Battery case having explosion-proof notch and manufacturing method therefor, battery and electric device

Abstract

A battery case having an explosion-proof notch and a manufacturing method therefor, a battery and an electric device. The battery case comprises a housing (100); an explosion-proof valve area (300) is arranged on the outer surface or the inner surface of the housing (100), an explosion-proof notch (200) is formed in the explosion-proof valve area (300) by means of laser etching, and the notch residual value of the explosion-proof notch (200) is 0.01-0.5 mm. By directly etching the explosion-proof notch (200) on the housing (100), the explosion-proof effect of the explosion-proof structure is prevented from being affected by a welding failure during welding of an explosion-proof valve; and during etching of the explosion-proof notch (200), the range of the tearing air pressure value of the explosion-proof notch (200) can be defined by selecting a suitable notch residual value, to ensure that the explosion-proof notch (200) can be torn in a timely manner to release high-pressure gas inside the housing (100) when the air pressure inside the housing (100) reaches a predetermined air pressure value range, thereby preventing the battery from exploding, and guaranteeing the personal safety of producers and users.

Description

Battery casing with explosion-proof notches, manufacturing method thereof, battery, and electrical equipment Technical Field

[0001] The invention belongs to the technical field of secondary batteries and relates to a battery shell with explosion-proof notches and a manufacturing method thereof, a battery, and electrical equipment. Background Art

[0002] New energy vehicles and electric vehicles have become a new trend in the automotive industry. Secondary batteries, as power sources for devices such as pure electric vehicles, plug-in hybrid vehicles, and electric bicycles, are also widely used in the new energy sector. Currently, most secondary batteries are lithium batteries enclosed in aluminum casings. Pressure relief holes are typically provided in the battery's top cover, and explosion-proof valves are welded to the holes to release internal pressure when the battery is under high pressure, preventing safety accidents such as explosions. However, when the pressure in the battery fluctuates and becomes excessive, if the explosion-proof valve is not welded firmly to the top cover, it may crack during use due to collisions, resulting in battery failure. Furthermore, traditional methods require drilling holes in the top cover and separately fabricating the explosion-proof valve, requiring high-precision laser welding equipment. The welds must be airtight and cannot burn through the thin explosion-proof valve. The explosion-proof valve also requires separate stamping and scoring. Furthermore, the material used for the explosion-proof valve is still imported, which is costly and compromises the integrity of the battery casing.

[0003] Summary of the Invention

[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 casing with explosion-proof notches and a manufacturing method thereof, a battery, and an electrical device.

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

[0006] A battery casing with explosion-proof notches, characterized in that it includes a shell, an explosion-proof valve area is provided on the outer surface or the inner surface of the shell, the explosion-proof valve area is formed with explosion-proof notches by laser etching, and the residual value of the explosion-proof notches is 0.01mm to 0.5mm.

[0007] In the present invention, by directly etching explosion-proof notches on the rectangular shell, the explosion-proof structure and shell are integrated, preventing welding errors during the explosion-proof valve from affecting the explosion-proof structure's explosion-proof effectiveness. By selecting an appropriate notch residual value when etching the explosion-proof notch, the tear pressure range of the notch can be limited. This ensures that when the air pressure inside the shell reaches a predetermined pressure range, the notch will tear open promptly to release the high-pressure gas inside the shell, preventing battery explosion and ensuring the personal safety of manufacturers and users. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] 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:

[0009] 1 and 2 are schematic structural diagrams of an embodiment of a battery housing with explosion-proof notches according to the present invention.

[0010] FIG3 is a schematic cross-sectional view of an explosion-proof notch.

[0011] FIG4 is a schematic structural diagram of a circular explosion-proof notch with a notch.

[0012] FIG5 is a schematic structural diagram of an elliptical explosion-proof notch with a notch.

[0013] FIG6 is a schematic structural diagram of a runway-shaped explosion-proof notch with a notch.

[0014] FIG7 is a schematic structural diagram of a cross-shaped explosion-proof notch.

[0015] FIG8 is a schematic diagram of the structure after two arc notches are added to the cross-shaped explosion-proof notch.

[0016] FIG9 is a flow chart of an embodiment of a method for manufacturing a battery casing with explosion-proof notches according to the present invention.

[0017] The meanings of the reference numerals in the accompanying drawings are:

[0018] Shell 100; top surface 111; bottom surface 112; wide side 121; narrow side 131; explosion-proof notch 200; notch 201; semicircular notches 211, 212; straight line widening notches 221, 222; first straight line notch 231; second straight line notch 232; circular notch 233; explosion-proof valve area 300. DETAILED DESCRIPTION

[0019] 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 unless there is any conflict.

[0020] The present invention discloses a battery casing with explosion-proof notches. Referring to Figures 1 and 2, one embodiment of a battery casing with explosion-proof notches according to the present invention includes a housing 100. An explosion-proof valve region 300 is provided on the outer or inner surface of the housing 100. The explosion-proof notches 200 are formed in the explosion-proof valve region 300 by laser etching, thereby forming an explosion-proof structure. In this embodiment, the housing 100 is made of stainless steel. The thickness of the stainless steel material can range from 0.05mm to 0.8mm. Generally, stainless steel materials with a thickness in the range of 0.1mm to 0.3mm are selected to manufacture the housing 100. In this embodiment, the thickness of the stainless steel housing 100 is 0.20mm±0.005mm. Of course, the housing 100 can also be made of an aluminum alloy material. When using an aluminum alloy material, the thickness of the aluminum alloy material can range from 0.2mm to 1.5mm. Generally, an aluminum alloy material with a thickness of 0.5mm is selected to manufacture the housing 100. The casing 100 of a secondary battery in the prior art is generally made of aluminum alloy. Because aluminum alloy is relatively soft, it requires a thicker aluminum alloy material. When forming the explosion-proof notch 200 on an aluminum alloy casing 100, a groove is generally pre-formed in the explosion-proof valve region 300 by stamping or other means to reduce the thickness of this region. The explosion-proof notch 200 is then formed within the groove. Given the same strength requirements for the battery casing 100, a casing 100 made of stainless steel can be made of thinner material than a casing 100 made of aluminum alloy. This allows the explosion-proof notch 200 to be directly formed on the casing 100 without first stamping a groove. For example, in this embodiment, the thickness of the stainless steel casing 100 is 0.20 mm ± 0.005 mm, which is much smaller than the 0.5 mm thickness commonly used when the casing 100 is made of aluminum alloy.

