Single cell, battery pack, and power utilization device

Abstract

The utility model relates to a battery technical field discloses a kind of single battery, battery pack and electric equipment, single battery includes: shell, one side in first direction is provided with pressure relief piece, pressure relief piece includes cocking portion, weak portion and connecting portion, weak portion includes at least one first weak section and at least two second weak sections alternately arranged along the outer edge of cocking portion;The thickness of the thinnest part of first weak section is less than the thickness of the thinnest part of second weak section;Second weak section is arc in the projection on the plane perpendicular to first direction, the projection of first weak section on the plane perpendicular to first direction is arc, and the minimum value of the curvature radius of first weak section is greater than the minimum value of the curvature radius of second weak section, or first weak section is straight line;Connecting portion connects shell, and connecting portion is around cocking portion and weak portion setting.The pressure relief piece of the utility model embodiment not only can realize multiple pressure relief function, and pressure relief stability is high.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to a single battery cell, a battery pack, and an electrical device. Background Technology

[0002] A single battery cell typically includes a pressure relief device. In the event of thermal runaway in a single battery cell, the pressure relief device bursts under the pressure difference between the inside and outside of the cell, which can release the high-temperature gas inside the cell in a timely manner and prevent spontaneous combustion and explosion.

[0003] In related technologies, the compressive strength of each area of ​​the pressure relief component is consistent. Therefore, each area of ​​the pressure relief component will burst almost simultaneously. The pressure relief component can only achieve pressure relief once, and the high-temperature gas in the single cell is ejected at once. This cannot meet the demand for multiple pressure reliefs and may lead to the risk of heat spread caused by the combustion of the battery sidewall. Utility Model Content

[0004] In view of this, the present invention provides a single battery, a battery pack, and an electrical device to solve the problem that the pressure relief component cannot meet the requirements for multiple pressure reliefs.

[0005] Firstly, a housing has a first direction, and a pressure relief hole is provided on one side of the housing in the first direction; a pressure relief component covers the pressure relief hole, the pressure relief component includes a raised portion, a weak portion, and a connecting portion, the weak portion includes at least one first weak segment and at least two second weak segments, the first weak segments and the second weak segments are alternately arranged along the outer edge of the raised portion; the thickness of the weakest point of the first weak segment is less than the thickness of the weakest point of the second weak segment; the projections of the first weak segment and the second weak segment on a plane perpendicular to the first direction Z are both arcs, the radius of curvature of the projection of the first weak segment with the smallest radius of curvature is R1, the radius of curvature of the projection of the second weak segment with the smallest radius of curvature is R2, and satisfies: R1 < R2; or, the projection of the first weak segment on a plane perpendicular to the first direction Z is an arc, and the projection of the second weak segment on a plane perpendicular to the first direction is a straight line; the connecting portion connects to the housing, and the connecting portion is arranged around the raised portion and the weak portion.

[0006] Beneficial effects: The single-cell battery of this utility model has a weak section on the pressure relief component. When the internal pressure of the single-cell battery increases, the weak section will break in response to the pressure difference between the internal and external pressure of the single-cell battery. Since R1 is actually smaller than R2, that is, the bending degree of the first weak section is greater than that of the second weak section, the pressure on the weak section is more concentrated on the first weak section. Combined with the fact that the thickness of the first weak section is smaller than that of the second weak section, when the pressure inside the single-cell battery reaches the first set pressure, the first weak section bursts and releases pressure. If the internal pressure of the single-cell battery continues to increase and reaches the second set pressure, the second weak section bursts and releases pressure. At this time, the entire weak section is torn apart and released pressure. The pressure relief component can achieve multiple pressure relief functions, avoiding the combustion of the single-cell battery sidewall caused by the one-time ejection of high-temperature gas, and reducing the risk of heat spread. In addition, since the first weak section is arc-shaped, the stress on the first weak section is relatively uniform. Therefore, even if the thickness of the first weak section is set to be thin, the first weak section will not have the problem of excessive local pressure. This avoids the first weak section from tearing before the pressure in the single cell reaches the first set pressure, ensuring that the pressure relief component starts to release pressure stably when the first set pressure is reached, improving the stability of the pressure relief pressure. The pressure relief component has good quality consistency, which is conducive to increasing the safety of the single cell in use.

[0007] In one optional embodiment, the weak portion has a primary groove on one side in the first direction, the primary groove having a first groove bottom and a first groove opening, and the width of the primary groove gradually increases along the direction from the first groove bottom to the first groove opening.

[0008] Beneficial effects: During the processing, the first-level scoring groove gradually decreases in size from the first groove opening to the first groove bottom, which can serve as a processing buffer to make the coating on the inner wall of the first-level scoring groove extend more evenly, reduce the loss of the coating on the material surface, and improve the corrosion resistance of the inner wall of the first-level scoring groove.

[0009] In one optional embodiment, the weak portion further has a secondary groove, which is formed at the bottom of the first groove. The secondary groove has a second bottom and a second opening, and the width of the secondary groove gradually increases along the direction from the second bottom to the second opening.

