Battery

Abstract

The utility model relates to the technical field of battery energy, in particular to a battery. The battery comprises a shell and a shell cover covering the shell, the shell and the shell cover are welded and sealed, and a welding mark is formed on the shell cover; the welding marks comprise a first welding mark and a second welding mark, and the first welding mark is connected with the second welding mark; the peel strength of the first welding mark is smaller than or equal to 80% of the peel strength of the second welding mark. Compared with the control of the depth of the notch groove on the shell and / or the shell cover, the peeling strength of the first welding mark and / or the second welding mark is easier to control. By controlling the peel strength of the first welding mark and the peel strength of the second welding mark, the problem that the pressure of the battery is not released in time is solved, and the safety of the battery is ensured.

Description

Technical Field

[0001] The present application relates to the field of battery energy technology, and in particular to a battery. Background Art

[0002] Batteries are a widely used energy device. Using batteries as an energy source can obtain stable voltage and current, and they play a great role in all aspects of modern social life. With the development of the battery industry, companies have higher and higher requirements for battery safety performance.

[0003] At present, the outer shell of the battery includes a shell and a shell cover arranged on the shell. The shell cover is arranged on the shell and fixed to the shell by welding. In order to ensure the safety of the battery, a thinning area is usually set on the outer shell of the battery by notching. The thickness of the outer shell in the thinning area is less than the thickness of the remaining area of ​​the outer shell. When the pressure difference between the inside and outside of the outer shell reaches the pressure relief threshold, the outer shell ruptures in the thinning area to achieve pressure relief.

[0004] However, the pressure relief threshold of the casing is difficult to control, and the battery pressure may not be released in time, affecting the safety of the battery. Utility Model Content

[0005] Based on this, the present application provides a battery to solve the problem in the related art that the pressure relief threshold of the shell is difficult to control, which may cause the battery to release pressure untimely, affecting the safety of the battery.

[0006] The battery provided in the present application comprises a shell and a shell cover arranged on the shell;

[0007] The shell body and the shell cover are welded and sealed, and a welding mark is formed on the shell cover; the welding mark includes a first welding mark and a second welding mark, and the first welding mark is connected to the second welding mark;

[0008] The peel strength of the first weld print is ≤ 80% of the peel strength of the second weld print.

[0009] In a possible implementation, the peel strength of the first weld print is greater than or equal to 20% of the tensile strength of the shell cover.

[0010] In a possible implementation, the battery further includes a battery cell located in the housing and an external lead-out member located on a first side wall of the housing;

[0011] The external lead-out part is connected to the battery core;

[0012] The external lead-out piece and the second weld mark are not located on the same side of the housing.

[0013] In a possible implementation, the first end of the first weld print is connected to the first end of the second weld print, the second end of the first weld print is connected to the second end of the second weld print, and the first weld print and the second weld print together form an annular structure surrounding the shell.

[0014] In a possible implementation, the width of the first weld mark is smaller than the width of the second weld mark.

[0015] In a possible implementation manner, a groove is formed between the first weld mark and the second weld mark, and the groove is located on a side of the first weld mark facing the interior of the annular structure.

[0016] In a possible implementation, the dimension H1 of the groove in the width direction of the second weld print and the dimension H2 of the second weld print in the width direction of the second weld print satisfy:

[0017] H2×10%≤H1≤H2×50%.

[0018] In a possible implementation, the annular structure has a long side, the first weld mark is located on the long side, and the length B of the first weld mark satisfies the length A of the long side:

[0019] 5%×A≤B≤30%×A.

[0020] In a possible implementation, an R angle is formed between two adjacent sides of the annular structure, the annular structure has a long side, the first weld mark is located on the long side, and the distance between the first weld mark and the adjacent R angle is less than or equal to half the length of the long side.

[0021] In a possible implementation, the annular structure includes a plurality of straight line segments and an R corner connecting two adjacent straight line segments, and the first weld mark is located on the R corner.

[0022] In a possible implementation, there is a third weld mark between the first weld mark and the second weld mark, and the length of the third weld mark is between 10% and 60% of the R corner radius of the first weld mark; and / or,

[0023] The number of the first weld marks is multiple.

[0024] In a possible implementation, the first weld mark includes two first connecting segments and a second connecting segment located between the two first connecting segments, one end of each first connecting segment is connected to the second connecting segment, and the other end of each first connecting segment is connected to the end of the second weld mark.

[0025] In a possible implementation, the second weld print is arranged around the shell, the first weld print is located inside the first weld print, one end of the first weld print is connected to the second weld print, and the first weld print has a plurality of gaps inside.