[0021] When the battery cells inside the battery are damaged, they will dissipate a large amount of heat and / or release gas, causing the pressure inside the shell 100 to expand rapidly. If the pressure is not relieved in time, when the air pressure inside the shell 100 is too high, there is a risk of explosion. In this embodiment, by providing an explosion-proof notch 200 on the shell 100, 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, allowing the gas inside the shell 100 to be discharged from the torn point of the explosion-proof notch 200, thereby releasing the high-pressure gas inside the shell 100, preventing the battery from exploding and ensuring the personal safety of the manufacturer and user. The air pressure value that causes the explosion-proof notch 200 to tear is the tearing pressure value of the explosion-proof structure. In addition, since the explosion-proof notches 200 are directly etched on the shell 100 to form the explosion-proof structure in this embodiment, the explosion-proof structure and the shell 100 are integrated as a whole. Compared with the existing technology of opening a pressure relief hole and welding an explosion-proof valve at the pressure relief hole, the process is simpler and does not require the use of a welding process, thereby avoiding the impact of errors in the welding process on the explosion-proof effect of the explosion-proof structure.

[0022] In this embodiment, the housing 100 is a generally thin, rectangular parallelepiped, comprising a top surface 111, a bottom surface 112 opposite the top surface 111, two oppositely disposed wide side surfaces 121, and two oppositely disposed narrow side surfaces 131. This type of housing 100 can be used to produce blade batteries, prismatic batteries, and the like. During installation, the two wide side surfaces 121 will closely adhere to the adjacent batteries on either side, thereby preventing the explosion-proof notch 200 from being torn. Therefore, the explosion-proof notch 200 is generally not provided on the two wide side surfaces 121 of the housing 100. Furthermore, the top surface 111 of the housing 100 is generally the top cover of the battery, on which components such as electrodes are disposed. This leaves less area for the explosion-proof notch 200, which also avoids placing the explosion-proof notch 200 on the top surface 111. Therefore, the explosion-proof notch 200 is generally provided on one of the narrow side surfaces 131 or on the bottom surface 112. Of course, it is not ruled out that the explosion-proof notch 200 is stamped on the top cover plate. If it is provided on the top cover plate, the volume of the processed product can be reduced and the dual requirements of the stamping equipment on size and precision can be lowered.

[0023] Because the blade battery's housing 100 is relatively long, considering that if a cell fails, the air pressure in different areas of the housing may vary significantly, a location too far from the explosion-proof notch 200 can also affect the explosion-proof structure's effectiveness. Therefore, in this embodiment, the explosion-proof notch 200 is located on the narrow side 131. The number of explosion-proof notches 200 can be more than one, depending on the length of the housing 100 (i.e., the length of the housing 100 along the z-axis in Figures 1 and 2). Generally, an explosion-proof structure formed by an explosion-proof notch 200 is provided every 300 mm along the length of the housing 100. For housings 100 lengths of 600 mm or less, only one explosion-proof valve area 300 (i.e., one explosion-proof notch 200) is sufficient. If the housing 100 length is greater than 600 mm, one explosion-proof valve area 300 is added for every 300 mm increase in length, with each explosion-proof valve area 300 evenly spaced along the length of the housing 100. This ensures that when a battery cell fails at any location, an explosion-proof notch 200 is provided within a relatively close range. This ensures that when the air pressure inside the shell 100 reaches the tearing pressure value, the explosion-proof notch 200 can be torn open normally to discharge the expanded gas inside the shell 100 and prevent the battery from exploding.

[0024] The 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. In this embodiment, the shape of the explosion-proof notch 200 is preferably a curve without sharp angles, such as a quasi-circular curve or a spline curve. For example, the shape of the explosion-proof notch 200 can be a circular, elliptical, or runway-shaped quasi-circular curve. Of course, the shape of the explosion-proof notch 200 can also be other curves, such as a hyperbola, a swooping curve, or a parabola.

[0025] The shape of the explosion-proof notch 200 is generally a curve with a notch formed by cutting a section off a closed curve. This curve with the notch 201 serves as the shape of the explosion-proof notch 200. For example, the shape of the explosion-proof notch 200 can be a non-closed curve arranged along the outline of the explosion-proof valve region 300. The outline of the explosion-proof valve region 300 is preferably a closed curve without forming a sharp angle. For example, the shape of the explosion-proof valve region 300 is preferably circular, elliptical, or a racetrack. Of course, the shape of the explosion-proof valve region 300 can also be formed by other closed spline curves. The explosion-proof notch 200 can be formed by laser etching. Laser etching uses a high-energy laser beam to illuminate the surface of the workpiece, melting and vaporizing it, forming grooves of a certain depth to achieve the purpose of etching the material. Laser etching is characterized by high precision, small notch width, high etching yield, high stability, and the absence of consumables, pollution, and low cost. In the prior art, the explosion-proof notch 200 of an aluminum alloy housing is typically formed by stamping. Due to the limitations of the stamping process, existing machines cannot meet both the required dimensions and high precision. This requires the purchase or investment of a large number of high-precision stamping equipment, resulting in very high manufacturing costs. Furthermore, existing stamping equipment cannot precisely control the depth of the formed explosion-proof notch 200, and the cross-sectional width (i.e., the groove width) of the explosion-proof notch 200 is generally wide. Laser etching, which forms the explosion-proof notch 200, allows for precise control of both its depth and width, significantly reducing the groove width of the explosion-proof notch 200.