[0010] Beneficial effects: On the one hand, during the processing, the secondary scoring groove gradually decreases in size from the second groove opening to the second groove bottom, which can act as a processing buffer to make the coating on the inner wall of the secondary scoring groove extend more evenly and reduce the loss of the coating on the material surface. On the other hand, processing the primary and secondary scoring grooves in two separate processes can reduce the pressure on the primary and secondary scoring grooves during each processing while ensuring that the overall depth of the primary and secondary scoring grooves is large. This further reduces the loss of the coating on the material surface and effectively improves the corrosion resistance of the inner wall of the secondary scoring groove.

[0011] In one optional embodiment, the connecting portion includes: a connecting portion body surrounding the raised portion and the weak portion; a first recess surrounding the outer edge of the connecting portion body; and a connecting boss surrounding the outer edge of the first recess, the connecting boss being connected to the housing.

[0012] Beneficial effects: The connecting part forms a concave-convex structure. When gas is generated inside the single cell and the pressure increases, the concave-convex structure can deform to absorb the increased pressure caused by the gas changes inside the single cell. This prevents the weak parts of the single cell from being torn apart under normal operating conditions, enhances the overall strength of the pressure relief component, and extends the battery's lifespan. Furthermore, when there is excessive gas inside the single cell causing excessive pressure, the gas in the area where the connecting part is located can apply pressure evenly to the weak parts, ensuring that each area of ​​the weak part is torn uniformly, improving pressure relief efficiency, and reducing the risk of thermal runaway.

[0013] In one optional embodiment, the raised portion includes: a raised portion body, wherein the weak portion is disposed along the outer edge of the raised portion body; a second recess having a through hole; and a third recess surrounding the second recess, wherein the raised portion body is disposed around the outer edge of the third recess.

[0014] Beneficial effects: By setting through holes, electrolyte can be injected into the individual cells, enabling normal use of the individual cells. Furthermore, the raised part forms an uneven structure that can absorb excessive pressure during electrolyte injection, preventing the weak parts from being torn during the injection process. It can also absorb the increased pressure caused by gas changes inside the individual cells, further preventing the weak parts of the individual cells from being torn under normal operating conditions. This enhances the overall strength of the pressure relief component and extends the service life of the battery.

[0015] In one alternative embodiment, the weak portion is disposed around the raised portion, and the first weak segment and the second weak segment are alternately disposed around the outer edge of the raised portion.

[0016] Beneficial effects: The weak part is ring-shaped. When the weak part is torn, the pressure relief in each area of ​​the single cell is more uniform, avoiding excessive local pressure in the single cell.

[0017] The projection of the weak part onto a plane perpendicular to the first direction is a rounded octagon, heptagon, hexagon, pentagon, quadrilateral, or triangle. The projection of the first weak segment onto the plane perpendicular to the first direction is located on the side, and the projection of the second weak segment onto the plane perpendicular to the first direction (Z) is located at the corner.

[0018] Beneficial effects: It can control the bending angle of the first weak segment, avoid the problem of local stress concentration caused by excessive bending of the first weak segment, help ensure uniform stress distribution in the first weak segment, and further improve the pressure relief stability.

[0019] In one optional implementation, the thickness of the bottom of the first weak segment is T1 mm, and the thickness of the bottom of the second weak segment is T2 mm, satisfying: T1 ≥ T2.

[0020] Beneficial effects: It further improves the pressure thresholds for primary and secondary pressure relief, avoids excessive processing precision, reduces processing difficulty, improves production efficiency, reduces production costs, and ensures that the first and second weakest segments are torn apart in time for pressure relief, which is conducive to improving battery safety.

[0021] Secondly, this utility model also provides a battery pack, including: the single battery cell described in the first aspect embodiment.

[0022] Beneficial effects: The second type of battery pack, by utilizing the individual cells of the first type, can improve the overall pressure relief stability and reduce the risk of thermal runaway.

[0023] Thirdly, this utility model also provides an electrical device, including: a single battery as described in the first aspect embodiment, or a battery pack as described in the second aspect.

[0024] Beneficial effects: The third-party battery pack, by utilizing the individual cells of the first-party battery pack, can improve the overall pressure relief stability and reduce the risk of thermal runaway. Attached Figure Description

[0025] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the structure of a single battery cell according to an embodiment of the present invention;

[0027] Figure 2 This is an exploded view of a single battery cell according to an embodiment of the present invention;

[0028] Figure 3 This is one of the structural schematic diagrams of the pressure relief component according to an embodiment of the present utility model;

[0029] Figure 4 This is the second structural schematic diagram of the pressure relief component according to an embodiment of this utility model;

[0030] Figure 5 This is the third structural schematic diagram of the pressure relief component according to an embodiment of this utility model;

[0031] Figure 6 This is a cross-sectional view of the pressure relief component according to an embodiment of the present utility model;

[0032] Figure 7 for Figure 6 A magnified view of a portion of region A in the middle;

[0033] Figure 8 This is a cross-sectional view of the pressure relief component when the cross-section of the secondary groove in this embodiment of the present invention is triangular;

[0034] Figure 9 This is a cross-sectional view of the pressure relief component when the cross-section of the primary groove in this embodiment of the present invention is semi-circular;

[0035] Figure 10 This is a cross-sectional view of the pressure relief component when the cross-section of the primary groove in this embodiment is trapezoidal.

