Battery cell, battery device, energy storage device and power utilization device

Abstract

The utility model discloses a battery monomer, a battery device, an energy storage device and a power utilization device. The battery monomer comprises a shell and an electrode assembly, the shell comprises a shell body and an end cover, the shell body is provided with an opening, and the end cover seals the opening. The electrode assembly is arranged in the shell and provided with a straight area, electrode pieces of the electrode assembly are arranged in the straight area in a stacked mode in the first direction, and the first direction is perpendicular to the thickness direction of the end cover. Wherein the shell is provided with a first wall, the thickness direction of the first wall is parallel to the first direction, the first wall is connected with the end cover through a first welding mark, and the end cover is provided with a first groove; the first groove and the first welding mark are arranged in the first direction, and the first groove penetrates through a first center line, parallel to the first direction, of the end cover. According to the technical scheme, the reliability of the battery device can be improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to a battery cell, a battery device, an energy storage device, and an electrical device. Background Technology

[0002] With the promotion and popularization of the concept of green development, new energy batteries are being used more and more widely in life and industry. For example, new energy vehicles equipped with batteries have been widely used. In addition, batteries are being used more and more in the field of energy storage.

[0003] In the development of battery technology, how to improve the reliability of battery devices is a technical problem that urgently needs to be solved. Utility Model Content

[0004] This application provides a battery cell, a battery device, an energy storage device, and an electrical device. The technical solution provided by this application can improve the reliability of the battery device.

[0005] This application is achieved through the following technical solution:

[0006] In a first aspect, some embodiments of this application provide a battery cell, which includes a casing and an electrode assembly. The casing includes a housing and an end cap, the housing having an opening and the end cap closing the opening. The electrode assembly is disposed inside the housing, and the electrode assembly has a flat region. The electrode sheets of the electrode assembly are stacked in the flat region along a first direction, the first direction being perpendicular to the thickness direction of the end cap. The housing has a first wall, the thickness direction of the first wall being parallel to the first direction. The first wall is connected to the end cap via a first solder joint, and the end cap has a first groove. The first groove and the first solder joint are arranged along the first direction, and the first groove passes through a first center line of the end cap parallel to the first direction.

[0007] In the above solution, a first groove is provided on the end cap along the first direction with the first solder mark, and the first groove passes through the first center line of the end cap. When the battery cell expands inside, it can disperse the stress at the joint between the end cap and the first wall (especially corresponding to the middle part of the end cap along the first direction), reduce the degree of stress concentration, effectively reduce the risk of fatigue cracking of the casing, thereby effectively improving the reliability of the battery cell, and thus effectively improving the reliability of the battery device.

[0008] According to some embodiments of this application, the battery cell further includes a pressure relief mechanism disposed on the end cap, and along the first direction, the first groove is located between the first solder mark and the pressure relief mechanism.

[0009] In the above solution, a first groove is provided on the end cap, and along the first direction (that is, the direction in which the battery cell is most affected by the internal expansion force), the first groove is located between the first solder mark and the pressure relief mechanism. On the one hand, when the battery cell expands internally, it can disperse the stress at the joint between the end cap and the first wall, reduce the degree of stress concentration, and effectively reduce the risk of fatigue cracking of the casing. On the other hand, it reduces the risk of structural damage to the pressure relief mechanism due to the pulling force of the internal expansion force of the battery cell, and can play a certain role in protecting the structural integrity of the pressure relief mechanism, thereby effectively improving the reliability of the battery cell and thus effectively improving the reliability of the battery device.

[0010] According to some embodiments of this application, along the first direction, the size of the end cap is W, and the distance between the first groove and the pressure relief mechanism is h1, satisfying that 0 < h1 ≤ 0.4W.

[0011] In the above solution, by limiting the distance h1 between the first groove and the pressure relief mechanism to no more than 0.4W (W is the width of the end cap), the risk of the first groove failing to disperse stress due to excessive distance between the first groove and the pressure relief mechanism, i.e., the first groove being too close to the first wall, can be reduced. This can improve the problem of fatigue cracking of the casing due to internal expansion of the battery cell, making the battery cell more reliable, and thus making the battery device more reliable.

[0012] According to some embodiments of this application, the following condition is satisfied: 0.3mm≤h1≤0.4W.

[0013] In the above scheme, by limiting the distance h1 between the first groove and the pressure relief mechanism to no less than 0.3mm, the manufacturing precision and structural strength of the pressure relief mechanism can be reduced due to the small distance between the first groove and the pressure relief mechanism, thus ensuring the pressure relief function of the pressure relief mechanism to a certain extent and reducing the risk of thermal runaway of the battery cell. By limiting the distance h1 between the first groove and the pressure relief mechanism to no more than 0.4W (W is the width of the end cap), the risk of the first groove failing to disperse stress due to the large distance between the first groove and the pressure relief mechanism can be reduced. This can improve the problem of fatigue cracking of the casing due to the internal expansion of the battery cell, making the battery cell more reliable and thus making the battery device more reliable.

[0014] According to some embodiments of this application, the following condition is satisfied: 0.5mm≤h1≤0.4W.

[0015] In the above scheme, by limiting the distance h1 between the first groove and the pressure relief mechanism to not less than 0.5mm, the manufacturing precision and structural strength of the pressure relief mechanism can be further reduced due to the small distance between the first groove and the pressure relief mechanism. This ensures the pressure relief function of the pressure relief mechanism to a certain extent and reduces the risk of thermal runaway of the battery cell. In this regard, by limiting the distance h1 between the first groove and the pressure relief mechanism to not less than 0.5mm and not greater than 0.4W (W is the width of the end cap), the manufacturing and functional reliability of the pressure relief mechanism can be taken into account, as well as the stress concentration effect at the junction of the end cap and the first wall can be dispersed, thereby making the reliability of the battery cell high, and thus making the reliability of the battery device high.

[0016] According to some embodiments of this application, along the second direction, the two ends of the first groove extend beyond the pressure relief mechanism, and the first direction, the second direction, and the thickness direction of the end cap are perpendicular to each other.

[0017] In the above solution, by setting the two ends of the first groove to extend beyond the pressure relief mechanism along the first direction, the influence of the expansion force along the first direction on the pressure relief mechanism when the battery cell expands can be effectively improved, and the structural integrity of the pressure relief mechanism can be guaranteed to a certain extent, so as to reduce the risk of the pressure relief mechanism structure being damaged and failing due to the expansion of the battery cell.

[0018] According to some embodiments of this application, along a first direction, the first wall has a first surface facing away from the electrode assembly, and along the first direction, the distance between the first groove and the first surface is h2, satisfying that 1mm≤h2≤20mm.

[0019] In the above solution, by limiting the distance h2 between the first groove and the first surface to not less than 1 mm, the manufacturing precision of the first groove can be reduced, the manufacturing difficulty caused by the small distance between the first groove and the first surface can be improved, and the risk of affecting the strength of the first solder mark structure due to the small distance between the first groove and the first surface can be reduced. By limiting the distance h2 between the first groove and the first surface to not more than 20 mm, the risk of not being able to effectively disperse stress due to the large distance between the first groove and the first surface can be reduced, so as to a certain extent, the manufacturing efficiency of the first groove and the effect of reducing fatigue cracking at the joint between the first wall and the end cap can be balanced.

[0020] According to some embodiments of this application, the following condition is satisfied: 1.5mm ≤ h2 ≤ 15mm.

[0021] In the above solution, by limiting the distance h2 between the first groove and the first surface to not less than 1.5 mm and not more than 15 mm, the first groove and the first surface have a suitable distance, which can effectively reduce the manufacturing difficulty of the first groove and enable the first groove to effectively disperse the stress generated by the internal expansion of the battery cell between the end cap and the first wall, thereby improving the reliability of the battery cell and thus improving the reliability of the battery device.

[0022] According to some embodiments of this application, the first groove is a strip-shaped groove that extends along a second direction, and the second direction, the first direction, and the thickness direction of the end cap are perpendicular to each other.

[0023] In the above solution, by setting the first groove as a strip extending along the second direction, on the one hand, stress concentration can be effectively dispersed and alleviated, reducing the risk of fatigue cracking at the junction of the end cover and the first wall due to the internal expansion force of the battery cell; on the other hand, it can adapt to multi-directional loads, improve the overall stability of the end cover under the influence of the internal expansion force of the battery cell and abnormal internal gas generation, thereby ensuring the integrity of the outer shell to a certain extent, which is conducive to improving the reliability of the battery cell, and thus to improving the reliability of the battery device.

[0024] According to some embodiments of this application, along the first direction, the width of the first groove is h3, satisfying 0.1mm≤h3≤15mm.

[0025] In the above solution, by limiting the width h3 of the first groove to not less than 0.1 mm and not more than 15 mm along the first direction, the risk of manufacturing difficulties due to the width of the first groove being too small can be reduced, thus reducing the manufacturing cost of the battery cell. On the other hand, it can avoid the problem that the end cap structure strength is greatly affected due to the width of the first groove being too large, resulting in the shell strength failing to meet the requirements.

[0026] According to some embodiments of this application, the following condition is satisfied: 0.3mm ≤ h3 ≤ 10mm.

[0027] In the above scheme, by limiting the width h3 of the first groove to not less than 0.3 mm and not more than 10 mm along the first direction, the manufacturing efficiency of the first groove and the stress dispersion effect of the first groove can be taken into account, so that the reliability of the battery cell is high, and thus the reliability of the battery device is high.

[0028] According to some embodiments of this application, along the second direction, the length of the first groove is h4 and the length of the end cap is L, satisfying that 0 < h4 ≤ L.

[0029] According to some embodiments of this application, the following condition is met: 10mm≤h4≤L.

[0030] In the above scheme, by setting the length h4 of the first groove to be no less than 10mm along the second direction, the stress at the junction of the end cap and the first wall can be effectively dispersed, the degree of stress concentration can be reduced, and the risk of fatigue cracking of the casing can be reduced, thereby effectively improving the reliability of the battery cell and thus effectively improving the reliability of the battery device.

[0031] According to some embodiments of this application, the following condition is met: 30mm≤h4≤L.

[0032] In the above scheme, along the second direction, by setting the length h4 of the first groove to be no less than 30mm, the first groove can effectively act on the part between the end cap and the first wall that is fatigued and cracked by expansion force, effectively reducing the degree of stress concentration and reducing the risk of fatigue cracking of the casing, thereby effectively improving the reliability of the battery cell and thus effectively improving the reliability of the battery device.

[0033] According to some embodiments of this application, the thickness of the end cap corresponding to the location of the first groove is t1, which satisfies 0.5mm≤t1≤3mm.

[0034] In the above scheme, by limiting the thickness t1 of the end cap corresponding to the location of the first groove to not less than 0.5mm, the risk of battery cell failure due to the small thickness of this part being easily damaged can be reduced. By limiting the thickness of the end cap corresponding to the location of the first groove to not more than 3mm, the effect of the first groove in dispersing and alleviating stress concentration can be guaranteed to a certain extent, reducing the risk of fatigue cracking of the casing, making the battery cell highly reliable, and thus making the battery device highly reliable.

[0035] According to some embodiments of this application, the following condition is satisfied: 0.7mm ≤ t1 ≤ 2mm.

[0036] In the above solution, by limiting the thickness t1 of the end cap corresponding to the location of the first groove to not less than 0.7 mm and not more than 2 mm, the structural strength of the end cap itself and the effect of the first groove in dispersing and alleviating stress concentration can be taken into account, thereby making the battery cell highly reliable.

[0037] According to some embodiments of this application, along a first direction, the end cap includes a first region located between a first groove and a first solder mark, wherein the thickness of the end cap corresponding to the location of the first groove is less than the thickness of the first region.

[0038] In the above solution, by limiting the thickness of the part where the first groove is located to be less than the thickness of the first region, when the first wall is deformed by the internal expansion force of the battery cell, the end cap deforms along the part of the first groove corresponding to the offset of the first wall, so as to disperse and alleviate the stress between the first wall and the end cap, reduce the risk of fatigue cracking at the joint between the end cap and the first wall, thereby making the battery cell highly reliable, and thus making the battery device highly reliable.

[0039] According to some embodiments of this application, along the thickness direction of the end cap, a first groove is formed on one side of the end cap, and a first protrusion is formed on the other side of the end cap, the position of the first protrusion corresponding to the first groove; along the thickness direction of the end cap, the thickness of the first protrusion is less than the thickness of the end cap.

[0040] In the above solution, by setting a first groove on one side of the end cap and a first protrusion on the other side corresponding to the first groove, the molding difficulty of the first groove can be reduced and the manufacturing efficiency of the battery cell can be improved. At the same time, by setting the thickness of the first protrusion to be less than the thickness of the end cap, the first groove can effectively disperse and alleviate the phenomenon of stress concentration, reduce the risk of fatigue cracking of the casing, and improve the reliability of the battery cell and battery device.

[0041] According to some embodiments of this application, along the first direction, the housing has a second wall, the second wall is opposite to the first wall, the second wall is connected to the end cap by a second solder mark, and at least one side of the end cap in the thickness direction is provided with a second groove, along the first direction, the second groove is located between the second solder mark and the pressure relief mechanism.

[0042] In the above solution, a second groove is provided on the end cap, along the first direction (that is, the direction in which the battery cell is most affected by the internal expansion force). The second groove is located between the second solder mark and the pressure relief mechanism. On the one hand, when the battery cell expands internally, it can disperse the stress at the joint between the end cap and the second wall, reduce the degree of stress concentration, and effectively reduce the risk of fatigue cracking of the casing. On the other hand, it reduces the risk of structural damage to the pressure relief mechanism due to the pulling force of the internal expansion force of the battery cell, and can play a certain role in protecting the structural integrity of the pressure relief mechanism, thereby effectively improving the reliability of the battery cell and thus effectively improving the reliability of the battery device.

[0043] According to some embodiments of this application, the end cap has a second center line perpendicular to the first direction, and the second groove and the second groove are symmetrically arranged about the second center line.

[0044] In the above scheme, by setting the first groove and the second groove to be symmetrical about the second center line, the risk of fatigue cracking at the junction of the large surface of the battery cell (i.e., the first wall and the second wall) and the end cap can be effectively reduced. At the same time, the structural integrity of the pressure relief mechanism can be guaranteed to a certain extent, which is conducive to improving the reliability of the battery cell and thus to improving the reliability of the battery device.