[0026] Because the explosion-proof notch 200 is shaped like a closed curve, laser etching of the explosion-proof notch 200 may result in the start and end points of each etching process coinciding. Normally, both the start and end points are etched during each etching cycle. Consequently, the start and end points of each etching cycle may be etched twice, increasing the etching depth at that location and potentially causing a through-cut. To avoid this, this embodiment utilizes a non-closed curve arranged along the contour of the explosion-proof valve region 300 as the shape of the explosion-proof notch 200. This results in the explosion-proof notch 200 being shaped like a curve with a notch 201, thereby preventing the start and end points from coinciding and ensuring the depth of the explosion-proof notch 200 is uniform throughout. The linear width W3 of the notch 201 can range from 0.1 mm to 80 mm. Since laser etching is not required at the notch 201, forming the notch 201 in the explosion-proof notch 200 can also shorten the laser etching time. For the same closed curve, the longer the curve cut at notch 201, the shorter the time required for laser etching. Of course, if the curve cut at notch 201 is too long, it will also increase the tear pressure value of the explosion-proof structure. To avoid the impact of the curve cut at notch 201 being too long on the tear pressure value of the explosion-proof structure, while minimizing the time required for laser etching, generally only a small section of the closed curve is cut to form notch 201. The straight line width at notch 201 is generally 1mm≤W3≤5mm. Within this range, the straight line width of notch 201 has almost no impact on the tear pressure value of the explosion-proof structure. Of course, when the straight line width W3 of notch 201 is large and may increase the tear pressure value of the explosion-proof structure, the tear pressure value of the explosion-proof structure can also be reduced by changing other parameters of the explosion-proof notch 200. In addition, by leaving a notch 201 on the explosion-proof notch 200 without etching, when the explosion-proof notch 200 is torn due to the expansion of the gas inside the shell due to the heat of the battery cell, the notch 201 will not be torn because it has a normal thickness, thereby ensuring that the explosion-proof valve area 300 remains connected to the shell 100, preventing the explosion-proof valve area 300 from being torn as a whole and being blown away by high pressure, causing secondary damage to other battery cells or water cooling plates and surrounding connected circuits.

[0027] The tearing pressure value at the explosion-proof notch 200 is mainly affected by the residual value t of the explosion-proof notch 200; by selecting a suitable residual value t, the range of the tearing pressure of the explosion-proof notch 200 can be limited. Please refer to Figure 3. 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. The residual value of the explosion-proof notch 200 is 0.01mm to 0.5mm. If the residual value t of the explosion-proof notch 200 is small, the strength of the shell 100 will be greatly reduced. When the battery collides with other products during use, it is very likely that the shell 100 will be broken, allowing external gas to enter the shell 100 through the rupture and react chemically with the material of the battery cell, thereby causing battery failure and even battery explosion accidents. If the value of t is large, when the internal pressure of the battery reaches the upper limit pressure, the pressure relief hole formed by tearing from the explosion-proof notch 200 will be relatively small, so the gas inside the battery cannot be discharged in time, which may also cause the battery to over-expand and cause an explosion.

[0028] When selecting the residual value t of the explosion-proof notch 200, the influence of the thickness T of the shell 100 also needs to be considered. It should be noted that the thickness of the shell 100 refers to the wall thickness of the shell 100, that is, the thickness of the material used to make the shell 100, rather than the thickness of the entire battery shell. The ratio of the thickness T of the shell 100 to the residual value t of the explosion-proof notch 200 is in the range of 1.1≤T / t≤30. Generally, the ratio of T / t is in the range of 1.5 to 10. For example: under the condition that the ratio range of T / t is met, when the shell 100 adopts a stainless steel material with a thickness of 0.05mm to 0.8mm, the residual value t of the explosion-proof notch 200 is generally 0.01mm to 0.3mm, preferably 0.01mm to 0.08mm. When the housing 100 is made of an aluminum alloy material with a thickness of 0.2 mm to 1.5 mm, the residual value t of the explosion-proof notch 200 is generally 0.05 mm to 0.5 mm, preferably 0.05 mm to 0.2 mm. Specifically, in this embodiment, when the housing 100 is made of stainless steel material with a thickness of 0.20 mm ± 0.005 mm, the residual value t of the explosion-proof notch 200 is generally in the range of 0.02 mm ≤ t ≤ 0.08 mm.

[0029] For example, referring to FIG. 4 , when the explosion-proof notch 200 is in the shape of a circle with a notch 201, the diameter D1 of the circle ranges from 5 mm to 80 mm, preferably 10 mm ≤ D1 ≤ 18 mm. For example, D1 can be 15 mm. In the figure, the length of notch 201 is 2 mm. Notch 201 can be located at any position on the circle, and notch 201 is oriented in the length direction of the rectangular surface where explosion-proof notch 200 is located (i.e., when explosion-proof notch 200 is located on narrow side 131 of housing 100, notch 201 is oriented in the z-axis direction of FIG. 1 and FIG. 2 , and when explosion-proof notch 200 is located on bottom surface 112 of housing 100, notch 201 is oriented in the x-axis direction of FIG. 1 and FIG. 2 ).

[0030] Referring to FIG. 5 , when the explosion-proof notch 200 is shaped like an ellipse with a notch 201, the major axis of the ellipse is aligned with the length of the housing 100 (i.e., the major axis of the ellipse is parallel to the z-axis of the coordinate system in FIG. 1 and FIG. 2 ). The distance L1 between the two foci (F1, F2) of the ellipse is 5 mm ≤ L1 ≤ 80 mm, preferably 25 mm ≤ L1 ≤ 50 mm. The difference between the length L2 of the major axis of the ellipse and the distance L1 between the two foci (F1, F2) of the ellipse is 5 mm ≤ (L2 - L1) ≤ 80 mm, and the value of (L2 - L1) is less than or equal to the value of L1, preferably 10 mm ≤ (L2 - L1) ≤ 18 mm; for example, L1 = 35 mm and L2 - L1 = 15 mm. In the figure, the length of the notch 201 is 2 mm, and the notch 201 is preferably located at one end of the major axis of the ellipse.