[0036] Explanation of reference numerals in the attached figures:

[0037] 1. Single cell battery;

[0038] 100. Housing; 110. Pressure relief vent;

[0039] 200. Pressure relief component; 210. Raised portion; 211. Raised portion body; 212. Second recess; 213. Third recess; 214. Through hole; 220. Weak part; 221. First weak section; 222. Second weak section; 230. Connecting part; 231. Connecting part body; 232. First recess; 233. Connecting boss; 240. Primary groove; 241. First groove bottom; 242. First groove opening; 250. Secondary groove; 251. Second groove bottom; 252. Second groove opening; 260. Gas storage chamber. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0041] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0042] In the description of this utility model, "a plurality of" means two or more. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0043] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0044] In related technologies, the pressure relief component of the battery is equipped with explosion-proof grooves. These grooves are closed structures with multiple corners. The apex of each corner forms a first weak zone, and the line connecting two first weak zones forms a second weak zone. The thickness of the first weak zone is less than that of the second weak zone. Due to stress concentration at the abrupt shape change, under the pressure of the internal gas in the battery cell, the corner of the explosion-proof groove bursts first, meaning the first weak zone bursts first. Under continuous pressure, the two first weak zones cause the second weak zone to tear. The pressure relief component can provide multiple pressure reliefs.

[0045] However, since the thickness is smallest at the apex of the corner and the sharp corner is prone to stress concentration, when the above two factors are combined, some of the first weak areas may burst before the internal pressure of the battery reaches the preset pressure. This results in poor pressure relief stability of the pressure relief component, making it difficult to guarantee the stability of the pressure relief component's quality and reducing the safety of the battery.

[0046] The following is combined Figures 1 to 10 The following describes embodiments of the present invention.

[0047] According to an embodiment of the present invention, a single battery 1 is provided, including a housing 100 and a pressure relief component 200.

[0048] The housing 100 has a pressure relief hole 110 on one side in the first direction Z. A pressure relief component 200 covers the pressure relief hole 110. The pressure relief component 200 includes a raised portion 210, a weak portion 220, and a connecting portion 230. The connecting portion 230 connects to the housing 100 and surrounds the raised portion 210 and the weak portion 220. The weak portion 220 is located along the outer edge of the raised portion 210. The weak portion 220 includes at least one first weak segment 221 and at least two second weak segments 222. The first weak segments 221 and the second weak segments 222 are alternately arranged along the outer edge of the raised portion 210. That is, the weak portion 220 is constructed as follows: second weak segment 222 - first weak segment 221 - second weak segment 222... connected sequentially. The thickness of the weakest point of the first weak segment 221 is less than the thickness of the weakest point of the second weak segment 222.

[0049] The projections of the first weak segment 221 and the second weak segment 222 onto the plane perpendicular to the first direction Z are both arcs. The radius of curvature at the minimum point of the projection of the first weak segment 221 is R1, and the radius of curvature at the minimum point of the projection of the second weak segment 222 is R2, and satisfying: R1 < R2; or, the projection of the first weak segment 221 onto the plane perpendicular to the first direction Z is an arc, and the projection of the second weak segment 222 onto the plane perpendicular to the first direction Z is a straight line.

[0050] The individual battery 1 can be either cylindrical or prismatic. When the individual battery 1 is cylindrical, the pressure relief component 200 can also serve as an end cap for the cylindrical battery, connecting to the housing 100 and sealing the opening at one end of the housing 100. Furthermore, the pressure relief component 200 can be welded to the housing 100 to seal the pressure relief hole 110.

[0051] For example, the weak portion 220 can be a ring-shaped structure surrounding the raised portion 210, or it can be a C-shaped arc-shaped structure surrounding the raised portion 210. The number of first weak segments 221 and the number of second weak segments 222 can be the same, or the number of first weak segments 221 can be one less than the number of second weak segments 222. For example, the number of first weak segments 221 can be two, four, five, six, seven, or eight, and the number of second weak segments 222 can be three, four, five, six, seven, or eight.

[0052] Furthermore, the extension dimensions of multiple first weak segments 221 can all be the same, or at least two first weak segments 221 can have different extension dimensions; the extension dimensions of multiple second weak segments 222 can all be the same, or at least two second weak segments 222 can have different extension dimensions; multiple R1 can all be the same, or at least two R1 can be different; multiple R2 can all be the same, or at least two R2 can be different.

[0053] In various embodiments of this application, the projection of the first weak segment 221 onto a plane perpendicular to the first direction Z is an arc shape, and the projection of the second weak segment 222 onto a plane perpendicular to the first direction Z is a straight line shape. In this case, the second weak segment 222 can be considered as a special arc shape with a very large radius of curvature R2. Similarly, in some other embodiments, the first weak segment 221 is located at the acute angle between two adjacent second weak segments 222. In this case, the first weak segment 221 can be considered as a special arc shape with a very small radius of curvature R1. Both of these special cases, or combinations thereof, should be considered as technical solutions that conform to the spirit of this utility model and achieve the technical effects described in this utility model, and therefore should be considered to fall within the scope defined by the appended claims. Generally, R2≤4cm and R1≥10cm are sufficient to meet the requirements of secondary blasting.