[0045] According to some embodiments of this application, the battery cell further includes a first electrode terminal and a second electrode terminal. Along a second direction, the first electrode terminal and the second electrode terminal are spaced apart, and the second direction, the first direction, and the thickness direction of the end cap are mutually perpendicular. Along the second direction, the housing has a third wall, which is connected to the end cap via a third solder joint. At least one side of the end cap in the thickness direction has a third groove. Along the second direction, the third groove is located between the third solder joint and the first electrode terminal, and the first electrode terminal is located between the third groove and the second electrode terminal.

[0046] In the above solution, a third groove is provided on the end cap, and along the second direction, the third groove is located between the third solder mark and the first electrode terminal. This can effectively improve the problem of stress concentration and fatigue cracking at the joint between the third wall and the end cap caused by the abnormal gas production inside the battery cell, which leads to the expansion and contraction of the outer shell. This makes the battery cell more reliable, and thus the battery device more reliable.

[0047] According to some embodiments of this application, the first groove and the third groove are spaced apart from each other.

[0048] In the above solution, by setting the first groove and the third groove to be spaced apart from each other, the risk of the overall structural strength of the end cover being reduced due to the groove on the end cover, and the other structural components on the end cover deforming when the battery cell expands or abnormally generates gas, causing the battery cell to open circuit, can be reduced. This makes the battery cell more reliable, and thus the battery device more reliable.

[0049] According to some embodiments of this application, the end cap has a first through hole, and a first electrode terminal is disposed in the first through hole; along the second direction, the minimum distance between the third groove and the first through hole is h5, which satisfies 0.3mm≤h5≤40mm.

[0050] In the above scheme, along the second direction, by limiting the distance between the third groove and the first through hole to not less than 0.3mm, the structural strength of the end cover corresponding to the first electrode terminal can be reduced due to the distance between the third groove and the first through hole being too small, so that the end cover can effectively support the first electrode terminal and reduce the risk of the first electrode terminal detaching from the end cover; by limiting the distance between the third groove and the first through hole to not more than 40mm, the risk of the third groove being too close to the third wall and failing to disperse stress can be reduced due to the distance between the third groove and the first through hole being too large, thereby improving the problem of fatigue cracking of the casing due to abnormal gas generation inside the battery cell, so that the battery cell has higher reliability, and thus the battery device has higher reliability.

[0051] According to some embodiments of this application, the following condition is met: 0.5mm ≤ h5 ≤ 30mm.

[0052] In the above scheme, by limiting the distance between the third groove and the first through hole to not less than 0.5 mm and not more than 30 mm along the second direction, the structural stability between the first electrode terminal and the end cover can be effectively improved, and the problem of fatigue cracking caused by abnormal gas generation inside the battery cell at the joint between the third wall and the end cover can be effectively improved, so that the battery cell has high reliability and the battery device has high reliability.

[0053] According to some embodiments of this application, along the second direction, the third wall has a third surface facing away from the electrode assembly, and along the second direction, the distance between the third groove and the third surface is h6, satisfying that 1mm≤h6≤30mm.

[0054] In the above scheme, by limiting the distance h6 between the third groove and the third surface to not less than 1mm, the manufacturing precision of the third groove can be reduced, the manufacturing difficulty caused by the small distance between the third groove and the third surface can be improved, and the risk of affecting the strength of the third solder mark structure due to the small distance between the third groove and the third surface can be reduced. By limiting the distance h6 between the third groove and the third surface to not more than 30mm, the risk of not being able to effectively disperse stress due to the large distance between the third groove and the third surface can be reduced, thereby taking into account both the manufacturing efficiency of the first groove and the effect of reducing fatigue cracking at the joint between the third wall and the end cap.

[0055] According to some embodiments of this application, the following condition is met: 1.5mm ≤ h6 ≤ 20mm.

[0056] In the above scheme, by limiting the distance h6 between the third groove and the third surface to not less than 1.5mm and not more than 20mm, the third groove and the third surface have a suitable distance, which can effectively reduce the manufacturing difficulty of the third groove and enable the third groove to effectively disperse the stress generated between the end cap and the third wall due to abnormal gas generation inside the battery cell, resulting in the breathing effect of the outer shell, continuous contraction and expansion, thereby improving the reliability of the battery cell and thus improving the reliability of the battery device.

[0057] According to some embodiments of this application, the third groove is a strip-shaped groove, and the third groove extends along the first direction.

[0058] In the above solution, by setting the third groove as a strip-shaped groove extending along the first direction, on the one hand, stress concentration can be effectively dispersed and alleviated, reducing the risk of cracking at the junction of the end cover and the third wall due to abnormal gas generation inside the battery cell; on the other hand, it can adapt to multi-directional loads, improve the overall stability of the end cover under the influence of internal expansion force and abnormal gas generation inside the battery cell, thereby ensuring the integrity of the casing to a certain extent, which is conducive to improving the reliability of the battery cell, and thus to improving the reliability of the battery device.

[0059] According to some embodiments of this application, along the second direction, the width of the third groove is h7, satisfying 0.1mm≤h7≤25mm.

[0060] In the above solution, by limiting the width h7 of the third groove to not less than 0.1 mm and not more than 25 mm along the first direction, the risk of manufacturing difficulties due to the excessively small width of the third groove can be reduced, thereby reducing the manufacturing cost of the battery cell. On the other hand, it can avoid the problem that the end cap structure strength is greatly affected due to the excessively large width of the third groove, resulting in the shell strength failing to meet the requirements.

[0061] According to some embodiments of this application, the following condition is met: 0.3mm ≤ h7 ≤ 20mm.

[0062] In the above scheme, by limiting the width h7 of the third groove to not less than 0.3 mm and not more than 20 mm along the first direction, the manufacturing efficiency of the third groove and the stress dispersion effect of the third groove can be taken into account, so that the reliability of the battery cell is high, and thus the reliability of the battery device is high.

[0063] According to some embodiments of this application, along the first direction, the length of the third groove is h8, and the width of the end cap is W, satisfying 1.5mm≤h8≤W.

[0064] According to some embodiments of this application, the following condition is satisfied: 1.5mm≤h8≤W.

[0065] In the above scheme, by setting the length h8 of the third groove to not less than 1.5mm along the first direction, the stress at the junction of the end cap and the third wall can be effectively dispersed, the degree of stress concentration can be reduced, and the risk of fatigue cracking of the casing can be reduced, thereby effectively improving the reliability of the battery cell and thus effectively improving the reliability of the battery device.

[0066] According to some embodiments of this application, the following condition is satisfied: 2mm≤h8≤W.

[0067] In the above scheme, along the second direction, by setting the length h8 of the third groove to not less than 2mm, the third groove can effectively act on the part between the end cap and the third wall that is fatigued and cracked due to abnormal gas generation, effectively reducing the degree of stress concentration and reducing the risk of fatigue cracking of the casing, thereby effectively improving the reliability of the battery cell and thus effectively improving the reliability of the battery device.

[0068] According to some embodiments of this application, the thickness of the end cap corresponding to the location of the third groove is t2, which satisfies 0.4mm≤t2≤3mm.

[0069] In the above scheme, by limiting the thickness t2 of the end cap corresponding to the location of the third groove to not less than 0.4 mm, the risk of battery cell failure due to the small thickness of this part can be reduced. By limiting the thickness of the end cap corresponding to the location of the third groove to not more than 3 mm, the effect of the third groove in dispersing and alleviating stress concentration can be guaranteed to a certain extent, reducing the risk of fatigue cracking of the casing, making the battery cell highly reliable, and thus making the battery device highly reliable.

[0070] According to some embodiments of this application, the following condition is satisfied: 0.6mm ≤ t2 ≤ 2mm.

[0071] In the above scheme, by limiting the thickness t2 of the end cap corresponding to the location of the third groove to not less than 0.6 mm and not more than 2 mm, the structural strength of the end cap itself and the effect of the third groove in dispersing and alleviating stress concentration can be taken into account, thereby making the battery cell highly reliable.

[0072] According to some embodiments of this application, along the second direction, the end cap includes a third region located between the third groove and the third solder mark, wherein the thickness of the end cap corresponding to the location of the third groove is less than the thickness of the third region.

[0073] In the above scheme, by limiting the thickness of the third groove to be less than the thickness of the third region, when the third wall expands and deforms outward due to abnormal gas generation inside the battery cell, the end cap deforms along the third groove in accordance with the deformation of the third wall, so as to disperse and alleviate the stress between the third wall and the end cap, reduce the risk of fatigue cracking at the joint between the end cap and the third wall, thereby making the battery cell highly reliable, and thus making the battery device highly reliable.

[0074] According to some embodiments of this application, a third groove is formed on one side of the end cap along the thickness direction, and a third protrusion is formed on the other side of the end cap, the position of the third protrusion corresponding to the third groove; along the thickness direction of the end cap, the thickness of the third protrusion is less than the thickness of the end cap.

[0075] In the above solution, by setting a third groove on one side of the end cap and a third protrusion on the other side corresponding to the third groove, the molding difficulty of the third groove can be reduced and the manufacturing efficiency of the battery cell can be improved. At the same time, by setting the thickness of the third protrusion to be less than the thickness of the end cap, the third groove can effectively disperse and alleviate the phenomenon of stress concentration, reduce the risk of fatigue cracking of the casing, and improve the reliability of the battery cell and battery device.

[0076] According to some embodiments of this application, along the second direction, the housing has a fourth wall, which is opposite to the third wall. The fourth wall is connected to the end cap by a fourth solder mark. At least one side of the end cap in the thickness direction is provided with a fourth groove. Along the second direction, the fourth groove is located between the fourth solder mark and the second electrode terminal.

[0077] In the above solution, a fourth groove is provided on the end cap, and along the second direction, the second groove is located between the fourth solder mark and the second electrode terminal. This can effectively improve the problem of stress concentration and fatigue cracking at the joint between the fourth wall and the end cap caused by the abnormal gas production inside the battery cell, which leads to the expansion and contraction of the outer shell. This makes the battery cell more reliable, and thus the battery device more reliable.

[0078] According to some embodiments of this application, the third groove and the fourth groove are symmetrically arranged about the first center line.

[0079] In the above scheme, by setting the third groove and the fourth groove to be symmetrical about the first center line, the risk of fatigue cracking at the junction of the third wall and the end cap and the junction of the fourth wall and the end cap can be effectively reduced, thereby improving the reliability of the battery cell and thus the reliability of the battery device.

[0080] According to some embodiments of this application, the outer shell is a square shell, the dimension of the outer shell in the first direction is T1, the dimension of the outer shell in the second direction is W1, and the dimension of the outer shell in the thickness direction of the end cap is H1, satisfying that 3720cm3≤W1*T1*H1≤12500cm3, 60mm≤T1≤150mm, 120mm≤H1≤400mm, 200mm≤W1≤1500mm, and the first direction, the second direction, and the thickness direction of the first wall are mutually perpendicular.

[0081] In the above scheme, by limiting the external contour dimensions of the battery cell, the internal space of the battery cell is made larger to accommodate more electrochemical substances, thus forming a battery cell with a larger capacity. For battery cells with larger capacity, the risk of internal expansion leading to structural damage is greater. To address this, by providing a first groove on the end cap, the risk of casing fatigue cracking can be effectively reduced; on the other hand, it can also protect the structural integrity of the pressure relief mechanism to a certain extent, thus ensuring the high reliability of this type of battery cell with a larger capacity, and consequently, the high reliability of the battery device using this type of battery cell.

[0082] According to some embodiments of this application, the outer casing is a steel casing.

[0083] In the above scheme, by setting the outer shell as a steel shell, the wall thickness of the outer shell can be designed to be thin, which is conducive to improving the volumetric energy density of the battery cell, and thus to improving the volumetric energy density of the battery device.

[0084] Secondly, some embodiments of this application also provide a battery device, which includes the battery cell provided in the first aspect.

[0085] Thirdly, some embodiments of this application also provide an energy storage device, which includes the battery cell provided in the first aspect and / or the battery device provided in the second aspect.

[0086] Fourthly, some embodiments of this application also provide an electrical device, which includes a battery cell provided in the first aspect and / or a battery device provided in the second aspect.

[0087] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0088] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0089] Figure 1 This is a schematic diagram of the vehicle structure in some embodiments of this application;

[0090] Figure 2 This is a schematic diagram of an energy storage device in some embodiments of this application;

[0091] Figure 3 This is an exploded perspective view of the battery device in some embodiments of this application;

[0092] Figure 4 This is an exploded perspective view of a battery cell in some embodiments of this application;

[0093] Figure 5 This is a schematic diagram of a partial structure of the end cap and electrode assembly in some embodiments of this application;

[0094] Figure 6 This is a top view of a battery cell in some embodiments of this application;

[0095] Figure 7 for Figure 6 A sectional view along the AA direction;

[0096] Figure 8 for Figure 7 Enlarged view of point B in the middle;

[0097] Figure 9 This is a partial structural diagram of the end cap in some other embodiments of this application;

[0098] Figure 10 This is a partial structural diagram of the end cap in some other embodiments of this application;

[0099] Figure 11 This is a partial structural diagram of the end cap in some embodiments of this application;

[0100] Figure 12 for Figure 6 A sectional view in the CC direction;

[0101] Figure 13 for Figure 12 Enlarged view at point D;

[0102] Figure 14 This is a schematic diagram of the structure of the end cap and the third groove in other embodiments of this application;

[0103] Figure 15 This is a schematic diagram of the structure of the end cap and the third groove in some other embodiments of this application;

[0104] Figure 16 This is a partial structural diagram of the end cap and third wall in some embodiments of this application;

[0105] Figure 17 This is a perspective view of a battery cell in some embodiments of this application.

[0106] Icons: 1000 - Vehicle; 100 - Battery Unit; 200 - Controller; 300 - Motor; 2000 - Energy Storage Unit; 2001 - Cabinet; 20 - Box; 21 - First Box Body; 22 - Second Box Body; 10 - Battery Cell; 11 - Outer Shell; 110 - Housing; 111 - End Cap; 1110 - First Through Hole; 1111 - Second Through Hole; 1112 - First Region; 1113 - Third Region; 112 - First Wall; 1120 - First Surface; 113 - Second Wall ; 114-Third wall; 1140-Third surface; 115-Fourth wall; 116-First solder mark; 117-Third solder mark; 12-Pressure relief mechanism; 13-First electrode terminal; 14-Second electrode terminal; 15-Electrode assembly; 150-Straight area; 151-Electrode sheet; 16-First groove; 160-First protrusion; 17-Second groove; 18-Third groove; 180-Third protrusion; 19-Fourth groove; x-First direction; y-Second direction; z-Thickness direction of end cap. Detailed Implementation

[0107] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0108] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0109] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0110] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0111] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0112] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0113] In this application, "multiple" means two or more (including two).

