Battery cells, batteries and power consuming devices

Abstract

This application provides a battery cell, a battery, and a power consuming device in the field of battery technology. The battery cell includes a housing including a pressure release member, the pressure release member having a groove formed therein, the pressure release member configured to rupture along the groove to release internal pressure in the battery cell, and the pressure release member having an explosion point. The groove includes a first groove segment, a second groove segment, and a third groove segment, the first groove segment facing the third groove segment, the second groove segment connecting the first groove segment and the third groove segment, and the explosion point is formed in the first groove segment and / or the third groove segment. Because the explosion point is not formed in the second groove segment, the fatigue strength of the pressure release member in the area of ​​the second groove segment is high, reducing the possibility of the pressure release member rupturing in the middle area of ​​the second groove segment during normal use of the battery cell, improving the long-term reliability of the pressure release member and extending the service life of the battery cell.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority to Chinese patent application No. 2023106406395, entitled "Battery Cell, Battery and Power Consumption Device," filed on May 31, 2023, the entire contents of which are incorporated herein by reference.

[0002] This application relates to the field of battery technology, and more particularly to battery cells, batteries, and power consuming devices. [Background technology]

[0003] BACKGROUND ART With the development of new energy technology, batteries are increasingly being applied in mobile phones, notebook computers, electric motorcycles, electric cars, electric airplanes, electric boats, electric car toys, electric boat toys, electric airplane toys, power tools, etc.

[0004] In the case of a typical battery cell, a pressure release member is installed in the battery cell. In the event of thermal runaway, the pressure release member releases the internal pressure of the battery cell, thereby improving the reliability of the battery cell. In addition to improving the reliability of the battery cell, the service life of the battery cell is also an issue that needs to be considered. Therefore, how to extend the service life of battery cells is an issue that needs to be resolved as soon as possible in battery technology. Summary of the Invention

[0005] The embodiments of the present application provide a battery cell, a battery, and a power consuming device that can effectively extend the service life of the battery cell.

[0006] According to a first aspect, an embodiment of the present application provides a battery cell, the battery cell comprising a housing, the housing including a pressure release member, the pressure release member having a groove formed therein, the pressure release member being configured to rupture along the groove to release internal pressure of the battery cell, the pressure release member having an explosion position, the groove including a first groove segment, a second groove segment, and a third groove segment, the first groove segment being positioned opposite the third groove segment, the second groove segment connecting the first groove segment and the third groove segment, and the explosion position being formed in the first groove segment and / or the third groove segment.

[0007] In the above technical solution, the explosion position of the pressure release member is formed in the first groove segment and / or the third groove segment, and the explosion position is not formed in the second groove segment. Therefore, the fatigue strength of the pressure release member in the area of ​​the second groove segment is high, and the possibility of the pressure release member rupturing in the second groove segment during normal use of the battery cell is reduced, thereby improving the long-term reliability of the pressure release member and extending the service life of the battery cell.

[0008] In some embodiments, the first groove segment has an explosion point, and the remaining thickness of the first groove segment is smaller than the remaining thickness of the second groove segment. In this way, the explosion point may be formed near the connection point between the second groove segment and the first groove segment. When pressure is released, the pressure release member ruptures at this explosion point, and the crack can then propagate along both the first groove segment and the second groove segment. Furthermore, since the remaining thickness of the first groove segment is smaller than the remaining thickness of the second groove segment, this is equivalent to increasing the remaining thickness of the second groove segment, improving the fatigue strength of the pressure release member in the area where the second groove segment is installed, and further reducing the likelihood of the pressure release member rupturing in the area of ​​the second groove segment during normal use of the battery cell.

[0009] In some embodiments, the remaining thickness of the first groove segment is D1, and the remaining thickness of the second groove segment is D2, where 0.15≦D1 / D2≦0.95 is satisfied. If D1 / D2<0.15, the remaining thickness of the second groove segment is too large, which increases the risk that the pressure release member will not rupture along the second groove segment when pressure is released, reducing the timeliness of pressure release. If D1 / D2>0.95, the remaining thickness of the second groove segment is too small, which increases the risk that the pressure release member will rupture along the second groove segment during normal use of the battery cell, affecting the service life of the battery cell. In contrast, if 0.15≦D1 / D2≦0.95, the timeliness of pressure release of the battery cell can be improved and the service life of the battery cell can be extended.

[0010] In some embodiments, 0.3≦D1 / D2≦0.9, which can provide better performance of the battery cell, improve the timeliness of pressure relief of the battery cell, and extend the service life of the battery cell.

[0011] In some embodiments, 0.5≦D1 / D2≦0.85, which not only further improves the overall performance of the battery cell and reduces the probability of the pressure release member rupturing along the second groove segment during normal use of the battery cell, but also reduces the probability of the battery cell exploding during thermal runaway.

[0012] In some embodiments, 0.03 mm≦D1≦0.5 mm.

[0013] In some embodiments, 0.15 mm≦D1≦0.4 mm.

[0014] In some embodiments, 0.05 mm≦D2≦0.65 mm.

[0015] In some embodiments, 0.25 mm≦D2≦0.5 mm.

[0016] In some embodiments, the depth of the first groove segment is greater than the depth of the second groove segment, so that the remaining thickness of the first groove segment is less than the remaining thickness of the second groove segment. By forming the first groove segment deeper than the second groove segment in the pressure release member during molding, the remaining thickness of the first groove segment can be made less than the remaining thickness of the second groove segment, which is simple to achieve.

[0017] In some embodiments, the first groove segment includes a first-stage groove and a second-stage groove, the first-stage groove and the second-stage groove are arranged along the thickness direction of the pressure release member, and the second-stage groove is located on the groove bottom surface of the first-stage groove. During molding, the first groove segment can be molded by first molding the first-stage groove in the pressure release member and then molding the second-stage groove on the groove bottom surface of the first-stage groove. In this way, the molding depth of each stage groove in the first groove segment can be reduced, the molding force received by the pressure release member when molding the first groove segment can be reduced, and the possibility of cracks occurring in the pressure release member when molding the first groove segment can be reduced.

[0018] In some embodiments, the groove bottom surface of the first-stage groove is flush with the groove bottom surface of the second groove segment, so that the groove bottom surface of the first-stage groove is flush with the groove bottom surface of the second groove segment, and during molding, the first-stage groove of the first groove segment and the second groove segment can be molded together, and then the second-stage groove of the first groove segment can be molded, improving the molding efficiency of the groove portion.

[0019] In some embodiments, the pressure release member has a first surface and a second surface facing each other along the thickness direction of the pressure release member, the first-stage groove and the second-stage groove are sequentially arranged along the direction from the first surface to the second surface, the groove bottom surface of the second-stage groove is closer to the second surface than the groove bottom surface of the second groove segment, and the groove bottom surface of the second-stage groove is connected to the groove bottom surface of the second groove segment via a first inclined surface or a first arc surface. When the pressure release member ruptures at the explosion position during pressure release, the crack at the groove bottom surface of the second-stage groove can quickly spread along the first inclined surface or the first arc surface to the groove bottom surface of the second groove segment, thereby shortening the time for the crack to spread from the first groove segment to the second groove segment and further shortening the time for the pressure release member to rupture along the groove portion.

[0020] In some embodiments, the third groove segment has an explosion point, and the remaining thickness of the third groove segment is smaller than the remaining thickness of the second groove segment. In this way, the explosion point can be formed near the connection point between the second groove segment and the third groove segment. When pressure is released, after the pressure release member ruptures at this explosion point, the crack can propagate along the third groove segment and also along the second groove segment. Because the remaining thickness of the third groove segment is smaller than the remaining thickness of the second groove segment, this is equivalent to increasing the remaining thickness of the second groove segment, improving the fatigue strength of the pressure release member in the area where the second groove segment is installed and further reducing the possibility of the pressure release member rupturing in the area of ​​the second groove segment during normal use of the battery cell. In addition, since explosion positions are formed in both the first groove segment and the third groove segment, when the internal pressure of the battery cell reaches the explosion pressure, the explosion positions of both the first groove segment and the third groove segment can rupture, causing the crack to spread along the first groove segment and the third groove segment, and also to spread from both ends of the second groove segment to the middle position, thereby shortening the time it takes for the pressure release member to rupture along the groove portion.

[0021] In some embodiments, the remaining thickness of the third groove segment is equal to the remaining thickness of the first groove segment, and when the pressure of the battery cell is released, the synchronization of the pressure release member rupturing along the first groove segment and the third groove segment is better, the time for the pressure release member to rupture along the groove is further shortened, and the timeliness of the pressure release is improved.

[0022] In some embodiments, the remaining thickness of the second groove segment is D2, and the remaining thickness of the third groove segment is D3, where 0.15≦D3 / D2≦0.95 is satisfied. If D3 / D2<0.15, the remaining thickness of the second groove segment is too large, which increases the risk that the pressure release element will not rupture along the second groove segment when pressure is released, reducing the timeliness of pressure release. If D3 / D2>0.95, the remaining thickness of the second groove segment is too small, which increases the risk that the pressure release element will rupture along the second groove segment during normal use of the battery cell, affecting the service life of the battery cell. In contrast, if 0.15≦D3 / D2≦0.95, the timeliness of pressure release of the battery cell can be improved and the service life of the battery cell can be extended.

[0023] In some embodiments, 0.3≦D3 / D2≦0.9, which results in better performance of the battery cell and improves the timeliness of pressure relief of the battery cell while extending the service life of the battery cell.

[0024] In some embodiments, 0.5≦D3 / D2≦0.85, which not only further improves the overall performance of the battery cell and reduces the probability of the pressure release member rupturing along the second groove segment during normal use of the battery cell, but also reduces the probability of the battery cell exploding during thermal runaway.

[0025] In some embodiments, 0.03 mm≦D3≦0.5 mm.

[0026] In some embodiments, 0.15 mm≦D3≦0.4 mm.

[0027] In some embodiments, the depth of the third groove segment is greater than the depth of the second groove segment, so that the remaining thickness of the third groove segment is less than the remaining thickness of the second groove segment. By forming the third groove segment deeper than the second groove segment in the pressure release member during molding, the remaining thickness of the third groove segment can be made less than the remaining thickness of the second groove segment, which is easy to achieve.

[0028] In some embodiments, the third groove segment includes a third-stage groove and a fourth-stage groove, the third-stage groove and the fourth-stage groove are arranged along the thickness direction of the pressure release member, and the fourth-stage groove is located on the groove bottom surface of the third-stage groove. During molding, the third groove segment can be molded by first molding the third-stage groove in the pressure release member and then molding the fourth-stage groove on the groove bottom surface of the third-stage groove. In this way, the molding depth of each groove step in the third groove segment can be reduced, the molding force applied to the pressure release member when molding the third groove segment can be reduced, and the possibility of cracks occurring in the pressure release member when molding the third groove segment can be reduced.

[0029] In some embodiments, the groove bottom surface of the third-stage groove is flush with the groove bottom surface of the second-stage groove, so that the groove bottom surface of the third-stage groove is located on the same plane as the groove bottom surface of the second groove segment, and during molding, the third-stage groove of the third groove segment and the second groove segment can be molded together, and then the fourth-stage groove of the third groove segment can be molded, improving the molding efficiency of the groove portion.

[0030] In some embodiments, the pressure release member has a first surface and a second surface facing each other along the thickness direction of the pressure release member, the third and fourth grooves are sequentially arranged along the direction from the first surface to the second surface, the bottom surface of the fourth groove is closer to the second surface than the bottom surface of the second groove segment, and the bottom surface of the fourth groove is connected to the bottom surface of the second groove segment via a second inclined surface or a second arc surface. When pressure is released, after the pressure release member ruptures at the explosion position, the crack at the bottom surface of the fourth groove can quickly spread along the second inclined surface or the second arc surface to the bottom surface of the second groove segment, thereby shortening the time for the crack to spread from the third groove segment to the second groove segment and further shortening the time for the pressure release member to rupture along the groove portion.

[0031] In some embodiments, both ends of the second groove segment are connected to the first groove segment and the third groove segment, respectively, along the extension direction of the second groove segment. In this way, both ends of the second groove segment do not extend beyond the first groove segment and the third groove segment, respectively. Therefore, during the pressure release process, pressure can be released precisely through the area defined by the first groove segment, the second groove segment, and the third groove segment, and other areas of the pressure release member are less likely to burst and release pressure, making it easier to achieve directional pressure release.

[0032] In some embodiments, the first groove segment and the second groove segment are connected at a first position, and the first position is located away from both ends of the first groove segment along the extension direction of the first groove segment. During the pressure release process, after the pressure release member ruptures at the first position, the crack can spread from the first position to both ends along the first groove segment, thereby shortening the time it takes for the pressure release member to rupture along the first groove segment.

[0033] In some embodiments, the first position is located at the midpoint of the first groove segment along the extension direction of the first groove segment, and during the pressure release process, the cracks propagate an equal distance from the first position to both ends along the first groove segment, further shortening the time it takes for the pressure release member to rupture along the first groove segment.

[0034] In some embodiments, the third groove segment and the second groove segment are connected at a second position, and the second position is located away from both ends of the third groove segment along the extension direction of the third groove segment. During the pressure release process, after the pressure release member ruptures at the second position, the crack can spread from the second position to both ends along the third groove segment, thereby shortening the time it takes for the pressure release member to rupture along the third groove segment.

[0035] In some embodiments, the second position is located at the midpoint of the third groove segment along the extension direction of the third groove segment, and the cracks propagate from the second position to both ends along the third groove segment over an equal distance during the pressure release process, further shortening the time it takes for the pressure release member to rupture along the third groove segment.

[0036] In some embodiments, the first groove segment, the second groove segment, and the third groove segment are all grooves that extend along a straight line, which can reduce the difficulty of forming the first groove segment, the second groove segment, and the third groove segment.

[0037] In some embodiments, the first groove segment is perpendicular to the second groove segment and / or the third groove segment is perpendicular to the second groove segment. When the first groove segment is perpendicular to the second groove segment, stress is more concentrated near the connection position between the first groove segment and the second groove segment. If the explosion position is located near the connection position between the first groove segment and the second groove segment, the processing depth of the first groove segment can be reduced and the processing difficulty of the first groove segment can be reduced when the explosion pressure of the battery cell is constant. When the third groove segment is perpendicular to the second groove segment, stress is more concentrated near the connection position between the third groove segment and the second groove segment. If the explosion position is located near the connection position between the third groove segment and the second groove segment, the processing depth of the third groove segment can be reduced and the processing difficulty of the third groove segment can be reduced when the explosion pressure of the battery cell is constant.

[0038] In some embodiments, the first groove segment, the second groove segment, and the third groove segment define a pressure relief area, and the pressure relief member has a guide groove spaced apart from the second groove segment to guide the pressure relief area to reverse and open. The guide groove facilitates the pressure relief area to reverse and open, reducing the difficulty of reversing the pressure relief area and effectively improving the timeliness of pressure release.

[0039] In some embodiments, the first, second, and third groove segments define two pressure relief areas, each located on either side of the second groove segment, and the pressure relief member has two guide grooves, with the second groove segment located between the two guide grooves, which respectively guide the two pressure relief areas to reverse and open. During the pressure release process, the two guide grooves respectively guide the two pressure relief areas, improving the opening speed of the two pressure relief areas and allowing for more timely pressure release.

[0040] In some embodiments, neither the first groove segment nor the second groove segment contacts the guide groove. Because the guide groove is less likely to affect the first groove segment and the third groove segment, the fatigue strength of the pressure release member at the first groove segment and the third groove segment is improved, and the possibility of the pressure release member rupturing at the connection position during normal use of the battery cell due to stress concentration caused by the connection between the guide groove and the first groove segment and the third groove segment is reduced. Furthermore, after the pressure release member ruptures along the first groove segment and the third groove segment during the pressure release process, the crack is less likely to spread to the guide groove, reducing the possibility of the pressure release member detaching and scattering after the pressure release area is opened.