[0031] Please refer to Figure 6. When the explosion-proof notch 200 is a runway-shaped notch with a notch 201, the runway-shaped notch includes a symmetrically arranged semicircular notch 211 and a semicircular notch 212, and two straight-line segment widening notches (221, 222) connecting the corresponding endpoints of the semicircular notch 211 and the semicircular notch 212. Among them, the straight-line segment widening notch 221 is used to connect a pair of endpoints corresponding to the semicircular notch 211 and the semicircular notch 212, and the straight-line segment widening notch 222 is used to connect the other pair of endpoints corresponding to the semicircular notch 211 and the semicircular notch 212. The directions of the straight-line segment widening notches 221 and the straight-line segment widening notches 222 are consistent with the length direction of the shell 100 (that is, the straight-line segment widening notches 221 and the straight-line segment widening notches 222 are parallel to the z-axis of the coordinate system in Figures 1 and 2). The diameter D2 of the semicircular notches 211 and 212 ranges from 5 mm to 80 mm, preferably 10 mm ≤ D2 ≤ 18 mm. The length L3 of the straight-line widening notches 221 and 222 (also the distance between the center O1 of the semicircular notches 211 and the center O2 of the semicircular notches 212) ranges from 5 mm ≤ L3 ≤ 80 mm. For example, D2 = 15 mm and L3 = 35 mm can be used. In the figure, the length of the notch 201 is 2 mm, and the notch 201 is preferably located at the midpoint of the semicircular notch 211 or 212.

[0032] When the gap 201 occupies a large proportion of the closed curve, the gap length cannot accurately describe the actual shape of the gap. In this case, the gap shape can also be described by the ratio of the length of the closed curve to the length of the cut-off portion. The ratio of the length of the closed curve to the length of the cut-off portion ranges from 12 / 11 to 72. Taking the closed curve as a circle as an example, the shape of the explosion-proof notch 200 after the notch 201 is formed is an arc of 30° to 355°. Generally, the ratio of the length of the closed curve to the length of the cut-off portion is 2 to 12, that is, the explosion-proof notch 200 generally adopts an arc shape of 180° to 330°, preferably an arc shape of 270°. Of course, the explosion-proof notch 200 can also be an arc with an arc angle θ of 60°, 90°, 120°, or 150°. Under the same circumstances, when the explosion-proof notch 200 is in the shape of an arc with an arc θ less than 90°, the air pressure required to tear the explosion-proof notch 200 will increase significantly. When the explosion-proof notch 200 is in the shape of an arc with an arc θ between 90° and 180°, the air pressure required to tear the explosion-proof notch 200 will decrease significantly with the increase of the arc θ. When the explosion-proof notch 200 is in the shape of an arc with an arc θ greater than 180°, the air pressure required to tear the explosion-proof notch 200 changes little with the arc θ value.

[0033] When the ratio of the length of the explosion-proof notch 200 to the length of the outline of the explosion-proof valve area 300 is 2 / 3 to 71 / 72, the linear width of the notch 201 has little effect on the tearing air pressure value of the explosion-proof structure. At this time, the area size of the area where the explosion-proof notch 200 is located has a greater influence on the tearing air pressure value of the explosion-proof structure. The area where the explosion-proof notch 200 is located refers to the area formed by connecting the two end points of the explosion-proof notch 200 and enclosing the explosion-proof notch 200. The smaller the area S of the area where the explosion-proof notch 200 is located, the higher the tearing air pressure value of the explosion-proof structure. The larger the area S of the area where the explosion-proof notch 200 is located, the lower the tearing air pressure value of the explosion-proof structure. The value range of the area S of the area where the explosion-proof notch 200 is located can be: 78.5mm 2 ≤S≤1500mm 2 ; Normally, the area S of the explosion-proof notch 200 is in the range of: 200mm 2 ≤S≤800mm 2 .

[0034] The explosion-proof notch 200 may also be in the form of two intersecting linear notches. For example, referring to FIG7 , the explosion-proof notch 200 may be composed of a first linear notch 231 and a second linear notch 232, wherein the first linear notch 231 and the second linear notch 232 intersect at a point O3. The notch depths of the first linear notch 231, the second linear notch 232, and the intersection O3 of the first linear notch 231 and the second linear notch 232 are all the same.

[0035] In this embodiment, the first linear score 231 is arranged along the width direction of the narrow side 131 of the housing 100 (i.e., the y-axis direction in FIG. 7 ). The length of the first linear score 231 can be determined based on the width of the narrow side 131 of the housing 100. If the length of the first linear score 231 is too small, when the air pressure inside the housing 100 is too high and the explosion-proof score 200 needs to be torn, it will be more difficult to tear the explosion-proof score 200, and the opening formed after tearing will be small, which will slow the gas discharge speed inside the housing 100. If the length of the first linear score 231 is too close to the width of the narrow side 131 of the housing 100, the overall strength of the housing 100 will be affected. The length L4 of the first linear score 231 can be 6 mm to 80 mm, generally 12 mm ≤ L4 ≤ 20 mm, and preferably L4 = 16 mm. The second linear score 232 is arranged along the length of the narrow side 131 of the housing 100 (i.e., the z-axis direction in FIG. 7 ). Since the narrow side 131 of the housing 100 is relatively long, it generally does not limit the length of the second linear score 232. Therefore, the length L5 of the second linear score 232 can be relatively long. This allows the long opening formed by the tearing to quickly discharge the high-pressure gas inside the housing 100 when the gas pressure inside the housing 100 is too high and the explosion-proof score 200 needs to be torn. The length L5 of the second linear score 232 can be 12 mm to 100 mm, and generally takes 20 mm ≤ L5 ≤ 50 mm, preferably L5 = 32 mm. It will be understood that when the explosion-proof score 200 is arranged on the bottom surface 112, the second linear score 212 is arranged along the length of the bottom surface 112 of the housing 100 (i.e., the x-axis direction in FIG. 1 and FIG. 2 ).

[0036] In this embodiment, the intersection O3 of the first linear score 231 and the second linear score 232 is the midpoint of the first linear score 231 and the second linear score 232, thereby forming a symmetrical "X" shape in the explosion-proof score 200. Since the explosion-proof score 200 is provided in four directions at the intersection O3 of the first linear score 231 and the second linear score 232, the intersection O3 can be easily torn when the air pressure inside the shell 100 is too high. This avoids the situation where the explosion-proof score 200 cannot be torn even when the air pressure inside the shell 100 exceeds the predetermined tearing pressure value due to large errors in the depth parameters of the explosion-proof score 200.