[0026] In one possible implementation, in a first cross section of the first weld print, a total area of ​​the plurality of gaps is less than or equal to 50% of a total area of ​​the first weld print on the first cross section, and a total area of ​​the plurality of gaps is greater than or equal to 10% of a total area of ​​the first weld print on the first cross section; and / or,

[0027] The depth of the first weld mark is greater than or equal to 50% of the thickness of the shell cover, and the depth of the first weld mark is less than or equal to 90% of the thickness of the shell cover; and / or,

[0028] The extension direction of the portion of the second weld mark connected to the first weld mark is perpendicular to the extension direction of the first weld mark;

[0029] A third weld mark is provided between the first weld mark and the second weld mark, and an extension direction of a portion of the second weld mark connected to the first weld mark is parallel to an extension direction of the first weld mark.

[0030] The battery provided in the present application includes a shell and a shell cover arranged on the shell, and the shell and the shell cover are sealed by welding. After welding, a first weld mark and a second weld mark are formed on the shell cover. The sealing between the shell and the shell cover is achieved by the first weld mark and the second weld mark. Compared with controlling the depth of the grooves on the shell and / or the shell cover, the peel strength of the first weld mark and / or the second weld mark is easier to control. During the welding process, the peel strength of the first weld mark is controlled not to exceed 80% of the peel strength of the second weld mark. Compared with the second weld mark, the first weld mark is weaker. When the pressure difference between the inside and outside of the battery reaches a preset value, the weak first weld mark begins to break, that is, cracks are generated on the first weld mark. As the internal pressure of the battery further increases, the cracks on the first weld mark may penetrate the first weld mark or extend to the second weld mark and penetrate the second weld mark, the weld mark breaks, and the battery is depressurized in time. In this way, the battery is not prone to the problem of untimely depressurization, which ensures the safety of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 A schematic diagram of the structure of a battery provided in an embodiment of the present application;

[0033] Figure 2 for Figure 1 An exploded view of the battery shown;

[0034] Figure 3 A schematic diagram of the structure of the first welding print provided in the embodiment of the present application;

[0035] Figure 4 A schematic diagram of the structure of a second welding stamp provided in an embodiment of the present application;

[0036] Figure 5A schematic diagram of the structure of a third welding print provided in an embodiment of the present application;

[0037] Figure 6 A schematic diagram of the structure of the fourth welding print provided in the embodiment of the present application;

[0038] Figure 7 A schematic diagram of the structure of the fifth welding print provided in the embodiment of the present application;

[0039] Figure 8 A schematic diagram of the structure of the sixth welding print provided in the embodiment of the present application;

[0040] Fig. 9 A schematic diagram of the structure of a seventh welding stamp provided in an embodiment of the present application;

[0041] Fig.10 A cross-sectional view of the shell cover provided in an embodiment of the present application at a first welding position;

[0042] Fig.11 The housing and the housing cover provided in the embodiment of the present application are Fig. 9 Schematic diagram of the cross-sectional structure at the weld mark location shown.

[0043] Description of reference numerals:

[0044] 100-housing;

[0045] 200-shell cover;

[0046] 300-weld mark; 310-first weld mark; 311-first connecting section; 312-second connecting section; 313-gap; 320-second weld mark; 330-third weld mark; 340-groove; 350-R angle;

[0047] 400-battery cells. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme in the embodiment of the present application will be described in more detail below in conjunction with the drawings in the preferred embodiments of the present application. In the drawings, the same or similar reference numerals throughout represent the same or similar parts or parts with the same or similar functions. The described embodiments are part of the embodiments of the present application, not all of the embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limitations on the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application. The embodiments of the present application are described in detail below in conjunction with the drawings.

[0049] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, or it can be an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0050] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are orientations or positional relationships based on the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0051] The terms "first", "second" and "third" (if any) in the specification and claims of this application and the above drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0052] In addition, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, system, product, or display comprising a series of steps or elements is not necessarily limited to those steps or elements explicitly listed, but may include other steps or elements not explicitly listed or inherent to such process, method, product, or display.

[0053] In the prior art, in order to ensure the safety of battery use, a thinned area is usually set on the outer shell of the battery by means of grooves. When the pressure difference between the inside and outside of the outer shell reaches the pressure relief threshold, the outer shell ruptures in the thinned area to achieve pressure relief. However, the pressure relief threshold of the battery is affected by the consistency of the process and the consistency of the materials, making the pressure relief threshold difficult to control. When the groove depth is too small, it cannot rupture and release pressure in time, and there will be safety risks of explosion and failure during use, which is manifested as untimely pressure relief of the battery (failure to reach the safety level), affecting the safety of the battery.