[0114] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0115] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0116] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, helps prevent short circuits to some extent while allowing active ions to pass through.

[0117] 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.

[0118] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0119] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0120] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxide may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM1), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM6), LiNi 0.8Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0121] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloys, etc. When foamed metal is used as the positive electrode, the surface of the foamed metal may or may not contain a positive electrode active material. As an example, lithium source material, potassium metal, or sodium metal can also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0122] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0123] As an example, the negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrode, nickel, or titanium, etc. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0124] As an 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.

[0125] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0126] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this 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 of two or more.

[0127] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0128] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0129] In some embodiments, the separator is a separator membrane. The separator membrane can be of various types, and any known porous separator membrane with good chemical and mechanical stability can be selected.

[0130] As an example, the material of the separator may include 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. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator may be a separate component located between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes.

[0131] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0132] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like, or solid. Liquid electrolytes include electrolyte salts and solvents.

[0133] 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 difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0134] In some embodiments, the solvent may include at least one selected from ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl 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 also be an ether solvent. Ether solvents may include one or more selected from ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0135] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0136] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0137] As an example, polymer solid electrolytes can be polyether (polyoxyethylene), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids-lithium salts, cellulose, etc.

[0138] As an example, inorganic solid electrolytes may include one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphate sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0139] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0140] In some implementations, the electrode assembly has a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0141] In some implementations, the electrode assembly has a stacked structure.

[0142] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0143] As an example, multiple positive electrode plates can be provided, and negative electrode plates can be folded to form multiple stacked folded segments, with a positive electrode plate sandwiched between adjacent folded segments.

[0144] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0145] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0146] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0147] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0148] In some embodiments, the electrode assembly has tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0149] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0150] As an example, a battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include, but are not limited to, square battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries.

[0151] The battery apparatus mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells connected in series, parallel, or mixed connections via a busbar.

[0152] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form a single module. As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0153] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0154] As an example, the battery cell assembly can be a battery module, and the battery cell assembly can be housed in the housing by fixing the battery module in the housing.

[0155] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0156] As an example, the enclosure may include a first enclosure body and a second enclosure body. The first enclosure body and the second enclosure body are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, which can be either sealed or unsealed. The first enclosure body may be a top cover or a bottom plate.

[0157] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0158] As an example, the housing can be part of the vehicle's chassis structure. For instance, the housing's roof can be at least part of the vehicle's floor, or the housing's frame can be at least part of the vehicle's crossbeams and longitudinal beams.

[0159] In some embodiments, the battery device refers to an energy storage device, which includes a housing with a door on at least one side. The energy storage device includes energy storage containers, energy storage cabinets, etc. In some embodiments, one or more energy storage devices may constitute at least part of an energy storage system.

[0160] Battery devices possess outstanding advantages such as high energy density, low environmental pollution, high power density, long service life, wide applicability, and low self-discharge coefficient, making them an important component of today's new energy development. The development of battery technology must simultaneously consider multiple design factors, such as performance parameters like energy density, cycle life, and discharge capacity. Furthermore, the reliability of the battery device must also be taken into account.

[0161] Generally, a battery cell includes a casing and an electrode assembly. The electrode assembly has a flat region, and the electrode plates of the electrode assembly are stacked in the flat region along a first direction.

[0162] The casing includes a housing and end caps. The housing has an opening through which the electrode assembly is inserted. The end caps are welded to the housing to close the opening, placing the electrode assembly within a closed space. However, as the number of charge-discharge cycles of a single battery cell increases, the electrochemical reactions within the cell continue, causing the electrode assembly to expand cyclically and press against the wall of the housing. The wall of the housing most affected by the expansion force is the wall along the first direction. Deformation of this wall, especially the larger deformation at the center along the first direction, causes tension at the junction of the end cap and the housing, leading to cracking at the junction and ultimately causing the casing to fail. This affects the reliability of the single battery cell and, consequently, the reliability of the battery assembly.

[0163] In view of this, to improve the problem of low battery device reliability caused by the cracking of the casing due to the internal expansion force of the battery cell, especially corresponding to the position of the end cap along the middle of the first direction, some embodiments of this application provide a battery cell, which includes a casing and an electrode assembly. The casing includes a housing and an end cap, the housing having an opening and the end cap closing the opening. The electrode assembly is disposed inside the housing, and the electrode assembly has a flat region. The electrode plates of the electrode assembly are stacked in the flat region along the first direction, the first direction being perpendicular to the thickness direction of the end cap. The housing has a first wall, the thickness direction of the first wall being parallel to the first direction, the first wall being connected to the end cap by a first solder mark, and the end cap having a first groove, the first groove and the first solder mark being arranged along the first direction, the first groove passing through the end cap parallel to a first center line of the first direction.

[0164] In the above solution, a first groove is provided on the end cap along the first direction with the first solder mark, and the first groove passes through the first center line of the end cap. When the battery cell expands inside, it can disperse the stress at the joint between the end cap and the first wall (especially corresponding to the middle part of the end cap along the first direction), reduce the degree of stress concentration, effectively reduce the risk of fatigue cracking of the casing, thereby effectively improving the reliability of the battery cell, and thus effectively improving the reliability of the battery device.

[0165] The battery cells disclosed in this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft, and can also be used in energy storage devices, such as energy storage cabinets and energy storage containers.

[0166] This application provides an electrical device that uses a single battery cell or battery assembly as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0167] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device according to an embodiment of this application.

[0168] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1000 in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 100 is installed inside the vehicle 1000. The battery device 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, it can serve as the operating power source or general power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 controls the battery device 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during startup, navigation, and driving.

[0169] In some embodiments of this application, the battery device 100 can not only serve as the operating power or power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0170] Please see Figure 2 , Figure 2This is a schematic diagram of an energy storage device 2000 in some embodiments of this application.

[0171] The energy storage device 2000 may include a cabinet 2001 and multiple battery cells 10. The multiple battery cells 10 may be housed within the cabinet 2001. The multiple battery cells 10 may be connected in series, in parallel, or in a mixed configuration.

[0172] In some embodiments, multiple battery cells 10 may first form a battery device 100 and then be housed within a cabinet 2001. In some embodiments, the cabinet 2001 has an openable and closable door structure to facilitate the transfer of battery cells 10 or battery devices 100.

[0173] Please refer to Figure 3 , Figure 3 This is an exploded perspective view of a battery device 100 in some embodiments of this application. The battery device 100 includes a battery cell 10 and a housing 20, wherein the battery cell 10 is housed within the housing.

[0174] The housing 20 provides assembly space for the battery cell 10 and can adopt various structures. In some embodiments, the housing 20 may include a first housing body 21 and a second housing body 22, which overlap each other and together define an assembly space for accommodating the battery cell 10. The second housing body 22 may be a hollow structure open at one end, and the first housing body 21 may be a plate-like structure, with the first housing body 21 covering the open side of the second housing body 22 so that the first housing body 21 and the second housing body 22 together define the assembly space; alternatively, the first housing body 21 and the second housing body 22 may both be hollow structures open on one side, with the open side of the first housing body 21 covering the open side of the second housing body 22.

[0175] Of course, the box 20 formed by the first box body 21 and the second box body 22 can be of various shapes, such as a cylinder, a cuboid, or a cube. For example, in the figure, the shape of the box 20 is a cuboid.

[0176] In the battery device 100, there can be one or more battery cells 10 disposed within the housing 20. When there are multiple battery cells 10 disposed within the housing, they can be connected in series, in parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 10 are connected in both series and parallel configurations. Multiple battery cells 10 can be directly connected in series, in parallel, or in a mixed configuration, and then the entire assembly of the multiple battery cells 10 is housed within the housing. Alternatively, the battery device 100 can also consist of multiple battery cells 10 first connected in series, in parallel, or in a mixed configuration to form battery modules, and then multiple battery modules are connected in series, in parallel, or in a mixed configuration to form a whole, which is then housed within the housing.

[0177] In some embodiments, the battery device 100 may also include other structures. For example, the battery device 100 may also include a busbar for connecting multiple battery cells 10 to achieve electrical connection between the multiple battery cells 10.

[0178] For example, the housing contains multiple battery cell assemblies, each battery cell assembly including multiple stacked battery cells 10, which are connected in series via a busbar. In some embodiments, the multiple battery cell assemblies can be connected in series via a busbar.

[0179] Each battery cell 10 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. The battery cell 10 can be in the form of a cuboid, cylinder, prism, or other shapes.

[0180] Some embodiments of this application provide a single battery cell 10; please refer to [link to relevant documentation]. Figures 4-8 , Figure 4 This is an exploded perspective view of the battery cell 10 in some embodiments of this application. Figure 5 This is a schematic diagram of a partial structure of the end cap 111 and the electrode assembly in some embodiments of this application. Figure 6 This is a top view of a battery cell 10 in some embodiments of this application. Figure 7 for Figure 6 Sectional view in the middle AA direction. Figure 8 for Figure 7 Enlarged view of point B in the middle.

[0181] The battery cell 10 includes a housing 11 and an electrode assembly 15. The housing 11 includes a shell 110 and an end cap 111. The shell 110 has an opening, and the end cap 111 closes the opening. The electrode assembly 15 is disposed inside the housing 11. The electrode assembly 15 has a flat region 150, and the electrode plates 151 of the electrode assembly 15 are stacked in the flat region 150 along a first direction x, which is perpendicular to the thickness direction z of the end cap. The shell 110 has a first wall 112, the thickness direction of which is parallel to the first direction x. The first wall 112 is connected to the end cap 111 by a first solder mark 116. The end cap has a first groove 16, which and the first solder mark 116 are arranged along the first direction x. The first groove 16 passes through a first center line of the end cap 111 parallel to the first direction x.

[0182] The housing 11 is a component for housing the electrode assembly 15. The housing 11 can also be used to house an electrolyte, such as an electrolyte solution. See also... Figure 4In some embodiments, the housing 11 includes a housing 110 and an end cap 111. The housing 110 has an internal cavity for accommodating the electrode assembly 15. The housing 110 has an opening communicating with the cavity. The end cap 111 closes to the opening of the housing 110 and forms a sealed connection to form a sealed space for accommodating the electrode assembly 15 and the electrolyte.

[0183] Optionally, there are two end caps 111, and the two opposite ends of the housing 110 are open, that is, they have two opposite openings. One opening can be closed by one end cap 111, and the other opening can be closed by the other end cap 111.

[0184] In some embodiments, the material of the housing 11 can be metal or a combination of metal and non-metal. For example, the housing 11 can be made of metal, such as aluminum, copper, iron, steel or aluminum alloy. Alternatively, some parts of the housing 11 can be made of metal, while the rest can be made of non-metal. For example, the end cap 111 of the housing 11 can be made of metal, while the shell 110 or other parts of the housing 11 can be made of non-metallic materials.

[0185] In some embodiments, the outer casing 11 may be prismatic in shape, such as square. See also Figure 4 The housing 110 is square, and the end cap 111 has a corresponding shape. The housing 110 includes a first wall 112 and a second wall 113 that are opposite to each other along a first direction x, and a third wall 114 and a fourth wall 115 that are opposite to each other along a second direction y. The first wall 112, the third wall 114, the second wall 113, and the fourth wall 115 are connected to each other to form the housing 110. The end cap 111 is located at one end of the housing 110 along the thickness direction z of the end cap, and the end cap 111 is connected to the first wall 112, the second wall 113, the third wall 114, and the fourth wall 115 respectively.

[0186] In some embodiments, the end cap 111 is welded to the first wall 112 to form a first weld mark 116. Optionally, the end cap 111 and the first wall 112 are connected to each other by welding processes such as laser welding and ultrasonic welding. Optionally, the first weld mark 116 may be located between the end cap 111 and the first wall 112 along the thickness direction of the first wall 112. Optionally, the first weld mark 116 may be located between the end cap 111 and the first wall 112 along the thickness direction z of the end cap.

[0187] The connection between the end cap 111 and the second wall 113 can be varied, including but not limited to welding, bonding, riveting, or threaded connection. For example, the end cap 111 is connected to the second wall 113 by a second solder mark.

[0188] The connection between the end cap 111 and the third wall 114 can be varied, including but not limited to welding, bonding, riveting, or threaded connection. For example, the end cap 111 is connected to the third wall 114 via a third weld mark 117.

[0189] The connection between the end cap 111 and the fourth wall 115 can be varied, including but not limited to welding, bonding, riveting, or threaded connection. For example, the end cap 111 is connected to the fourth wall 115 via a fourth solder joint.

[0190] In some embodiments, when assembling the battery cell 10, the electrode assembly 15 can be placed into the housing 110 first, and electrolyte can be filled into the housing 110. Then, the end cap 111 can be closed onto the opening of the housing 110 to complete the assembly of the battery cell 10. Alternatively, in some embodiments, when assembling the battery cell 10, the electrode assembly 15 can be placed into the housing 110 first, and then the end cap 111 can be closed onto the opening of the housing 110. Electrolyte can then be filled into the housing 110 through the injection hole on the end cap 111, and then the injection hole can be closed to complete the assembly of the battery cell 10.

[0191] The electrode assembly 15 is a component in the battery cell 10 where electrochemical reactions occur. The structure of the electrode assembly 15 can be various. For example, the electrode assembly 15 includes an electrode and a separator. For example, the electrode assembly 15 can be a wound structure formed by winding a positive electrode, a separator and a negative electrode, or a stacked structure formed by arranging a positive electrode, a separator and a negative electrode in layers.

[0192] Optionally, the separator is a separator membrane, and the main material of the separator membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.