[0041] In some embodiments, the guide groove and the groove portion are respectively installed on both sides of the pressure release member along the thickness direction of the pressure release member, which on the one hand reduces the influence of the guide groove on the groove portion during molding, and on the other hand, the guide groove can have a better guiding effect on the pressure release area, making it easier for the pressure release area to invert and open.

[0042] In some embodiments, the guide groove extends along the extension direction of the second groove segment.

[0043] In some embodiments, the first and third groove segments are located on opposite sides of the guide groove along the extension direction of the second groove segment. The length of the second groove segment between the first and third groove segments is L1, and the length of the guide groove is L2, satisfying 1 mm≦L1−L2≦10 mm. When L1−L2<1 mm, the distance between at least one of the first and third groove segments and the guide groove is small, and the influence of the guide groove on the first and third groove segments is large. This increases the possibility of the pressure release member prematurely rupturing at a position close to the guide groove of the first or third groove segment, increasing the possibility of premature pressure release. When L1−L2>10 mm, the length of the guide groove is short, reducing the ability of the guide groove to contribute to the reversal of the pressure release region. In contrast, when 1 mm≦L1−L2≦10 mm, not only is the possibility of the pressure release member prematurely releasing pressure reduced, but the guide groove's ability to contribute to the reversal of the pressure release region is also improved.

[0044] In some embodiments, 2 mm≦L1−L2≦6 mm, which further reduces the likelihood that the pressure release member will prematurely release pressure and further improves the guiding ability of the pressure release area of ​​the guide groove to contribute to the reversal and opening of the pressure release area.

[0045] In some embodiments, along the extending direction of the first groove segment, the distance between the guide groove and the second groove segment is L3, and the length of the portion of the first groove segment extending from the second groove segment towards the guide groove is L4, and 0.5 mm ≤ |L3 - L4| ≤ 15 mm. When |L3 - L4| < 0.5 mm, since the distance between the end of the first groove segment and the guide groove is small, when a crack in the pressure relief member diffuses along the first groove segment to the end of the first groove segment, the crack easily diffuses into the guide groove. As a result, the pressure relief region detaches. When |L3 - L4| > 15 mm, if L3 > L4, the distance between the guide groove and the second groove segment is large, and the ability to contribute to the inversion of the pressure relief region of the guide groove is low. If L3 < L4, the distance between the guide groove and the second groove segment is small, the area of the inverted opening of the pressure relief region is small, and the pressure relief area of the pressure relief region decreases. In contrast, when 0.5 mm ≤ |L3 - L4| ≤ 15 mm, not only can the possibility of detachment and scattering in the pressure relief region be reduced, but also the difficulty of the inverted opening of the pressure relief region can be lowered, and the opening area of the pressure relief region can be increased.

[0046] In some embodiments, 1 mm ≤ |L3 - L4| ≤ 10 mm.

[0047] In some embodiments, the housing includes a first wall portion, the pressure relief member is the first wall portion, or the pressure relief member and the first wall portion are installed separately, and the pressure relief member is attached to the first wall portion. When the first wall portion is used as the pressure relief member, since the groove portion can be directly formed on the first wall portion to form an integrated pressure relief structure, the reliability is higher, the attachment process of the pressure relief member is omitted, and the manufacturing cost of the battery cell can be reduced. When the pressure relief member is attached to the first wall portion, the pressure relief member is a member independent of the housing, and the pressure relief member and the housing may be manufactured and assembled separately. The manufacturing difficulty is low and the efficiency is high.

[0048] In some embodiments, the housing includes a case and an end cover, the case having an opening, the end cover sealing the opening, and the end cover being the first wall, whereby the end cover has a pressure relief function and it is less difficult to mold a groove in the end cover.

[0049] In some embodiments, the housing includes a case and an end cover, the case has an opening, the end cover seals the opening, and at least one wall of the case is a first wall, whereby the case has a pressure release function, and when pressure is released, waste matter discharged from inside the battery cells is less likely to affect an external member outside the end cover, reducing the possibility of damage to the external member due to the waste matter.

[0050] In some embodiments, the case includes a bottom wall and a plurality of side walls, the side walls are disposed around the bottom wall, the case has an opening at an end opposite the bottom wall, and the bottom wall is a first wall portion. The bottom wall has a pressure release function, and when a battery cell experiences thermal runaway, pressure can be released through the bottom wall. In the battery, the pressure release member is not easily blocked by other battery cells.

[0051] In some embodiments, the first wall is a rectangular wall, the second groove segment extends along the length of the first wall, and both the first and third groove segments extend along the width of the first wall. In this manner, the second wall can provide more space for the second groove segment, making it longer and increasing the pressure relief area of ​​the pressure relief member.

[0052] In some embodiments, along the thickness direction of the pressure relief member, the first wall portion has an outer surface, the outer surface faces away from the interior of the housing, the first groove segment has a first intermediate surface extending along its extending direction, the second groove segment has a second intermediate surface extending along its extending direction, the third groove segment has a third intermediate surface extending along its extending direction, the minimum distance from the center point of the outer surface to the first intermediate surface is M1, the minimum distance from the center point of the outer surface to the second intermediate surface is M2, the minimum distance from the center point of the outer surface to the third intermediate surface is M3, and M2 < M1 and M2 < M3 are satisfied. When the internal pressure of the battery cell changes, the closer the first wall portion is to the center point, the easier it is to deform. Since M2 < M1 and M2 < M3, the first groove segment and the third groove segment are farther from the center point, and the fatigue strength of the pressure relief member at the first groove segment and the third groove segment is improved.

[0053] In some embodiments, along the thickness direction of the pressure relief member, the projection of the center point of the outer surface is located within the second groove segment, and / or |M3 - M1| ≤ 5 mm. When the projection of the center point of the outer surface is located within the second groove segment, since the second groove segment is closer to the center point of the outer surface, when the pressure is released, the pressure relief member can rupture more timely along the second groove segment, and the timeliness of the pressure relief of the pressure relief member is improved. When |M3 - M1| ≤ 5 mm, since both the first groove segment and the third groove segment are far from the center point, the influence on the first groove segment and the third groove segment due to the deformation near the center point of the pressure relief member is reduced.

[0054] According to a second aspect, an embodiment of the present application provides a battery, and the battery includes a battery cell according to any one of the embodiments of the first aspect.

[0055] According to a third aspect, an embodiment of the present application provides an electrical consumer device, and the electrical consumer device includes a battery cell according to any one of the embodiments of the first aspect for supplying electrical energy to the electrical consumer device.

Brief Description of the Drawings

[0056] In order to more clearly explain the technical solutions of the embodiments of the present application, the following will briefly describe the drawings that need to be used in the embodiments. It should be understood that the following drawings only illustrate some embodiments of the present application, and should not be considered as limiting the scope. Those skilled in the art can obtain other related drawings based on these drawings without exerting creative efforts.

[0057] [Figure 1] 1 is a structural schematic diagram of a vehicle according to some embodiments of the present application. [Figure 2] FIG. 1 is an exploded view of a battery according to some embodiments of the present application. [Figure 3] FIG. 1 is an exploded view of a battery cell according to some embodiments of the present application. [Figure 4] FIG. 1 is an axonometric view of a battery cell according to some embodiments of the present application. [Figure 5] FIG. 5 is a partial view of the pressure release member shown in FIG. 4. [Figure 6] 6 is a cross-sectional view of the pressure release member shown in FIG. 5 along the line AA. [Figure 7] FIG. 7 is a partial enlarged view of a portion B in FIG. 6. [Figure 8] FIG. 7 is a partial enlarged view of a portion C in FIG. 6. [Figure 9] FIG. 2 is a partial enlarged view of a battery cell according to some other embodiments of the present application. [Figure 10] FIG. 10 is a partial view of the pressure release member shown in FIG. 9. [Figure 11] 11 is a cross-sectional view of the pressure release member shown in FIG. 10; FIG. [Figure 12] FIG. 12 is a partial enlarged view of a portion E in FIG. [Figure 13] 10A and 10B are partial cross-sectional views of a pressure relief member according to some alternative embodiments of the present application. [Figure 14] 12 is a partially enlarged view of a portion F of the pressure release member shown in FIG. 11. FIG. [Figure 15] 10A and 10B are partial cross-sectional views of a pressure relief member according to still other embodiments of the present application. [Figure 16] 10A-10C are partial views of a pressure relief member according to some alternative embodiments of the present application. [Figure 17] 17 is a cross-sectional view of the pressure release member shown in FIG. 16 . [Figure 18] FIG. 2 is an exploded view of a housing according to some embodiments of the present application. [Figure 19] FIG. 10 is an exploded view of a housing according to some alternative embodiments of the present application. [Figure 20] FIG. 10 is an exploded view of a housing according to still other embodiments of the present application. [Figure 21] FIG. 10 is an exploded view of a housing according to still other embodiments of the present application. [Figure 22] 1 is a partial view of a first wall according to some embodiments of the present application.

[0058] Explanation of symbols 1-housing, 11-case, 111-bottom wall, 112-side wall, 12-end cover, 13-pressure release member, 131-groove portion, 1311-first groove segment, 1311a-first groove bottom surface, 1311b-first groove side surface, 1311c-first step groove, 1311d-second step groove, 1311e-first arc surface, 1311f-first intermediate surface, 1312-second groove segment, 1312b-second groove bottom surface, 1312c-second intermediate surface, 1313-third groove segment, 1313a-third groove bottom surface, 1313c-third step groove, 1313d-fourth step groove, 1313e-second arc surface, 1313f-third 3 intermediate surface, 1314—explosion location, 1315—first location, 1316—second location, 132—first surface, 133—second surface, 134—pressure release area, 135—guide groove, 14—first wall portion, 141—pressure release hole, 142—external surface, 1421—center point, 2—electrode assembly, 21—tab, 3—electrode terminal, 4—current collecting member, 5—insulating member, 10—battery cell, 20—casing, 201—first part, 202—second part, 100—battery, 200—controller, 300—motor, 1000—vehicle, X—thickness direction of pressure release member, Y—longitudinal direction of first wall portion, Z—width direction of first wall portion DETAILED DESCRIPTION OF THE INVENTION

[0059] In order to clarify the objectives, technical solutions and advantages of the embodiments of the present application, the following will clearly describe the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only some of the embodiments of the present application, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without any creative efforts fall within the scope of protection of the present application.

[0060] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by those skilled in the art of this application, and the terms used in the specification of this application are only for describing specific embodiments and are not intended to limit this application, and the terms "comprises," "has," and any variations thereof in the specification and claims of this application and the brief description of the drawings above are intended to cover a non-exclusive "comprise." The terms "first," "second," etc. in the specification and claims of this application or the drawings above are not intended to describe a specific order or a hierarchical relationship, but are intended to distinguish different objects.

[0061] An "embodiment" referred to in this application means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of this phrase in various places in the specification do not necessarily all refer to the same embodiment, nor are they mutually exclusive, separate, or alternative embodiments of other embodiments.

[0062] The term "and / or" in this application merely describes the relationship between related objects and indicates that three relationships may exist, for example, A and / or B may represent three cases: A alone, a combination of A and B, and B alone. Also, the character " / " in this application generally indicates that the related objects before and after are in an "or" relationship.

[0063] In the embodiments of the present application, the same reference numerals represent the same elements, and for the sake of brevity, detailed descriptions of the same elements will be omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various elements in the embodiments of the present application shown in the drawings, and the overall thickness, length, width, and other dimensions of the integrated device, are illustrative examples and should not be construed as any limitation on the present application.

[0064] The term "plurality" as used herein refers to two or more (including two).

[0065] In the embodiments of the present application, the battery cell may be a secondary battery, and a secondary battery refers to a battery cell that can be continuously used after being discharged by activating the active material through charging.

[0066] Battery cells include, but are not limited to, lithium ion batteries, sodium ion batteries, sodium lithium ion batteries, lithium metal batteries, sodium metal batteries, lithium sulfur batteries, magnesium ion batteries, nickel metal hydride batteries, nickel cadmium batteries, lead acid batteries, and the like.

[0067] A battery cell generally comprises an electrode assembly, which includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of the battery cell, active ions (e.g., lithium ions) shuttle between the positive electrode and the negative electrode, undergoing intercalation and deintercalation. The separator, located between the positive electrode and the negative electrode, serves to reduce the risk of the positive electrode and the negative electrode while allowing the active ions to pass through.

[0068] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0069] For example, the positive electrode current collector has two surfaces that face each other in the thickness direction thereof, and the positive electrode active material is disposed on one or both of the two facing surfaces of the positive electrode current collector.

[0070] For example, the positive electrode current collector can be a metal foil sheet or a composite current collector. For example, the metal foil sheet can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, or titanium. The composite current collector can include a polymeric material base layer and a metal layer. The composite current collector can be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, or silver alloy) on a polymeric material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, or polyethylene).

[0071] For example, the positive electrode active material may include at least one of a lithium-containing phosphate, a lithium transition metal oxide, and a modified compound thereof. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery positive electrode active material may also be used. These positive electrode active materials may be used alone or in combination of two or more. Here, examples of the lithium-containing phosphate may include, but are not limited to, at least one of lithium iron phosphate (e.g., LiFePO4 (also abbreviated as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (e.g., LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon. Examples of lithium transition metal oxides include lithium cobalt oxide (e.g., LiCoO), lithium nickel oxide (e.g., LiNiO), lithium manganese oxide (e.g., LiMnO, LiMnO), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (e.g., LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM 333 (may be abbreviated as "LiNi") 0.5 Co 0.2Mn 0.3 O2(NCM 523 (may be abbreviated as "LiNi") 0.5 Co 0.25 Mn 0.25 O2(NCM 211 (may be abbreviated as "LiNi") 0.6 Co 0.2 Mn 0.2 O2(NCM 622 (may be abbreviated as "LiNi") 0.8 Co 0.1 Mn 0.1 O2(NCM 811 ), lithium nickel cobalt aluminum oxide (e.g., LiNi 0.85 Co 0.15 Al 0.05 O2) and modifying compounds thereof.

[0072] In some embodiments, the positive electrode may be a metal foam. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam. When the metal foam is used as the positive electrode, a positive electrode active material may or may not be provided on the surface of the metal foam. For example, a lithium source material, such as potassium metal or sodium metal, may be filled and / or deposited in the metal foam, and the lithium source material may be lithium metal and / or a lithium-rich material.

[0073] In some examples, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0074] For example, the negative electrode current collector can be a metal foil sheet, a metal foam, or a composite current collector. For example, the metal foil sheet can be made of silver-surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, or titanium. The metal foam can be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam. The composite current collector can include a polymeric material base layer and a metal layer. The composite current collector can be formed by forming a metal material (such as copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, or silver alloy) on a polymeric material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, or polyethylene).

[0075] For example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0076] For example, the negative electrode current collector has two surfaces that face each other in the thickness direction of the negative electrode current collector, and the negative electrode active material is disposed on either one or both of the two facing surfaces of the negative electrode current collector.

[0077] For example, the negative electrode active material may be any negative electrode active material for battery cells well known in the art. For example, the negative electrode active material may include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate. The silicon-based material may be selected from at least one of silicon elemental, silicon oxide, silicon carbon composite, silicon nitrogen composite, and silicon alloy. The tin-based material may be selected from at least one of tin elemental, tin oxide, and tin alloy. However, the present application is not limited to these materials, and other conventional materials that can be used as battery negative electrode active materials may also be used. These negative electrode active materials may be used alone or in combination.

[0078] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0079] In some embodiments, the separator is a separator membrane, which can be selected from any well-known separator membrane with a porous structure that has excellent chemical and mechanical stability.

[0080] For example, the separator may be made of at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film, and when the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator may be located between the positive electrode and the negative electrode as a separate component, or may be attached to the surfaces of the positive electrode and the negative electrode.

[0081] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive and negative electrodes and simultaneously serves to transport ions and separate the positive and negative electrodes.

[0082] In some embodiments, the battery cell further includes an electrolyte, which serves as ionic conductor between the positive electrode and the negative electrode. The electrolyte may be in a liquid, gel, or solid state. Here, the liquid electrolyte includes an electrolyte salt and a solvent.