[0054] like Figure 3 In the embodiment shown, the second weak segment 222 is a straight line. Even if R2 is considered to be infinite, it cannot be represented in the figure, so it is not shown in the figure.

[0055] By providing a weak section 220 on the pressure relief component 200, when the internal pressure of the single cell 1 increases, the weak section 220 will break in response to the pressure difference between the internal and external pressures of the single cell 1. Since R1 is substantially smaller than R2, that is, the bending degree of the first weak section 221 is greater than that of the second weak section 222, the pressure borne by the weak section 220 is more concentrated on the first weak section 221. Combined with the fact that the thickness of the first weak section 221 is smaller than that of the second weak section 222, when the pressure inside the single cell 1 reaches the first set pressure, the first weak section 221 bursts and releases pressure. If the internal pressure of the single cell 1 continues to increase and reaches the second set pressure, the second weak section 222 bursts and releases pressure. At this time, the entire weak section 220 is torn apart and released pressure. The pressure relief component 200 can achieve multiple pressure relief functions, avoiding the combustion of the side wall of the single cell 1 caused by the one-time ejection of high-temperature gas, and reducing the risk of heat spread.

[0056] In addition, since the first weak segment 221 is arc-shaped, the force on the first weak segment 221 is relatively uniform. Therefore, even if the thickness of the first weak segment 221 is set to be relatively thin, the first weak segment 221 will not have the problem of excessive local pressure. This avoids the first weak segment 221 from tearing before the pressure in the single cell 1 reaches the first set pressure, ensuring that the pressure relief component 200 starts to release pressure stably at the first set pressure, improving the stability of the pressure relief pressure. The pressure relief component 200 has good quality consistency, which is conducive to increasing the safety of the single cell 1 in use.

[0057] like Figure 7 As shown, in the technical solution of this embodiment, the weak part 220 has a first-level groove 240 on one side in the first direction Z. The first-level groove 240 has a first groove bottom 241 and a first groove opening 242. The width of the first-level groove 240 gradually increases along the direction from the first groove bottom 241 to the first groove opening 242.

[0058] For example, the processing method of the first-level groove 240 can be stamping. In actual production, the traditional square groove is prone to corrosion. The stamping process has a strong stretching effect on the material, which will lead to poor uniformity of the coating on the material surface, uneven coating, or even damage.

[0059] By setting the width of the primary groove 240 to gradually increase from the bottom 241 to the opening 242, i.e., the cross-sectional structure of the primary groove 240 is a "wide at the top and narrow at the bottom" type, the primary groove 240 gradually decreases from the opening 242 to the bottom 241 during the processing, which can serve as a processing buffer, so that the coating on the inner wall of the primary groove 240 is more uniformly extended, reducing the loss of the coating on the material surface and improving the corrosion resistance of the inner wall of the primary groove 240.

[0060] like Figures 7-10 As shown, in the technical solution of this embodiment, the cross-sectional shape of the primary scoring groove 240 includes at least one of a semi-circle, a trapezoid, and a triangle. That is, the cross-sectional shape of the primary scoring groove 240 can be a semi-circle, a trapezoid, or a triangle, or the cross-sectional shape of the primary scoring groove 240 can be a combination of a semi-circle and a trapezoid, a combination of a triangle and a trapezoid, a combination of two trapezoids, or a combination of two trapezoids, or the cross-sectional shape of the primary scoring groove 240 can be a component of a semi-circle, a trapezoid, and a triangle.

[0061] In this way, the construction methods of the primary groove 240 are more diverse, which is conducive to the application of primary grooves 240 with different structures in different products, so as to meet the explosion-proof requirements of different products and improve the applicability of the pressure relief component 200.

[0062] like Figure 7 As shown, in the technical solution of this embodiment, the weak part 220 also has a secondary groove 250. The secondary groove 250 is formed at the bottom of the first groove 241. The secondary groove 250 has a second groove bottom 251 and a second groove opening 252. The width of the secondary groove 250 gradually increases along the direction from the second groove bottom 251 to the second groove opening 252.

[0063] The primary groove 240 can be trapezoidal, with a relatively flat bottom wall, which facilitates the machining of the secondary groove 250. The second groove 122 can be trapezoidal or semi-circular to avoid stress concentration on the second groove 122 and improve pressure relief stability.

[0064] In this way, on the one hand, by setting the width of the secondary scoring groove 250 to gradually increase from the bottom 251 of the second groove to the opening 252 of the second groove, that is, the cross-sectional structure of the secondary scoring groove 250 is a "wider at the top and narrower at the bottom" type, during the processing, the secondary scoring groove 250 gradually decreases from the opening 252 of the second groove to the bottom 251 of the second groove, which can act as a processing buffer, so that the coating on the inner wall of the secondary scoring groove 250 is more uniformly extended, reducing the loss of the coating on the material surface; on the other hand, the primary scoring groove 240 and the secondary scoring groove 250 are processed and formed in two stages to form A deeper groove is formed to ensure that the overall depth of the primary groove 240 and the secondary groove 250 is large, so that the thickness of the weak part 220 meets the requirements. In the event of thermal runaway of the single cell 1, the weak part 220 can burst in time. At the same time, it can reduce the pressure on the primary groove 240 and the secondary groove 250 during each processing, and better ensure that the coating on the inner wall of the primary groove 240 and the secondary groove 250 is more uniformly extended, further reducing the loss of the coating on the material surface and effectively improving the corrosion resistance of the inner wall of the secondary groove 250.