[0193] The electrode assembly 15 has tabs for inputting or outputting the positive or negative terminal of the electrode assembly 15. The tabs are electrically connected to the electrode terminals to enable charging and discharging of the battery cell 10. Exemplarily, the battery cell 10 includes a first electrode terminal 13 and a second electrode terminal 14 with opposite polarities. The first electrode terminal 13 is electrically connected to the tab of the corresponding polarity, and the second electrode terminal 14 is electrically connected to the tab of the corresponding polarity. For example, the first electrode terminal 13 is negative and is connected to the negative electrode tab. Optionally, the first electrode terminal 13 is disposed on the end cap 111 or on the housing 110.

[0194] Please see Figure 5The electrode assembly 15 has a flat region 150. The electrode sheets 151 of the electrode assembly 15 are stacked along a first direction x in portions of the flat region 150, and the first direction x is perpendicular to the thickness direction z of the end cap. Exemplarily, the electrode assembly 15 has a flat region 150 and a corner region, the corner region being located at the end of the flat region 150 along a second direction y. The first direction x, the second direction y, and the thickness direction z of the end cap are mutually perpendicular. The positive electrode sheet, the negative electrode sheet, and the separator of the electrode assembly 15 are stacked along the first direction x corresponding to portions of the flat region 150. Generally, the direction in which the internal expansion of the battery cell 10 has the greatest impact is parallel to the first direction x. In some embodiments, the surface of the electrode assembly 15 along the first direction x is the surface with the largest area of ​​the electrode assembly 15. In some embodiments, the surface of the housing 110 along the first direction x is the surface with the largest area of ​​the housing 110. For example, along the first direction x, the first wall 112 has a first surface 1120 facing away from the electrode assembly 15, and the first surface 1120 is the surface with the largest area of ​​the housing 110.

[0195] Optionally, the electrode assembly 15 housed within the housing 11 can be one or more. For example, in... Figure 4 In this embodiment, two electrode assemblies 15 are disposed inside the outer casing 11 of the battery cell 10. The two electrode assemblies 15 are stacked along their thickness direction. In other words, the two electrode assemblies 15 are stacked along the thickness direction of the battery cell 10. Of course, in other embodiments, the electrode assemblies 15 housed in the outer casing 11 can be one, three, four, five, six, seven, or eight, etc.

[0196] The first groove 16 is a groove-shaped structure formed on the end cap 111. The first groove 16 is a recessed structure formed on the end cap 111, and the thickness of the part of the end cap 111 corresponding to the first groove 16 is less than the thickness of the end cap 111 itself. For example, the end cap 111 is a plate-shaped structure, and the first groove 16 is formed on the end cap 111 by processes such as stamping, etching, casting or die casting.

[0197] The first groove 16 can have various shapes, including but not limited to strips, arcs, etc.

[0198] Optionally, please see Figure 8 Along the thickness direction z of the end cap, a first groove 16 is formed on the side of the end cap 111 opposite to the electrode assembly 15. Alternatively, please refer to... Figure 9 , Figure 9 This is a partial structural diagram of the end cap 111 in some other embodiments of this application. Along the thickness direction z of the end cap, a first groove 16 is formed on the side of the end cap 111 facing the electrode assembly 15. Optionally, please refer to... Figure 10 , Figure 10This is a partial structural diagram of the end cap 111 in some other embodiments of this application. Along the thickness direction z of the end cap, the two opposite sides of the end cap 111 are respectively formed with first grooves 16.

[0199] The phrase "the first groove 16 and the first solder mark 116 are arranged along the first direction x" can be understood as follows: along the first direction x, the first groove 16 is located on one side of the first solder mark 116. Optionally, the first groove 16 is adjacent to the first solder mark 116. Optionally, the first groove 16 and the first solder mark 116 are spaced apart.

[0200] The straight line containing the first center line is parallel to the first direction x, that is, the straight line containing the first center line is perpendicular to the second direction y and perpendicular to the thickness direction z of the end cap.

[0201] Please see Figure 5 , Figure 5 The first centerline is indicated by the label s1.

[0202] In some embodiments, the location of the first center line corresponds to the middle of the end cap 111 along the first direction.

[0203] The first groove 16 passing through the first center line can be understood as the first groove 16 passing through the middle of the end cap 111 along the first direction x. That is, the two ends of the first groove 16 are located on both sides of the first center line.

[0204] In the above scheme, a first groove 16 is provided on the end cap 111 along the first direction x with the first solder mark 116, and the first groove 16 passes through the first center line of the end cap 111. When the battery cell 10 expands inside, it can disperse the stress at the joint between the end cap 111 and the first wall 112 (especially corresponding to the middle part of the end cap 111 along the first direction x), reduce the degree of stress concentration, effectively reduce the risk of fatigue cracking of the casing, thereby effectively improving the reliability of the battery cell 10, and thus effectively improving the reliability of the battery device 100.

[0205] According to some embodiments of this application, the battery cell 10 further includes a pressure relief mechanism 12, which is disposed on the end cap 111 along the first direction x, and the first groove 16 is located between the first solder mark 116 and the pressure relief mechanism 12.

[0206] A pressure relief mechanism 12 is disposed on the end cap 111. The pressure relief mechanism 12 is used to release the pressure inside the battery cell 10. The pressure relief mechanism 12 can take various forms, including but not limited to forms such as explosion-proof valves, gas valves, pressure relief valves, safety valves, or grooves. For example, when the internal pressure or temperature of the battery cell 10 reaches a threshold, the pressure relief mechanism 12 is broken, thereby forming an opening or channel for the internal pressure or temperature to be released. The high-temperature and high-pressure gas inside the battery cell 10 will be discharged outward from the broken part. In this way, the battery cell 10 can be depressurized and de-temperatured under controllable pressure or temperature, thereby avoiding potential more serious accidents. Exemplarily, the pressure relief mechanism 12 is a groove disposed on the end cap 111. Optionally, the groove can be strip-shaped, multi-segmented, or annular.

[0207] Please combine Figure 6 and Figure 8 Along the first direction x, the first groove 16 is located between the first solder mark 116 and the pressure relief mechanism 12. Exemplarily, the pressure relief mechanism 12 is located in the middle of the end cap 111, and the first groove 16 is located on the side of the end cap 111 facing the first wall 112.

[0208] In the above scheme, a first groove 16 is provided on the end cap 111, and along the first direction x (that is, the direction in which the battery cell 10 is most affected by the internal expansion force), the first groove 16 is located between the first solder mark 116 and the pressure relief mechanism 12. On the one hand, when the battery cell 10 expands internally, it can disperse the stress at the joint between the end cap 111 and the first wall 112, reduce the degree of stress concentration, and effectively reduce the risk of fatigue cracking of the outer shell 11. On the other hand, it reduces the risk of structural damage to the pressure relief mechanism 12 due to the pulling force of the internal expansion force of the battery cell 10, and can play a certain role in protecting the structural integrity of the pressure relief mechanism 12, thereby effectively improving the reliability of the battery cell 10, and thus effectively improving the reliability of the battery device 100.

[0209] According to some embodiments of this application, along the first direction x, the size of the end cap 111 is W, and the distance between the first groove 16 and the pressure relief mechanism 12 is h1, satisfying that 0 < h1 ≤ 0.4W.

[0210] In some embodiments, along the first direction x, the dimension W of the end cap 111 can refer to the width of the end cap 111. Along the first direction x, the distance h1 between the first groove 16 and the pressure relief mechanism 12 can refer to the distance between the closest part of the pressure relief mechanism 12 to the first groove 16 and the first groove 16 along the first direction x. The value of h1 can be a value greater than 0 and less than or equal to 0.4W. For example, with the width of the end cap 111 being 60mm and 0.4W being 24mm, the value of h1 can be any value from 0mm to 0.1mm, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm…3.8mm, 3.9mm, 4mm…23.8mm, 23.9mm, 24mm, or any value between two adjacent values.

[0211] In the above solution, by limiting the distance h1 between the first groove 16 and the pressure relief mechanism 12 to no more than 0.4W (W is the width of the end cap 111), the risk of the first groove 16 failing to disperse stress due to excessive distance between the first groove 16 and the pressure relief mechanism 12, i.e., the first groove 16 being too close to the first wall 112, can be reduced. This can improve the problem of fatigue cracking of the outer casing 11 due to internal expansion of the battery cell 10, making the battery cell 10 have higher reliability, and thus making the battery device 100 have higher reliability.

[0212] According to some embodiments of this application, the following condition is satisfied: 0.3mm≤h1≤0.4W.

[0213] Optionally, the value of h1 can be greater than or equal to 0.3 mm and less than or equal to 0.4 mm. For example, with the width of the end cap 111 being 60 mm and 0.4 mm being 24 mm, the value of h1 can be 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm...3.8 mm, 3.9 mm, 4 mm...23.8 mm, 23.9 mm, 24 mm, or any value between two adjacent values.

[0214] In the above scheme, by limiting the distance h1 between the first groove 16 and the pressure relief mechanism 12 to not less than 0.3mm, the manufacturing precision and structural strength of the pressure relief mechanism 12 can be reduced due to the small distance between the first groove 16 and the pressure relief mechanism 12, thus ensuring the pressure relief function of the pressure relief mechanism 12 to a certain extent and reducing the risk of thermal runaway of the battery cell 10. By limiting the distance h1 between the first groove 16 and the pressure relief mechanism 12 to not more than 0.4W (W is the width of the end cap 111), the risk of the first groove 16 being too close to the first wall 112 and failing to disperse stress can be reduced due to the large distance between the first groove 16 and the pressure relief mechanism 12, thereby improving the problem of fatigue cracking of the outer shell 11 due to the internal expansion of the battery cell 10, making the battery cell 10 have higher reliability, and thus making the battery device 100 have higher reliability.

[0215] In some other embodiments, the value of h1 can be less than or equal to 0.3 mm, such as 0.2 mm, 0.1 mm, or other values.

[0216] According to some embodiments of this application, the following condition is satisfied: 0.5mm≤h1≤0.4W.

[0217] In some embodiments, the value of h1 can be greater than or equal to 0.5 mm and less than or equal to 0.4 W. For example, with the width of the end cap 111 being 60 mm and 0.4 W being 24 mm, the value of h1 can be 0.5 mm, 0.6 mm, 0.7 mm...3.8 mm, 3.9 mm, 4 mm...23.8 mm, 23.9 mm, 24 mm or any value between two adjacent values.

[0218] In the above scheme, by limiting the distance h1 between the first groove 16 and the pressure relief mechanism 12 to not less than 0.5mm, the manufacturing precision and structural strength of the pressure relief mechanism 12 can be further reduced due to the small distance between the first groove 16 and the pressure relief mechanism 12. This ensures the pressure relief function of the pressure relief mechanism 12 to a certain extent and reduces the risk of thermal runaway of the battery cell 10. In this regard, by limiting the distance h1 between the first groove 16 and the pressure relief mechanism 12 to not less than 0.5mm and not greater than 0.4W (W is the width of the end cap 111), the manufacturing and functional reliability of the pressure relief mechanism 12 can be taken into account, as well as the stress concentration effect at the junction of the end cap 111 and the first wall 112 can be dispersed, thereby making the reliability of the battery cell 10 high, and thus making the reliability of the battery device 100 high.

[0219] According to some embodiments of this application, along the second direction y, the two ends of the first groove 16 extend beyond the pressure relief mechanism 12, and the first direction x, the second direction y, and the thickness direction z of the end cap are mutually perpendicular.

[0220] The second direction y, the first direction x, and the thickness direction z of the end cap are all perpendicular to each other. Optionally, the first direction x can be the thickness direction of the battery cell 10, the second direction y can be the length direction of the battery cell 10, and the thickness direction z of the end cap can be the height direction of the battery cell 10. In this case, the first direction x can be the width direction of the end cap 111, and the second direction y can be the length direction of the end cap 111.

[0221] Along the second direction y, the two ends of the first groove 16 extend beyond the pressure relief mechanism 12, which can be understood as the pressure relief mechanism 12 being located between the two ends of the first groove 16 along the second direction y.

[0222] In the above solution, by setting the two ends of the first groove 16 to extend beyond the pressure relief mechanism 12 along the first direction x, the influence of the expansion force along the first direction x on the pressure relief mechanism 12 when the battery cell 10 expands can be effectively reduced, and the structural integrity of the pressure relief mechanism 12 can be guaranteed to a certain extent, so as to reduce the risk of the pressure relief mechanism 12 being damaged and failing due to the expansion of the battery cell 10.

[0223] In some other embodiments, along the second direction y, one end of the first groove 16 may extend beyond the pressure relief mechanism 12, and the other end may not extend beyond the pressure relief mechanism 12.

[0224] In some other embodiments, along the second direction y, the two ends of the first groove 16 may not exceed the pressure relief mechanism 12.

[0225] According to some embodiments of this application, please refer to Figure 8 Along the first direction x, the first wall 112 has a first surface 1120 facing away from the electrode assembly 15. Along the first direction x, the distance between the first groove 16 and the first surface 1120 is h2, which satisfies 1mm≤h2≤20mm.

[0226] The first surface 1120 can be understood as the outer side of the first wall 112 along the first direction x. The distance between the first groove 16 and the first surface 1120 along the first direction x can be understood as the distance between the side of the first groove 16 closest to the first surface 1120 and the first surface 1120. The value of h2 can be 1mm, 2mm, 3mm, 4mm…18mm, 19mm, 20mm or any value between two adjacent values.

[0227] In the above solution, by limiting the distance h2 between the first groove 16 and the first surface 1120 to not less than 1mm, the manufacturing precision of the first groove 16 can be reduced, the manufacturing difficulty caused by the small distance between the first groove 16 and the first surface 1120 can be improved, and the risk of affecting the structural strength of the first solder mark 116 due to the small distance between the first groove 16 and the first surface 1120 can be reduced. By limiting the distance h2 between the first groove 16 and the first surface 1120 to not more than 20mm, the risk of not being able to effectively disperse stress due to the large distance between the first groove 16 and the first surface 1120 can be reduced, so as to a certain extent take into account the manufacturing efficiency of the first groove 16 and the effect of reducing fatigue cracking at the joint between the first wall 112 and the end cap 111.

[0228] In some other embodiments, the value of h2 can also be less than 1 mm or greater than 20 mm, such as 0.6 mm or 21 mm.

[0229] According to some embodiments of this application, the following condition is satisfied: 1.5mm ≤ h2 ≤ 15mm.

[0230] In some embodiments, the value of h2 can be 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm...13.5mm, 14mm, 14.5mm, 15mm or any value between two adjacent values.