[0083] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoro(oxalato)borate, lithium bis(oxalato)borate, lithium difluorobis(oxalato)phosphate, and lithium tetrafluoro(oxalato)phosphate.

[0084] In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may optionally be an ether-based solvent. The ether-based solvent may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether, and crown ether.

[0085] Here, the gel electrolyte comprises a polymer-based electrolyte skeletal network combined with an ionic liquid-lithium salt.

[0086] Here, the solid electrolyte includes polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0087] By way of example, the polymer solid electrolyte may be polyether (polyoxyethylene), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, single ion polymer, polyionic liquid-lithium salt, cellulose, and the like.

[0088] By way of example, the inorganic solid electrolyte may include one or more of oxide solid electrolytes (crystalline perovskites, sodium superionic conductors, garnets, amorphous LiPON thin films), sulfide solid electrolytes (crystalline lithium superionic conductors (lithium germanium phosphate sulfur, sulfur silver germanite), amorphous sulfides), and halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0089] For example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0090] In some embodiments, the electrode assembly is a wound structure, in which the positive electrode sheet and the negative electrode sheet are wound into the wound structure.

[0091] In some embodiments, the electrode assembly is a laminate structure.

[0092] For example, a plurality of positive electrode sheets and a plurality of negative electrode sheets may be provided, and the plurality of positive electrode sheets and the plurality of negative electrode sheets are provided by alternately stacking them.

[0093] For example, multiple positive electrode sheets may be installed, and the negative electrode sheet may be folded to form multiple folded segments that are stacked and installed, with one positive electrode sheet sandwiched between adjacent folded segments.

[0094] By way of example, both the positive and negative electrode sheets are folded to form a plurality of folded segments arranged in a stack.

[0095] For example, a plurality of separators may be provided, and each may be provided between any adjacent positive electrode sheets or negative electrode sheets.

[0096] For example, the separator may be disposed continuously, or may be disposed by folding or winding between any adjacent positive or negative electrode sheets.

[0097] In some embodiments, the electrode assembly may have a cylindrical, flat, or polygonal prism shape.

[0098] In some embodiments, the electrode assembly is provided with tabs that allow current to be conducted from the electrode assembly. The tabs include a positive electrode tab and a negative electrode tab.

[0099] In some embodiments, the battery cell may include a housing for packaging components such as an electrode assembly and an electrolyte. The housing may be a steel housing, an aluminum housing, a plastic housing (such as polypropylene), a composite metal housing (such as a copper-aluminum composite housing), or an aluminum-plastic film.

[0100] For example, the battery cells may be cylindrical battery cells, prismatic battery cells, soft-pack battery cells, or battery cells of other shapes, where the prismatic battery cells include square-housing battery cells, blade-shaped battery cells, and polygonal prism battery cells, and the polygonal prism battery cells are, for example, hexagonal prism battery cells, etc., and are not particularly limited in this application.

[0101] A battery as referred to in the examples of this application refers to a single physical module containing one or more battery cells to provide higher voltage and capacity.

[0102] In some embodiments, the battery may be a battery module, and when there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0103] In some embodiments, the battery may be a battery pack, which includes a housing and battery cells, and the battery cells or modules are housed in the housing.

[0104] In some embodiments, the housing may be used as part of a chassis structure of a vehicle, for example, a portion of the housing may form at least a portion of the floor of the vehicle, or a portion of the housing may form at least a portion of the transverse and longitudinal beams of the vehicle.

[0105] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage electrical cabinet, or the like.

[0106] The development of battery technology requires simultaneous consideration of multiple design factors, such as performance parameters such as energy density, cycle life, discharge capacity, and charge / discharge ratio, as well as battery safety.

[0107] To improve the safety of the battery cell, a pressure release member can be installed on the battery cell, so that if the battery cell experiences thermal runaway, the pressure release member can release the internal pressure of the battery cell. To ensure timely pressure release by the pressure release member, a groove can be installed on the pressure release member, so that the pressure release member is thinner at the position where the groove is installed, and when the internal pressure of the battery cell reaches a threshold, the pressure release member will burst at the position of the groove, thereby achieving the purpose of releasing the internal pressure of the battery cell.

[0108] To further improve the timeliness of the pressure release member's pressure release, the groove of the pressure release member may be divided into multiple segments, such as a first groove segment, a second groove segment, and a third groove segment, with the first groove segment and the third groove segment facing each other and the second groove segment connecting the first groove segment and the third groove segment. In this way, the pressure release member has a large pressure release area after rupturing along the first groove segment, the second groove segment, and the third groove segment, thereby achieving rapid pressure release. In such a battery cell, the pressure release member has an explosion position, i.e., when the internal pressure of the battery cell reaches the explosion pressure, the pressure release member ruptures first at the explosion position. The explosion position is generally formed in the second groove segment, and when the internal pressure of the battery cell reaches the explosion pressure, the pressure release member ruptures at the explosion position, and the crack spreads along the second groove segment to the first groove segment and the third groove segment.

[0109] During normal use of the battery cell, the internal pressure of the battery cell may change, and during long-term use, the pressure release member may be deformed due to the pressure change in the battery cell, causing the pressure release member to rupture at the position of the second groove segment. In particular, the fatigue strength of the second groove segment in the area near the explosion position is lower, so there is a risk that the pressure release member will rupture in the area of ​​the second groove segment during normal use of the battery cell, which will affect the service life of the battery cell.

[0110] In view of this, an embodiment of the present application provides a battery cell, in which a groove is provided in a pressure release member within the battery cell, the groove including a first groove segment, a second groove segment, and a third groove segment, the first groove segment is provided opposite the third groove segment, the second groove segment connects the first groove segment and the third groove segment, and an explosion position of the pressure release member is formed in the first groove segment and / or the third groove segment.

[0111] The battery cells described in the embodiments of the present application are applied to batteries and power consuming devices that use the battery cells.

[0112] The power consuming devices may be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, power tools, etc. The vehicles may be fuel oil vehicles, gas vehicles, or new energy vehicles, and the new energy vehicles may be pure electric vehicles, hybrid vehicles, or range extender vehicles, etc. The spacecraft may include airplanes, rockets, space shuttles, spaceships, etc. The electric toys may include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric plane toys, etc. The power tools may include metal cutting power tools, polishing power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, hammer drills, concrete vibrators, and electric planers, etc. The embodiments of the present application do not particularly limit the above power consuming devices.

[0113] In the following embodiment, for ease of explanation, the power consuming device is a vehicle.

[0114] Referring to Fig. 1, Fig. 1 is a structural schematic diagram of a vehicle 1000 according to some embodiments of the present application. A battery 100 is installed inside the vehicle 1000, and the battery 100 may be installed at the bottom, front, or rear of the vehicle 1000. The battery 100 may be used to power the vehicle 1000, for example, the battery 100 can function as an operating power source for the vehicle 1000.

[0115] The vehicle 1000 may also include a controller 200 and a motor 300, where the controller 200 is used to control the battery 100 to power the motor 300, for example, for the operating power consumption needs of the vehicle 1000 during startup, navigation, and driving.

[0116] In some embodiments of the present application, the battery 100 can provide not only the operating power source for the vehicle 1000, but also the driving power for the vehicle 1000, in place of, or in place of, fuel oil or natural gas.

[0117] 2, which is an exploded view of a battery 100 according to some embodiments of the present application. The battery 100 includes a battery cell 10 and a housing 20, and the battery cell 10 is housed within the housing 20.

[0118] Here, the housing 20 is a member that houses the battery cells 10 and provides an accommodation space for the battery cells 10. The housing 20 can have various structures. In some embodiments, the housing 20 may include a first portion 201 and a second portion 202, which cover each other to define an accommodation space for accommodating the battery cells 10. The first portion 201 and the second portion 202 may have various shapes, such as a rectangular parallelepiped or a cylindrical body. The first portion 201 may have a hollow structure with one side open, and the second portion 202 may also have a hollow structure with one side open. When the open side of the second portion 202 is covered by the open side of the first portion 201, the housing 20 having an accommodation space is formed. Alternatively, the first part 201 may have a hollow structure with one side open, and the second part 202 may have a plate-like structure, and when the second part 202 covers the open side of the first part 201, a housing 20 having an accommodation space is formed. The first part 201 and the second part 202 may be sealed by a sealing element, which may be a sealing ring, a sealant, or the like.

[0119] The battery 100 may have one or more battery cells 10. When there are multiple battery cells 10, the multiple battery cells 10 may be connected in series, parallel, or series-parallel, where series-parallel connection means that the multiple battery cells 10 are connected in both series and parallel. First, multiple battery cells 10 may be connected in series, parallel, or series-parallel to form a battery module, and then multiple battery modules may be connected in series, parallel, or series-parallel to form an entire battery module, which is then housed in the housing 20. Alternatively, all of the battery cells 10 may be directly connected in series, parallel, or series-parallel, and then all of the battery cells 10 may be housed in the housing 20 as a whole.

[0120] 3, which is an exploded view of a battery cell 10 according to some embodiments of the present application. The battery cell 10 may include a housing 1 and an electrode assembly 2, and the electrode assembly 2 is housed within the housing 1.

[0121] In some embodiments, the housing 1 may include a case 11 and an end cover 12, where the case 11 has an opening and the end cover 12 seals the opening of the case 11.

[0122] The case 11 is a member for housing the electrode assembly 2, and may have a hollow structure with an opening formed at one end, or may have a hollow structure with openings formed at both opposing ends. The case 11 may have various shapes such as a cylindrical shape or a rectangular parallelepiped shape. The case 11 may be made of a variety of materials such as copper, iron, aluminum, steel, and aluminum alloy.

[0123] The end cover 12 is a component that seals the opening of the case 11 and isolates the internal environment of the battery cell 10 from the external environment. The end cover 12 and the case 11 collectively define an accommodation space for accommodating the electrode assembly 2, electrolyte, and other components. The end cover 12 may be connected to the case 11 by welding or seaming to seal the opening of the case 11. The shape of the end cover 12 may match the shape of the housing 1. For example, if the case 11 has a rectangular parallelepiped structure, the end cover 12 may have a rectangular plate-like structure that fits the housing 1. Alternatively, for example, if the case 11 has a cylindrical structure, the end cover 12 may have a circular plate-like structure that fits the case 11. The end cover 12 may be made of a variety of materials, such as copper, iron, aluminum, steel, aluminum alloy, or plastic. The end cover 12 and the case 11 may be made of the same or different materials.

[0124] In an embodiment in which the case 11 is a hollow structure with an opening formed at one end, one end cover 12 may be provided correspondingly. In an embodiment in which the case 11 is a hollow structure with openings formed at opposite ends, two end covers 12 may be provided correspondingly, with the two end covers 12 sealing the two openings of the case 11, respectively, and the two end covers 12 and the case 11 jointly defining an accommodating space.

[0125] In some embodiments, the battery cell 10 may further include an electrode terminal 3. The electrode terminal 3 is installed in the housing 1 and electrically connected to a tab 21 of the electrode assembly 2 for outputting electrical energy from the battery cell 10. The electrode terminal 3 may be installed in the case 11 of the housing 1 or in the end cover 12 of the housing 1. The electrode terminal 3 and the tab 21 may be directly connected, for example, by direct welding. The electrode terminal 3 and the tab 21 may also be indirectly connected, for example, by a current collecting member 4. The current collecting member 4 may be a metal conductor such as copper, iron, aluminum, steel, or an aluminum alloy.

[0126] For example, as shown in FIG. 3 , an opening is formed at one end of the case 11, and there is one end cover 12 in the housing 1, which seals one opening of the case 11. Two electrode terminals 3 are installed on the end cover 12, and the two electrode terminals 3 are a positive terminal and a negative terminal, respectively. A positive electrode tab and a negative electrode tab are formed on the end of the electrode assembly 2 facing the end cover 12, and the positive electrode terminal is connected to the positive electrode tab via one current collecting member 4, and the negative electrode terminal is connected to the negative electrode tab via another current collecting member 4.

[0127] 3 , in some embodiments, the battery cell 10 may further include an insulating member 5. The insulating member 5 is a member that separates the case 11 from the electrode assembly 2, and the insulating member 5 provides insulation and separation between the case 11 and the electrode assembly 2. The insulating member 5 is made of an insulating material, and examples of the material of the insulating member 5 include, but are not limited to, plastic, rubber, etc.

[0128] For example, the insulating member 5 is wrapped around the outside of the electrode assembly 2 along the circumferential direction of the opening of the case 11. The number of electrode assemblies 2 in the housing 1 may be one or more. When there is one electrode assembly 2, the insulating member 5 wraps around this electrode assembly 2. When there are multiple electrode assemblies 2, one insulating member 5 may be provided for each electrode assembly 2, and each insulating member 5 may wrap around one electrode assembly 2. Alternatively, multiple electrode assemblies 2 may function as an integrated member, and the insulating member 5 may wrap around this integrated member.

[0129] 4 and 5, Fig. 4 is an axonometric view of a battery cell 10 according to some embodiments of the present application, and Fig. 5 is a partial view of the pressure release member 13 shown in Fig. 4. The embodiments of the present application provide a battery cell 10, which includes a housing 1, which includes a pressure release member 13, which has a groove 131 formed therein, which is configured to be able to rupture along the groove 131 to release the internal pressure of the battery cell 10, and which has an explosion position 1314. Here, the groove portion 131 includes a first groove segment 1311, a second groove segment 1312, and a third groove segment 1313, the first groove segment 1311 is located opposite the third groove segment 1313, the second groove segment 1312 connects the first groove segment 1311 and the third groove segment 1313, and the explosion position 1314 is formed in the first groove segment 1311 and / or the third groove segment 1313.

[0130] The pressure release member 13 is a member within the battery cell 10 for releasing internal pressure of the battery cell 10. The end cover 12 of the housing 1 may be used as the pressure release member 13, or at least a portion of the case 11 of the housing 1 may be used as the pressure release member 13; for example, the housing 1 includes multiple walls that collectively define an internal space of the housing 1, and at least one wall of the housing 1 is used as the pressure release member 13. The pressure release member 13 may be a member independent of the case 11 and the end cover 12; for example, the pressure release member 13 is a member attached to the end cover 12, or for example, the pressure release member 13 is a member attached to the case 11. As can be understood, when the end cover 12 is used as the pressure release member 13, the groove 131 is provided in the end cover 12, and when at least a portion of the case 11 is used as the pressure release member 13, the groove 131 is provided in the case 11.

[0131] The groove portion 131 may be formed by various methods, such as stamping, milling, and etching. The first groove segment 1311, the second groove segment 1312, and the third groove segment 1313 may be linear grooves extending along a straight line, or may be non-linear grooves extending along a non-linear line, such as arcuate grooves extending along an arcuate line. When the first groove segment 1311, the second groove segment 1312, and the third groove segment 1313 are linear grooves, the first groove segment 1311 and the third groove segment 1313 may be arranged parallel to each other or at a small angle therebetween, for example, the angle between the first groove segment 1311 and the third groove segment 1313 is 10 degrees or less. The first groove segment 1311 and the second groove segment 1312 may be disposed perpendicularly or at an acute or obtuse angle, and the third groove segment 1313 and the second groove segment 1312 may be disposed perpendicularly or at an acute or obtuse angle. The groove portion 131 may include only the first groove segment 1311, the second groove segment 1312, and the third groove segment 1313. Alternatively, the groove portion 131 may include groove segments other than the first groove segment 1311, the second groove segment 1312, and the third groove segment 1313. For example, the groove portion 131 may further include a fourth groove segment connected to the second groove segment 1312 and located between the first groove segment 1311 and the third groove segment 1313. The first groove segment 1311 may be a single-step groove or a multi-step groove. When the first groove segment 1311 is a multi-step groove, it is a stepped groove that can be machined in stages along the thickness direction X of the pressure release member during molding. The second groove segment 1312 can be a single-step groove or a multi-step groove. When the second groove segment 1312 is a multi-step groove, it is a stepped groove that can be machined in stages along the thickness direction X of the pressure release member during molding. The third groove segment 1313 can be a single-step groove or a multi-step groove.When the third groove segment 1313 is a multi-step groove, the third groove segment 1313 is a stepped groove, and during molding, the third groove segment 1313 can be processed in stages along the thickness direction X of the pressure release member.