[0054] After repeated thinking and verification, the inventor found that after the shell cover of the battery is set on the shell, it is generally fixed on the shell by welding and sealed with the shell. Compared with controlling the depth of the groove, the peel strength of the weld mark during welding is easier to control. Some weld marks are set as weak weld marks, and the weak weld marks are connected to non-weak weld marks. The peel strength of the weak weld mark and the non-weak weld mark is set. When the internal and external pressure difference of the battery is abnormal, the weak weld mark begins to rupture. As the internal pressure of the battery continues to increase, the cracks on the weak weld mark penetrate the weak weld mark or the cracks on the weak weld mark extend to the non-weak weld mark and penetrate the non-weak weld mark. The battery is depressurized in time through the rupture of the weld mark. In this way, the problem of untimely pressure relief of the battery can be avoided, and the safety of the battery can be ensured.

[0055] In view of this, the inventors designed a battery, the shell and shell cover of the battery are sealed by welding, and a first weld mark and a second weld mark are formed on the shell cover. The peel strength of the first weld mark is controlled not to exceed 80% of the peel strength of the second weld mark, so that the first weld mark can generate cracks when the pressure difference between the inside and outside of the battery reaches a preset value, and the cracks on the first weld mark can penetrate the first weld mark or extend to the second weld mark and penetrate the second weld mark, so that the battery can be depressurized in time by the rupture of the weld mark.

[0056] The technical solution of the battery provided in the embodiments of the present application is described in detail below in conjunction with the accompanying drawings.

[0057] Reference Figures 1 to 3 As shown, the battery provided in the embodiment of the present application includes a shell 100 and a shell cover 200 covered on the shell 100. The shell 100 and the shell cover 200 are welded and sealed, and a weld mark 300 is formed on the shell cover 200. The weld mark 300 includes a first weld mark 310 and a second weld mark 320, and the first weld mark 310 is connected to the second weld mark 320. The peel strength of the first weld mark 310 is ≤80% of the peel strength of the second weld mark 320.

[0058] Schematically, the housing 100 is provided with a receiving cavity, through which the battery cell 400 of the battery can be received, the battery cell 400 is electrically connected to the housing 100, and the battery cell 400 can be a rolled core or a stacked core, which is not limited here. The housing cover 200 can be a sheet structure, and the housing cover 200 can seal the receiving cavity after being covered on the housing 100 and welded to the housing 100.

[0059] At least part of the weld mark 300 passes through the shell cover 200 and extends to the side wall of the shell 100, and the weld mark 300 is arranged around the side wall of the shell 100 to achieve sealing between the shell 100 and the shell cover 200. The weld mark 300 for sealing is arranged around the side wall of the shell 100, and its shape matches the shape of the side wall of the shell 100.

[0060] It can be understood that the peel strength of the second weld mark 320 is greater than the peel strength of the first weld mark 310. Optionally, the peel strength of each of the first weld mark 310 and the second weld mark 320 can be set by adjusting the welding process parameters. Among them, the first weld mark 310 is connected to the second weld mark 320, so that the crack on the first weld mark 310 can extend to the second weld mark 320. When the pressure difference between the inside and outside of the battery is too large, the first weld mark 310 and the second weld mark 320 can both rupture to achieve faster pressure relief.

[0061] The battery provided in this embodiment includes a shell 100 and a shell cover 200 disposed on the shell 100. The shell 100 and the shell cover 200 are sealed by welding. After welding, a first weld mark 310 and a second weld mark 320 are formed on the shell cover 200. The seal between the shell 100 and the shell cover 200 is achieved by the first weld mark 310 and the second weld mark 320. Compared with controlling the depth of the grooves on the shell 100 and / or the shell cover 200, the peel strength of the first weld mark 310 and / or the second weld mark 320 is easier to control. During the welding process, the peel strength of the first weld mark 310 is controlled not to exceed 80% of the peel strength of the second weld mark 320. Compared with the second weld mark 320, the first weld mark 310 is weaker. When the pressure difference between the inside and outside of the battery reaches a preset value, the weak first weld mark 310 begins to break, that is, cracks are generated on the first weld mark 310. As the internal pressure of the battery further increases, the crack on the first weld mark 310 may penetrate the first weld mark 310 or extend to the second weld mark 320 and penetrate the second weld mark 320, and the weld mark 300 ruptures, and the battery is depressurized in time. In this way, the battery is not prone to the problem of untimely depressurization, ensuring the safety of the battery.