[0065] Specifically, in some embodiments, the first weak segment 221 has a primary groove 240 and a secondary groove 250, and the second weak segment 222 is only provided with a primary groove 240, and the depth of the primary groove 240 of the second weak segment 222 is the same as the depth of the primary groove 240 of the first weak segment 221.

[0066] In some other embodiments, both the first weak segment 221 and the second weak segment 222 have a primary groove 240 and a secondary groove 250, and the sum of the depths of the primary groove 240 and the secondary groove 250 on the first weak segment 221 is greater than the sum of the depths of the primary groove 240 and the secondary groove 250 on the second weak segment 222. For example, the depth of the primary groove 240 of the first weak segment 221 is the same as the depth of the primary groove 240 of the second weak segment 222, and the depth of the secondary groove 250 of the first weak segment 221 is greater than the depth of the secondary groove 250 of the second weak segment 222; or the depth of the primary groove 240 of the first weak segment 221 is greater than the depth of the primary groove 240 of the second weak segment 222, and the depth of the secondary groove 250 of the first weak segment 221 is the same as the depth of the secondary groove 250 of the second weak segment 222; or the depth of the primary groove 240 of the first weak segment 221 is greater than the depth of the primary groove 240 of the second weak segment 222, and the depth of the secondary groove 250 of the first weak segment 221 is greater than the depth of the secondary groove 250 of the second weak segment 222.

[0067] like Figure 6 As shown, in the technical solution of this embodiment, the connecting part 230 includes a connecting part body 231, a first recess 232 and a connecting boss 233.

[0068] The connecting body 231 is provided around the raised portion 210 and the weak portion 220. The first recess 232 is provided around the outer edge of the connecting body 231. The connecting boss 233 is provided around the outer edge of the first recess 232, and the connecting boss 233 is connected to the housing 100.

[0069] Along the first direction Z, the connecting body 231 can protrude relative to the first recess 232 in a direction away from the housing 100, and the connecting boss 233 can also protrude relative to the first recess 232 in a direction away from the housing 100. That is to say, along the radial direction of the pressure relief member 200 from the inside to the outside, the connecting body 231, the first recess 232 and the connecting boss 233 form a "convex-concave-convex" structure.

[0070] It should be noted that in all embodiments of this application, the first direction Z refers to the direction indicated by the arrow "Z" in the accompanying drawings; it should be understood that the first direction Z is the direction indicated by the straight line perpendicular to the outer surface of the pressure relief component 200. A cylindrical coordinate system is constructed with the straight line passing through the center of the pressure relief component 200 and parallel to the first direction Z as the axis (which can be considered the axis of the pressure relief component 200). The radial direction refers to the direction indicated by the ray formed on the plane perpendicular to the first direction Z, starting from the intersection of the aforementioned axis and the aforementioned plane, along the direction of the radius line of the circle.

[0071] It should be understood that the introduction of concepts such as the first direction Z and radial direction in all embodiments of this application is merely for the convenience of describing spatial positional relationships and should not be construed as limiting the scope of the embodiments of this application. Therefore, the first direction Z and radial direction are mutually perpendicular. Such a positional relationship can be reasonably interpreted, based on the actual technical scenario, as a nearly perpendicular directional relationship between the first direction Z and radial direction, for example, the included angle between the first direction Z and radial direction is in the range of 85°-95°. As long as the technical solution can conform to the spirit of this utility model or achieve the technical effect described in this utility model, it can be considered to fall within the scope defined by the appended claims.

[0072] During the use of a single cell battery 1, gas is usually generated inside the single cell battery 1. By setting the connecting part 230 as a concave-convex structure, when the pressure increases due to the generation of gas inside the single cell battery 1, the connecting part 230 can deform to absorb the increased pressure inside the single cell battery 1 due to the increase of gas, thereby preventing the weak part 220 of the single cell battery 1 from being torn apart under normal working conditions, enhancing the overall strength of the pressure relief component 200, and extending the service life of the single cell battery 1.

[0073] In addition, the gas generated inside the single cell 1 can be stored in the connecting body 231. When there is too much gas in the single cell 1 and the pressure increases, the gas in the first gas storage chamber 260 can apply pressure evenly to the weak part 220, so as to avoid the weak part 220 from being torn due to excessive local pressure, and ensure that each area of ​​the weak part 220 can be torn evenly, thereby improving the pressure relief efficiency.

[0074] In addition, the connecting part 230 is designed with a concave-convex structure, which can absorb the stress generated by local heating during welding, thereby strengthening the structural strength of the pressure relief part 200.

[0075] like Figure 6 As shown, in the technical solution of this embodiment, the raised portion 210 includes a raised portion body 211, a second recess 212, and a third recess 213.