[0132] The second groove segment 1312 is connected to the first groove segment 1311 and the third groove segment 1313, and both ends of the second groove segment 1312 may be connected to the first groove segment 1311 and the third groove segment 1313, respectively, or at least one of the first groove segment 1311 and the third groove segment 1313 may be connected at a position offset from the end of the second groove segment 1312, thereby positioning at least one of the first groove segment 1311 and the third groove segment 1313 between both ends of the second groove segment 1312. The connection position between the first groove segment 1311 and the second groove segment 1312 may be located at one end of the first groove segment 1311 or offset from both ends of the first groove segment 1311. The connection position between the third groove segment 1313 and the second groove segment 1312 may be located at one end of the third groove segment 1313 or offset from both ends of the third groove segment 1313. The first groove segment 1311, the second groove segment 1312 and the third groove segment 1313 may be formed in various shapes, such as a U-shape, an N-shape, an H-shape, etc.

[0133] The explosion position 1314 is a position where the pressure release member 13 will rupture first when the internal pressure of the battery cell 10 reaches the explosion pressure. The number of explosion positions 1314 in the groove portion 131 may be one or more. When the pressure release member 13 releases pressure, the explosion position 1314 may be formed on the groove bottom surface of the first groove segment 1311 and / or the groove bottom surface of the third groove segment 1313. The explosion position 1314 may be formed only on the first groove segment 1311, or only on the third groove segment 1313, or the explosion position 1314 may be formed on both the first groove segment 1311 and the third groove segment 1313. In an embodiment in which the explosion point 1314 is formed in the first groove segment 1311, the explosion point 1314 may be located at any position on the first groove segment 1311. For example, the explosion point 1314 may be located near an end of the first groove segment 1311. For example, the explosion point 1314 may be located near the connection point between the first groove segment 1311 and the second groove segment 1312. For example, assuming that both ends of the second groove segment 1312 are connected to the first groove segment 1311 and the third groove segment 1313, respectively, when viewed along the thickness direction X of the pressure release member, the explosion point 1314 can be understood to be located near the connection point between the first groove segment 1311 and the second groove segment 1312 as long as the minimum distance between the end of the second groove segment 1312 connected to the first groove segment 1311 and the explosion point 1314 is smaller than the width of the first groove segment 1311. In embodiments in which the explosion location 1314 is formed in the third groove segment 1313, the explosion location 1314 may be located at any position in the third groove segment 1313, for example, the explosion location 1314 may be located near the end of the third groove segment 1313, or for example, the explosion location 1314 may be located near the connection location between the third groove segment 1313 and the second groove segment 1312.For example, if both ends of the second groove segment 1312 are connected to the first groove segment 1311 and the third groove segment 1313, respectively, when observed along the thickness direction X of the pressure release member, it can be understood that the explosion point 1314 is located near the connection point between the third groove segment 1313 and the second groove segment 1312 as long as the minimum distance between the end of the second groove segment 1312 connected to the third groove segment 1313 and the explosion point 1314 is smaller than the width of the third groove segment 1313.

[0134] In the embodiment of the present application, the explosion position 1314 of the pressure release member 13 is formed only in the first groove segment 1311 and / or the third groove segment 1313, and not in the second groove segment 1312, so that the fatigue strength of the pressure release member 13 in the area of ​​the second groove segment 1312 is high, and the possibility of the pressure release member 13 rupturing in the area of ​​the second groove segment 1312 during normal use of the battery cell 10 is reduced, thereby improving the long-term reliability of the pressure release member 13 and extending the service life of the battery cell 10.

[0135] 6 to 8, in some embodiments, Fig. 6 is a cross-sectional view of the pressure release member 13 shown in Fig. 5 taken along line AA, Fig. 7 is a partially enlarged view of part B in Fig. 6, and Fig. 8 is a partially enlarged view of part C in Fig. 6. An explosion position 1314 (not shown in Fig. 5) is formed in the first groove segment 1311, and the remaining thickness of the first groove segment 1311 is smaller than the remaining thickness of the second groove segment 1312.

[0136] The remaining thickness of the first groove segment 1311 refers to the thickness of the remaining part after the first groove segment 1311 of the pressure relief member 13 is installed, and this remaining part may be the groove bottom wall of the first groove segment 1311. The thickness of the groove bottom wall of the first groove segment 1311 may be uniform or non-uniform. When the thickness of the groove bottom wall of the first groove segment 1311 is non-uniform, the thickness at the thinnest position of the groove bottom wall of the first groove segment 1311 is the remaining thickness of the first groove segment 1311. The remaining thickness of the second groove segment 1312 refers to the thickness of the remaining part after the second groove segment 1312 of the pressure relief member 13 is installed, and this remaining part may be the groove bottom wall of the second groove segment 1312. The thickness of the groove bottom wall of the second groove segment 1312 may be uniform or non-uniform. When the thickness of the groove bottom wall of the second groove segment 1312 is non-uniform, the thickness at the thinnest position of the groove bottom wall of the second groove segment 1312 is the remaining thickness of the second groove segment 1312.

[0137] As shown in FIGS. 7 and 8, the remaining thickness of the first groove segment 1311 is D1, the remaining thickness of the second groove segment 1312 is D2, and the remaining thickness of the third groove segment 1313 is D3. As can be understood, D1 < D2. Here, D1 and D3 may be equal or may not be equal.

[0138] In this embodiment, because the remaining thickness of the first groove segment 1311 is smaller than that of the second groove segment 1312, an explosion point 1314 may be formed near the connection point between the second groove segment 1312 and the first groove segment 1311. When pressure is released, the pressure release member 13 ruptures at the explosion point 1314, and the crack can then spread along both the first groove segment 1311 and the second groove segment 1312. Furthermore, because the remaining thickness of the first groove segment 1311 is smaller than that of the second groove segment 1312, this is equivalent to increasing the remaining thickness of the second groove segment 1312. This improves the fatigue strength of the pressure release member 13 in the area where the second groove segment 1312 is installed, and further reduces the possibility of the pressure release member 13 rupturing in the area of ​​the second groove segment 1312 during normal use of the battery cell 10. In addition, since stress is more concentrated at the connection position between the first groove segment 1311 and the second groove segment 1312, the explosion position 1314 of the first groove segment 1311 may be formed near the connection position between the first groove segment 1311 and the second groove segment 1312.

[0139] In some embodiments, the remaining thickness of the first groove segment 1311 is D1 and the remaining thickness of the second groove segment 1312 is D2, where 0.15≦D1 / D2≦0.95 is satisfied.

[0140] D1 / D2 may be any one point value or a range value between any two of 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, etc.

[0141] The inventors conducted tests on multiple groups, with different D2 values ​​for the battery cells 10 in different groups, and measured the explosion rate of the battery cells 10 in each group during thermal runaway and the rupture rate at which the pressure release member 13 ruptures along the second groove segment 1312 under normal use conditions of the battery cells 10. The test results are shown in Table 1.

[0142] The method for measuring the remaining thickness of the first groove segment 1311 and the third groove segment 1313 is as follows: the pressure release member 13 is cut into three segments, the cutting direction is perpendicular to the extension direction of the first groove segment 1311, the cross section of the middle segment is polished to thoroughly remove burrs, and then placed in a three-dimensional coordinate measuring machine, and the remaining thickness of the first groove segment 1311 and the third groove segment 1313 at the cross section are measured using the three-dimensional coordinate measuring machine.

[0143] The method for measuring the remaining thickness of the second groove segment 1312 is as follows: the above-mentioned intermediate segment is cut into three segments, and the cutting direction is perpendicular to the extension direction of the second groove segment 1312. The cross section of the intermediate segment of these three segments is polished to thoroughly remove burrs, and then it is placed in a three-dimensional coordinate measuring machine, and the remaining thickness of the second groove segment 1312 at the cross section is measured using the three-dimensional coordinate measuring machine.

[0144] The method for measuring the explosion rate of a battery cell 10 during thermal runaway is as follows: a small heating film is built into the battery cell 10, and electricity is passed through the heating film to heat the battery cell 10 until it experiences thermal runaway, and it is observed whether the battery cell 10 explodes. For each group of tests, 1,000 battery cells 10 are used, and the explosion rate of the battery cells 10 is calculated as follows: explosion rate Q1 = number of exploded battery cells 10 / total number of battery cells 10 × 100%.

[0145] The method for measuring the rupture rate of the pressure release member 13 along the second groove segment 1312 under normal use conditions of the battery cell 10 is as follows: the battery cell 10 is left at 25±2°C and cycled charged and discharged in the charge / discharge range of 5% to 97% SOC, and 1,000 groups of tests are simultaneously performed to observe whether the pressure release member 13 ruptures along the second groove segment 1312 when the service life of the battery cell 10 drops to 80% SOH. The rupture rate of the pressure release member 13 along the second groove segment 1312 is calculated, where the rupture rate Q2 = number of ruptured battery cells 10 / total number of battery cells 10 × 100%.

[0146] [Table 1]

[0147] From Table 1 above, it can be seen that when D1 / D2<0.15, the timeliness of pressure release is low and the probability of explosion during thermal runaway of the battery cell 10 is high, and when D1 / D2>0.95, the probability of rupture of the pressure release member 13 along the second groove segment 1312 during normal use of the battery cell 10 is high, affecting the service life of the battery cell 10. In contrast, when 0.15≦D1 / D2≦0.95, not only is the timeliness of pressure release of the battery cell 10 improved, but the service life of the battery cell 10 can also be extended.

[0148] In some embodiments, 0.3≦D1 / D2≦0.9.

[0149] In this embodiment, D1 / D2 may be any one of the following point values ​​or a range value between any two of 0.3, 0.32, 0.35, 0.38, 0.4, 0.42, 0.45, 0.48, 0.5, 0.52, 0.55, 0.58, 0.6, 0.62, 0.65, 0.68, 0.7, 0.72, 0.75, 0.78, 0.8, 0.82, 0.85, 0.88, 0.9, etc.

[0150] From Table 1 above, it can be seen that when 0.3≦D1 / D2≦0.9, the performance of the battery cell 10 is better, and the timeliness of pressure release of the battery cell 10 can be improved, while the service life of the battery cell 10 can be extended.

[0151] In some embodiments, 0.5≦D1 / D2≦0.85.

[0152] In this embodiment, D1 / D2 may be any one of the following point values ​​or a range value between any two of 0.5, 0.52, 0.53, 0.55, 0.57, 0.58, 0.59, 0.6, 0.62, 0.63, 0.65, 0.67, 0.68, 0.69, 0.7, 0.72, 0.73, 0.75, 0.77, 0.78, 0.79, 0.8, 0.82, 0.83, 0.85, etc.

[0153] It can be seen from Table 1 above that when 0.5≦D1 / D2≦0.85, the overall performance of the battery cell 10 is further improved, and not only is the probability of the pressure release member 13 rupturing along the second groove segment 1312 during normal use of the battery cell 10 controlled to a low level, but the probability of the battery cell 10 exploding during thermal runaway can also be controlled to a low level.

[0154] In some embodiments, 0.03 mm≦D1≦0.5 mm.

[0155] In this embodiment, D1 may be any one of the following point values ​​or a range value between any two of 0.03 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, etc.

[0156] In some embodiments, 0.15 mm≦D1≦0.4 mm.

[0157] D1 may be any one point value or a range value between any two of 0.15mm, 0.18mm, 0.2mm, 0.22mm, 0.25mm, 0.28mm, 0.3mm, 0.32mm, 0.35mm, 0.38mm, 0.4mm, etc.

[0158] In some embodiments, 0.05 mm≦D2≦0.65 mm.

[0159] In this embodiment, D2 may be any one of the point values ​​of 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, etc., or a range value between any two of them.

[0160] In some embodiments, 0.25 mm≦D2≦0.5 mm.

[0161] D2 may be any one point value or a range value between any two of 0.25mm, 0.27mm, 0.3mm, 0.32mm, 0.35mm, 0.37mm, 0.4mm, 0.42mm, 0.45mm, 0.47mm, 0.5mm, etc.

[0162] In some embodiments, with continued reference to FIG. 7, the depth of the first groove segment 1311 is greater than the depth of the second groove segment 1312, such that the remaining thickness of the first groove segment 1311 is less than the remaining thickness of the second groove segment 1312.

[0163] For example, along the thickness direction X of the pressure release member, the pressure release member 13 includes a first surface 132 and a second surface 133 arranged opposite each other, a first groove segment 1311 and a second groove segment 1312 arranged on the first surface 132, the first surface 132 and the second surface 133 may be parallel surfaces, the distance between the first surface 132 and the second surface 133 is H0, the distance between the groove bottom surface (first groove bottom surface 1311a) of the first groove segment 1311 and the second surface 133 is D1, the distance between the groove bottom surface (second groove bottom surface 1312b) of the second groove segment 1312 and the second surface 133 is D2, the depth of the first groove segment 1311 is H0-D1, and the depth of the second groove segment 1312 is H0-D2, where H0-D1>H0-D2. Here, H0 may be the thickness of the pressure release member 13.

[0164] The first groove segment 1311 may include a first groove bottom surface 1311a and two first groove side surfaces 1311b, which are arranged opposite each other along the width direction of the first groove segment 1311 and connected via the first groove bottom surface 1311a. The two first groove side surfaces 1311b may be arranged parallel to each other or at an acute angle. For example, the distance between the two first groove side surfaces 1311b in the width direction of the first groove segment 1311 gradually decreases along the depth direction of the first groove segment 1311, so that the two first groove side surfaces 1311b form inclined slopes. Here, the first groove bottom surface 1311a may be a flat surface or a circular arc surface.

[0165] The second groove segment 1312 may include a second groove bottom surface 1312b and two second groove side surfaces (not shown in FIG. 7 ), which are arranged opposite each other along the width direction of the second groove segment 1312 and connected via the second groove bottom surface 1312b. The two second groove side surfaces may be arranged parallel to each other or at an acute angle. For example, the distance between the two second groove side surfaces in the width direction of the second groove segment 1312 gradually decreases along the depth direction of the second groove segment 1312, resulting in the two second groove side surfaces forming inclined slopes. Here, the second groove bottom surface 1312b may be a flat surface or a circular arc surface.

[0166] During molding, the first groove segment 1311 is machined deeper than the second groove segment 1312 in the pressure release member 13, so that the remaining thickness of the first groove segment 1311 can be made smaller than the remaining thickness of the second groove segment 1312, which is a simple method of implementation.

[0167] 9 to 12, in some embodiments, Fig. 9 is a partially enlarged view of a battery cell 10 according to some other embodiments of the present application, Fig. 10 is a partially enlarged view of the pressure release member 13 shown in Fig. 9, Fig. 11 is a DD cross-sectional view of the pressure release member 13 shown in Fig. 10, and Fig. 12 is a partially enlarged view of a portion E in Fig. 11. The first groove segment 1311 includes a first-stage groove 1311c and a second-stage groove 1311d, which are arranged along the thickness direction X of the pressure release member, and the second-stage groove 1311d is located on the groove bottom surface of the first-stage groove 1311c.