[0062] In one embodiment, Figure 1-Figure 3 As shown, the peel strength of the first weld mark 310 is greater than or equal to 20% of the tensile strength of the housing cover 200 .

[0063] The peeling strength of the second weld mark 320 is greater than the peeling strength of the first weld mark 310 , that is, the peeling strength of the second weld mark 320 is greater than 20% of the tensile strength of the shell cover 200 .

[0064] This structure prevents the first weld mark 310 and / or the second weld mark 320 from rupturing during a drop test of the battery by controlling the peel strength of the first weld mark 310 and the second weld mark 320, thereby ensuring that the battery can pass the drop test, that is, preventing the battery from being too sensitive to pressure release.

[0065] In a possible implementation, the battery further includes a battery cell 400 located in the housing 100 and an external lead-out member located on the first side wall of the housing 100. The external lead-out member is connected to the battery cell 400. The external lead-out member and the second weld mark 320 are not located on the same side of the housing 100.

[0066] Schematically, the external lead-out member may be a columnar structure, which may be made of a conductive material. After the external lead-out member is mounted on the first side wall of the housing 100, the external lead-out member may be electrically connected to the tab of the battery cell 400. The external lead-out member may be used to realize electrical connection between the battery cell 400 and an external device, so that the battery cell 400 of the battery may supply power to the external device, or the external device may charge the battery cell 400 of the battery.

[0067] Exemplarily, the external lead-out member and the second weld mark 320 may be located on two adjacent sides of the housing 100 , or the external lead-out member and the second weld mark 320 may be located on two opposite sides of the housing 100 , which is not limited here.

[0068] In this structure, the external lead-out member and the second weld mark 320 are not located on the same side of the housing 100 , ensuring that the second weld mark 320 will not interfere with the connection between the external lead-out member and the battery cell 400 , thereby ensuring the normal operation of the battery cell 400 .

[0069] In one embodiment, Figure 3-Figure 7 As shown, the first end of the first weld mark 310 is connected to the first end of the second weld mark 320 , and the second end of the first weld mark 310 is connected to the second end of the second weld mark 320 . The first weld mark 310 and the second weld mark 320 together form an annular structure surrounding the shell 100 .

[0070] The housing 100 and the housing cover 200 are sealed together by the first weld mark 310 and the second weld mark 320. The shape of the annular structure formed by the first weld mark 310 and the second weld mark 320 matches the shape of the side wall of the housing 100. Specifically, the first weld mark 310 and the second weld mark 320 both pass through the housing cover 200 and extend to one end of the side wall of the housing 100 facing the housing cover 200, that is, the depth of the first weld mark 310 and the depth of the second weld mark 320 are both greater than the thickness of the housing cover 200.

[0071] In a specific embodiment, Figure 3-Figure 7 As shown, the width of the first weld mark 310 is smaller than the width of the second weld mark 320 .

[0072] In a possible implementation, the weld mark 300 includes a plurality of overlapping weld marks, and the first weld mark 310 may have a narrower width, or the number of weld marks of the first weld mark 310 is less than the number of weld marks of the second weld mark 320, for example, the first weld mark 310 may include only one weld mark. Optionally, a narrower weld mark width may be stably achieved by changing the welding power and the welding speed. The above setting may make the width of the first weld mark 310 smaller than the width of the second weld mark 320.

[0073] It is understandable that the greater the width of the weld mark 300, the greater its peel strength. By setting the widths of the first weld mark 310 and the second weld mark 320, the peel strength of the first weld mark 310 can be controlled to be smaller than the peel strength of the second weld mark 320. When the pressure difference between the inside and outside of the battery reaches a preset value, the weak first weld mark 310 begins to rupture first, so that the battery can be depressurized in time.

[0074] In a specific embodiment, Figure 3-Figure 7 As shown, a groove 340 is formed between the first weld stamp 310 and the second weld stamp 320. The groove 340 is located on a side of the first weld stamp 310 facing the inside of the annular structure.

[0075] Schematically, the width of the groove 340 is the same as the length of the first weld mark 310, wherein the width of the groove 340, that is, the groove 340 at Figure 3 The dimension in the direction indicated by the Y axis is the length of the first weld mark 310, that is, the length of the first weld mark 310 in Figure 3 In a possible implementation, the weld mark 300 includes a plurality of overlapping weld marks, and the width of the weld mark of the first weld mark 310 toward the inside of the annular structure may be narrower, or the number of weld marks of the first weld mark 310 is less than the number of weld marks of the second weld mark 320 and the weld marks of the first weld mark 310 are arranged close to the outside of the annular structure, for example, the first weld mark 310 may include only one weld mark. The above arrangement forms a groove 340 between the first weld mark 310 and the second weld mark 320 on one side facing the inside of the annular structure.