[0037] Because the explosion-proof notch 200 is shaped like a cross, if the pressure inside the shell 100 is too high, the area that can be rolled outward under the impact of the high-pressure gas after the explosion-proof notch 200 is torn is small, thus preventing the formation of a large opening. This still affects the discharge rate of the high-pressure gas inside the shell 100. To further increase the discharge rate of the high-pressure gas inside the shell 100 after the explosion-proof notch 200 is torn, the explosion-proof notch 200 may also include at least one arc notch 233, the center of each arc notch 233 being the intersection point O3 of the first linear notch 231 and the second linear notch 232. The arc notch 233 generally has an arc shape with a curvature of approximately 90°, and each end of the arc notch 233 intersects the first linear notch 231 and the second linear notch 232, respectively. The diameter of the arc notch 233 is less than or equal to the length of the shorter of the first linear notch 231 and the second linear notch 232.

[0038] [Corrected 12.10.2024 in accordance with Rule 91] Referring to FIG. 8 , in this embodiment, the explosion-proof notch 200 includes two arcuate notches 233 of equal diameter. The diameter of each arcuate notch 233 is 15 mm, slightly less than the length of the first linear notch 231 . Furthermore, the two arcuate notches 233 are symmetrical about the intersection O3 . The arc angles of each arcuate notch 233 are both 90°; however, the arc angles of each arcuate notch 233 may also be greater than 90°. The notch depths of the two arcuate notches 233 and the notch depths at the intersections of the two arcuate notches 233 with the first linear notch 231 and the second linear notch 232 , respectively, are equal to the notch depths of the first linear notch 231 and the second linear notch 232 . By providing two arc notches 233, when the air pressure inside the shell 100 is too high and causes the explosion-proof notch 200 to tear, the two fan-shaped areas formed by the two arc notches 233 and the first straight line notch 231 and the second straight line notch 232 will completely roll outward during the tearing process, thereby greatly increasing the opening area formed when the explosion-proof notch 200 is torn, so that the high-pressure gas inside the shell 100 can be quickly discharged.

[0039] Please continue to refer to Figure 3. In the embodiment, the cross-sectional shape of the explosion-proof notch 200 is a trapezoid; the connection between the waist and the lower base of the trapezoid is a rounded structure. Of course, in other embodiments, the cross-sectional shape of the explosion-proof notch 200 can also be other shapes such as a "V" shape. The value of the lower base width W1 of the cross-sectional area of ​​the explosion-proof notch 200 is in the range of 0 to 0.5 mm, preferably 0.03 mm ≤ W1 ≤ 0.1 mm. When the cross-sectional shape of the explosion-proof notch 200 is a trapezoid, the angle a between the waist of the trapezoid and the vertical direction (i.e., the height of the trapezoid) and the value of the lower base width W1 of the trapezoid will have a certain influence on the tearing gas pressure value of the explosion-proof valve. The value of the angle a between the waist of the trapezoid and the height of the trapezoid is in the range of 5° to 60°, preferably 25° ≤ a ≤ 45°.

[0040] In this embodiment, a stainless steel shell 100 with a thickness of 0.20mm±0.005mm was used, and an explosion-proof notch 200 with a trapezoidal cross-section and a circular overall shape with a notch 201 was used as a verification object to verify the effect of the ratio of the thickness T of the shell 100 to the notch residual value t of the explosion-proof notch 200 on the explosion-proof effect. The shell 100 is in the shape of a rectangular parallelepiped, and the explosion-proof notch 200 is set on the narrow side 131. The straight width of the notch 201 is 2mm, the bottom width W1 of the trapezoid is 0.08mm, the angle between the waist of the trapezoid and the height of the trapezoid is 25°≤a≤45°, and the diameter of the circle is 15mm. Since the thickness of the stainless steel shell 100 is not easy to change, the ratio of T / t is changed by changing the notch residual value t when the thickness T of the stainless steel shell 100 is fixed. Multiple verifications were performed for each value of the notch residual value t. The verification data are shown in Table 1:

[0041] Table 1

[0042] The pressure injection speed in the table is the speed at which pressure is injected into the shell 100 during the test. Since the above verification only focuses on the tearing pressure when the explosion-proof notch 200 is torn, and does not simulate the process of shell 100 exploding, the time required for the explosion-proof notch 200 to tear is not used as a verification parameter.

[0043] This embodiment also uses a stainless steel housing 100 with a thickness of 0.20mm±0.005mm, and an explosion-proof notch 200 with a trapezoidal cross-section and an arc-shaped overall shape as a verification object. The effects of the notch 201 of the arc on the explosion-proof effect when facing the length direction and the width direction of the rectangular surface are verified. The housing 100 is rectangular, the explosion-proof notch 200 is set on the narrow side 131, the notch residual value t is 0.08mm, the width W1 of the lower base of the trapezoid is 0.08mm, the angle between the waist of the trapezoid and the height of the trapezoid is 25°≤a≤45°, and the diameter of the arc is 15mm. The verification data is shown in Table 2:

[0044] Table 2

[0045] From the verification data in Table 2, it can be seen that the tearing pressure when the arc notch 201 faces the length direction of the rectangular surface is significantly lower than the tearing pressure when the arc notch 201 faces the width direction of the rectangular surface.

[0046] This example also uses a stainless steel housing 100 with a thickness of 0.20mm±0.005mm. A circular explosion-proof notch 200 with a trapezoidal cross-section and a notch 201 as a validation object was used to verify the effect of the circular diameter on the explosion-proof effect. The housing 100 is rectangular, and the explosion-proof notch 200 is located on the narrow side 131. The linear width of the notch 201 is 2mm, the width W1 of the lower base of the trapezoid is 0.08mm, the angle between the waist and the height of the trapezoid is 25°≤a≤45°, and the residual value t of the notch is 0.04mm. Multiple validations were conducted for each diameter, and the validation data is shown in Table 3:

[0047] Table 3

[0048] The valve opening time in the table refers to the time required from the start of pressurization to the tearing of the explosion-proof notch 200; since this verification and subsequent verifications are all simulations of the process of shell 100 explosion, the valve opening time parameter is added. The ideal valve opening time is in the range of 30s to 40s.