[0168] The first groove segment 1311 may be a two-stage groove, one of which is a first-stage groove 1311c and the other is a second-stage groove 1311d. The extension direction of the first-stage groove 1311c coincides with the extension direction of the second-stage groove 1311d, and the width direction of the first-stage groove 1311c coincides with the width direction of the second-stage groove 1311d. When the first groove segment 1311 is a groove extending along a straight line, both the first-stage groove 1311c and the second-stage groove 1311d are grooves extending along straight lines. When the first groove segment 1311 is a groove extending along a circular arc, both the first-stage groove 1311c and the second-stage groove 1311d are grooves extending along circular arc lines. Along the depth direction of the first groove segment 1311, the second-stage groove 1311d is located at the bottom of the first-stage groove 1311c. The groove bottom wall of the second-stage groove 1311d is the groove bottom wall of the first groove segment 1311, and the groove bottom surface of the second-stage groove 1311d is the groove bottom surface (first groove bottom surface 1311a) of the first groove segment 1311. For example, along the thickness direction X of the pressure release member, the pressure release member 13 has opposing first and second surfaces 132 and 133, the first-stage groove 1311c and the second-stage groove 1311d are sequentially arranged along the direction from the first surface 132 to the second surface 133, and the distance between the groove bottom surface of the second-stage groove 1311d and the second surface 133 is D1.

[0169] Here, the groove bottom surface of the first-stage groove 1311c and the groove bottom surface of the second groove segment 1312 (second groove bottom surface 1312b) may be flush with each other or may be offset from each other along the thickness direction X of the pressure release member. For example, along the thickness direction X of the pressure release member, the groove bottom surface of the first-stage groove 1311c is closer to the second surface 133 than the groove bottom surface of the second groove segment 1312 (second groove bottom surface 1312b).

[0170] During molding, the first groove segment 1311 can be formed by first molding a first-stage groove 1311c in the pressure release member 13, and then molding a second-stage groove 1311d on the bottom surface of the first-stage groove 1311c.In this way, the molding depth of each stage groove in the first groove segment 1311 can be reduced, the molding force that the pressure release member 13 receives when molding the first groove segment 1311 can be reduced, and the possibility of cracks occurring in the pressure release member 13 when molding the first groove segment 1311 can be reduced.

[0171] In some embodiments, with continued reference to FIG. 12, the groove bottom surface of the first-stage groove 1311c is flush with the groove bottom surface of the second groove segment 1312 (second groove bottom surface 1312b).

[0172] For example, both the groove bottom surface of the first-stage groove 1311c and the groove bottom surface (second groove bottom surface 1312b) of the second groove segment 1312 are flat, and both are located on the same plane.

[0173] In this embodiment, the groove bottom surface of the first-stage groove 1311c is flush with the groove bottom surface (second groove bottom surface 1312b) of the second groove segment 1312, so the groove bottom surface of the first-stage groove 1311c is located in the same plane as the groove bottom surface (second groove bottom surface 1312b) of the second groove segment 1312. During molding, the first-stage groove 1311c of the first groove segment 1311 and the second groove segment 1312 can be molded together, and then the second-stage groove 1311d of the first groove segment 1311 can be molded, thereby improving the molding efficiency of the groove portion 131.

[0174] 13, which is a partial cross-sectional view of a pressure release member 13 according to some embodiments of the present application. Along the thickness direction X of the pressure release member 13, the pressure release member 13 has opposing first and second surfaces 132 and 133. A first-stage groove 1311c and a second-stage groove 1311d are sequentially arranged along the direction from the first surface 132 to the second surface 133. The groove bottom surface (first groove bottom surface 1311a) of the second-stage groove 1311d is closer to the second surface 133 than the groove bottom surface (second groove bottom surface 1312b) of the second groove segment 1312. The groove bottom surface (first groove bottom surface 1311a) of the second-stage groove 1311d is connected to the groove bottom surface (second groove bottom surface 1312b) of the second groove segment 1312 via a first inclined surface (not shown in FIG. 13) or a first arcuate surface 1311e.

[0175] The groove bottom surface (first groove bottom surface 1311a) of the second-stage groove 1311d and the groove bottom surface (second groove bottom surface 1312b) of the second groove segment 1312 may be connected via a first inclined surface or a first arcuate surface 1311e. In the embodiment shown in Fig. 13, the groove bottom surface (first groove bottom surface 1311a) of the second-stage groove 1311d and the groove bottom surface (second groove bottom surface 1312b) of the second groove segment 1312 are connected via the first arcuate surface 1311e. For example, the groove bottom surface (first groove bottom surface 1311a) of the second-stage groove 1311d is parallel to the groove bottom surface (second groove bottom surface 1312b) of the second groove segment 1312, the first arc surface 1311e is in contact with the groove bottom surface (second groove bottom surface 1312b) of the second groove segment 1312, and the first arc surface 1311e is one groove side surface of the second-stage groove 1311d.

[0176] When the pressure is released, after the pressure release member 13 ruptures at the explosion position 1314, the crack at the groove bottom of the second stage groove 1311d can quickly spread along the first inclined surface or the first arc surface 1311e to the groove bottom of the second groove segment 1312, thereby shortening the time for the crack to spread from the first groove segment 1311 to the second groove segment 1312, and further shortening the time for the pressure release member 13 to rupture along the groove portion 1311.

[0177] 8 and 14, in some embodiments, Fig. 14 is a partial enlarged view of section F of the pressure release member 13 shown in Fig. 11. The third groove segment 1313 has an explosion point 1314 (not shown in Figs. 5 and 10) formed therein, and the remaining thickness of the third groove segment 1313 is smaller than the remaining thickness of the second groove segment 1312.

[0178] The remaining thickness of the third groove segment 1313 refers to the thickness of the remaining portion of the pressure release member 13 after the third groove segment 1313 is installed, and this remaining portion may be the groove bottom wall of the third groove segment 1313. The thickness of the groove bottom wall of the third groove segment 1313 may be uniform or non-uniform. If the thickness of the groove bottom wall of the third groove segment 1313 is non-uniform, the thickness of the groove bottom wall of the third groove segment 1313 at its thinnest point is the remaining thickness of the second groove segment 1312.

[0179] Here, the remaining thickness of the second groove segment 1312 is D2, and the remaining thickness of the third groove segment 1313 is D3. As can be seen, D3 <D2である。

[0180] In this embodiment, because the remaining thickness of the third groove segment 1313 is smaller than that of the second groove segment 1312, an explosion point 1314 may be formed near the connection point between the second groove segment 1312 and the third groove segment 1313. When pressure is released, the pressure release member 13 ruptures at the explosion point 1314, and the crack can then propagate along the third groove segment 1313 and the second groove segment 1312. Because the remaining thickness of the third groove segment 1313 is smaller than that of the second groove segment 1312, this is equivalent to increasing the remaining thickness of the second groove segment 1312, which improves the fatigue strength of the pressure release member 13 in the area where the second groove segment 1312 is installed, and further reduces the possibility of the pressure release member 13 rupturing in the area of ​​the second groove segment 1312 during normal use of the battery cell 10. In addition, since explosion positions 1314 are formed in both the first groove segment 1311 and the third groove segment 1313, when the internal pressure of the battery cell 10 reaches the explosion pressure, the explosion positions 1314 of both the first groove segment 1311 and the third groove segment 1313 can rupture, and the crack spreads along the first groove segment 1311 and the third groove segment 1313, as well as from both ends of the second groove segment 1312 to the middle position, thereby shortening the time it takes for the pressure release member 13 to rupture along the groove portion 131.

[0181] In some embodiments, the remaining thickness of the third groove segment 1313 is equal to the remaining thickness of the first groove segment 1311 .

[0182] As can be seen, D1 = D3. For example, the depth of the first groove segment 1311 is equal to the depth of the third groove segment 1313, so that the remaining thickness of the first groove segment 1311 is equal to the remaining thickness of the third groove segment 1313.

[0183] When the pressure of the battery cell 10 is released, the synchronization of the pressure release member 13 rupturing along the first groove segment 1311 and the third groove segment 1313 is better, so the time for the pressure release member 13 to rupture along the groove portion 131 is further shortened, and the timeliness of pressure release is improved.

[0184] In some embodiments, the remaining thickness of the second groove segment 1312 is D2, and the remaining thickness of the third groove segment 1313 is D3, where 0.15≦D3 / D2≦0.95 is satisfied.

[0185] D3 / D2 may be any one point value or a range value between any two of 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, etc.

[0186] From Table 1 above, it can be seen that when D3 / D2<0.15, the timeliness of pressure release is low and the probability of explosion during thermal runaway of the battery cell 10 is high, and when D3 / D2>0.95, the probability of rupture of the pressure release member 13 along the second groove segment 1312 during normal use of the battery cell 10 is high, affecting the service life of the battery cell 10. In contrast, when 0.15≦D3 / D2≦0.95, not only is the timeliness of pressure release of the battery cell 10 improved, but the service life of the battery cell 10 can also be extended.

[0187] In some embodiments, 0.3≦D3 / D2≦0.9.

[0188] In this embodiment, D3 / D2 may be any one of the following point values ​​or a range value between any two of 0.3, 0.32, 0.35, 0.38, 0.4, 0.42, 0.45, 0.48, 0.5, 0.52, 0.55, 0.58, 0.6, 0.62, 0.65, 0.68, 0.7, 0.72, 0.75, 0.78, 0.8, 0.82, 0.85, 0.88, 0.9, etc.

[0189] From Table 1 above, it can be seen that when 0.3≦D3 / D2≦0.9, the performance of the battery cell 10 is better, and the timeliness of pressure release of the battery cell 10 can be improved, while the service life of the battery cell 10 can be extended.

[0190] In some embodiments, 0.5≦D3 / D2≦0.85.

[0191] In this embodiment, D3 / D2 may be any one of the following point values ​​or a range value between any two of 0.5, 0.52, 0.53, 0.55, 0.57, 0.58, 0.59, 0.6, 0.62, 0.63, 0.65, 0.67, 0.68, 0.69, 0.7, 0.72, 0.73, 0.75, 0.77, 0.78, 0.79, 0.8, 0.82, 0.83, 0.85, etc.

[0192] It can be seen from Table 1 above that when 0.5≦D3 / D2≦0.85, the overall performance of the battery cell 10 is further improved, and not only is the probability of the pressure release member 13 rupturing along the second groove segment 1312 during normal use of the battery cell 10 reduced, but the probability of the battery cell 10 exploding during thermal runaway can also be reduced.

[0193] In some embodiments, 0.03 mm≦D3≦0.5 mm.

[0194] In this embodiment, D3 may be any one of the point values ​​of 0.03 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, etc., or a range value between any two of them.

[0195] In some embodiments, 0.15 mm≦D3≦0.4 mm.

[0196] D3 may be any one point value or a range value between any two of 0.15mm, 0.18mm, 0.2mm, 0.22mm, 0.25mm, 0.28mm, 0.3mm, 0.32mm, 0.35mm, 0.38mm, 0.4mm, etc.

[0197] In some embodiments, the depth of the third groove segment 1313 is greater than the depth of the second groove segment 1312 , so that the remaining thickness of the third groove segment 1313 is less than the remaining thickness of the second groove segment 1312 .

[0198] For example, along the thickness direction X of the pressure release member, the pressure release member 13 includes a first surface 132 and a second surface 133 arranged opposite each other, a first groove segment 1311 and a second groove segment 1312 arranged on the first surface 132, the first surface 132 and the second surface 133 may be parallel surfaces, the distance between the first surface 132 and the second surface 133 is H0, the distance between the groove bottom surface (third groove bottom surface 1313a) of the third groove segment 1313 and the second surface 133 is D3, the distance between the groove bottom surface (second groove bottom surface 1312b) of the second groove segment 1312 and the second surface 133 is D2, the depth of the third groove segment 1313 is H0-D3, and the depth of the second groove segment 1312 is H0-D2, where H0-D3>H0-D2. Here, H0 may be the thickness of the pressure release member 13. Here, the third groove bottom surface 1313a may be a flat surface or a circular arc surface.

[0199] During molding, the third groove segment 1313 is machined deeper than the second groove segment 1312 in the pressure release member 13, so that the remaining thickness of the third groove segment 1313 can be made smaller than the remaining thickness of the second groove segment 1312, which is a simple method of implementation.

[0200] In some embodiments, still referring to FIG. 14 , the third groove segment 1313 includes a third-stage groove 1313c and a fourth-stage groove 1313d, the third-stage groove 1313c and the fourth-stage groove 1313d being arranged along the thickness direction X of the pressure release member, and the fourth-stage groove 1313d being located on the bottom surface of the third-stage groove 1313c.

[0201] The third groove segment 1313 may be a two-stage groove, one of which is a third-stage groove 1313c and the other is a fourth-stage groove 1313d. The extension direction of the third-stage groove 1313c coincides with the extension direction of the fourth-stage groove 1313d, and the width direction of the third-stage groove 1313c coincides with the width direction of the fourth-stage groove 1313d. When the third groove segment 1313 is a groove extending along a straight line, both the third-stage groove 1313c and the fourth-stage groove 1313d also extend along straight lines. When the third groove segment 1313 is a groove extending along a circular arc, both the third-stage groove 1313c and the fourth-stage groove 1313d also extend along circular lines. Along the depth direction of the third groove segment 1313, the fourth-stage groove 1313d is located at the bottom of the third-stage groove 1313c. The groove bottom wall of the fourth-step groove 1313d is the groove bottom wall of the third groove segment 1313, and the groove bottom surface of the fourth-step groove 1313d is the groove bottom surface (third groove bottom surface 1313a) of the third groove segment 1313. For example, along the thickness direction X of the pressure release member, the pressure release member 13 has opposing first and second surfaces 132 and 133, the third-step groove 1313c and the fourth-step groove 1313d are sequentially arranged along the direction from the first surface 132 to the second surface 133, and the distance between the groove bottom surface of the fourth-step groove 1313d and the second surface 133 is D3.

[0202] Here, the groove bottom surface of the third-stage groove 1313c and the groove bottom surface of the second groove segment 1312 (second groove bottom surface 1312b) may be flush with each other or may be offset from each other along the thickness direction X of the pressure release member. For example, along the thickness direction X of the pressure release member, the groove bottom surface of the third-stage groove 1313c is closer to the second surface 133 than the groove bottom surface of the second groove segment 1312 (second groove bottom surface 1312b).

[0203] During molding, the third groove segment 1313 can be formed by first molding the third-stage groove 1313c in the pressure release member 13, and then molding the fourth-stage groove 1313d on the bottom surface of the third-stage groove 1313c.In this way, the molding depth of each stage groove in the third groove segment 1313 can be reduced, the molding force that the pressure release member 13 receives when molding the third groove segment 1313 can be reduced, and the possibility of cracks occurring in the pressure release member 13 when molding the third groove segment 1313 can be reduced.

[0204] In some embodiments, the groove bottom surface of the third-tier groove 1313c is flush with the groove bottom surface of the second groove segment 1312 (second groove bottom surface 1312b).

[0205] For example, both the groove bottom surface of the third-stage groove 1313c and the groove bottom surface (second groove bottom surface 1312b) of the second groove segment 1312 are flat, and both are located on the same plane.

[0206] In this embodiment, the groove bottom surface of the third-stage groove 1313c is flush with the groove bottom surface (second groove bottom surface 1312b) of the second groove segment 1312, so the groove bottom surface of the third-stage groove 1313c is located in the same plane as the groove bottom surface (second groove bottom surface 1312b) of the second groove segment 1312. During molding, the third-stage groove 1313c of the third groove segment 1313 and the second groove segment 1312 can be molded together, and then the fourth-stage groove 1313d of the third groove segment 1313 can be molded, thereby improving the molding efficiency of the groove portion 131.

[0207] 15 is a partial cross-sectional view of a pressure release member 13 according to another embodiment of the present application, in which the pressure release member 13 has a first surface 132 and a second surface 133 facing each other along the thickness direction X of the pressure release member 13, and a third-step groove 1313c and a fourth-step groove 1313d are sequentially arranged along the direction from the first surface 132 to the second surface 133, and the groove bottom surface of the fourth-step groove 1313d is closer to the second surface 133 than the groove bottom surface of the second groove segment 1312. Here, the groove bottom surface of the fourth-step groove 1313d (third groove bottom surface 1313a) is connected to the groove bottom surface of the second groove segment 1312 (second groove bottom surface 1312b) via a second inclined surface or a second arcuate surface 1313e.