[0076] It should be noted that an end of the side wall of the shell 100 facing the shell cover 200 forms an arc-shaped flange extending toward the outside of the shell 100, and the groove 340 is arranged on the side of the first weld mark 310 facing the inside of the annular structure, ensuring that the first weld mark 310 can reliably connect the shell cover 200 and the end of the shell 100 facing the shell cover 200, thereby ensuring the airtightness between the shell 100 and the shell cover 200 at the position of the first weld mark 310.

[0077] like Figure 3 As shown, in a specific embodiment, a dimension H1 of the groove 340 in the width direction of the second weld mark 320 and a dimension H2 of the second weld mark 320 in the width direction of the second weld mark 320 satisfy: H2×10%≤H1≤H2×50%.

[0078] The width of the first weld mark 310 is equal to the difference between H2 and H1. It is understandable that the width of the first weld mark 310 is greater than or equal to 50% of the width H2 of the second weld mark 320, and the width of the first weld mark 310 is less than or equal to 90% of the width H2 of the second weld mark 320. When the depth of the groove 340 is less than H2×10%, the width of the first weld mark 310 is wider, and the battery may not release pressure in time; when the depth of the groove 340 is greater than H2×50%, the width of the first weld mark 310 is narrower, and the battery may be too sensitive to pressure release, and the weld mark 300 is prone to rupture and failure during the battery drop test.

[0079] Through the above settings, it is ensured that the sensitivity of the battery pressure relief is moderate, and the problem of insensitive pressure relief or untimely pressure relief is not likely to occur, thereby ensuring the safety of the battery.

[0080] Continue to refer to Figure 3 In a specific embodiment, the annular structure has a long side, the first weld mark 310 is located on the long side, and the length B of the first weld mark 310 and the length A of the long side satisfy: 5%×A≤B≤30%×A.

[0081] like Figure 3 As shown, the shape of the annular structure is approximately rectangular, and the housing 100 can be formed into a rectangular box structure. The rectangular annular structure can achieve sealing between the side walls of the housing 100 and the shell cover 200. The long side of the annular structure is the longer side of the annular structure. When the pressure difference between the inside and outside of the battery is large, the stress of the weld mark 300 at the long side of the annular structure is more concentrated than the stress at the short side of the annular structure. The first weld mark 310 is arranged on the long side of the annular structure so that the battery can be depressurized in time.

[0082] When B<5%×A, the length of the first weld mark 310 is too short, and the battery may not be able to release pressure in time when an abnormality occurs inside the battery; when B>30%×A, the length of the first weld mark 310 is too long, the battery pressure release is too sensitive, and the weld mark 300 may abnormally rupture during the use of the battery.

[0083] Through the above settings, it is ensured that the sensitivity of the battery pressure relief is moderate, and the problem of insensitive pressure relief or untimely pressure relief is not likely to occur, thereby ensuring the safety of the battery.

[0084] Figure 3 It is shown that an R angle 350 is formed between two adjacent sides of the annular structure, the annular structure has a long side, the first weld mark 310 is located on the long side, and the distance C between the first weld mark 310 and the adjacent R angle 350 is less than or equal to half of the length A of the long side.

[0085] The radius of the R angle 350 is not limited in this embodiment, and those skilled in the art can set it according to actual needs. It is worth mentioning that when the pressure difference between the inside and outside of the battery is large, the closer the weld mark 300 of the annular structure is to the corner position of the rectangle, the more concentrated the stress is. In this embodiment, C≤50%×A makes the first weld mark 310 close to the stress concentration area between the shell 100 and the shell cover 200, so that the first weld mark 310 can be broken in time to achieve pressure relief of the battery.

[0086] In one possible implementation, Figure 4 and Figure 5 As shown, the annular structure includes a plurality of straight line segments and an R corner 350 connecting two adjacent straight line segments, and the first weld mark 310 is located on the R corner 350 .

[0087] It can be understood that the first weld mark 310 is set at the R angle 350 position of the annular structure, so that when an abnormality occurs inside the battery, the stress at the first weld mark 310 position is more concentrated, and then the first weld mark 310 can be broken in time to achieve battery pressure relief.

[0088] like Figure 4 As shown, a third weld mark 330 is provided between the first weld mark 310 and the second weld mark 320 , and the length of the third weld mark 330 is between 10% and 60% of the radius of the R angle 350 where the first weld mark 310 is located.