[0231] In the above solution, by limiting the distance h2 between the first groove 16 and the first surface 1120 to not less than 1.5mm and not more than 15mm, the first groove 16 and the first surface 1120 have a suitable distance, which can effectively reduce the manufacturing difficulty of the first groove 16 and enable the first groove 16 to effectively disperse the stress generated between the end cap 111 and the first wall 112 due to the internal expansion of the battery cell 10, thereby improving the reliability of the battery cell 10 and thus improving the reliability of the battery device 100.

[0232] According to some embodiments of this application, please refer to Figure 6 The first groove 16 is a strip-shaped groove that extends along the second direction y. The second direction y, the first direction x, and the thickness direction z of the end cap are all perpendicular to each other.

[0233] In some embodiments, the strip groove of the first groove 16, that is, the shape of the first groove 16, can be rectangular. The length direction of the first groove 16 is parallel to the second direction y, and the width direction of the first groove 16 is parallel to the first direction x.

[0234] In the above solution, by setting the first groove 16 as a strip groove extending along the second direction y, on the one hand, stress concentration can be effectively dispersed and alleviated, reducing the risk of fatigue cracking at the junction of the end cover 111 and the first wall 112 due to the internal expansion force of the battery cell 10; on the other hand, it can adapt to multi-directional loads, improve the overall stability of the end cover 111 under the influence of the internal expansion force of the battery cell 10 and the abnormal internal gas generation, thereby ensuring the integrity of the outer shell 11 to a certain extent, which is conducive to improving the reliability of the battery cell 10, and thus conducive to improving the reliability of the battery device 100.

[0235] According to some embodiments of this application, please refer to Figure 8 Along the first direction x, the width of the first groove 16 is h3, which satisfies 0.1mm≤h3≤15mm.

[0236] Along the first direction x, the width h3 of the first groove 16 can be 0.1mm, 0.2mm, 0.3mm, 0.4mm...14.5mm, 14.6mm, 14.7mm, 14.8mm, 14.9mm, 15mm or any value between two adjacent values.

[0237] In the above solution, by limiting the width h3 of the first groove 16 to not less than 0.1 mm and not more than 15 mm along the first direction x, the risk of manufacturing difficulties due to the width of the first groove 16 being too small can be reduced, thereby reducing the manufacturing cost of the battery cell 10. On the other hand, it can avoid the problem that the structural strength of the end cap 111 is greatly affected due to the width of the first groove 16 being too large, resulting in the shell 11's strength failing to meet the requirements.

[0238] In some other embodiments, the width h3 of the first groove 16 may be a value less than 0.1 mm or greater than 15 mm, such as 0.05 mm or 15.1 mm.

[0239] According to some embodiments of this application, the following condition is satisfied: 0.3mm ≤ h3 ≤ 10mm.

[0240] Along the first direction x, the width h3 of the first groove 16 can be 0.3mm, 0.4mm, 0.5mm, 0.6mm...9.5mm, 9.6mm, 9.7mm, 9.8mm, 9.9mm, 10mm or any value between two adjacent values.

[0241] In the above scheme, by limiting the width h3 of the first groove 16 to not less than 0.3 mm and not more than 10 mm along the first direction x, the manufacturing efficiency of the first groove 16 and the stress dispersion effect of the first groove 16 can be taken into account, so that the reliability of the battery cell 10 is high, and thus the reliability of the battery device 100 is high.

[0242] According to some embodiments of this application, please refer to Figure 6 Along the second direction y, the length of the first groove 16 is h4, and the length of the end cap 111 is L, satisfying 0 < h4 ≤ L.

[0243] Along the second direction y, the length of the end cap 111 is L, and the length h4 of the first groove 16 can be greater than 0 mm and not greater than L. For example, the value of L is 100 mm, and the value of h4 can be any value between 0 mm and 10 mm, 10 mm, 20 mm, 30 mm, 40 mm...60 mm, 70 mm, 80 mm, 90 mm, 100 mm, or any value between two adjacent values.

[0244] According to some embodiments of this application, the following condition is met: 10mm≤h4≤L.

[0245] Along the second direction y, the length of the end cap 111 is L, and the length h4 of the first groove 16 can be a value that is not less than 10mm and not greater than L. For example, the value of L is 100mm, and the value of h4 can be 10mm, 20mm, 30mm, 40mm...60mm, 70mm, 80mm, 90mm, 100mm or any value between two adjacent values.

[0246] In the above scheme, by setting the length h4 of the first groove 16 to be no less than 10mm along the second direction y, the stress at the junction of the end cap 111 and the first wall 112 can be effectively dispersed, the degree of stress concentration can be reduced, and the risk of fatigue cracking of the outer casing 11 can be reduced, thereby effectively improving the reliability of the battery cell 10 and thus effectively improving the reliability of the battery device 100.

[0247] In some other embodiments, the length h4 of the first groove 16 can be less than 10 mm, for example, 9 mm.

[0248] According to some embodiments of this application, the following condition is met: 30mm≤h4≤L.

[0249] Along the second direction y, the length of the end cap 111 is L, and the length h4 of the second groove 17 can be not less than 30mm and not greater than L. For example, the value of L is 100mm, and the value of h4 can be 30mm, 40mm...60mm, 70mm, 80mm, 90mm, 100mm or any value between two adjacent values.

[0250] In the above scheme, along the second direction y, by setting the length h4 of the first groove 16 to be not less than 30mm, the first groove 16 can effectively act on the part between the end cap 111 and the first wall 112 that is fatigued and cracked by expansion force, effectively reducing the degree of stress concentration and reducing the risk of fatigue cracking of the outer shell 11, thereby effectively improving the reliability of the battery cell 10, and further effectively improving the reliability of the battery device 100.

[0251] According to some embodiments of this application, the thickness of the end cap 111 corresponding to the location of the first groove 16 is t1, which satisfies 0.5mm≤t1≤3mm.

[0252] Please see Figure 8 The thickness of the end cap 111 corresponding to the location of the first groove 16 can be understood as the thickness of the remaining material in that area after the end cap 111 has undergone grooving, etching, or stamping to form the first groove 16. It should be noted that the value of t1 is less than the thickness of the end cap 111 itself. The value of t1 can be 0.5mm, 0.6mm, 0.7mm, 0.8mm…2.7mm, 2.8mm, 2.9mm, 3mm, or any value between two adjacent values.

[0253] In the above solution, by limiting the thickness t1 of the end cap 111 corresponding to the location of the first groove 16 to not less than 0.5mm, the risk of battery cell 10 failure due to the small thickness of this part being easily damaged can be reduced. By limiting the thickness of the end cap 111 corresponding to the location of the first groove 16 to not more than 3mm, the effect of the first groove 16 in dispersing and alleviating stress concentration can be guaranteed to a certain extent, reducing the risk of fatigue cracking of the outer shell 11, making the battery cell 10 highly reliable, and thus making the battery device 100 highly reliable.

[0254] In some other embodiments, the value of t1 can be less than 0.5 mm or greater than 3 mm, such as 0.4 mm or 4 mm. It should be noted that the value of t1 is less than the thickness of the end cap 111 itself.

[0255] According to some embodiments of this application, the following condition is satisfied: 0.7mm ≤ t1 ≤ 2mm.

[0256] In some embodiments, the value of t1 can be 0.7mm, 0.8mm...1.7mm, 1.8mm, 1.9mm, 2mm or any value between two adjacent values.

[0257] In the above solution, by limiting the thickness t1 of the end cap 111 corresponding to the location of the first groove 16 to not less than 0.7 mm and not more than 2 mm, the structural strength of the end cap 111 itself and the effect of the first groove 16 in dispersing and relieving stress concentration can be taken into account, thereby making the battery cell 10 highly reliable.

[0258] According to some embodiments of this application, please refer to Figure 8 Along the first direction x, the end cap 111 includes a first region 1112 located between the first groove 16 and the first solder mark 116, and the thickness of the end cap 111 corresponding to the location of the first groove 16 is less than the thickness of the first region 1112.

[0259] Along the first direction x, the first region 1112 is the area between the first groove 16 and the first solder mark 116. In some embodiments, the portion of the end cap 111 corresponding to the first region 1112 is connected to the first wall 112 via the first solder mark 116.

[0260] The fact that the thickness of the end cap 111 corresponding to the location of the first groove 16 is less than the thickness of the first region 1112 can be understood as the thickness of the end cap 111 corresponding to the location of the first groove 16 being reduced due to the provision of the first groove 16, and being less than the thickness of the first region 1112.

[0261] In the above solution, by limiting the thickness of the portion where the first groove 16 is located to be less than the thickness of the first region 1112, when the first wall 112 is deformed by the internal expansion force of the battery cell 10, the end cap 111 deforms along the portion of the first groove 16 corresponding to the offset of the first wall 112, so as to disperse and alleviate the stress between the first wall 112 and the end cap 111, reduce the risk of fatigue cracking at the joint between the end cap 111 and the first wall 112, thereby making the battery cell 10 highly reliable, and thus making the battery device 100 highly reliable.

[0262] According to other embodiments of this application, please refer to Figure 11 , Figure 11 This is a partial structural diagram of the end cap 111 in some embodiments of this application.

[0263] Along the thickness direction z of the end cap, a first groove 16 is formed on one side of the end cap 111, and a first protrusion 160 is formed on the other side of the end cap 111. The position of the first protrusion 160 corresponds to the first groove 16. Along the thickness direction z of the end cap, the thickness of the first protrusion 160 is less than the thickness of the end cap 111.

[0264] In some embodiments, a first groove 16 is formed on one side of the end cap 111 in the thickness direction, and a first protrusion 160 is formed on the other side of the end cap 111 in the thickness direction corresponding to the position of the first groove 16. The thickness of the first protrusion 160 is less than the thickness of the end cap 111 itself, or in other words, less than the maximum thickness of the end cap 111.

[0265] Optionally, a first groove 16 is formed on the outer side of the end cap 111, and a first protrusion 160 is formed on the inner side of the end cap 111.

[0266] Alternatively, the first groove 16 can be formed by stamping or die casting processes.

[0267] In the above solution, by providing a first groove 16 on one side of the end cap 111 and a first protrusion 160 on the other side corresponding to the first groove 16, the molding difficulty of the first groove 16 can be reduced and the manufacturing efficiency of the battery cell 10 can be improved. At the same time, by setting the thickness of the first protrusion 160 to be less than the thickness of the end cap 111, the first groove 16 can effectively disperse and alleviate the stress concentration phenomenon, reduce the risk of fatigue cracking of the casing 11, and improve the reliability of the battery cell 10 and the battery device 100.

[0268] According to some embodiments of this application, along the first direction x, the housing 110 has a second wall 113, the second wall 113 is opposite to the first wall 112, the second wall 113 is connected to the end cap 111 by a second solder mark, and the end cap has a second groove 17 provided on at least one side in the thickness direction z, along the first direction x, the second groove 17 is located between the second solder mark and the pressure relief mechanism 12.

[0269] In some embodiments, the second wall 113 is welded to the end cap 111 to form a second weld mark (not shown in the figure, but can be referred to as the first weld mark 116).

[0270] The second groove 17 is a groove-shaped structure formed on the end cap 111. The second groove 17 is a recessed structure formed on the end cap 111, and the thickness of the end cap 111 corresponding to the second groove 17 is less than the thickness of the end cap 111 itself. For example, the end cap 111 is a plate-shaped structure, and the second groove 17 is formed on the end cap 111 by processes such as stamping, etching, casting or die casting.

[0271] The second groove 17 can have various shapes, including but not limited to strips, arcs, etc.

[0272] Optionally, along the thickness direction z of the end cap, a second groove 17 is formed on the side of the end cap 111 facing away from the electrode assembly 15. Optionally, along the thickness direction z of the end cap, a second groove 17 is formed on the side of the end cap 111 facing the electrode assembly 15. Optionally, along the thickness direction z of the end cap, second grooves 17 are formed on opposite sides of the end cap 111.

[0273] Consistent with the relative positions of the first groove 16, the first solder mark 116, and the first wall 112, the second groove 17 is located between the second solder mark and the pressure relief mechanism 12 along the first direction x. For example, the pressure relief mechanism 12 is located in the middle of the end cap 111, and the second groove 17 is located on the side of the end cap 111 facing the second wall 113; that is, along the first direction x, the pressure relief mechanism 12 is located between the first groove 16 and the second groove 17.

[0274] In the above scheme, a second groove 17 is provided on the end cap 111, and along the first direction x (that is, the direction in which the battery cell 10 is most affected by the internal expansion force), the second groove 17 is located between the second solder mark and the pressure relief mechanism 12. On the one hand, when the battery cell 10 expands internally, it can disperse the stress at the joint between the end cap 111 and the second wall 113, reduce the degree of stress concentration, and effectively reduce the risk of fatigue cracking of the outer shell 11. On the other hand, it reduces the risk of structural damage to the pressure relief mechanism 12 due to the pulling force of the internal expansion force of the battery cell 10, and can play a certain role in protecting the structural integrity of the pressure relief mechanism 12, thereby effectively improving the reliability of the battery cell 10, and thus effectively improving the reliability of the battery device 100.

[0275] According to some embodiments of this application, the end cap 111 has a second center line perpendicular to the first direction x, and the first groove 16 and the second groove 17 are symmetrically arranged about the second center line.

[0276] Please see Figure 5 , Figure 5 The second centerline is denoted by the symbol s2.

[0277] The second centerline is the centerline of the end cap 111 perpendicular to the first direction x, which is also the centerline of the end cap 111 parallel to the second direction y. In some embodiments, the first groove 16 and the second groove 17 are symmetrically arranged about the second centerline, that is, the relative positional relationship between the second groove 17 and the pressure relief mechanism 12, the relative positional relationship of the second groove 17 on the outer side of the second wall 113, the shape and size of the second groove 17 can be consistent with the above description of the first groove 16.

[0278] In the above scheme, by setting the first groove 16 and the second groove 17 symmetrical about the second center line, the risk of fatigue cracking at the junction of the large surface of the battery cell 10 (that is, the first wall 112 and the second wall 113) and the end cap 111 can be effectively reduced. At the same time, the structural integrity of the pressure relief mechanism 12 can be guaranteed to a certain extent, which is conducive to improving the reliability of the battery cell 10 and thus to improving the reliability of the battery device 100.