[0208] The groove bottom surface (third groove bottom surface 1313a) of the fourth-step groove 1313d and the groove bottom surface (second groove bottom surface 1312b) of the second groove segment 1312 may be connected via a second inclined surface or a second arcuate surface 1313e. In the embodiment shown in Fig. 14, the groove bottom surface (third groove bottom surface 1313a) of the fourth-step groove 1313d and the groove bottom surface (second groove bottom surface 1312b) of the second groove segment 1312 are connected via the second arcuate surface 1313e. For example, the groove bottom surface (third groove bottom surface 1313a) of the fourth-stage groove 1313d is parallel to the groove bottom surface (second groove bottom surface 1312b) of the second groove segment 1312, and the second arc surface 1313e is in contact with the groove bottom surface (second groove bottom surface 1312b) of the second groove segment 1312, and the second arc surface 1313e is one groove side surface of the fourth-stage groove 1313d.

[0209] When the pressure is released, after the pressure release member 13 ruptures at the explosion position 1314, the crack at the groove bottom of the fourth groove 1313d can quickly spread along the second inclined surface or the second arc surface 1313e to the groove bottom of the second groove segment 1312, thereby shortening the time for the crack to spread from the third groove segment 1313 to the second groove segment 1312, and further shortening the time for the pressure release member 13 to rupture along the groove portion 131.

[0210] 5, 10 and 16, Fig. 16 is a partial view of a pressure release member 13 according to some other embodiments of the present application. Along the extension direction of the second groove segment 1312, both ends of the second groove segment 1312 are connected to the first groove segment 1311 and the third groove segment 1313, respectively.

[0211] Here, along the extension direction of the second groove segment 1312, one end of the second groove segment 1312 is connected to the first groove segment 1311 at a first position 1315, and the other end of the second groove segment 1312 is connected to the third groove segment 1313 at a second position 1316. For example, the explosion position 1314 on the first groove segment 1311 is located near the first position 1315, and the explosion position 1314 on the third groove segment 1313 is located near the second position 1316.

[0212] In this embodiment, both ends of the second groove segment 1312 are connected to the first groove segment 1311 and the third groove segment 1313, respectively, and both ends of the second groove segment 1312 do not extend beyond the first groove segment 1311 and the third groove segment 1313, respectively. During the pressure release process, pressure can be released precisely through the area defined by the first groove segment 1311, the second groove segment 1312, and the third groove segment 1313. The pressure release member 13 is not likely to burst and release pressure in other areas, making it easier to achieve directional pressure release.

[0213] In some embodiments, the first groove segment 1311 and the second groove segment 1312 are connected at a first position 1315, and along the extension direction of the first groove segment 1311, the first position 1315 is spaced from both ends of the first groove segment 1311.

[0214] The first position 1315 is offset from both ends of the first groove segment 1311, i.e., the first position 1315 is not located at either end of the first groove segment 1311, but is located between both ends of the first groove segment 1311 along the extension direction of the first groove segment 1311. The first position 1315 may be at the midpoint of the first groove segment 1311 or may be offset from the midpoint of the first groove segment 1311.

[0215] During the pressure release process, after the pressure release member 13 ruptures at the first position 1315, the crack can spread from the first position 1315 to both ends along the first groove segment 1311, thereby shortening the time it takes for the pressure release member 13 to rupture along the first groove segment 1311.

[0216] In some embodiments, the first position 1315 is located at the midpoint of the first groove segment 1311 along the extension direction of the first groove segment 1311 .

[0217] Along the extension direction of the first groove segment 1311, the first position 1315 can divide the first groove segment 1311 into two parts of equal length.

[0218] For example, along the extension direction of the first groove segment 1311 , the explosion position 1314 on the first groove segment 1311 is at the midpoint position of the first groove segment 1311 .

[0219] It should be noted that in an embodiment in which the first groove segment 1311 includes a first-stage groove 1311c and a second-stage groove 1311d, along the extension direction of the first groove segment 1311, both ends of the first-stage groove 1311c are both ends of the first groove segment 1311, and the midpoint position of the first-stage groove 1311c is the midpoint position of the first groove segment 1311.

[0220] In this embodiment, the first position 1315 is located at the midpoint of the first groove segment 1311, and during the pressure release process, the distance that the crack spreads from the first position 1315 to both ends along the first groove segment 1311 is equal, thereby further shortening the time it takes for the pressure release member 13 to burst along the first groove segment 1311.

[0221] In some embodiments, the third groove segment 1313 and the second groove segment 1312 are connected at a second location 1316, and along the extension direction of the third groove segment 1313, the second location 1316 is spaced from both ends of the third groove segment 1313.

[0222] The second position 1316 is offset from both ends of the third groove segment 1313, i.e., the second position 1316 is not located at either end of the third groove segment 1313, but is located between both ends of the third groove segment 1313 along the extension direction of the third groove segment 1313. The second position 1316 may be at the midpoint of the third groove segment 1313 or may be offset from the midpoint of the third groove segment 1313.

[0223] When the first position 1315 is off both ends of the first groove segment 1311 and the second position 1316 is off both ends of the third groove segment 1313, the first groove segment 1311, the second groove segment 1312 and the third groove segment 1313 jointly define two pressure release areas 134, which are located on both sides of the second groove segment 1312. During the pressure release process, both pressure release areas 134 can be opened, which effectively improves the timeliness of the pressure release.

[0224] During the pressure release process, after the pressure release member 13 ruptures at the second position 1316, the crack can spread from the second position 1316 to both ends along the third groove segment 1313, thereby shortening the time it takes for the pressure release member 13 to rupture along the third groove segment 1313.

[0225] In some embodiments, the second position 1316 is located at the midpoint of the third groove segment 1313 along the extension direction of the third groove segment 1313 .

[0226] Along the extension direction of the third groove segment 1313, the second position 1316 can divide the third groove segment 1313 into two parts of equal length.

[0227] For example, along the extension direction of the third groove segment 1313 , the explosion position 1314 on the third groove segment 1313 is at the midpoint position of the third groove segment 1313 .

[0228] It should be noted that in an embodiment in which the third groove segment 1313 includes a third-stage groove 1313c and a fourth-stage groove 1313d, along the extension direction of the third groove segment 1313, both ends of the third-stage groove 1313c are both ends of the third groove segment 1313, and the midpoint position of the third-stage groove 1313c is the midpoint position of the third groove segment 1313.

[0229] In this embodiment, the second position 1316 is located at the midpoint of the third groove segment 1313, and during the pressure release process, the distance that the crack spreads from the second position 1316 to both ends along the third groove segment 1313 is equal, thereby further shortening the time it takes for the pressure release member 13 to burst along the third groove segment 1313.

[0230] In some embodiments, the first groove segment 1311, the second groove segment 1312, and the third groove segment 1313 are all grooves that extend along a linear locus.

[0231] The first groove segment 1311, the second groove segment 1312, and the third groove segment 1313 are all linear grooves. The first groove segment 1311 and the second groove segment 1312 may be perpendicular or may be disposed at an acute or obtuse angle. The third groove segment 1313 and the second groove segment 1312 may be perpendicular or may be disposed at an acute or obtuse angle. The lengths of the first groove segment 1311 and the third groove segment 1313 may or may not be equal. In the embodiments shown in FIGS. 5, 10, and 16, the length of the first groove segment 1311 is equal to the length of the third groove segment 1313. In the embodiments shown in FIGS. 10 and 15, the length of the step groove 1311c is the length of the first groove segment 1311, and the length of the third step groove 1313c is the length of the third groove segment 1313. For example, the length of the first groove step 1311c is equal to the length of the third groove step 1313c, and the length of the second groove step 1311d is equal to the length of the fourth groove step 1313d.

[0232] In this embodiment, the first groove segment 1311, the second groove segment 1312, and the third groove segment 1313 are all linear grooves, which reduces the difficulty of forming the first groove segment 1311, the second groove segment 1312, and the third groove segment 1313.

[0233] In some embodiments, the first groove segment 1311 is perpendicular to the second groove segment 1312 and / or the third groove segment 1313 is perpendicular to the second groove segment 1312.

[0234] As can be appreciated, if the first groove segment 1311 is perpendicular to the second groove segment 1312, the third groove segment 1313 can be perpendicular to the second groove segment 1312, and the third groove segment 1313 and the second groove segment 1312 can be disposed at an acute or obtuse angle; if the third groove segment 1313 is perpendicular to the second groove segment 1312, the first groove segment 1311 can be perpendicular to the second groove segment 1312, and the first groove segment 1311 and the second groove segment 1312 can be disposed at an acute or obtuse angle. In the embodiments shown in Figures 5, 10, and 16, both the first groove segment 1311 and the third groove segment 1313 are perpendicular to the second groove segment 1312.

[0235] When the first groove segment 1311 is perpendicular to the second groove segment 1312, stress is more concentrated near the connection position between the first groove segment 1311 and the second groove segment 1312, and the explosion position 1314 is located near the connection position between the first groove segment 1311 and the second groove segment 1312. If the explosion pressure of the battery cell 10 is constant, the machining depth of the first groove segment 1311 can be reduced, and the machining difficulty of the first groove segment 1311 can be reduced. When the third groove segment 1313 is perpendicular to the second groove segment 1312, stress is more concentrated near the connection position between the third groove segment 1313 and the second groove segment 1312. If the explosion pressure of the battery cell 10 is constant, the machining depth of the third groove segment 1313 can be reduced, and the machining difficulty of the third groove segment 1313 can be reduced.

[0236] 16 , in some embodiments, the first groove segment 1311, the second groove segment 1312, and the third groove segment 1313 define a pressure relief region 134. The pressure relief member 13 includes a guide groove 135 spaced apart from the second groove segment 1312, and the guide groove 135 is configured to guide the pressure relief region 134 to invert and open.

[0237] The pressure release area 134 is an area defined by the first groove segment 1311, the second groove segment 1312 and the third groove segment 1313 of the pressure release member 13, and the first groove segment 1311, the second groove segment 1312 and the third groove segment 1313 are located at the edge positions of the pressure release area 134, and when the pressure release member 13 ruptures along the first groove segment 1311, the second groove segment 1312 and the third groove segment 1313, the pressure release area 134 can be inverted outward and opened. The first groove segment 1311, the second groove segment 1312, and the third groove segment 1313 can define one pressure release area 134, for example, the first groove segment 1311, the second groove segment 1312, and the third groove segment 1313 are sequentially connected to form a U-shaped structure, or the first groove segment 1311, the second groove segment 1312, and the third groove segment 1313 can also define two pressure release areas 134, for example, the first groove segment 1311, the second groove segment 1312, and the third groove segment 1313 form an H-shaped structure.

[0238] In an embodiment in which the first groove segment 1311, the second groove segment 1312, and the third groove segment 1313 are sequentially connected to form a U-shaped structure, the connecting line between the end of the first groove segment 1311 remote from the second groove segment 1312 and the end of the third groove segment 1313 remote from the second groove segment 1312 is the first connecting line, and the area surrounded by the first groove segment 1311, the second groove segment 1312, the third groove segment 1313, and the first connecting line is the pressure release area 134. In an embodiment in which the first groove segment 1311, the second groove segment 1312, and the third groove segment 1313 form an H-shaped structure, the connecting line between one end of the first groove segment 1311 and one end of the third groove segment 1313 is the second connecting line, the connecting line between the other end of the first groove segment 1311 and the other end of the third groove segment 1313 is the third connecting line, the area surrounded by the first groove segment 1311, the second groove segment 1312, the third groove segment 1313, and the second connecting line is one pressure release region 134, and the area surrounded by the first groove segment 1311, the second groove segment 1312, the third groove segment 1313, and the third connecting line is the other pressure release region 134.

[0239] The guide groove 135 is a groove provided in the pressure release member 13 to contribute to the reversal and opening of the pressure release area 134. The guide groove 135 may be a linear groove or a non-linear groove such as an arc-shaped groove. For example, the guide groove 135 is a linear groove parallel to the second groove segment 1312.

[0240] For example, the remaining thickness of the first groove segment 1311 and the remaining thickness of the third groove segment 1313 are both smaller than the remaining thickness of the guide groove 135 .

[0241] In this embodiment, the installation of the guide groove 135 contributes to the reversal and opening of the pressure release area 134, reduces the difficulty of reversing the pressure release area 134, and effectively improves the timeliness of pressure release.

[0242] 16 , in some embodiments, the first groove segment 1311, the second groove segment 1312, and the third groove segment 1313 define two pressure release areas 134, each located on either side of the second groove segment 1312. The pressure release member 13 is provided with two guide grooves 135, and the second groove segment 1312 is located between the two guide grooves 135. The two guide grooves 135 are configured to guide the two pressure release areas 134 to reverse and open.

[0243] The areas of the two pressure relief regions 134 may or may not be equal. For example, the two pressure relief regions 134 are symmetrically distributed on both sides of the second groove segment 1312. In the embodiment shown in FIG. 16 , the first groove segment 1311, the second groove segment 1312, and the third groove segment 1313 are all linear grooves. The first groove segment 1311 is parallel to the third groove segment 1313, the first groove segment 1311 is perpendicular to the second groove segment 1312, the length of the first groove segment 1311 is equal to the length of the third groove segment 1313, and the second groove segment 1312 is connected to the midpoint of the first groove segment 1311 and the midpoint of the third groove segment 1313 to achieve the two pressure relief regions 134 symmetrically distributed on both sides of the second groove segment 1312.

[0244] For example, the two guide grooves 135 are parallel to the second groove segment 1312, the distances between the two guide grooves 135 and the second groove segment 1312 are equal, and the two guide grooves 135 are symmetrically distributed on both sides of the second groove segment 1312.

[0245] During the pressure release process, the two guide grooves 135 respectively act as guides for the two pressure release areas 134, thereby improving the release speed of the two pressure release areas 134 and allowing the pressure to be released more timely.

[0246] In some embodiments, both the first groove segment 1311 and the third groove segment 1313 do not contact the guide groove 135 .

[0247] The first groove segment 1311 does not contact the guide groove 135, i.e., the first groove segment 1311 is not connected to the guide groove 135. The first groove segment 1311 and the guide groove 135 may be spaced apart so as to be non-contacting, for example, the first groove segment 1311 and the guide groove 135 may be spaced apart along the extension direction of the first groove segment 1311 and / or the first groove segment 1311 and the guide groove 135 may be spaced apart along the extension direction of the guide groove 135 and / or the first groove segment 1311 and the guide groove 135 may be spaced apart along the thickness direction X of the pressure release member. The third groove segment 1313 does not contact the guide groove 135, i.e., the third groove segment 1313 is not connected to the guide groove 135. The third groove segment 1313 and the guide groove 135 may be spaced apart so as to be out of contact with each other, for example, the third groove segment 1313 and the guide groove 135 may be spaced apart along the extension direction of the third groove segment 1313, and / or the third groove segment 1313 and the guide groove 135 may be spaced apart along the extension direction of the guide groove 135, and / or the third groove segment 1313 and the guide groove 135 may be spaced apart along the thickness direction X of the pressure release member.

[0248] In this embodiment, neither the first groove segment 1311 nor the third groove segment 1313 contacts the guide groove 135, and the guide groove 135 is less likely to affect the first groove segment 1311 and the third groove segment 1313. This improves the fatigue strength of the pressure release member 13 at the first groove segment 1311 and the third groove segment 1313, and reduces the possibility of the pressure release member 13 rupturing at the connection position during normal use of the battery cell 10 due to stress concentration caused by the connection between the guide groove 135 and the first groove segment 1311 and the third groove segment 1313. Furthermore, after the pressure release member 13 ruptures along the first groove segment 1311 and the third groove segment 1313 during the pressure release process, the crack is less likely to spread to the guide groove 135, reducing the possibility of the pressure release member 13 rupturing and scattering after the pressure release area 134 opens.

[0249] In some embodiments, referring to Figure 17, Figure 17 is a cross-sectional view taken along the line G-G of the pressure release member 13 shown in Figure 16. Along the thickness direction X of the pressure release member, the guide groove 135 and the groove portion 131 are respectively installed on both sides of the pressure release member 13.