[0089] Schematically, there are two third weld marks 330, and the two third weld marks 330 are respectively located at the two ends of the first weld mark 310. The lengths of the two third weld marks 330 can be C1 and C2 respectively. Among them, the sizes of C1 and C2 are both between 10% and 60% of the radius of the R angle 350. The lengths of the two third weld marks 330 can be the same or different, and are not limited here. Figure 4 It is shown that the width of the third weld mark 330 gradually increases from the first weld mark 310 toward the second weld mark 320 , and the third weld mark 330 plays a transition role between the first weld mark 310 and the second weld mark 320 .

[0090] When the length of the third weld mark 330 is less than 10% of the radius of the R angle 350 where the first weld mark 310 is located, the length of the first weld mark 310 is relatively long, and the pressure release of the battery is too sensitive, and the weld mark 300 may abnormally rupture during the use of the battery or the drop test; when the length of the third weld mark 330 is greater than 60% of the radius of the R angle 350 where the first weld mark 310 is located, the length of the first weld mark 310 is relatively short, and the battery may not be able to release pressure in time when an abnormality occurs inside the battery.

[0091] The above settings ensure that the sensitivity of the battery pressure relief is moderate, and the problem of insensitive pressure relief or untimely pressure relief is not likely to occur, thereby ensuring the safety of the battery.

[0092] like Figure 5 As shown, there are multiple first weld marks 310 .

[0093] The ring structure formed by the first weld mark 310 and the second weld mark 320 can be Figure 5 The approximately "step-like" structure shown in FIG. 1 matches the shape of the annular structure formed by the side wall of the housing 100, and the first weld mark 310 can be located between two step portions of the "step-like" structure. This embodiment does not limit the specific number of the first weld marks 310, and those skilled in the art can set it as needed.

[0094] Through the above arrangement, when the pressure difference between the inside and outside of the battery reaches a preset value, the plurality of first weld marks 310 may rupture, which is beneficial to improving the pressure relief efficiency of the battery, thereby enabling the battery to achieve faster pressure relief.

[0095] In one possible implementation, Figure 6 As shown, the first weld mark 310 includes two first connecting segments 311 and a second connecting segment 312 located between the two first connecting segments 311. One end of each first connecting segment 311 is connected to the second connecting segment 312, and the other end of each first connecting segment 311 is connected to the end of the second weld mark 320.

[0096] like Figure 6 As shown, the two first connecting segments 311 and the second connecting segment 312 of the first weld mark 310 form an approximate "U"-shaped structure, and the two ends of the first weld mark 310 are respectively connected to the two ends of the second weld mark 320. The shape of the annular structure formed by the first weld mark 310 and the second weld mark 320 is approximately a "concave" shape, and the first weld mark 310 is located in the middle of the "concave" shape. When the pressure difference between the inside and outside of the battery is large, the stress of the weld mark 300 in the middle of the "concave" shape is more concentrated. It can be understood that the side wall of the shell 100 is also enclosed in an approximate "concave" shape.

[0097] Through the above arrangement, when the pressure difference between the inside and outside of the battery is large, the first weld mark 310 can rupture in time to release the pressure. At this time, both the first connecting segments 311 and the second connecting segments 312 of the first weld mark 310 can rupture to improve the pressure release efficiency of the battery, so that the battery can achieve faster pressure release.

[0098] like Figure 7 As shown, in a possible implementation, the shape of the annular structure is circular.

[0099] The housing 100 is a circular cylindrical structure matching the annular structure. When the pressure difference between the inside and outside of the battery is large, the first weld mark 310 can be broken in time to release the pressure.

[0100] In one embodiment, Figure 8-Figure 11 As shown, the second weld mark 320 is arranged around the shell 100, the first weld mark 310 is located inside the first weld mark 310, one end of the first weld mark 310 is connected to the second weld mark 320, and the first weld mark 310 has a plurality of gaps 313 inside.

[0101] After the shell cover 200 is placed on the shell 100, it is sealed by the second weld mark 320. The second weld mark 320 passes through the shell cover 200 and is embedded in the side wall of the shell 100 facing one end of the shell cover 200. The shape formed by the second weld mark 320 matches the shape enclosed by the side wall of the shell 100. Fig.10 and Fig.11 As shown, the first weld mark 310 is embedded in the interior of the shell cover 200 , and the depth of the first weld mark 310 is less than the thickness of the shell cover 200 .