[0049] This example also uses a stainless steel housing 100 with a thickness of 0.20 mm ± 0.005 mm. A test was conducted using an explosion-proof notch 200 with a trapezoidal cross-section, a 120° arc shape, and a 15 mm diameter. The effect of the lower base width W1 of the trapezoid on the explosion-proof performance was verified. The housing 100 is rectangular, the explosion-proof notch 200 is located on the narrow side 131, the notch residual value t is 0.04 mm, and the angle between the waist and the height of the trapezoid is 25° ≤ a ≤ 45°. Multiple tests were conducted for each type of trapezoidal bottom base width W1, and the verification data is shown in Table 4.

[0050] Table 4

[0051] This example also uses a stainless steel housing 100 with a thickness of 0.20mm±0.005mm and an explosion-proof notch 200 with a trapezoidal cross-section and an arc-shaped overall shape as the verification object. The effects of the arc's radian (which represents the ratio of the length of the closed curve to the length of the cutout) and diameter on the explosion-proof effect are verified. The notch residual value t is 0.04mm, and the angle between the trapezoid's waist and height is 25°≤a≤45°. Multiple verifications were conducted for each arc's radian and diameter, and the verification data are shown in Table 5.

[0052] Table 5

[0053] In this embodiment, an explosion-proof structure is formed by directly etching an explosion-proof notch 200 on a rectangular parallelepiped housing 100, thereby integrating the explosion-proof structure and the housing 100. This prevents welding errors during the welding of the explosion-proof valve from affecting the explosion-proof structure's explosion-proof effect. When etching the explosion-proof notch 200, by setting the area of ​​the explosion-proof valve region 300 within a predetermined range and selecting an appropriate notch residual value t so that the ratio of the housing thickness to the notch residual value is within a predetermined range, the range of the tear pressure value of the explosion-proof notch 200 can be limited. When etching the explosion-proof notch 200, by ensuring that the angle a between the side of the cross-sectional shape of the explosion-proof notch 200 and the vertical direction is within a predetermined range, the effect of the angle a on the tear pressure value can be reduced. Laser etching forms a groove structure with a cross-section that is wide at the top and narrow at the bottom as the explosion-proof notch 200. This creates a higher precision explosion-proof notch 200. When etching the explosion-proof notch, the tearing pressure at the explosion-proof notch 200 can be adjusted by adjusting the bottom width W1 of the groove structure and the angle a between the side of the groove structure cross-section and the vertical direction, making it more convenient to adjust the tearing pressure at the explosion-proof notch 200. This ensures that when the air pressure inside the shell 100 reaches a predetermined pressure range, the explosion-proof notch 200 will be torn open in time to release the high-pressure gas inside the shell 100, preventing the battery from exploding and ensuring the personal safety of the manufacturer and user. Using a curve with a notch as the shape of the explosion-proof notch 200 facilitates the formation of the explosion-proof notch 200 by laser etching.

[0054] [Corrected 12.10.2024 according to Rule 91] Referring to FIG. 9 , the present invention further discloses a method for manufacturing a battery casing having explosion-proof notches. An embodiment of the method for manufacturing a battery casing having explosion-proof notches of the present invention includes the following steps:

[0055] S100: Take a battery housing 100. The battery housing 100 can be made of an iron-based alloy, a nickel-based alloy, a titanium alloy, or an aluminum alloy. In this embodiment, the battery housing is made of stainless steel, and the thickness of the stainless steel is 0.20 mm ± 0.005 mm.

[0056] 1 and 2 , in this embodiment, the battery housing 100 is a thin rectangular parallelepiped, including a top surface 111 , a bottom surface 112 opposite to the top surface 111 , two oppositely disposed wide side surfaces 121 , and two oppositely disposed narrow side surfaces 131 .

[0057] S200, determining the laser etching path according to the pattern of the explosion-proof notch. The shape of the explosion-proof notch 200 can be a curve that does not form a sharp angle, such as a quasi-circular curve, a spline curve, etc. The explosion-proof notch 200 uses a quasi-circular curve or a spline curve, which can avoid including sharp angles in the shape of the explosion-proof notch 200, thereby facilitating laser etching. If the shape of the explosion-proof notch 200 includes a sharp angle, the laser irradiation position of the laser etching equipment cannot turn along the sharp angle at the previous moving speed at the angle, and needs to stop at the corner point of the angle and then change direction to complete the turn, which will increase the overall time of laser etching. In addition, when the laser irradiation position stops at the corner point, it is necessary to temporarily turn off the laser to avoid excessive etching depth at the corner point, and then turn on the laser again after changing direction, which also increases the control process of the laser equipment. When the explosion-proof notch 200 adopts a quasi-circular curve, since the quasi-circular curve is an overall smooth curve, no sharp angle will be formed on the curve; when using laser to etch the explosion-proof notch 200, it is convenient for the laser irradiation position of the laser etching equipment to move at a uniform speed, avoiding the laser irradiation position from stopping at the corner point of the angle due to the need to turn, thereby increasing the overall etching process time.

[0058] The shape of the explosion-proof notch 200 can be a curve with a notch 201 formed by cutting off a section on a closed curve. When the explosion-proof notch 200 is etched on the battery shell 100 by laser, a point is selected from the curve as the starting point of etching each time the laser is etched, and another point is selected from the curve as the end point of etching. Generally, when laser etching starts, the two end points of the curve are used as the starting point and end point of etching along the curve; thereafter, each time a predetermined number of etchings are made, the starting point and end point of etching are moved a predetermined distance along the curve toward the midpoint of the curve until the etching is completed. Since the curve is non-closed, the starting point and end point will not overlap when laser etching is performed using the above method, thereby avoiding the situation where over-etching is easily caused at the starting point (end point) of etching when the shape of the explosion-proof notch 200 is a closed curve.

