less than the second radius of curvature threshold in the explosion-proof markings is a small curvature region. The maximum length of the second notch in the region of high curvature is greater than the maximum length of the second notch in the region of low curvature. and / or The residual value of the second groove in the region of high curvature is less than the residual value of the second groove in the region of low curvature.

2. A method for manufacturing a battery casing with explosion-proof grooves, characterized in that, Includes the following steps: S201. Take a shell; S202, A first continuous line-shaped groove is formed on the outer and / or inner surface of the housing by laser etching; S203. Multiple second marks are formed by laser-interval etching along the length direction of the first mark, thereby forming an explosion-proof mark. The residual value of the second mark is less than the residual value of the first mark. A first radius of curvature threshold and a second radius of curvature threshold are preset, wherein the first radius of curvature threshold is greater than the second radius of curvature threshold; the explosion-proof markings include symmetrically arranged first and second curved markings and connecting markings connecting the first and second curved markings, wherein one end of the first curved marking is connected to the first end of the connecting marking, and one end of the second curved marking is connected to the second end of the connecting marking; the first and second curved markings are not connected, thereby forming a gap between the first and second curved markings. The first and second curved grooves are circular arcs, elliptical arcs, or planar spirals, and the maximum radius of curvature of the first and second curved grooves is less than the second radius of curvature threshold; the angle range of the first and second curved grooves is 240° to 270°, so that the beginning and end of the explosion-proof grooves are concave inward. The shape of the connecting groove is a straight line segment, an arc with a radius greater than the first radius of curvature threshold, or an elliptical arc with a minimum radius of curvature greater than the first radius of curvature threshold. The shape of the explosion-proof markings includes curves with a radius of curvature less than a second radius of curvature threshold and curves or straight line segments with a radius of curvature greater than a first radius of curvature threshold. The straight line segment region or the curve region with a radius of curvature greater than the first radius of curvature threshold in the explosion-proof markings is a large curvature region, and the curve region with a radius of curvature less than the second radius of curvature threshold in the explosion-proof markings is a small curvature region. The maximum length of the second notch in the region of high curvature is greater than the maximum length of the second notch in the region of low curvature. and / or The residual value of the second groove in the region of high curvature is less than the residual value of the second groove in the region of low curvature.

3. The method for manufacturing a battery casing with explosion-proof grooves according to claim 1 or 2, characterized in that: The shell is made of stainless steel with a thickness of 0.15mm to 0.3mm. The residual value of the first groove is 0.10mm to 0.15mm; the residual value of the second groove is 0.03mm to 0.09mm; both the first groove and the second groove are groove structures with a wider top and a narrower bottom, and the bottom width of the cross section is 0.03mm to 0.1mm.

4. A battery casing, characterized in that: It is manufactured using the method for producing an explosion-proof, serrated battery casing as described in any one of claims 1 to 3.

5. A secondary battery, characterized in that: Includes the battery casing as described in claim 4.

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