[0102] In one possible implementation, active gas (such as H2 or O2, etc.) can be input during the welding process of the first weld mark 310 to stably form a multi-void 313, i.e., a porous first weld mark 310 on the shell cover 200. By controlling the concentration of the active gas, the density of the internal voids 313 of the first weld mark 310 can be stably set.

[0103] Schematically, the shell cover 200 is equivalent to a combination of a strip-shaped groove and a non-dense metal adhesive at the position of the first weld mark 310. When the battery is subjected to a drop test, the material of the first weld mark 310, i.e., the non-dense metal adhesive, is subjected to planar compressive stress, and the first weld mark 310 can ensure that the battery will not have abnormal pressure relief; when the pressure difference between the inside and outside of the battery is abnormal, the first weld mark 310 is subjected to tensile stress, and the first weld mark 310 and the position of the shell cover 200 corresponding to the first weld mark 310 can be broken in time for pressure relief. As the internal pressure of the battery continues to increase, the crack on the first weld mark 310 can extend to the second weld to improve the pressure relief efficiency of the battery. In addition, compared with the method of simply setting a groove on the shell cover 200, it is easier to control the pressure relief threshold of the battery. Compared with setting weld marks 300 of different widths, the processing of porous weld marks 300 is easier, and pressure relief can be more stable when the pressure difference between the inside and outside of the battery is abnormal.

[0104] In one possible implementation, in the first cross-section of the first weld mark 310, the total area of ​​the plurality of voids 313 is less than or equal to 50% of the total area of ​​the first weld mark 310 on the first cross-section, and the total area of ​​the plurality of voids 313 is greater than or equal to 10% of the total area of ​​the first weld mark 310 on the first cross-section.

[0105] Schematically, the first section is perpendicular to the extension direction of the first weld mark 310. The ratio between the total area of ​​the voids 313 and the total area of ​​the first weld mark 310 on the first section can be controlled by the concentration of the active gas when welding the first weld mark 310. When the total area of ​​the plurality of voids 313 is greater than 50% of the total area of ​​the first weld mark 310 on the first section, the ability of the first weld mark 310 to withstand tensile stress is too small, the pressure relief of the battery is too sensitive, and the first weld mark 310 and the position of the shell cover 200 corresponding to the first weld mark 310 may be abnormally broken during the use of the battery; when the total area of ​​the plurality of voids 313 is less than 10% of the total area of ​​the first weld mark 310 on the first section, the ability of the first weld mark 310 to withstand tensile stress is too large, and the battery may not be able to relieve pressure in time when an abnormality occurs inside the battery.

[0106] like Fig.10 As shown, the depth H3 of the first weld mark 310 is greater than or equal to 50% of the thickness H4 of the shell cover 200 , and the depth H3 of the first weld mark 310 is less than or equal to 90% of the thickness H4 of the shell cover 200 .

[0107] Among them, the specific depth of the first weld mark 310 can be set according to actual needs and is not limited here. When the depth H3 of the first weld mark 310 is less than 50% of the thickness H4 of the shell cover 200, the thickness of the shell cover 200 corresponding to the position of the first weld mark 310 is thicker, and when an abnormality occurs inside the battery, the portion of the shell cover 200 corresponding to the position of the first weld mark 310 cannot be broken in time to release pressure; when the depth H3 of the first weld mark 310 is greater than 90% of the thickness H4 of the shell cover 200, the thickness of the shell cover 200 corresponding to the position of the first weld mark 310 is thinner, and the first weld mark 310 and the position of the shell cover 200 corresponding to the first weld mark 310 may be abnormally broken during the use of the battery.

[0108] The above settings can ensure that the sensitivity of battery pressure relief is moderate, and the problem of insensitive pressure relief or untimely pressure relief is not likely to occur, thereby ensuring the safety of the battery.

[0109] In one possible implementation, Figure 8 As shown, the extension direction of the portion where the second weld mark 320 is connected to the first weld mark 310 is perpendicular to the extension direction of the first weld mark 310 .

[0110] At this time, when an abnormality occurs inside the battery, the strain direction of the shell cover 200 at the position of the first weld mark 310 is parallel to the extension direction of the portion where the second weld mark 320 is connected to the first weld mark 310, that is, the strain direction of the shell cover 200 at the position of the first weld mark 310 is perpendicular to the extension direction of the first weld mark 310. In this way, when an abnormality occurs inside the battery, the first weld mark 310 is more likely to crack and release pressure.

[0111] In another possible implementation, Fig. 9 As shown, a third weld mark 330 is provided between the first weld mark 310 and the second weld mark 320 , and an extension direction of a portion where the second weld mark 320 is connected to the first weld mark 310 is parallel to an extension direction of the first weld mark 310 .