[0059] The explosion-proof scoring 200 may also be in the form of two intersecting linear scorings. For example, referring to Figures 7 and 8 , the explosion-proof scoring 200 may also be composed of a first linear scoring 231 and a second linear scoring 232, wherein the first linear scoring 231 and the second linear scoring 232 intersect at a point O3. It should be noted that the first linear scoring 231 and the second linear scoring 232 intersect at point O3 only in terms of shape. In step S200 , when determining the laser etching path based on the pattern of the explosion-proof scoring 200 , the second linear scoring 232 is divided into two segments at the intersection O3 of the first linear scoring 231 and the second linear scoring 232. Thus, the two segments of the second linear scoring 232, together with the first linear scoring 231, form a laser etching path consisting of three non-intersecting line segments. Of course, the first linear scoring 231 may also be divided into two segments, thereby forming a laser etching path consisting of three non-intersecting line segments.

[0060] Because the laser etching path is composed of three non-intersecting line segments, when the laser is used to etch the first linear mark 231 and the second linear mark 232 in step S400, the etching paths of the first linear mark 231 and the second linear mark 232 also do not intersect. That is, during the laser etching process, each time the first linear mark 231 and the second linear mark 232 are etched (i.e., within one etching cycle), point O3 is only etched along with the first linear mark 231 (when the laser etching path divides the first linear mark 231 into two segments, point O3 is only etched along with the second linear mark 232). As a result, point O3 is only etched once within one etching cycle, and is not etched twice by being etched along with the first linear mark 231 and the second linear mark 232 simultaneously. This avoids the situation where the etching depth at the intersection point O3 is increased due to excessive etching times, resulting in the intersection point being etched through. Thus, the depths of the first linear score 231 , the second linear score 232 , and the intersection O3 between the first linear score 231 and the second linear score 232 are all the same.

[0061] The explosion-proof score 200 may also include at least one arc score 233. The center of each arc score 233 is the intersection O3 of the first linear score 231 and the second linear score 232. The arc score 233 generally has an arc shape of approximately 90°, with both ends of each arc score 233 intersecting the first linear score 231 and the second linear score 232. The diameter of each arc score 233 is less than or equal to the shorter of the first linear score 231 and the second linear score 232.

[0062] S300. Adjust the parameters of the laser etching equipment based on the material and thickness of the battery housing; perform calibration and adjustment to ensure accurate material processing. In this embodiment, the battery housing 100 is made of stainless steel with a thickness of 0.20 mm ± 0.005 mm. The laser etching equipment has a power of 10 W to 2000 W, a frequency of 1 kHz to 1000, and a speed of 1 mm / s to 4000 mm / s.

[0063] S400: Place the battery casing on the processing platform of the laser etching equipment, and use the laser etching equipment to etch an explosion-proof notch on the battery casing according to the laser etching path. In this embodiment, the cross-sectional shape of the explosion-proof notch 200 is a trapezoid; the junction between the waist and the bottom of the trapezoid is a rounded structure. Of course, in other embodiments, the cross-sectional shape of the explosion-proof notch 200 can also be a "V" or "U" shape, etc.

[0064] S500: Post-process the battery housing after etching. Post-processing is used to remove the residual oxide layer from the laser etching and to improve the etching quality of the details through fine-tuning.

[0065] The present invention also discloses a secondary battery, which can be a power battery or an energy storage battery. The housing of the secondary battery can adopt a battery housing with explosion-proof notches according to any of the aforementioned embodiments. Of course, the secondary battery also includes a cell housed within the battery housing and other structures required for conventional secondary batteries. These are all prior art and will not be described in detail here.

[0066] The present invention also discloses an electrical device, comprising a secondary battery according to any of the aforementioned embodiments, for powering the electrical device via the secondary battery. For example, the electrical device may be a new energy electric vehicle or a hybrid vehicle. It is understood that the electrical device may also be a power tool, an energy storage device, a power unit, or other electrically powered device such as a mobile phone, tablet computer, or computer.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, which should all be included in the scope of the claims of the present invention.

Claims

1. A battery casing with explosion-proof notches, characterized in that: The invention comprises a shell, wherein an explosion-proof valve area is arranged on the outer surface or the inner surface of the shell, and an explosion-proof notch is formed on the explosion-proof valve area by laser etching, and the residual value of the explosion-proof notch is 0.01 mm to 0.5 mm.

2. The battery casing with explosion-proof notches according to claim 1, characterized in that: The shell is made of stainless steel with a thickness of 0.05 mm to 0.8 mm, and the residual value of the explosion-proof notch is 0.01 mm to 0.3 mm.

3. The battery casing with explosion-proof notches according to claim 2, characterized in that: The residual value of the explosion-proof notch is 0.01 mm to 0.08 mm.

4. The battery casing with explosion-proof notches according to claim 1, characterized in that: The shell is made of an aluminum alloy material with a thickness of 0.2 mm to 1.5 mm, and the residual value of the explosion-proof notch is 0.05 mm to 0.5 mm.

5. The battery casing with explosion-proof notches according to claim 4, characterized in that: The residual value of the explosion-proof notch is 0.05 mm to 0.2 mm.

6. The battery casing with explosion-proof notches according to claim 1, characterized in that: The shell is a cuboid, comprising a top surface, a bottom surface opposite to the top surface, two wide side surfaces and two narrow side surfaces, and the explosion-proof notches are etched on the narrow side surfaces and / or the bottom surface.

7. The battery casing with explosion-proof notches according to claim 6, characterized in that: More than one explosion-proof valve region is arranged on one of the narrow sides.

8. The battery casing with explosion-proof notches according to claim 1, characterized in that: The explosion-proof notch is a groove structure with a cross section that is wide at the top and narrow at the bottom, and the bottom width of the cross section is 0 to 0.5 mm.

9. The battery casing with explosion-proof notches according to claim 11, characterized in that: The cross-sectional shape of the explosion-proof notch is a trapezoid, "V" shape or "U" shape that is wide at the top and narrow at the bottom, and the angle between the side of the cross-sectional shape and the vertical direction is 5° to 60°.

10. The battery casing with explosion-proof notches according to claim 12, characterized in that: The angle between the side of the cross-sectional shape and the vertical direction is 25° to 45°.

11. The battery casing with explosion-proof notches according to claim 13, characterized in that: The cross-sectional shape of the explosion-proof notch is a trapezoid that is wide at the top and narrow at the bottom, and the bottom width of the trapezoid is 0.03 mm to 0.1 mm.