[0076] The weak part 220 is provided along the outer edge of the raised part body 211, the raised part body 211 is provided around the outer edge of the third recess 213, the second recess 212 is provided with a through hole 214, and the third recess 213 is provided around the outer edge of the second recess 212.

[0077] Along the first direction Z, the raised portion body 211 can protrude away from the housing 100 relative to the second recess 212 and the third recess 213. That is, along the radial direction of the pressure relief member 200 from the inside to the outside, the third recess 213 and the raised portion body 211 form a "concave-convex" structure. By providing the through hole 214, electrolyte can be injected into the single cell 1, enabling the normal use of the single cell 1. When the electrolyte injection device injects electrolyte into the single cell 1 through the through hole 214, the electrolyte injection device applies pressure to the pressure relief member 200. By setting the raised portion body 211 to a concave-convex structure, the raised portion body 211 can absorb the pressure of the electrolyte injection device through deformation, preventing the weak part 220 from being torn during the electrolyte injection process.

[0078] Furthermore, by setting the raised part body 211 as a concave-convex structure, the concave-convex structure can absorb the increased pressure inside the single cell 1 due to the increase of gas through deformation, preventing the weak part 220 of the single cell 1 from being torn apart under normal working conditions, thereby enhancing the overall strength of the pressure relief part 200 and extending the service life of the single cell 1.

[0079] In addition, the gas generated inside the single cell 1 can be stored in the lifting part body 211. When there is too much gas inside the single cell 1 and the pressure increases, the gas in the lifting part body 211 can apply pressure evenly to the weak part 220, so as to avoid the weak part 220 being torn due to excessive local pressure, and ensure that each area of ​​the weak part 220 can be torn evenly, thereby improving the pressure relief efficiency.

[0080] like Figures 1-5 As shown, in the technical solution of this embodiment, the connecting part body 231 and the lifting part body 211 are connected by the weak part 220 to increase the gas volume that the connecting part body 231 and the lifting part body 211 can store. This ensures that when the single cell 1 experiences thermal runaway, the high-temperature gas can more quickly tear the weak part 220 to be discharged outside the single cell 1. It also helps to ensure the uniformity of tearing of the weak part 220 and effectively ensures the pressure relief efficiency.

[0081] like Figures 1-5 As shown, in the technical solution of this embodiment, the weak portion 220 is arranged around the raised portion 210, and the first weak segment and the second weak segment 222 are alternately arranged around the outer edge of the raised portion 210. At this time, at least two first weak segments 221 and at least two second weak segments 222 are alternately arranged and connected end to end to form a closed ring.

[0082] In this way, the weak part 220 is constructed in a ring shape. When the weak part 220 is torn, the pressure relief in each region of the single cell 1 is more uniform, thus avoiding excessive local pressure in the single cell 1.

[0083] like Figures 1-5 As shown, in the technical solution of this embodiment, the projection of the weak part 220 on the plane perpendicular to the first direction Z is a rounded octagon, heptagon, hexagon, pentagon, quadrilateral, or triangle. The projection of the first weak segment 221 on the plane perpendicular to the first direction Z is located on the side, and the projection of the second weak segment 222 on the plane perpendicular to the first direction Z is located at the corner.

[0084] It should be noted that in the various embodiments of this application, the introduction of octagons, heptagons, hexagons, pentagons, quadrilaterals, or triangles is merely for the convenience of describing the spatial shape of the weak part 220. These octagons, heptagons, hexagons, pentagons, quadrilaterals, or triangles should not be understood as strictly mathematical figures, but rather as the approximate shape of the weak part 220, which is formed by alternating first weak segments 221 and second weak segments 222 connected end-to-end. Correspondingly, the projection of the first weak segment 221 onto the plane perpendicular to the first direction Z is located on each side of this approximate shape; that is, the projection of the first weak segment 221 onto the plane perpendicular to the first direction Z is located on the sides. Similarly, the projection of the second weak segment 222 onto the plane perpendicular to the first direction Z is located at each corner of this approximate shape; that is, the projection of the second weak segment 222 onto the plane perpendicular to the first direction Z is located at the corners. For example, the octagon, heptagon, hexagon, pentagon, quadrilateral, or triangle presented by the weak part 220 can be interpreted, depending on the actual technical scenario, as the first weak segment 221 forming each straight edge and the second weak segment 222 forming each rounded corner straight edge rounded corner figure, or it can be interpreted as the first weak segment 221 forming each arc edge and the second weak segment 222 forming each rounded corner smooth curve figure... As long as the pattern presented by the weak part 220 as a whole is an octagon, heptagon, hexagon, pentagon, quadrilateral, or triangle, it should be regarded as a technical solution that can conform to the spirit of this application or achieve the technical effect described in this application, and can be considered to fall within the scope defined by the appended claims.

[0085] Beneficial effects: It can control the bending angle of the first weak segment, avoid the problem of local stress concentration caused by excessive bending of the first weak segment, help ensure uniform stress distribution in the first weak segment, and further improve the pressure relief stability.

[0086] like Figure 8As shown, in the technical solution of this embodiment, the thickness of the first weak segment 221 is T1, where 0.2mm ≥ T1 ≥ 0.01mm. T1 can be 0.01mm, 0.02mm, 0.03mm, 0.04mm, 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm, 0.1mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, 0.16mm, 0.17mm, 0.18mm, 0.19mm, or 0.2mm.