[0250] During molding, a guide groove 135 can be molded on one side of the pressure release member 13 along the thickness direction X of the pressure release member, and a groove portion 131 can be molded on the other side of the pressure release member 13. In some embodiments, the groove portion 131 faces the outside of the housing 1, and the guide groove 135 faces the inside of the housing 1. In other embodiments, the groove portion 131 faces the inside of the housing 1, and the guide groove 135 faces the outside of the housing 1.

[0251] For example, along the thickness direction X of the pressure release member, the pressure release member 13 includes a first surface 132 and a second surface 133 disposed opposite to each other, and the groove portion 131 may be disposed on the first surface 132, and the guide groove 135 may be disposed on the second surface 133. As can be seen, the first groove segment 1311, the second groove segment 1312, and the third groove segment 1313 are all disposed on the first surface 132.

[0252] In this embodiment, the guide groove 135 and the groove portion 131 are respectively installed on both sides of the pressure release member 13, so that the influence of the guide groove 135 on the groove portion 131 during molding is reduced; on the other hand, the guide groove 135 can exert a better guiding effect on the pressure release area 134, making it easier for the pressure release area 134 to invert and open.

[0253] In some embodiments, with continued reference to FIG. 16, the guide groove 135 extends along the extension direction of the second groove segment 1312.

[0254] As can be seen, the extension direction of the guide groove 135 coincides with the extension direction of the second groove segment 1312. In some embodiments, both the guide groove 135 and the second groove segment 1312 are grooves extending along arcuate loci, and when observed along the thickness direction X of the pressure release member, the center of the arcuate locus of the guide groove 135 overlaps with the center of the arcuate locus of the second groove segment 1312. In other embodiments, as shown in FIG. 16 , both the guide groove 135 and the second groove segment 1312 are grooves extending along linear loci, and the guide groove 135 is parallel to the second groove segment 1312.

[0255] In some embodiments, along the extension direction of the second groove segment 1312, the first groove segment 1311 and the third groove segment 1313 are located on both sides of the guide groove 135, respectively, the length of the portion of the second groove segment 1312 located between the first groove segment 1311 and the third groove segment 1313 is L1, and the length of the guide groove 135 is L2, satisfying 1 mm≦L1−L2≦10 mm.

[0256] Along the extension direction of the second groove segment 1312, one end of the guide groove 135 and the first groove segment 1311 are spaced apart, and the other end of the guide groove 135 and the third groove segment 1313 are spaced apart, and there is a distance between them. For example, along the extension direction of the second groove segment 1312, the distance between one end of the guide groove 135 and the first groove segment 1311 is equal to the distance between the other end of the guide groove 135 and the third groove segment 1313.

[0257] L1-L2 may be any one point value of 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc. or a range value between any two.

[0258] When L1-L2<1 mm, the distance between at least one of the first groove segment 1311 and the third groove segment and the guide groove 135 is small, and the influence of the guide groove 135 on the first groove segment 1311 and the third groove segment 1313 is large. This increases the possibility that the pressure release member 13 will prematurely burst at a position close to the guide groove 135 of the first groove segment 1311 or the third groove segment 1313, increasing the possibility of premature pressure release. When L1-L2>10 mm, the length of the guide groove 135 is short, and the guide groove 135's ability to contribute to the reversal of the pressure release region 134 is low. In contrast, when 1 mm≦L1-L2≦10 mm, not only can the possibility of the pressure release member 13 prematurely releasing pressure be reduced, but the guide groove 135's ability to contribute to the reversal and release of the pressure release region 134 can also be improved.

[0259] In some embodiments, 2 mm≦L1−L2≦6 mm.

[0260] In this embodiment, L1-L2 may be any one of the following point values ​​or a range value between any two of 2mm, 2.3mm, 2.5mm, 2.8mm, 3mm, 3.3mm, 3.5mm, 3.8mm, 4mm, 4.3mm, 4.5mm, 4.8mm, 5mm, 5.3mm, 5.5mm, 5.8mm, 6mm, etc.

[0261] In this embodiment, 2 mm≦L1-L2≦6 mm, which further reduces the possibility that the pressure release member 13 will release the pressure prematurely, and further improves the guiding ability of the guide groove 135 to contribute to the reversal and opening of the pressure release area 134.

[0262] In some embodiments, the distance between the guide groove 135 and the second groove segment 1312 along the extension direction of the first groove segment 1311 is L3, and the length of the portion of the first groove segment 1311 extending from the second groove segment 1312 toward the guide groove 135 is L4, where 0.5 mm≦|L3-L4|≦15 mm.

[0263] The distance between the guide groove 135 and the second groove segment 1312 is equal to the length of the shortest connecting line between the guide groove 135 and the second groove segment 1312, and the shortest connecting line coincides with the extension direction of the first groove segment 1311.

[0264] In the embodiment where L3>L4, the guide groove 135 contributes more to the reversal and opening of the pressure release area 134.

[0265] |L3-L4| may be any one point value of 0.5mm, 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, etc. or a range value between any two of them.

[0266] When |L3 - L4| < 0.5 mm, since the distance between the end of the first groove segment 1311 and the guide groove 135 is small, when a crack in the pressure relief member 13 diffuses along the first groove segment 1311 to the end of the first groove segment 1311, the crack is likely to diffuse into the guide groove 135. As a result, the pressure relief region 134 detaches. If |L3 - L4| > 15 mm, when L3 > L4, the distance between the guide groove 135 and the second groove segment 1312 is large, and the ability to contribute to the inversion of the pressure relief region 134 of the guide groove 135 is low. When L3 < L4, the distance between the guide groove 135 and the second groove segment 1312 is small, the area of the inversion opening of the pressure relief region 134 is small, and the pressure relief area of the pressure relief region 134 decreases. In contrast, when 0.5 mm ≤ |L3 - L4| ≤ 15 mm, not only can the possibility of detachment and scattering in the pressure relief region 134 be reduced, but also the difficulty of the inversion opening of the pressure relief region 134 can be lowered, and the opening area of the pressure relief region 134 can be increased.

[0267] In some embodiments, 1 mm ≤ |L3 - L4| ≤ 10 mm.

[0268] In this embodiment, |L3 - L4| may be any one of the point values such as 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm or the range values between any two of them.

[0269] In some embodiments, referring to FIG. 18, FIG. 18 is an exploded view of the housing Ⅰ according to some embodiments of the present application. The housing Ⅰ includes a first wall portion 14, and the pressure relief member 13 (not shown in FIG. 18) is the first wall portion 14.

[0270] The housing 1 may include multiple walls, which collectively define an internal space of the housing 1. For example, if the housing 1 has a rectangular parallelepiped shape, the housing 1 has six walls, including two opposing walls in the longitudinal direction, two opposing walls in the width direction, and two opposing walls in the height direction.

[0271] In the housing 1, at least one wall is the first wall 14, i.e., at least one wall is provided with a groove 131. For example, in a case where the housing 1 includes a case 11 and an end cover 12, if the end cover 12 is used as one wall of the housing 1, the end cover 12 may be the first wall 14, or at least one wall of the case 11 may be the first wall 14.

[0272] As can be seen, the groove 131 is located in the first wall 14. The groove 131 may face the inside of the housing 1 or the outside of the housing 1.

[0273] In this embodiment, when the first wall portion 14 is used as the pressure release member 13, the groove portion 131 can be molded directly into the first wall portion 14 to form an integrated pressure release structure, which is more reliable, eliminates the installation process of the pressure release member 13, and reduces the manufacturing cost of the battery cell 10.

[0274] In some embodiments, referring to Figure 19, Figure 19 is an exploded view of a housing 1 according to some other embodiments of the present application. The housing 1 includes a first wall 14, and the pressure release member 13 is installed separately from the first wall 14, and the pressure release member 13 is attached to the first wall 14.

[0275] The pressure release member 13 and the housing 1 are two separate components that are molded separately and then attached together. The pressure release member 13 may be attached to the first wall 14 by welding, adhesive, etc. For example, a pressure release hole 141 is provided in the first wall 14, and the pressure release member 13 covers the pressure release hole 141.

[0276] In this embodiment, when the pressure release member 13 is attached to the first wall portion 14, the pressure release member 13 is a member independent of the housing 1, and the pressure release member 13 and the housing 1 may be manufactured and assembled separately, which reduces manufacturing difficulty and improves efficiency.

[0277] 18 and 19, in some embodiments of the present application, the housing 1 includes a case 11 and an end cover 12. The case 11 has an opening, and the end cover 12 seals the opening. At least one wall of the case 11 is a first wall 14.

[0278] Case 11 may include multiple walls, and the multiple walls define the interior space of case 11. In case 11, one wall may be first wall 14, or multiple walls may be first wall 14. For example, in Figures 18 and 19, only one wall in case 11 is first wall 14.

[0279] In this embodiment, the case 11 has a pressure release function, and when pressure is released, waste materials discharged from inside the battery cell 10 are less likely to affect the external components on the outside of the end cover 12, reducing the possibility of damage to the external components due to the waste materials. The external components here may be components that are located outside the battery cell 10 and connected to the electrode terminals 3 on the end cover 12.

[0280] 18 and 19, in some embodiments, the case 11 includes a bottom wall 111 and a plurality of side walls 112, the side walls 112 being disposed around the periphery of the bottom wall 111, and the case 11 has an opening formed at an end opposite the bottom wall 111. The bottom wall 111 is the first wall portion 14.

[0281] The bottom wall 111 is a wall portion facing the opening of the case 11, and the side walls 112 are walls portion installed around the bottom wall 111 of the case 11, and the bottom wall 111 and the side walls 112 are integrally formed. The number of side walls 112 of the case 11 may be three, four, five, six or more. For example, in Figures 18 and 19, the case 11 has a rectangular parallelepiped shape, and the number of side walls 112 of the case 11 is four.

[0282] In this embodiment, the bottom wall 111 has a pressure release function, and if the battery cell 10 experiences thermal runaway, the pressure can be released through the bottom wall 111, and in the battery 100, the pressure release member 13 is not easily blocked by other battery cells 10.

[0283] 20 and 21, Fig. 20 is an exploded view of a housing 1 according to some embodiments of the present application, and Fig. 21 is an exploded view of a housing 1 according to still other embodiments of the present application. The housing 1 includes a case 11 and an end cover 12, the case 11 has an opening, the end cover 12 seals the opening, and the end cover 12 is a first wall portion 14.

[0284] In the embodiment shown in FIG. 20, the end cover 12 is the pressure relief member 13 .

[0285] In the embodiment shown in FIG. 21, the pressure release member 13 and the end cover 12 are two separate components, and the pressure release member 13 is attached to the end cover 12.

[0286] In this embodiment, the end cover 12 has a pressure release function, and molding the groove 131 into the end cover 12 is less difficult.

[0287] In some embodiments, the first wall 14 is a rectangular wall, the second groove segment 1312 extends along the longitudinal direction Y of the first wall, and both the first groove segment 1311 and the third groove segment 1313 extend along the width direction Z of the first wall.

[0288] For better understanding, the length of the first wall portion 14 is greater than the width of the first wall portion 14, and both the first groove segment 1311 and the third groove segment 1313 are perpendicular to the second groove segment 1312.

[0289] In this embodiment, the second groove segment 1312 extends along the longitudinal direction Y of the first wall portion. The second wall portion can provide more space by the second groove segment 1312, and by making the second groove segment 1312 longer, the pressure relief area of the pressure relief member 13 can be increased.

[0290] In some other embodiments, the second groove segment 1312 extends along the width direction Z of the first wall portion, and both the first groove segment 1311 and the third groove segment 1313 may extend along the width direction Y of the first wall portion.

[0291] In some embodiments, referring to FIG. 22, FIG. 22 is a partial view of the first wall portion according to some embodiments of the present application. Along the thickness direction X of the pressure relief member (not shown in FIG. 22), the first wall portion 14 has an outer surface 142, and the outer surface 142 faces away from the inside of the housing 1. The first groove segment 1311 has a first intermediate surface 1311f extending along its extending direction, the second groove segment 1312 has a second intermediate surface 1312c extending along its extending direction, the third groove segment 1313 has a third intermediate surface 1313f extending along its extending direction. The minimum distance from the center point 1421 of the outer surface 142 to the first intermediate surface 1311f is M1, the minimum distance from the center point 1421 of the outer surface 142 to the second intermediate surface 1312c is M2, and the minimum distance from the center point 1421 of the outer surface 142 to the third intermediate surface 1313f is M3, satisfying M2 < M1 and M2 < M3.

[0292] Here, M1 = M3 may be true, or M1 < M3 may be true, or M1 > M3 may be true.

[0293] In embodiments in which the first wall 14 is used as the pressure relief member 13, the thickness direction X of the pressure relief member is the thickness direction of the first wall 14. In embodiments in which the pressure relief member 13 is attached to the first wall 14, the thickness direction X of the pressure relief member coincides with the thickness direction of the first wall 14.

[0294] The outer surface 142 is the surface of the first wall portion 14 facing away from the interior of the housing 1, i.e., the outer surface 142 faces the exterior of the housing 1. Along the thickness direction X of the pressure release member, the first wall portion 14 also has an inner surface facing the interior of the housing 1, and the first groove segment 1311, the second groove segment 1312, and the third groove segment 1313 may all be recessed along a direction from the outer surface 142 of the first wall portion 14 toward the inner surface, or along a direction from the inner surface of the first wall portion 14 toward the outer surface 142. In an embodiment in which the first wall portion 14 is used as the pressure release member 13, one of the inner surface and the outer surface 142 of the first wall portion 14 is the first surface 132 of the pressure release member 13, and the other is the second surface 133 of the pressure release member 13.

[0295] The center point 1421 of the outer surface 142 is the geometric center of the outer surface 142. The outer surface 142 may be circular, polygonal, etc. The polygon may be triangular, quadrilateral, pentagonal, hexagonal, etc.

[0296] The first intermediate surface 1311f coincides with the extension direction of the first groove segment 1311, and in the width direction of the first groove segment 1311, the first intermediate surface 1311f is located at the center of the first groove segment 1311, and the first intermediate surface 1311f is perpendicular to the width direction of the first groove segment 1311. In an embodiment in which the first groove segment 1311 is a multi-step groove, the first intermediate surface 1311f is located at the center of the deepest step of the first groove segment 1311 in the width direction of the first groove segment 1311. The second intermediate surface 1312c coincides with the extension direction of the second groove segment 1312, and in the width direction of the second groove segment 1312, the second intermediate surface 1312c is located at the center of the second groove segment 1312, and the second intermediate surface 1312c is perpendicular to the width direction of the second groove segment 1312. In an embodiment in which the second groove segment 1312 is a multi-step groove, the second intermediate surface 1312c is located at the center of the deepest groove step of the second groove segment 1312 in the width direction of the second groove segment 1312. The third intermediate surface 1313f coincides with the extension direction of the third groove segment 1313, and in the width direction of the third groove segment 1313, the third intermediate surface 1313f is located at the center of the third groove segment 1313, and the third intermediate surface 1313f is perpendicular to the width direction of the third groove segment 1313. In an embodiment in which the third groove segment 1313 is a multi-step groove, the third intermediate surface 1313f is located at the center of the deepest groove step of the third groove segment 1313 in the width direction of the third groove segment 1313.

[0297] The minimum distance from the center point 1421 of the outer surface 142 to the first intermediate surface 1311f can be measured on a perpendicular line to the first intermediate surface 1311f that passes through the center point 1421 of the outer surface 142. The minimum distance from the center point 1421 of the outer surface 142 to the second intermediate surface 1312c can be measured on a perpendicular line to the second intermediate surface 1312c that passes through the center point 1421 of the outer surface 142. The minimum distance from the center point 1421 of the outer surface 142 to the third intermediate surface 1313f can be measured on a perpendicular line to the third intermediate surface 1313f that passes through the center point 1421 of the outer surface 142.