[0279] According to some embodiments of this application, please refer to Figure 4 , Figure 5 , Figure 6 , Figure 12 and Figure 13 , Figure 12 for Figure 6 Sectional view in the CC direction, Figure 13 for Figure 12 Enlarged view of point D in the middle.

[0280] The battery cell 10 also includes a first electrode terminal 13 and a second electrode terminal 14. The first electrode terminal 13 and the second electrode terminal 14 are spaced apart along the second direction y. The second direction y, the first direction x, and the thickness direction z of the end cap are all perpendicular to each other. Along the second direction y, the housing 110 has a third wall 114, which is connected to the end cap 111 by a third solder mark 117. At least one side of the end cap in the thickness direction z is provided with a third groove 18. Along the second direction y, the third groove 18 is located between the third solder mark 117 and the first electrode terminal 13, and the first electrode terminal 13 is located between the third groove 18 and the second electrode terminal 14.

[0281] In some embodiments, the battery cell 10 includes a first electrode terminal 13 and a second electrode terminal 14. The polarity of the first electrode terminal 13 and the second electrode terminal 14 may be the same or different. Exemplarily, both the first electrode terminal 13 and the second electrode terminal 14 are positive electrodes, and the casing 11 of the battery cell 10 is a negative electrode. Exemplarily, the polarities of the first electrode terminal 13 and the second electrode terminal 14 are opposite, one being a positive electrode and the other a negative electrode. See also... Figure 5 Along the second direction y, the first electrode terminal 13 and the second electrode terminal 14 are spaced apart.

[0282] In some embodiments, see Figure 6The end cap 111 has a first through hole 1110 and a second through hole 1111. A first electrode terminal 13 is disposed in the first through hole 1110 and electrically connected to the tab of the electrode assembly 15. A second electrode terminal 14 is disposed in the second through hole 1111 and electrically connected to the tab of the electrode assembly 15. In some embodiments, the first through hole 1110 extends through the end cap 111 along its thickness. Optionally, the first through hole 1110 can be a stepped hole, which may include one, two, or more steps. In some embodiments, the second through hole 1111 extends through the end cap 111 along its thickness. Optionally, the second through hole 1111 can be a stepped hole, which may include one, two, or more steps.

[0283] The third groove 18 is a groove-shaped structure formed on the end cap 111. The third groove 18 is a recessed structure formed on the end cap 111, and the thickness of the part of the end cap 111 corresponding to the third groove 18 is less than the thickness of the end cap 111 itself. For example, the end cap 111 is a plate-shaped structure, and the third groove 18 is formed on the end cap 111 by processes such as stamping, etching, casting or die casting.

[0284] The third groove 18 can have various shapes, including but not limited to strips, arcs, etc.

[0285] Optionally, please see Figure 13 Along the thickness direction z of the end cap, a third groove 18 is formed on the side of the end cap 111 facing away from the electrode assembly 15. Optionally, please refer to Figure 14 , Figure 14 This is a schematic diagram of the structure of the end cap 111 and the third groove 18 in other embodiments of this application. Along the thickness direction z of the end cap, the third groove 18 is formed on the side of the end cap 111 facing the electrode assembly 15. Alternatively, please refer to... Figure 15 , Figure 15 The diagram below shows the structure of the end cap 111 and the third groove 18 in some other embodiments of this application. Along the thickness direction z of the end cap, the end cap 111 has a third groove 18 formed on each of its opposite sides.

[0286] Please combine Figure 6 and Figure 13 Along the second direction y, the third groove 18 is located between the third solder mark 117 and the first electrode terminal 13, and the first electrode terminal 13 is located between the third groove 18 and the second electrode terminal 14. That is, the second groove 17 is located between the third solder mark 117 and the first through hole 1110.

[0287] In the above solution, a third groove 18 is provided on the end cap 111, and along the second direction y, the third groove 18 is located between the third solder mark 117 and the first electrode terminal 13. This can effectively improve the problem of stress concentration and fatigue cracking at the joint between the third wall 114 and the end cap 111 caused by the expansion and contraction of the outer shell 11 due to the abnormal gas production inside the battery cell 10. This makes the battery cell 10 have higher reliability, and thus the battery device 100 has higher reliability.

[0288] In some embodiments, the breathing effect of abnormal internal gas production can be understood as follows: as the number of charge-discharge cycles increases, the internal electrochemical reaction continues, producing gas. As the gas increases, the outer casing 11 expands. Since some of the gas is reused by electrochemical substances, or absorbed by positive and negative electrode materials or separators, or discharged to the outside, the outer casing 11 expands and contracts like breathing.

[0289] According to some embodiments of this application, please refer to Figure 6 The first groove 16 and the third groove 18 are spaced apart from each other.

[0290] In some embodiments, the first groove 16 and the third groove 18 are spaced apart from each other and are not connected. It can be understood that the maximum thickness of the end cap 111 located between the first groove 16 and the third groove 18 is greater than the thickness of the end cap 111 corresponding to the first groove 16 and greater than the thickness of the end cap 111 corresponding to the third groove 18.

[0291] In some embodiments, the first groove 16, the second groove 17, and the third groove 18 are spaced apart from each other.

[0292] In the above solution, by setting the first groove 16 and the third groove 18 to be spaced apart from each other, the overall structural strength of the end cover 111 is reduced due to the groove on the end cover 111, which may cause other structural components on the end cover 111 to deform when the battery cell 10 expands or abnormally generates gas, resulting in a circuit break in the battery cell 10. This makes the battery cell 10 have higher reliability, and thus the battery device 100 has higher reliability.

[0293] According to some embodiments of this application, the end cap 111 has a first through hole 1110, and the first electrode terminal 13 is disposed in the first through hole 1110. Along the second direction y, the minimum distance between the third groove 18 and the first through hole 1110 is h5, which satisfies 0.3mm≤h5≤40mm.

[0294] A first through hole 1110 penetrates the end cap 111 along the thickness direction z. A first electrode terminal 13 is disposed in the first through hole 1110 and electrically connected to the electrode assembly 15. In some embodiments, the first through hole 1110 is a stepped hole. See also Figure 13 Along the second direction y, the minimum distance between the third groove 18 and the first through hole 1110 can be understood as the minimum distance between the side surface of the groove 18 and the wall surface of the first through hole 1110. In some embodiments, the value of h5 can be 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm...39.5mm, 39.6mm, 39.7mm, 39.8mm, 39.9mm, 40mm.

[0295] In the above scheme, along the second direction y, by limiting the distance between the third groove 18 and the first through hole 1110 to not less than 0.3mm, the structural strength of the end cover 111 corresponding to the first electrode terminal 13 can be reduced due to the distance between the third groove 18 and the first through hole 1110 being too small, so that the end cover 111 can effectively support the first electrode terminal 13 and reduce the risk of the first electrode terminal 13 detaching from the end cover 111. By limiting the distance between the third groove 18 and the first through hole 1110 to not more than 40mm, the risk of the third groove 18 being too large and thus failing to disperse stress due to the third wall 114 being too close can be reduced, thereby improving the problem of fatigue cracking of the outer casing 11 due to abnormal gas generation inside the battery cell 10, so that the battery cell 10 has high reliability, and thus the battery device 100 has high reliability.

[0296] In some other embodiments, the value of h5 can be less than 0.3 mm or greater than 40 mm, for example, h5 is 0.2 mm or 41 mm.

[0297] According to some embodiments of this application, the following condition is met: 0.5mm ≤ h5 ≤ 30mm.

[0298] In some embodiments, the value of h5 can be 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm...29.5mm, 29.6mm, 29.7mm, 29.8mm, 29.9mm, 30mm.

[0299] In the above scheme, by limiting the distance between the third groove 18 and the first through hole 1110 to not less than 0.5 mm and not more than 30 mm along the second direction y, the structural stability between the first electrode terminal 13 and the end cover 111 can be effectively improved, and the problem of fatigue cracking caused by abnormal gas generation inside the battery cell 10 at the joint between the third wall 114 and the end cover 111 can be effectively improved, so that the battery cell 10 has high reliability and the battery device 100 has high reliability.

[0300] According to some embodiments of this application, along the second direction y, the third wall 114 has a third surface 1140 facing away from the electrode assembly 15, and along the second direction y, the distance between the third groove 18 and the third surface 1140 is h6, satisfying 1mm≤h6≤30mm.

[0301] The third surface 1140 can be understood as the outer surface of the third wall 114. Along the second direction y, the distance between the third groove 18 and the third surface 1140 can be understood as the distance between the side of the third groove 18 closest to the third surface and the third surface 1140. The value of h6 can be 1mm, 2mm, 3mm, 4mm, 5mm...27mm, 28mm, 29mm, 30mm and any value between two adjacent values.

[0302] In the above solution, by limiting the distance h6 between the third groove 18 and the third surface 1140 to not less than 1 mm, the manufacturing precision of the third groove 18 can be reduced, the manufacturing difficulty caused by the small distance between the third groove 18 and the third surface 1140 can be improved, and the risk of affecting the structural strength of the third solder mark 117 due to the small distance between the third groove 18 and the third surface 1140 can be reduced. By limiting the distance h6 between the third groove 18 and the third surface 1140 to not more than 30 mm, the risk of not being able to effectively disperse stress due to the large distance between the third groove 18 and the third surface 1140 can be reduced, thereby taking into account both the manufacturing efficiency of the first groove 16 and the effect of reducing fatigue cracking at the joint between the third wall 114 and the end cap 111.

[0303] In some other embodiments, the value of h6 can also be less than 1 mm or greater than 30 mm, such as 0.6 mm or 31 mm.

[0304] According to some embodiments of this application, the following condition is met: 1.5mm ≤ h6 ≤ 20mm.

[0305] In some embodiments, the value of h6 can be 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm...18.5mm, 19mm, 19.5mm, 20mm, or any value between two adjacent values.

[0306] In the above solution, by limiting the distance h6 between the third groove 18 and the third surface 1140 to not less than 1.5mm and not more than 20mm, the third groove 18 and the third surface 1140 have a suitable distance, which can effectively reduce the manufacturing difficulty of the third groove 18 and enable the third groove 18 to effectively disperse the stress generated between the end cap 111 and the third wall 114 due to the abnormal gas generation inside the battery cell 10, which causes the outer casing 11 to breathe, continuously contract and expand, thereby improving the reliability of the battery cell 10 and thus improving the reliability of the battery device 100.

[0307] According to some embodiments of this application, the third groove 18 is a strip groove, and the third groove 18 extends along the first direction x.

[0308] In some embodiments, the strip groove of the third groove 18, that is, the shape of the third groove 18, can be rectangular, the length direction of the third groove 18 is parallel to the first direction x, and the width direction of the third groove 18 is parallel to the second direction y.

[0309] In the above scheme, by setting the third groove 18 as a strip groove extending along the first direction x, on the one hand, it can effectively disperse and alleviate stress concentration, and reduce the risk of cracking at the joint between the end cover 111 and the third wall 114 due to abnormal gas generation inside the battery cell 10; on the other hand, it can adapt to multi-directional loads, and improve the overall stability of the end cover 111 under the influence of internal expansion force and abnormal gas generation inside the battery cell 10, thereby ensuring the integrity of the outer shell 11 to a certain extent, which is conducive to improving the reliability of the battery cell 10, and thus conducive to improving the reliability of the battery device 100.

[0310] According to some embodiments of this application, along the second direction y, the width of the third groove 18 is h7, which satisfies 0.1mm≤h7≤25mm.

[0311] Along the second direction y, the width h7 of the third groove 18 can be 0.1mm, 0.2mm, 0.3mm, 0.4mm...24.5mm, 24.6mm, 24.7mm, 24.8mm, 24.9mm, 25mm or any value between two adjacent values.

[0312] In the above solution, by limiting the width h7 of the third groove 18 to not less than 0.1 mm and not more than 25 mm along the first direction x, on the one hand, the risk of manufacturing difficulties due to the width of the third groove 18 being too small can be reduced, and the manufacturing cost of the battery cell 10 can be reduced; on the other hand, the problem of the end cover 111 structural strength being greatly affected due to the width of the third groove 18 being too large can be avoided, which would cause the strength of the outer shell 11 to fail to meet the requirements.

[0313] In some other embodiments, the width h7 of the third groove 18 can also be a value less than 0.1 mm or greater than 25 mm, such as 0.05 mm or 25.1 mm.

[0314] According to some embodiments of this application, the following condition is met: 0.3mm ≤ h7 ≤ 20mm.

[0315] Along the second direction y, the width h7 of the third groove 18 can be 0.3mm, 0.4mm, 0.5mm, 0.6mm...19.5mm, 19.6mm, 19.7mm, 19.8mm, 19.9mm, 20mm or any value between two adjacent values.

[0316] In the above scheme, by limiting the width h7 of the third groove 18 to not less than 0.3 mm and not more than 20 mm along the first direction x, the manufacturing efficiency of the third groove 18 and the stress dispersion effect of the third groove 18 can be taken into account, so that the reliability of the battery cell 10 is high, and thus the reliability of the battery device 100 is high.

[0317] According to some embodiments of this application, see Figure 6 Along the first direction x, the length of the third groove 18 is h8, and the width of the end cap 111 is W, satisfying 0 < h8 ≤ W.

[0318] Along the second direction y, the width of the end cap 111 is W, and the length h8 of the third groove 18 can be greater than 0 mm and not greater than W. For example, W is 60 mm, and h4 can be any value between 0 and 1.5 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm...59.5 mm, 60 mm, or any value between two adjacent values.

[0319] According to some embodiments of this application, 1.5mm≤h8≤W is satisfied.

[0320] Along the second direction y, the width of the end cap 111 is W, and the length h8 of the third groove 18 can be not less than 1.5mm and not greater than W. For example, W is 60mm, and h4 can be 1.5mm, 2mm, 2.5mm, 3mm...59.5mm, 60mm or any value between two adjacent values.

[0321] In the above scheme, by setting the length h8 of the third groove 18 to be not less than 1.5mm along the first direction x, the stress at the junction of the end cap 111 and the third wall 114 can be effectively dispersed, the degree of stress concentration can be reduced, and the risk of fatigue cracking of the outer casing 11 can be reduced, thereby effectively improving the reliability of the battery cell 10 and thus effectively improving the reliability of the battery device 100.

[0322] According to some embodiments of this application, the following condition is satisfied: 2mm≤h8≤W.