[0087] In this way, on the one hand, the processing precision is avoided, the processing difficulty is reduced, the production efficiency is improved and the production cost is reduced, and on the other hand, the initial pressure relief will not be too high, ensuring that the first weak section 221 is torn apart in time for pressure relief, which is conducive to improving the safety of the battery.

[0088] like Figures 9-10 As shown, in the technical solution of this embodiment, the thickness of the second weak segment 222 is T2, where 0.2mm ≥ T2 ≥ 0.01mm. T2 can be 0.01mm, 0.02mm, 0.03mm, 0.04mm, 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm, 0.1mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, 0.16mm, 0.17mm, 0.18mm, 0.19mm, or 0.2mm.

[0089] In this way, on the one hand, the processing precision is avoided, the processing difficulty is reduced, the production efficiency is improved and the production cost is reduced, and on the other hand, the secondary pressure relief will not be too large, ensuring that the second weak section 222 is torn in time for pressure relief, which is conducive to improving the safety of the battery.

[0090] The thicknesses T1 and T2 of the first weak segment 221 can be obtained by metallographic sectioning of the pressure relief component 200.

[0091] Furthermore, the thickness T1mm at the bottom of the first weak segment 221 and the thickness T2mm at the bottom of the second weak segment 222 satisfy: T1≥T2. This can further increase the pressure threshold for primary and secondary pressure relief, avoid excessive processing precision, reduce processing difficulty, improve production efficiency, reduce production costs, and ensure that the first and second weak segments are torn apart in time for pressure relief, which is beneficial to improving battery safety.

[0092] The following describes the test data for pressure relief component 200:

[0093] Test subject: The weak part 220 of the pressure relief component 200 includes six first weak segments 221 and six second weak segments 222. The second weak segments 222 are straight lines. The six second weak segments 222 have the same length. The six first weak segments 221 have the same arc length. The central angle of each first weak segment 221 is 120°. The cross-sectional shape of the first-level groove 240 and the cross-sectional shape of the second-level groove 250 are both trapezoidal.

[0094] Test conditions: The pressure relief component 200 is fixed by tooling, and pressure is continuously applied to the pressure relief component 200 until the weak part 220 of the pressure relief component 200 is completely ruptured. The magnitude of the pressure relief in the two tests is observed.

[0095] The test results are as follows:

[0096]

[0097] The first pressure relief refers to the pressure borne by the pressure relief component 200 when the first weak section 221 is torn; the second pressure relief refers to the pressure borne by the pressure relief component 200 when the second weak section 222 is torn.

[0098] As can be seen from the above embodiments, when the conditions 0.2mm≥T1≥0.01mm, 0.2mm≥T2≥0.01mm, and T1<T2 are met, with T1 remaining constant, the larger the value of T2, the greater the second pressure relief of the pressure relief component 200; conversely, with T2 remaining constant, the larger the value of T1, the greater the first pressure relief of the pressure relief component 200. In other words, the thickness T1 of the first weak segment 221 is positively correlated with the first pressure relief of the weak portion 220, and the thickness T2 of the second weak segment 222 is positively correlated with the second pressure relief of the weak portion 220.

[0099] When T1 < 0.01 mm, the required processing precision for the first weak segment 221 is too high, potentially leading to lower production efficiency and higher production costs. When T1 ≥ 0.2 mm, the initial pressure relief is too high, which may prevent the first weak segment 221 from being torn apart and depressurized in time, resulting in excessive gas accumulation inside the single cell 1. Furthermore, when both T1 and T2 are greater than 0.2 mm, the pressure difference between the first and second pressure reliefs becomes insignificant, which is not conducive to improving the stability of pressure relief in the single cell through two pressure relief cycles. By setting 0.2 mm ≥ T1 ≥ 0.01 mm, on the one hand, excessively high processing precision is avoided, reducing processing difficulty, improving production efficiency, and reducing production costs. On the other hand, the initial pressure relief is not too high, which helps ensure that the first weak segment 221 is torn apart and depressurized in time, thus improving the safety of the single cell 1.

[0100] When T2 ≤ 0.01 mm, the required processing precision for the second weak segment 222 is too high, which may lead to low production efficiency and high production costs. When T1 ≥ 0.2 mm, the secondary pressure relief is too high, which may prevent the second weak segment 222 from being torn apart and depressurized in time, resulting in excessive gas accumulation inside the single cell 1. By setting 0.2 mm ≥ T2 ≥ 0.01 mm, on the one hand, excessive processing precision is avoided, reducing processing difficulty, improving production efficiency, and reducing production costs. On the other hand, the secondary pressure relief is not too high, which helps to ensure that the second weak segment 222 is torn apart and depressurized in time, thus improving the safety of the single cell 1.

[0101] like Figures 1-2 As shown, in the technical solution of this embodiment, the extension dimension of each second weak segment 222 is greater than the extension dimension of each first weak segment 221.