[0112] Schematically, the first weld mark 310 and the third weld mark 330 can form an approximately "L"-shaped structure, one end of which is connected to the second weld mark 320. When an abnormality occurs inside the battery, the strain direction of the shell cover 200 at the position of the first weld mark 310 is perpendicular to the extension direction of the portion where the second weld mark 320 is connected to the first weld mark 310, that is, the strain direction of the shell cover 200 at the position of the first weld mark 310 is perpendicular to the extension direction of the first weld mark 310. In this way, when an abnormality occurs inside the battery, the first weld mark 310 is more likely to crack and release pressure.

[0113] Through the above settings, the extension direction of the first weld mark 310 can be set according to the shape and size of the battery, so that the strain direction of the shell cover 200 at the position of the first weld mark 310 is perpendicular to the extension direction of the first weld mark 310. When an abnormality occurs inside the battery, the first weld mark 310 can be ruptured in time to release pressure.

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery, characterized in that: It comprises a shell and a shell cover arranged on the shell; The shell and the shell cover are welded and sealed, and a welding mark is formed on the shell cover; the welding mark includes a first welding mark and a second welding mark, and the first welding mark is connected to the second welding mark; The peel strength of the first weld mark is ≤ 80% of the peel strength of the second weld mark.

2. The battery according to claim 1, characterized in that The peel strength of the first weld print is greater than or equal to 20% of the tensile strength of the shell cover.

3. The battery according to claim 1, characterized in that The battery further comprises a battery cell located in the housing and an external lead-out member located on a first side wall of the housing; The external lead-out member is connected to the battery core; The external lead-out member and the second weld mark are not located on the same side of the housing.

4. The battery according to claim 1, characterized in that The first end of the first weld stamp is connected to the first end of the second weld stamp, the second end of the first weld stamp is connected to the second end of the second weld stamp, and the first weld stamp and the second weld stamp together form an annular structure surrounding the shell.

5. The battery according to claim 4, characterized in that The width of the first weld mark is smaller than the width of the second weld mark.

6. The battery according to claim 4, characterized in that A groove is formed between the first weld mark and the second weld mark, and the groove is located on a side of the first weld mark facing the interior of the annular structure.

7. The battery according to claim 6, characterized in that The dimension H1 of the groove in the width direction of the second weld print and the dimension H2 of the second weld print in the width direction of the second weld print satisfy: H2×10%≤H1≤H2×50%.

8. The battery according to claim 4, characterized in that The annular structure has a long side, the first weld mark is located on the long side, and the length B of the first weld mark satisfies the length A of the long side: 5%×A≤B≤30%×A.

9. The battery according to claim 4, characterized in that An R angle is formed between two adjacent sides of the annular structure, the annular structure has a long side, the first weld mark is located on the long side, and the distance between the first weld mark and the adjacent R angle is less than or equal to half the length of the long side.

10. The battery according to claim 4, characterized in that The annular structure includes a plurality of straight line segments and an R corner connecting two adjacent straight line segments, and the first weld mark is located on the R corner.

11. The battery according to claim 10, characterized in that There is a third weld mark between the first weld mark and the second weld mark, and the length of the third weld mark is between 10% and 60% of the R corner radius of the first weld mark; and / or, The number of the first weld marks is multiple.

12. The battery according to claim 4, characterized in that The first weld mark includes two first connecting segments and a second connecting segment located between the two first connecting segments, one end of each of the first connecting segments is connected to the second connecting segment, and the other end of each of the first connecting segments is connected to the end of the second weld mark.

13. The battery according to claim 1, characterized in that The second weld print is arranged around the shell, the first weld print is located inside the first weld print, one end of the first weld print is connected to the second weld print, and the first weld print has a plurality of gaps inside.

14. The battery according to claim 13, characterized in that In a first cross section of the first weld print, a total area of ​​the plurality of gaps is less than or equal to 50% of a total area of ​​the first weld print on the first cross section, and a total area of ​​the plurality of gaps is greater than or equal to 10% of a total area of ​​the first weld print on the first cross section; and / or, The depth of the first weld mark is greater than or equal to 50% of the thickness of the shell cover, and the depth of the first weld mark is less than or equal to 90% of the thickness of the shell cover; and / or, The extension direction of the portion of the second weld mark connected to the first weld mark is perpendicular to the extension direction of the first weld mark; A third weld mark is provided between the first weld mark and the second weld mark, and an extension direction of a portion of the second weld mark connected to the first weld mark is parallel to an extension direction of the first weld mark.

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