[0323] In some embodiments, the length h8 of the third groove 18 can be a value that is not less than 2 mm and not greater than W. For example, W is 60 mm, and h4 can be 2 mm, 2.5 mm, 3 mm...59.5 mm, 60 mm or any value between two adjacent values.

[0324] In the above scheme, along the second direction y, by setting the length h8 of the third groove 18 to be not less than 2mm, the third groove 18 can effectively act on the part between the end cap 111 and the third wall 114 that is fatigued and cracked due to abnormal gas generation, effectively reducing the degree of stress concentration and reducing the risk of fatigue cracking of the outer casing 11, thereby effectively improving the reliability of the battery cell 10, and further effectively improving the reliability of the battery device 100.

[0325] According to some embodiments of this application, see Figure 13 The thickness of the end cap 111 corresponding to the location of the third groove 18 is t2, which satisfies 0.4mm≤t2≤3mm.

[0326] Please see Figure 13 The thickness of the end cap 111 corresponding to the location of the third groove 18 can be understood as the thickness of the remaining material in that area after the end cap 111 has undergone grooving, etching, or stamping to form the third groove 18. It should be noted that the value of t2 is less than the thickness of the end cap 111 itself. The value of t2 can be 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm…2.7mm, 2.8mm, 2.9mm, 3mm, or any value between two adjacent values.

[0327] In the above scheme, by limiting the thickness t2 of the end cap 111 corresponding to the location of the third groove 18 to not less than 0.4mm, the risk of battery cell 10 failure due to the small thickness of this part being easily damaged can be reduced. By limiting the thickness of the end cap 111 corresponding to the location of the third groove 18 to not more than 3mm, the effect of the third groove 18 in dispersing and alleviating stress concentration can be guaranteed to a certain extent, reducing the risk of fatigue cracking of the casing 11, making the battery cell 10 highly reliable, and thus making the battery device 100 highly reliable.

[0328] In some other embodiments, the value of t2 can be less than 0.4 mm or greater than 3 mm, such as 0.3 mm or 4 mm. It should be noted that the value of t2 is less than the thickness of the end cap 111 itself.

[0329] According to some embodiments of this application, the following condition is satisfied: 0.6mm ≤ t2 ≤ 2mm.

[0330] In some embodiments, the value can be 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm...2.7mm, 2.8mm, 2.9mm, 3mm or any value between two adjacent values.

[0331] In the above solution, by limiting the thickness t2 of the end cap 111 corresponding to the location of the third groove 18 to not less than 0.6 mm and not more than 2 mm, the structural strength of the end cap 111 itself and the effect of the third groove 18 in dispersing and alleviating stress concentration can be taken into account, thereby making the battery cell 10 highly reliable.

[0332] According to some embodiments of this application, along the second direction y, the end cap 111 includes a third region 1113 located between the third groove 18 and the third solder mark 117, and the thickness of the end cap 111 corresponding to the location of the third groove 18 is less than the thickness of the third region 1113.

[0333] Along the second direction y, the third region 1113 is the area between the third groove 18 and the third solder mark 117. In some embodiments, the portion of the end cap 111 corresponding to the third region 1113 is connected to the third wall 114 via the third solder mark 117.

[0334] The fact that the thickness of the end cap 111 corresponding to the location of the third groove 18 is less than the thickness of the third region 1113 can be understood as the thickness of the end cap 111 corresponding to the location of the third groove 18 being reduced due to the setting of the third groove 18, and being less than the thickness of the third region 1113.

[0335] In the above scheme, by limiting the thickness of the part where the third groove 18 is located to be less than the thickness of the third region 1113, when the third wall 114 expands and deforms outward due to abnormal gas generation inside the battery cell 10, the end cap 111 deforms along the part of the third groove 18 corresponding to the deformation of the third wall 114, so as to disperse and alleviate the stress between the third wall 114 and the end cap 111, reduce the risk of fatigue cracking at the joint between the end cap 111 and the third wall 114, thereby making the battery cell 10 highly reliable, and thus making the battery device 100 highly reliable.

[0336] According to some embodiments of this application, please refer to Figure 16 , Figure 16 This is a partial structural diagram of the end cap 111 and the third wall 114 in some embodiments of this application.

[0337] Along the thickness direction z of the end cap, a third groove 18 is formed on one side of the end cap 111, and a third protrusion 180 is formed on the other side of the end cap 111. The position of the third protrusion 180 corresponds to the third groove 18. Along the thickness direction z of the end cap, the thickness of the third protrusion 180 is less than the thickness of the end cap 111.

[0338] In some embodiments, a third groove 18 is formed on one side of the end cap 111 in the thickness direction, and a third protrusion 180 is formed on the other side of the end cap 111 in the thickness direction corresponding to the position of the third groove 18. The thickness of the third protrusion 180 is less than the thickness of the end cap 111 itself, or in other words, less than the maximum thickness of the end cap 111.

[0339] Optionally, a third groove 18 is formed on the outer side of the end cap 111, and a third protrusion 180 is formed on the inner side of the end cap 111.

[0340] Alternatively, the third groove 18 can be formed by stamping or die casting processes.

[0341] In the above solution, by providing a third groove 18 on one side of the end cap 111 and a third protrusion 180 on the other side corresponding to the third groove 18, the molding difficulty of the third groove 18 can be reduced and the manufacturing efficiency of the battery cell 10 can be improved. At the same time, by setting the thickness of the third protrusion 180 to be less than the thickness of the end cap 111, the third groove 18 can effectively disperse and alleviate the stress concentration phenomenon, reduce the risk of fatigue cracking of the casing 11, and improve the reliability of the battery cell 10 and the battery device 100.

[0342] According to some embodiments of this application, along the second direction y, the housing 110 has a fourth wall 115, the fourth wall 115 is opposite to the third wall 114, the fourth wall 115 is connected to the end cap 111 by a fourth solder mark, and the end cap has a fourth groove 19 provided on at least one side in the thickness direction z, along the second direction y, the fourth groove 19 is located between the fourth solder mark and the second electrode terminal 14.

[0343] In some embodiments, the fourth wall 115 is welded to the end cap 111 to form a fourth weld mark (not shown in the figure, but can be referred to as the third weld mark 117).

[0344] The fourth groove 19 is a groove-shaped structure formed on the end cap 111. The fourth groove 19 is a recessed structure formed on the end cap 111, and the thickness of the end cap 111 corresponding to the fourth groove 19 is less than the thickness of the end cap 111 itself. For example, the end cap 111 is a plate-shaped structure, and the fourth groove 19 is formed on the end cap 111 by processes such as stamping, etching, casting, or die casting.

[0345] The fourth groove 19 has various shapes, including but not limited to strips, arcs, etc.

[0346] Optionally, a fourth groove 19 is formed on the side of the end cap 111 facing away from the electrode assembly 15 along the thickness direction z of the end cap. Optionally, a fourth groove 19 is formed on the side of the end cap 111 facing the electrode assembly 15 along the thickness direction z of the end cap. Optionally, a fourth groove 19 is formed on each of the opposite sides of the end cap 111 along the thickness direction z of the end cap.

[0347] Consistent with the relative positions of the third groove 18, the third solder mark 117, and the third wall 114, the fourth groove 19 is located between the fourth solder mark and the second electrode terminal 14 along the second direction y. Exemplarily, along the second direction y, the third groove 18, the first electrode terminal 13, the second electrode terminal 14, and the fourth groove 19 are arranged in a mutually spaced manner.

[0348] In the above solution, a fourth groove 19 is provided on the end cap 111, and along the second direction y, the second groove 17 is located between the fourth solder mark and the second electrode terminal 14. This can effectively improve the problem of stress concentration and fatigue cracking at the joint between the fourth wall 115 and the end cap 111 caused by the expansion and contraction of the outer shell 11 due to the abnormal gas production inside the battery cell 10. This makes the battery cell 10 have higher reliability, and thus the battery device 100 has higher reliability.

[0349] According to some embodiments of this application, the third groove 18 and the fourth groove 19 are symmetrically arranged about the first center line.

[0350] The first centerline is the centerline of the end cap 111 perpendicular to the second direction y, which is also the centerline of the end cap 111 parallel to the first direction x. In some embodiments, the third groove 18 and the fourth groove 19 are symmetrically arranged about the first centerline, that is, the relative positional relationship between the fourth groove 19 and the outer surface of the fourth wall 115. The shape and size of the fourth groove 19 can be consistent with the above description of the third groove 18.

[0351] In the above scheme, by setting the third groove 18 and the fourth groove 19 symmetrical about the first center line, the risk of fatigue cracking at the junction of the third wall 114 and the end cap 111 and the junction of the fourth wall 115 and the end cap 111 can be effectively reduced, thereby improving the reliability of the battery cell 10 and thus improving the reliability of the battery device 100.

[0352] According to some embodiments of this application, please refer to Figure 17 , Figure 17 This is a perspective view of a battery cell 10 in some embodiments of this application.

[0353] The outer casing 11 is a square casing. The dimension of the outer casing 11 in the first direction x is T1, the dimension of the outer casing 11 in the second direction y is W1, and the dimension of the outer casing 11 in the thickness direction z of the end cap is H1, satisfying 3720cm. 3 ≤W1*T1*H1≤12500cm 3 60mm≤T1≤150mm, 120mm≤H1≤400mm, 200mm≤W1≤1500mm, the first direction x, the second direction y and the thickness direction z of the first wall are mutually perpendicular.

[0354] The first direction x can be the thickness direction of the battery cell 10, the second direction y can be the width direction of the battery cell 10, and the thickness direction z of the end cap can be the height direction of the battery cell 10.

[0355] The statement “The outer casing 11 has a dimension of T1 in the first direction x, a dimension of W1 in the second direction y, and a dimension of H1 in the thickness direction z of the end cap” can be understood as follows: the outer casing 11 of the battery cell 10 has a thickness of T1, a width of W1, and a height of H1.

[0356] In some embodiments, the thickness of the outer casing 11 is T1, the width is W1, and the height is H1, which can satisfy the following condition: 3720cm 3 ≤W1*T1*H1≤12500cm 3 , 60mm≤T1≤150mm, 120mm≤H1≤400mm, 200mm≤W1≤1500mm.

[0357] For example, W1*T1*H1 is the value obtained by multiplying W1, T1, and H1, and W1*T1*H1 can take the value 3720cm. 3 Up to 12500cm 3 Any value between, and the two values.

[0358] For example, the value of T1 can be no less than 60mm and no more than 150mm. For example, the value of T1 can be 60mm, 70mm, 80mm, 90mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm or any value between two adjacent values.

[0359] For example, the value of H1 can be no less than 120mm and no more than 400mm. For example, the value of T1 can be 120mm, 130mm, 140mm, 150mm, 160mm...360mm, 370mm, 380mm, 390mm, 400mm or any value between two adjacent values.

[0360] For example, the value of W1 can be no less than 200mm and no more than 1500mm. For example, the value of T1 can be 200mm, 210mm, 220mm, 230mm, 240mm...1360mm, 1370mm, 1380mm, 1390mm, 1400mm or any value between two adjacent values.

[0361] In the above scheme, by limiting the external contour dimensions of the battery cell 10, the internal space of the battery cell 10 is made larger to accommodate more electrochemical substances, thereby forming a battery cell 10 with a larger capacity. For battery cells 10 with larger capacity, the risk of structural damage due to internal expansion is greater. By providing a first groove 16 on the end cap 111, the risk of fatigue cracking of the outer casing 11 can be effectively reduced. On the other hand, it can also protect the structural integrity of the pressure relief mechanism 12 to a certain extent, so that the battery cell 10 with such a large capacity can have high reliability, and thus the battery device 100 with such a large capacity battery cell 10 can have high reliability.

[0362] According to some embodiments of this application, the outer casing 11 is a steel casing.

[0363] In the above scheme, by setting the outer shell 11 as a steel shell, the wall thickness of the outer shell 11 can be designed to be thin, which is conducive to improving the volumetric energy density of the battery cell 10, and thus conducive to improving the volumetric energy density of the battery device 100.

[0364] Some embodiments of this application provide a battery device 100, which includes the battery cell 10 described above.

[0365] See Figure 3 As shown, the battery device 100 may also include a housing, in which the individual battery cells 10 are housed.

[0366] In some embodiments, the housing may include a first housing body 21 and a second housing body 22, the first housing body 21 and the second housing body 22 covering each other, the first housing body 21 and the second housing body 22 together defining an assembly space for accommodating the battery cell 10.

[0367] Optionally, the second box body 22 can be a hollow structure with one end open, and the first box body 21 can be a plate-like structure. The first box body 21 covers the open side of the second box body 22 so that the first box body 21 and the second box body 22 together define the assembly space; the first box body 21 and the second box body 22 can also be hollow structures with one side open, and the open side of the first box body 21 covers the open side of the second box body 22.

[0368] Of course, the box formed by the first box body 21 and the second box body 22 can be of various shapes, such as a cylinder or a cuboid. For example, in... Figure 3 In the middle, the box has a rectangular structure.

[0369] Optionally, there may be multiple battery cells 10 disposed within the casing. For example, in... Figure 3 In the battery device 100, multiple battery cells 10 are arranged inside the casing. These battery cells 10 can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that the multiple battery cells 10 are connected in both series and parallel configurations. The multiple battery cells 10 can be directly connected in series, parallel, or in a mixed configuration and then housed in the casing. Alternatively, the battery device 100 can also be composed of multiple battery cells 10 first connected in series, parallel, or in a mixed configuration to form battery modules, and then these battery modules can be connected in series, parallel, or in a mixed configuration to form a whole and housed in the casing.

[0370] It should be noted that in some embodiments, the battery device 100 may not have a casing. The battery device 100 includes multiple battery cells 10, and the battery device 100, composed of multiple battery cells 10 electrically connected together, can be directly mounted onto the electrical device to provide power to the electrical device through the multiple battery cells 10. That is, the casing can be part of the electrical device. Taking a vehicle 1000 as an example, the casing can be part of the chassis structure of the vehicle 1000. For example, a portion of the casing can be at least a part of the floor of the vehicle 1000, or a portion of the casing can be at least a part of the crossbeams and longitudinal beams of the vehicle 1000.

[0371] Some embodiments of this application provide an energy storage device 2000, which includes the battery cell 10 and / or battery device 100 provided above.