[0298] When the internal pressure of the battery cell changes, the first wall portion 14 is more likely to deform as it approaches the center point 1421. Since M2 < M1 and M2 < M3, the first groove segment 1311 and the third groove segment 1313 are farther from the center point 1421, and the fatigue strength of the pressure relief member 13 at the first groove segment 1311 and the third groove segment 1313 is improved.

[0299] In some embodiments, along the thickness direction X of the pressure relief member 13, the projection of the center point 1421 of the outer surface 142 is located within the second groove segment 1312, and / or |M3 - M1| ≤ 5 mm.

[0300] Along the thickness direction of the pressure relief member 13, the projection of the center point 1421 is located within the second groove segment 1312, that is, the perpendicular line passing through the center point 1421 of the outer surface 142 passes through the second groove segment 1312. As an example, the center point 1421 of the outer surface 142 is located within the second intermediate surface 1312c.

[0301] |M3 - M1| may be any one of the point values such as 0 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm or the range value between any two of them.

[0302] In this embodiment, the projection of the center point 1421 of the outer surface 142 is located within the second groove segment 1312, and the second groove segment 1312 is closer to the center point 1421 of the outer surface 142. When the pressure relief member 13 releases pressure, it can rupture more timely along the second groove segment 1312, and the timeliness of the pressure relief of the pressure relief member 13 is improved. When |M3 - M1| ≤ 5 mm, both the first groove segment 1311 and the third groove segment 1313 are farther from the center point 1421, and the influence on the first groove segment 1311 and the third groove segment 1313 due to the deformation near the center point 1421 of the pressure relief member 13 is reduced.

[0303] In some embodiments, the outer surface 142 is rectangular, circular or regular polygonal.

[0304] In an embodiment in which the outer surface 142 is rectangular, the intersection of the two diagonals of the rectangle is the center point 1421 of the outer surface 142. The first wall 14 is a rectangular wall, and the longitudinal direction of the outer surface 142 coincides with the longitudinal direction Y of the first wall, and the width direction of the outer surface 142 coincides with the width direction Z of the first wall. The outer surface 142 may be a regular rectangle or an irregular rectangle, and for example, two adjacent sides of the rectangle may be connected by a chamfer, which may be a circular arc chamfer.

[0305] In an embodiment where the outer surface 142 is circular, the center of the circle is the center point 1421 of the outer surface 142. The first wall 14 may be a circular wall since the outer surface 142 is circular.

[0306] In an embodiment in which the outer surface 142 is a regular polygon, the center of the inscribed circle of the regular polygon is the center point 1421 of the outer surface 142. The regular polygon may be an equilateral triangle, a regular quadrilateral, a regular pentagon, a regular hexagon, or the like. The outer surface 142 may be a regular regular polygon or an irregular regular polygon, for example, two adjacent sides of a regular polygon may be connected by a chamfer, and the chamfer may be an arc chamfer. Since the outer surface 142 is a regular polygon, the first wall portion 14 may be a regular polygon wall portion.

[0307] An embodiment of the present application provides a battery 100 including a battery cell 10 according to any one of the above embodiments.

[0308] An embodiment of the present application provides a power consuming device comprising a battery cell 10 according to any one of the above embodiments for supplying power to the power consuming device.

[0309] An embodiment of the present application further provides a battery cell 10, which includes a housing 1 and an electrode assembly 2. The electrode assembly 2 has a positive electrode tab and a negative electrode tab, and the electrode assembly 2 is housed within the housing 1. The housing 1 has a rectangular parallelepiped shape and includes a case 11 and an end cover 12. The case 11 has an opening, and the end cover 12 seals the opening. A positive electrode terminal and a negative electrode terminal are installed on the end cover 12. The positive electrode terminal is electrically connected to the positive electrode tab via one current collecting member 4, and the negative electrode terminal is electrically connected to the negative electrode tab via the other current collecting member 4. A wall of the case 11 facing the end cover 12 is a pressure release member 13. The pressure release member 13 is provided with a groove 131. The pressure release member 13 is configured to rupture along the groove 131 to release the internal pressure of the battery cell 10, and the pressure release member 13 has an explosion position 1314. The groove portion 131 includes a first groove segment 1311, a second groove segment 1312, and a third groove segment 1313. The first groove segment 1311 is disposed opposite to the third groove segment 1313. The second groove segment 1312 connects the first groove segment 1311 and the third groove segment 1313. The first groove segment 1311, the second groove segment 1312, and the third groove segment 1313 are all grooves extending along a linear locus. The first groove segment 1311 and the third groove segment 1313 are connected to each other. Both of the first groove segment 1311 and the third groove segment 1313 are perpendicular to the second groove segment 1312, one end of the second groove segment 1312 is connected to the midpoint of the first groove segment 1311, and the other end of the second groove segment 1312 is connected to the midpoint of the third groove segment 1313, and the remaining thicknesses of the first groove segment 1311 and the third groove segment 1313 are both smaller than the remaining thickness of the second groove segment 1312, and the remaining thickness of the first groove segment 1311 is equal to the remaining thickness of the third groove segment 1313. Explosion positions 1314 are formed in both the first groove segment 1311 and the third groove segment 1313. The remaining thickness of the first groove segment 1311 is D1, and the remaining thickness of the second groove segment 1312 is D2, where 0.15≦D1 / D2≦0.95, 0.03 mm≦D1≦0.5 mm, and 0.25 mm≦D2≦0.5 mm.

[0310] Here, the first groove segment 1311 includes a first-stage groove 1311c and a second-stage groove 1311d, which are arranged along the thickness direction X of the pressure release member, and the second-stage groove 1311d is installed on the groove bottom surface of the first-stage groove 1311c, and the groove bottom surface of the first-stage groove 1311c is flush with the groove bottom surface of the second groove segment 1312. The third groove segment 1313 includes a third-stage groove 1313c and a fourth-stage groove 1313d, which are arranged along the thickness direction X of the pressure release member, and the fourth-stage groove 1313d is located on the bottom surface of the third-stage groove 1313c, and the bottom surface of the third-stage groove 1313c is flush with the bottom surface of the second groove segment 1312.

[0311] It should be noted that, unless contradictory, the embodiments and features of the embodiments in the present application can be combined with each other.

[0312] The above examples are only intended to illustrate the technical solution of the present application and are not intended to limit the present application, and those skilled in the art may make various modifications and variations to the present application, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A battery cell, a housing including a pressure release member, the pressure release member having a groove formed therein, the pressure release member being configured to burst along the groove to release internal pressure of the battery cell, the pressure release member having an explosion position; The groove portion includes a first groove segment, a second groove segment, and a third groove segment, the first groove segment is disposed opposite the third groove segment, the second groove segment connects the first groove segment and the third groove segment, and the explosion position is formed in the first groove segment and / or the third groove segment.

2. The battery cell according to claim 1 , wherein the explosion location is formed in the first groove segment, and a remaining thickness of the first groove segment is smaller than a remaining thickness of the second groove segment.

3. The remaining thickness of the first groove segment is D １ and the remaining thickness of the second groove segment is D ２ and 0.15≦D １ / D ２ 3. The battery cell according to claim 2, wherein the σ is ≦0.

95.

4. 0.3≦D １ / D ２ 4. The battery cell of claim 3, wherein the ρ is ≦0.

9.

5. 0.5≦D １ / D ２ 5. The battery cell of claim 4, wherein the ρ is ≦0.

85.

6. 0.03 mm≦D １ The battery cell according to any one of claims 3 to 5, wherein the thickness is ≦0.5 mm.

7. 0.15 mm≦D １ 7. The battery cell of claim 6, wherein the thickness is ≦0.4 mm.

8. 0.05 mm≦D ２ The battery cell according to any one of claims 3 to 7, wherein the thickness is ≦0.65 mm.

9. 0.25≦D ２ 9. The battery cell of claim 8, wherein the thickness is ≦0.5 mm.

10. 10. The battery cell of claim 2, wherein a depth of the first groove segment is greater than a depth of the second groove segment, and therefore a remaining thickness of the first groove segment is smaller than a remaining thickness of the second groove segment.

11. 11. The battery cell according to claim 2, wherein the first groove segment includes a first-stage groove and a second-stage groove, the first-stage groove and the second-stage groove are arranged along the thickness direction of the pressure release member, and the second-stage groove is located on a groove bottom surface of the first-stage groove.

12. The battery cell according to claim 11 , wherein a groove bottom surface of the first-stage groove is flush with a groove bottom surface of the second groove segment.

13. The pressure release member has a first surface and a second surface facing each other along a thickness direction of the pressure release member, the first-stage groove and the second-stage groove are sequentially arranged along a direction from the first surface toward the second surface, and a groove bottom surface of the second-stage groove is closer to the second surface than a groove bottom surface of the second groove segment; The battery cell according to claim 11 , wherein the groove bottom surface of the second-stage groove is connected to the groove bottom surface of the second groove segment via a first inclined surface or a first arcuate surface.

14. The battery cell according to any one of claims 2 to 13, wherein the explosion position is formed in the third groove segment, and the remaining thickness of the third groove segment is smaller than the remaining thickness of the second groove segment.

15. 15. The battery cell of claim 14, wherein a remaining thickness of the third groove segment is equal to a remaining thickness of the first groove segment.

16. The remaining thickness of the second groove segment is D ２ and the remaining thickness of the third groove segment is D ３ and 0.15≦D ３ / D ２ 16. The battery cell according to claim 14 or 15, wherein the σ is ≦0.

95.

17. 0.3≦D ３ / D ２ 17. The battery cell of claim 16, wherein the R is ≦0.

9.

18. 0.5≦D ３ / D ２ 18. The battery cell of claim 17, wherein the Ratio of the Frictional Momentum of the Battery Cell is ≦0.

85.

19. 0.03 mm≦D ３ The battery cell according to any one of claims 16 to 18, wherein the thickness is ≦0.5 mm.

20. 0.15 mm≦D ３ 20. The battery cell of claim 19, wherein the thickness is ≦0.4 mm.

21. 21. The battery cell of claim 14, wherein a depth of the third groove segment is greater than a depth of the second groove segment, and therefore a remaining thickness of the third groove segment is smaller than a remaining thickness of the second groove segment.

22. 22. The battery cell of claim 14, wherein the third groove segment includes a third-step groove and a fourth-step groove, the third-step groove and the fourth-step groove being arranged along the thickness direction of the pressure release member, and the fourth-step groove being located on a groove bottom surface of the third-step groove.

23. The battery cell according to claim 22 , wherein a groove bottom surface of the third-stage groove is flush with a groove bottom surface of the second-stage groove.

24. the pressure release member has a first surface and a second surface facing each other along a thickness direction of the pressure release member, the third step groove and the fourth step groove are sequentially arranged along a direction from the first surface toward the second surface, and a groove bottom surface of the fourth step groove is closer to the second surface than a groove bottom surface of the second groove segment; The battery cell according to claim 22 , wherein the groove bottom surface of the fourth-stage groove is connected to the groove bottom surface of the second groove segment via a second inclined surface or a second arcuate surface.

25. The battery cell according to any one of claims 1 to 24, wherein both ends of the second groove segment are connected to the first groove segment and the third groove segment, respectively, along the extension direction of the second groove segment.

26. The battery cell according to any one of claims 1 to 25, wherein the first groove segment and the second groove segment are connected at a first position, and the first position is spaced apart from both ends of the first groove segment along the extension direction of the first groove segment.

27. 27. The battery cell of claim 26, wherein the first position is at a midpoint of the first groove segment along an extension direction of the first groove segment.

28. The battery cell of any one of claims 1 to 27, wherein the third groove segment and the second groove segment are connected at a second position, and the second position is spaced apart from both ends of the third groove segment along the extension direction of the third groove segment.

29. 29. The battery cell of claim 28, wherein the second position is at a midpoint of the third groove segment along the extension direction of the third groove segment.

30. The battery cell according to any one of claims 1 to 29, wherein the first groove segment, the second groove segment, and the third groove segment are grooves that extend along linear loci.

31. 31. The battery cell of claim 30, wherein the first groove segment is perpendicular to the second groove segment and / or the third groove segment is perpendicular to the second groove segment.

32. the first groove segment, the second groove segment, and the third groove segment define a pressure relief region; The battery cell according to any one of claims 1 to 31, wherein the pressure release member has a guide groove, the guide groove is spaced apart from the second groove segment, and the guide groove guides the pressure release area to invert and open.

33. the first groove segment, the second groove segment, and the third groove segment define two pressure relief regions, the two pressure relief regions being located on either side of the second groove segment, respectively; 33. The battery cell of claim 32, wherein the pressure release member has two guide grooves, the second groove segment is located between the two guide grooves, and the two guide grooves respectively guide the two pressure release areas to invert and open.

34. 34. The battery cell of claim 32 or 33, wherein both the first groove segment and the third groove segment are out of contact with the guide groove.

35. The battery cell according to any one of claims 32 to 34, wherein the guide groove and the groove portion are respectively installed on both sides of the pressure release member along the thickness direction of the pressure release member.

36. The battery cell according to any one of claims 32 to 35, wherein the guide groove extends along the extending direction of the second groove segment.

37. The first groove segment and the third groove segment are located on both sides of the guide groove along the extending direction of the second groove segment, and the length of the portion of the second groove segment located between the first groove segment and the third groove segment is L １ and the length of the guide groove is L ２ and 1 mm≦L １ -L ２ The battery cell according to any one of claims 32 to 36, wherein the thickness satisfies ≦10 mm.

38. 2 mm≦L １ -L ２ 38. The battery cell of claim 37, wherein the thickness is ≦6 mm.

39. The distance between the guide groove and the second groove segment along the extension direction of the first groove segment is L ３ and the length of the portion of the first groove segment extending from the second groove segment in a direction approaching the guide groove is L ４ and 0.5 mm≦|L ３ -L ４ The battery cell according to any one of claims 32 to 38, wherein |≦15 mm.

40. 1 mm≦|L ３ -L ４ 40. The battery cell of claim 39, wherein |≦10 mm.

41. the housing includes a first wall; The battery cell of any one of claims 1 to 40, wherein the pressure release member is the first wall portion, or the pressure release member and the first wall portion are installed separately, and the pressure release member is attached to the first wall portion.

42. The housing includes: a case having an opening; an end cover that seals the opening and is the first wall portion; 42. The battery cell of claim 41, comprising:

43. The housing includes: a case having an opening; an end cover that seals the opening; Including, 42. The battery cell of claim 41, wherein at least one wall of the case is the first wall.

44. the case includes a bottom wall and a plurality of side walls, the plurality of side walls are disposed around the periphery of the bottom wall, and the opening is formed at an end of the case facing the bottom wall; 44. The battery cell of claim 43, wherein the bottom wall is the first wall portion.

45. 45. The battery cell of claim 41, wherein the first wall is a rectangular wall, the second groove segment extends along a longitudinal direction of the first wall, and both the first groove segment and the third groove segment extend along a width direction of the first wall.

46. Along a thickness of the pressure relief member, the first wall portion has an outer surface, the outer surface being spaced away from an interior of the housing; The first groove segment has a first intermediate surface extending along its extension direction, The second groove segment has a second intermediate surface extending along the extension direction thereof, the third groove segment has a third intermediate surface extending along the extension direction thereof; The minimum distance from the center point of the outer surface to the first intermediate surface is M １ and The minimum distance from the center point of the outer surface to the second intermediate surface is M ２ and The minimum distance from the center point of the outer surface to the third intermediate surface is M ３ and M ２ <M １ , M ２ <M ３ The battery cell according to any one of claims 41 to 45, wherein

47. a projection of the center point of the outer surface along the thickness direction of the pressure release member lies within the second groove segment; and / or |M ３ -M １ 47. The battery cell of claim 46, wherein |≦5 mm.

48. 48. The battery cell of claim 46 or 47, wherein the outer surface is rectangular, circular, or a regular polygon.

49. A battery comprising the battery cell according to any one of claims 1 to 48.

50. A power consuming device comprising a battery cell according to any one of claims 1 to 48 for supplying electrical energy to the power consuming device.

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