[0102] Since the extension dimension of the second weak segment 222 is larger than that of the first weak segment 221, the ratio of the sum of the extension dimensions of the multiple first weak segments 221 to the total length of the weak portion 220 is less than 50%. That is, the ratio of the sum of the extension dimensions of the multiple first weak segments 221 to the total length of the weak portion 220 is small. Therefore, when the multiple first weak segments 221 are torn, the raised portion 210 and the connecting portion 230 are not easy to completely separate, and the pressure relief component 200 releases pressure slightly. When the multiple second weak segments 222 are torn, the raised portion 210 and the connecting portion 230 separate, and the raised portion 210 is completely detached from the single cell 1. At this time, the pressure relief component 200 releases pressure significantly.

[0103] In this way, the pressure relief component 200 can not only achieve two pressure relief functions, but also the pressure relief area of ​​the pressure relief component 200 during the second pressure relief is much larger than the pressure relief area during the first pressure relief, which is conducive to giving full play to the effect of the two pressure reliefs and effectively reducing the risk of thermal runaway.

[0104] Secondly, this utility model also provides a battery pack, which includes the aforementioned single battery cell 1.

[0105] The second aspect of the battery pack, utilizing the first aspect of the single cell 1, can improve the overall pressure relief stability and reduce the risk of thermal runaway.

[0106] Thirdly, this utility model also provides an electrical device, which includes the aforementioned single battery 1, or the electrical device includes the aforementioned battery pack.

[0107] The third type of battery pack, which utilizes the individual cells of the first type 1 or the second type of battery pack, can improve the overall pressure relief stability and reduce the risk of thermal runaway.

[0108] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A single-cell battery, characterized in that, include: The housing (100) has a first direction (Z), and the housing (100) has a pressure relief hole (110) on one side in the first direction (Z); A pressure relief component (200) covers the pressure relief hole (110). The pressure relief component (200) includes a raised portion (210), a weak portion (220), and a connecting portion (230). The weak portion (220) includes at least one first weak segment (221) and at least two second weak segments (222). The first weak segment (221) and the second weak segment (222) are alternately arranged along the outer edge of the raised portion (210). The thickness of the weakest point of the first weak segment (221) is less than the thickness of the weakest point of the second weak segment (222); the projections of the first weak segment (221) and the second weak segment (222) onto the plane perpendicular to the first direction (Z) are both arcs, the radius of curvature of the projection of the first weak segment (221) at its minimum is R1, and the radius of curvature of the projection of the second weak segment (222) at its minimum is R2, and satisfying: R1 < R2; or, the projection of the first weak segment (221) onto the plane perpendicular to the first direction (Z) is an arc, and the projection of the second weak segment (222) onto the plane perpendicular to the first direction (Z) is a straight line; The connecting part (230) connects to the housing (100), and the connecting part (230) is arranged around the raised part (210) and the weak part (220).

2. The single-cell battery according to claim 1, characterized in that, The weak part (220) has a first-level groove (240) on one side in the first direction (Z). The first-level groove (240) has a first groove bottom (241) and a first groove opening (242). The width of the first-level groove (240) gradually increases along the direction from the first groove bottom (241) to the first groove opening (242).

3. The single-cell battery according to claim 2, characterized in that, The weak part (220) also has a secondary groove (250), which is formed at the bottom of the first groove (241). The secondary groove (250) has a second groove bottom (251) and a second groove opening (252). The width of the secondary groove (250) gradually increases along the direction from the second groove bottom (251) to the second groove opening (252).

4. The single-cell battery according to claim 1, characterized in that, The connecting part (230) includes: The connecting body (231) is provided around the raised portion (210) and the weak portion (220); The first recess (232) is provided around the outer edge of the connecting body (231); A connecting boss (233) is provided around the outer edge of the first recess (232), and the connecting boss (233) is connected to the housing (100).

5. The single-cell battery according to claim 1, characterized in that, The raised portion (210) includes: The raised part body (211) has the weak part (220) provided along the outer edge of the raised part body (211); The second recess (212) has a through hole (214); The third recess (213) is provided around the outer edge of the second recess (212), and the raised part body (211) is provided around the outer edge of the third recess (213).

6. The single-cell battery according to any one of claims 1-5, characterized in that, The weak portion (220) is arranged around the raised portion (210), and the first weak segment (221) and the second weak segment (222) are arranged alternately around the outer edge of the raised portion (210).

7. The single-cell battery according to claim 6, characterized in that, The projection of the weak part (220) onto the plane perpendicular to the first direction (Z) is a rounded octagon, heptagon, hexagon, pentagon, quadrilateral, or triangle. The projection of the first weak segment (221) onto the plane perpendicular to the first direction (Z) is located on the side, and the projection of the second weak segment (222) onto the plane perpendicular to the first direction (Z) is located at the corner.

8. The single-cell battery according to any one of claims 1-5, characterized in that, The thickness of the bottom of the first weak segment (221) is T1mm, and the thickness of the bottom of the second weak segment (222) is T2mm, satisfying: T1≥T2.

9. A battery pack, characterized in that, Includes the single cell battery (1) as described in any one of claims 1-8.

10. An electrical appliance, characterized in that, It includes a single cell (1) as described in any one of claims 1-8, or a battery pack as described in claim 9.

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