[0372] Please see Figure 2 The energy storage device 2000 can be an energy storage cabinet, which includes a cabinet body 2001 and multiple battery cells 10. The multiple battery cells 10 can be installed inside the cabinet body 2001. The multiple battery cells 10 are interconnected in series, parallel, or in a mixed connection through a busbar component.

[0373] Optionally, a battery device 100 may also be installed inside the cabinet 2001.

[0374] Some embodiments of this application provide an electrical device, which includes the battery cell 10 and / or battery device 100 provided above.

[0375] The electrical device can be any of the aforementioned applications of battery cell 10 and / or battery device 100. For example, the electrical device can be a vehicle 1000, which can be a range-extended vehicle, a pure electric vehicle, or a gasoline-powered vehicle. The electrical energy provided by the battery cell 10 can be used to meet the power needs of the vehicle 1000 during startup, navigation, and operation.

[0376] Some embodiments of this application also provide a battery cell 10, please refer to [link to relevant documentation]. Figures 4-16 .

[0377] The battery cell 10 includes a casing 11, a pressure relief mechanism 12, electrode terminals, and an electrode assembly 15.

[0378] The outer casing 11 is square and includes a housing 110 and an end cap 111. An opening is formed at one end of the housing 110 along the thickness direction z of the end cap, and the end cap 111 is welded to the housing 110 to close the opening. The electrode assembly 15 is disposed inside the outer casing 11.

[0379] The housing 110 includes a first wall 112 and a second wall 113 facing each other along a first direction x, and a third wall 114 and a fourth wall 115 facing each other along a second direction y. The first direction x can be the thickness direction of the battery cell 10, the second direction y can be the length direction of the battery cell 10, and the first direction x, the second direction y, and the thickness direction z of the end cap are all perpendicular to each other. The first wall 112 is connected to the end cap 111 via a first solder mark 116, the second wall 113 is connected to the end cap 111 via a second solder mark, the third wall 114 is connected to the end cap 111 via a third solder mark 117, and the fourth wall 115 is connected to the end cap 111 via a fourth solder mark. Along the first direction x, the surface of the first wall 112 facing away from the second wall 113 is a first surface 1120. The surface of the third wall 114 facing away from the fourth wall 115 is a third surface 1140.

[0380] A pressure relief mechanism 12 is disposed on the end cap 111. Exemplarily, the pressure relief mechanism 12 is a groove disposed on the outer side of the end cap 111. The end cap 111 is provided with a first through hole 1110 and a second through hole 1111 spaced apart along the second direction y. The electrode terminals include a first electrode terminal 13 and a second electrode terminal 14. The first electrode terminal 13 is disposed in the first through hole 1110 and electrically connected to the electrode assembly 15, and the second electrode terminal 14 is disposed in the second through hole 1111 and electrically connected to the electrode assembly 15.

[0381] Please see Figure 6 The end cap 111 is provided with a first groove 16, a second groove 17, a third groove 18, and a fourth groove 19. The first groove 16, the second groove 17, the third groove 18, and the fourth groove 19 are used for stress relief.

[0382] In some embodiments, along the first direction x, the first groove 16 and the second groove 17 are respectively disposed on both sides of the pressure relief mechanism 12, and the two are spaced apart from each other from the pressure relief mechanism 12.

[0383] Some embodiments of this application are described using the first groove 16 as an example, and the relevant features of the second groove 17 can be explained with reference to the first groove 16.

[0384] Along the first direction x, the size of the end cap 111 is W, and the distance between the first groove 16 and the pressure relief mechanism 12 is h1, satisfying 0.3mm≤h1≤0.4W, optionally 0.5mm≤h1≤0.4W.

[0385] Along the first direction x, the distance between the first groove 16 and the first surface 1120 is h2, which satisfies 1mm≤h2≤20mm, and optionally 1.5mm≤h2≤15mm.

[0386] Along the first direction x, the width of the first groove 16 is h3, which satisfies 0.1mm≤h3≤15mm, and optionally 0.3mm≤h3≤10mm.

[0387] Along the second direction y, the length of the first groove 16 is h4, and the length of the end cap 111 is L, satisfying 10mm≤h4≤L, and optionally 30mm≤h4≤L.

[0388] The thickness of the end cap 111 corresponding to the location of the first groove 16 is t1, which satisfies 0.5mm≤t1≤3mm, and optionally 0.7mm≤t1≤2mm.

[0389] In some embodiments, the third groove 18 is located between the first electrode terminal 13 and the third wall 114, and the fourth groove 19 is located between the second electrode terminal 14 and the fourth wall 115.

[0390] Some embodiments of this application are illustrated using the third groove 18 as an example, and the relevant features of the fourth groove 19 can be explained with reference to the first groove 16.

[0391] Along the second direction y, the minimum distance between the third groove 18 and the first through hole 1110 is h5, which satisfies 0.3mm≤h5≤40mm, and optionally 0.5mm≤h5≤30mm.

[0392] Along the second direction y, the distance between the third groove 18 and the third surface 1140 is h6, which satisfies 1mm≤h6≤30mm, and optionally 1.5mm≤h6≤20mm.

[0393] Along the second direction y, the width of the third groove 18 is h7, which satisfies 0.1mm≤h7≤25mm, and optionally 0.3mm≤h7≤20mm.

[0394] Along the first direction x, the length of the third groove 18 is h8, and the width of the end cap 111 is W, satisfying 1.5mm≤h8≤W, and optionally, 2mm≤h8≤W.

[0395] The thickness of the end cap 111 corresponding to the location of the third groove 18 is t2, which satisfies 0.4mm≤t2≤3mm, and optionally 0.6mm≤t2≤2mm.

[0396] In the above scheme, a first groove 16 and a second groove 17 are provided on the end cap 111, along the first direction x (that is, the direction in which the battery cell 10 is most affected by the internal expansion force). The first groove 16 is located between the first solder mark 116 and the pressure relief mechanism 12, and the second groove 17 is located between the second solder mark and the pressure relief mechanism 12. On the one hand, when the battery cell 10 expands internally, it can disperse the stress at the joint between the end cap 111 and the second wall 113, reduce the degree of stress concentration, and effectively reduce the risk of fatigue cracking of the outer casing 11. On the other hand, it reduces the risk of structural damage to the pressure relief mechanism 12 due to the pulling force of the internal expansion force of the battery cell 10, and can play a certain role in protecting the structural integrity of the pressure relief mechanism 12. A third groove 16 is provided on the end cap 111. The third groove 18 and the fourth groove 19 are located along the second direction y. The third groove 18 is located between the third wall 114 and the first electrode terminal 13, and the fourth groove 19 is located between the fourth wall 115 and the second electrode terminal 14. This can effectively improve the problem of stress concentration and fatigue cracking at the joint between the fourth wall 115 and the end cap 111 caused by the expansion and contraction of the outer casing 11 due to the abnormal gas production inside the battery cell 10. In this regard, by setting the first groove 16, the second groove 17, the third groove 18 and the fourth groove 19, the problem of the outer casing 11 cracking due to the internal expansion or abnormal gas production of the battery cell 10 can be effectively improved, so that the battery cell 10 has high reliability, and thus the battery device 100 has high reliability.

[0397] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery cell, characterized by, The battery cell comprises: a shell comprising a shell body and an end cover, the shell body having an opening, and the end cover closing the opening; an electrode assembly arranged inside the shell, the electrode assembly having a flat area, and the electrode assembly having a tab arranged in a first direction in the flat area, the first direction being perpendicular to the thickness direction of the end cover; wherein the shell body has a first wall, the thickness direction of the first wall being parallel to the first direction, the first wall being connected to the end cover by a first welding mark, the end cover being provided with a first groove, the first groove and the first welding mark being arranged in the first direction, and the first groove being parallel to a first center line of the end cover.

2. The battery cell according to claim 1, wherein the battery cell further comprises a pressure relief mechanism arranged on the end cover, and the first groove is located between the first welding mark and the pressure relief mechanism in the first direction.

3. The battery cell according to claim 2, wherein in the first direction, the size of the end cover is W, the distance between the first groove and the pressure relief mechanism is h1, and 0 < h1 ≤ 0.4W is satisfied; optionally, 0.3mm ≤ h1 ≤ 0.4W is satisfied; optionally, 0.5mm ≤ h1 ≤ 0.4W is satisfied.

4. The battery cell according to claim 2, wherein in a second direction, both ends of the first groove exceed the pressure relief mechanism, respectively, and the first direction, the second direction and the thickness direction of the end cover are perpendicular to each other.

5. The battery cell according to claim 1, wherein in the first direction, the first wall has a first surface facing away from the electrode assembly, and the distance between the first groove and the first surface in the first direction is h2, and 1mm ≤ h2 ≤ 20mm is satisfied; optionally, 1.5mm ≤ h2 ≤ 15mm is satisfied.

6. The battery cell according to claim 1, wherein the first groove is a strip-shaped groove, and the first groove extends in a second direction, and the second direction, the first direction and the thickness direction of the end cover are perpendicular to each other.

7. The battery cell according to claim 6, wherein in the first direction, the width of the first groove is h3, and 0.1mm ≤ h3 ≤ 15mm is satisfied; optionally, 0.3mm ≤ h3 ≤ 10mm is satisfied.

8. The battery cell according to claim 6, wherein in the second direction, the length of the first groove is h4, and the length of the end cover is L, and 0 < h4 ≤ L is satisfied; optionally, 10mm ≤ h4 ≤ L is satisfied; optionally, 30mm ≤ h4 ≤ L is satisfied.

9. The battery cell according to claim 1, wherein the thickness of the end cover corresponding to the part where the first groove is located is t1, and 0.5mm ≤ t1 ≤ 3mm is satisfied; optionally, 0.7mm ≤ t1 ≤ 2mm is satisfied.

10. The battery cell according to claim 1, wherein In the first direction, the end cover includes a first region between the first groove and the first weld, and a thickness of the end cover corresponding to a position of the first groove is less than a thickness of the first region. 11.The battery cell of claim 1, wherein, In a thickness direction of the end cover, the first groove is formed on one side of the end cover, and a first protrusion is formed on the other side of the end cover, the first protrusion being located corresponding to the first groove; and in the thickness direction of the end cover, a thickness of the first protrusion is less than a thickness of the end cover. 12.The battery cell of claim 2, wherein, In the first direction, the shell has a second wall opposite to the first wall, and the second wall is connected to the end cover by a second weld; and at least one side of the end cover in the thickness direction is provided with a second groove, and the second groove is located between the second weld and the pressure relief mechanism in the first direction. 13.The battery cell of claim 12, wherein, The end cover has a second center line perpendicular to the first direction, and the first groove and the second groove are symmetrically arranged about the second center line. 14.The battery cell of any one of claims 1-13, wherein, The battery cell further includes a first electrode terminal and a second electrode terminal, and the first electrode terminal and the second electrode terminal are spaced apart in a second direction, the second direction, the first direction, and the thickness direction of the end cover being perpendicular to each other in pairs; In the second direction, the shell has a third wall connected to the end cover by a third weld, and at least one side of the end cover in the thickness direction is provided with a third groove, the third groove being located between the third weld and the first electrode terminal in the second direction, and the first electrode terminal being located between the third groove and the second electrode terminal. 15.The battery cell of claim 14, wherein, The first groove and the third groove are spaced apart from each other. 16.The battery cell of claim 14, wherein, The end cover has a first through hole, and the first electrode terminal is arranged in the first through hole; and in the second direction, a minimum distance between the third groove and the first through hole is h5, and 0.3mm≤h5≤40mm is satisfied. Alternatively, 0.5mm≤h5≤30mm is satisfied. 17.The battery cell of claim 14, wherein, In the second direction, the third wall has a third surface facing away from the electrode assembly, and in the second direction, a distance between the third groove and the third surface is h6, and 1mm≤h6≤30mm is satisfied. Alternatively, 1.5mm≤h6≤20mm is satisfied. 18.The battery cell of claim 14, wherein, The third groove is a strip-shaped groove, and the third groove extends in the first direction. 19.The battery cell of claim 18, wherein, In the second direction, the third groove has a width h7, and 0.1mm≤h7≤25mm is satisfied. Optionally, 0.3mm≤h7≤20mm is satisfied.

20. The battery cell according to claim 18, wherein In the first direction, the third groove has a length h8, and the end cover has a width W, and 0 Optionally, 1.5mm≤h8≤W is satisfied. Optionally, 2mm≤h8≤W is satisfied.

21. The battery cell according to claim 14, wherein The end cover has a thickness t2 corresponding to the position of the third groove, and 0.4mm≤t2≤3mm is satisfied. Optionally, 0.6mm≤t2≤2mm is satisfied.

22. The battery cell according to claim 14, wherein In the second direction, the end cover includes a third region between the third groove and the third weld, and the thickness of the end cover corresponding to the position of the third groove is smaller than the thickness of the third region.

23. The battery cell according to claim 14, wherein In the thickness direction of the end cover, the third groove is formed on one side of the end cover, and a third protrusion is formed on the other side of the end cover, and the third protrusion is located corresponding to the third groove; in the thickness direction of the end cover, the thickness of the third protrusion is smaller than the thickness of the end cover.

24. The battery cell according to claim 14, wherein In the second direction, the shell has a fourth wall opposite to the third wall, and the fourth wall is connected to the end cover by a fourth weld, and at least one side of the end cover in the thickness direction is provided with a fourth groove, and in the second direction, the fourth groove is located between the fourth weld and the second electrode terminal.

25. The battery cell according to claim 24, wherein The third groove and the fourth groove are symmetrically arranged about the first center line.

26. The battery cell according to claim 1, wherein The shell is a square shell, the size of the shell in the first direction is T1, the size of the shell in the second direction is W1, the size of the shell in the thickness direction of the end cover is H1, and satisfies, 3720cm 3 ≤W1*T1*H1≤12500cm 3 , 60mm≤T1≤150mm, 120mm≤H1≤400mm, 200mm≤W1≤1500mm, the first direction, the second direction and the thickness direction of the first wall are perpendicular to each other.

27. The battery cell according to claim 1, wherein The shell is a steel shell.

28. A battery device, characterized by The battery cell according to any one of claims 1-27.

29. An energy storage device, comprising: The battery cell according to any one of claims 1-27, and / or the battery device according to claim 28.

30. An electrical device, comprising: The battery cell according to any one of claims 1-27, and / or the battery device according to claim 28.

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