12. The battery casing with explosion-proof notches according to claim 11, characterized in that: The shape of the explosion-proof notch is a curve, and the ratio of the thickness of the shell to the residual value of the explosion-proof notch is 1.1-30.

13. The battery casing with explosion-proof notches according to claim 12, characterized in that: The ratio of the thickness of the shell to the residual value of the explosion-proof notch is 1.5-10.

14. A battery casing with explosion-proof notches according to any one of claims 1 to 13, characterized in that: The shape of the explosion-proof notch is a curve with a gap formed by cutting off a section from a closed curve.

15. The battery casing with explosion-proof notches according to claim 14, characterized in that: The explosion-proof notch is in the shape of a circular arc or an elliptical arc, and the notch of the circular arc or the elliptical arc faces the direction of the long side of the narrow side surface or the bottom surface.

16. The battery casing with explosion-proof notches according to claim 14, characterized in that: The ratio of the length of the closed curve to the length of the cut-off portion is 12 / 11-72.

17. A battery casing with explosion-proof notches according to claim 16, characterized in that: The ratio of the length of the closed curve to the length of the cut-off portion is 2-12.

18. The battery casing with explosion-proof notches according to claim 14, characterized in that: The linear width of the notch is 0.1 mm to 80 mm.

19. The battery casing with explosion-proof notches according to claim 18, characterized in that: The straight width of the notch is 1 mm to 5 mm.

20. The battery casing with explosion-proof notches according to claim 14, characterized in that: The closed curve is a quasi-circular curve.

21. The battery casing with explosion-proof notches according to claim 20, characterized in that: The explosion-proof notch is in the shape of an arc, the diameter of the arc is 5 mm to 80 mm, and the curvature of the arc is in the range of 30 to 355°.

22. The battery casing with explosion-proof notches according to claim 20, characterized in that: The ratio of the thickness of the shell to the residual value of the explosion-proof notch is 1.5 to 10; the diameter of the arc is 10 mm to 18 mm, and the curvature of the arc is in the range of 180° to 330°.

23. The battery casing with explosion-proof notches according to claim 20, characterized in that: The shape of the explosion-proof notch is an ellipse with a notch, and the distance between the two foci of the ellipse is 5mm to 80mm; the difference between the length of the major axis of the ellipse and the distance between the two foci of the ellipse is 5mm to 80mm, and the difference is less than or equal to the distance between the two foci of the ellipse; the center point of the notch is located on the major axis of the ellipse.

24. The battery casing with explosion-proof notches according to claim 20, characterized in that: The shape of the explosion-proof notch is a runway with a notch, including two symmetrically arranged semicircular notches and two straight line segment notches connecting the corresponding end points of the two semicircular notches, the diameter of the circle is 5mm to 80mm, and the length of the straight line segment notch is 5mm to 80mm; the center point of the notch is located on the straight line connecting the centers of the two semicircular notches.

25. A battery casing with explosion-proof notches according to any one of claims 1 to 13, characterized in that: The explosion-proof notch includes a first linear notch and a second linear notch, the first linear notch and the second linear notch intersect at one point, and the notch depths of the first linear notch, the second linear notch and the intersection of the first linear notch and the second linear notch are all the same.

26. A battery casing with explosion-proof notches according to claim 25, characterized in that: The first linear score and the second linear score bisect each other perpendicularly.

27. A battery casing with explosion-proof notches according to claim 26, characterized in that: The explosion-proof notch further comprises at least one arc notch, the center of which is the intersection of the first straight line notch and the second straight line notch, and the arc notch intersects with the first straight line notch and the second straight line notch respectively; The notch depth of the arc notch and the notch depth at the intersection of the arc notch, the first linear notch and the second linear notch are equal to the notch depth of the first linear notch and the second linear notch.

28. The battery casing with explosion-proof notches according to claim 27, characterized in that: The explosion-proof notch includes two arc notches with equal diameters, the diameters of the two arc notches are less than or equal to the length of the first straight line notch, and the diameters of the two arc notches are less than or equal to the length of the second straight line notch; the arcs of the two arc notches are 90° to 180°, and the two arc notches are symmetrical along the intersection of the first straight line notch and the second straight line notch.

29. A method for manufacturing a battery casing with explosion-proof notches, characterized in that: The following steps are involved: S100, taking a battery casing; S200, determining a laser etching path according to a pattern of explosion-proof notches; S300, adjusting laser etching parameters according to the material and thickness of the battery shell; S400, etching an explosion-proof notch on the battery housing according to an etching path by laser; the explosion-proof notch is a groove structure with a wide upper portion and a narrow lower portion in cross section; S500, post-processing the etched battery shell.

30. The method for manufacturing a battery casing with explosion-proof notches according to claim 29, characterized in that: The shape of the explosion-proof notch is a curve with a gap formed by cutting off a section on a closed curve. In the step S400, when the explosion-proof notch is etched on the battery shell by laser, a point is selected from the curve as the starting point of etching each time the laser etches, and another point is selected from the curve as the end point of etching.

31. The method for manufacturing a battery casing with explosion-proof notches according to claim 30, characterized in that: When starting laser etching, first use the two endpoints of the curve as the starting point and end point of etching and etch along the curve; then, after each predetermined number of etchings, move the starting point and end point of etching along the curve to the midpoint of the curve by a predetermined distance until the etching is completed.

32. The method for manufacturing a battery casing with explosion-proof notches according to claim 29, characterized in that: The explosion-proof notch comprises a first linear notch and a second linear notch, the first linear notch and the second linear notch intersect at one point, and the notch depths of the first linear notch, the second linear notch and the intersection of the first linear notch and the second linear notch are all the same; In the step S200, when determining the laser etching path, the first linear score is divided into two segments at the intersection of the first linear score and the second linear score, thereby forming a laser etching path including three non-intersecting line segments together with the second linear score; or When determining the laser etching path, the second linear score is divided into two segments at the intersection of the first linear score and the second linear score, thereby forming a laser etching path including three mutually non-intersecting line segments together with the first linear score.

33. A secondary battery, characterized in that: It comprises a battery casing with explosion-proof notches as described in any one of claims 1 to 28.

34. An electrical equipment, characterized in that: Comprising a secondary battery as claimed in claim 33.

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