Shaping mechanism for battery cell tab and battery cell

Abstract

The utility model discloses a shaping mechanism for a battery cell tab and a battery cell, and the shaping mechanism comprises: a fixing assembly for fixing the battery cell; the shaping assembly comprises a first shaping part and a second shaping part which relatively move in the thickness direction of the tab, the first shaping part and the second shaping part are oppositely arranged in the thickness direction of the tab, and the first shaping part is provided with a first shaping curved surface bent relative to the extending direction of the tab; the first shaping curved surface is provided with a first bending section and a second bending section which are opposite in bending direction. According to the shaping mechanism disclosed by the embodiment of the invention, by arranging the first shaping curved surface with the two bending sections with opposite bending directions, the battery cell tab can be pre-shaped before being welded, so that the non-welding part of the battery cell tab forms the bending buffer part, the internal stress is counteracted through the deformation of the bending buffer part when the size of the battery cell is changed, and the welding quality of the battery cell tab is improved. And the risk of tearing is reduced.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to the technical field of battery manufacturing. More particularly, the present disclosure relates to a shaping mechanism for a battery cell tab and a battery cell. BACKGROUND

[0002] In the existing lithium battery production process, a step of combining and packaging a plurality of tabs stacked in the thickness direction is included. Among them, the plurality of foil tabs stacked together need to be welded by means of ultrasonic welding or the like to form an overall battery cell tab. However, in the actual production and use process, the thickness and width dimensions of the battery cell may change due to the influence of the charging and discharging process. After the overall size of the battery cell changes, the plurality of tabs of the battery cell deviate from the original position, and the tab of the battery cell fixed in a welded manner will be pulled by the foil tabs of the plurality of tabs, so that an undesirable internal stress is generated inside the tab of the battery cell. If the internal stress exceeds the limit of the strength of the tab structure, it will cause the tab of the battery cell to tear or deform, causing the battery to fail, and even possibly causing the aluminum plastic film to tear, causing the risk of electrolyte leakage. In the existing design scheme, there are few corresponding solutions to such pulling stress.

[0003] Therefore, there is an urgent need to provide a shaping mechanism for a battery cell tab and a battery cell in order to improve the anti-cracking performance of the battery cell. SUMMARY

[0004] In order to at least solve one or more of the above-mentioned technical problems, the present disclosure proposes, in various aspects, a shaping mechanism for a battery cell tab and a battery cell.

[0005] The present disclosure provides, in a first aspect, a shaping mechanism for a battery cell tab, comprising: a fixing assembly for fixing a battery cell; a shaping assembly comprising a first shaping portion and a second shaping portion relatively movable along the thickness direction of the tab, the first shaping portion and the second shaping portion being oppositely arranged along the thickness direction of the tab, the first shaping portion having a first shaping curved surface curved relative to the extension direction of the tab, the first shaping curved surface having a first bending segment and a second bending segment with opposite bending directions.

[0006] In some embodiments, the second shaping portion has a second shaping curved surface adapted to the shape of the first shaping curved surface.

[0007] In some embodiments, along the thickness direction of the tab, the first bending segment and the second bending segment each have a quarter circular arc cross-sectional profile.

[0008] In some embodiments, a ratio of the tab thickness L to the radius R1 of the circular arc cross-sectional profile of the first bending section satisfies 0.15≤L / R1≤0.6, and a ratio of the tab thickness L to the radius R2 of the circular arc cross-sectional profile of the second bending section satisfies 0.17≤L / R2≤1.5.

[0009] In some embodiments, the first shaping surface further comprises a third bending section connected to the second bending section, the third bending section having a bending direction opposite to that of the second bending section.

[0010] In some embodiments, the second bending section comprises a first avoidance section, the first avoidance section being arranged obliquely to the extension direction of the tab and forming a first avoidance space towards one side of the tab.

[0011] In some embodiments, the first bending section comprises a first horizontal positioning section and a third vertical limiting section connected thereto, the first horizontal positioning section being arranged close to the main body of the battery cell and forming a second avoidance space towards one side of the tab with the third vertical limiting section.

[0012] In some embodiments, the first bending section and the second bending section are arranged spaced apart along the thickness direction of the tab, and a first vertical limiting section extending along the thickness direction of the tab is arranged between the first bending section and the second bending section.

[0013] In some embodiments, at least one driving mechanism is included, the driving mechanism driving at least one of the first shaping section and the second shaping section to move relative to the other along the thickness direction of the tab.

[0014] The present disclosure provides, in a second aspect, a battery cell comprising a battery cell main body and a tab, the shape of the tab being processed by the welding device of the second aspect.

[0015] By means of the shaping mechanism for the tab of a battery cell as provided above, the shaping mechanism of the embodiments of the present disclosure can pre-shape the tab of the battery cell before welding by arranging the first shaping surface with two bending sections having opposite bending directions, so that the non-welding part of the tab of the battery cell forms a bending buffer part, and the internal stress is offset by the deformation of the bending buffer part when the size of the battery cell changes, thereby reducing the risk of tearing. BRIEF DESCRIPTION OF DRAWINGS

[0016] The above and other objects, features and advantages of the exemplary embodiments of the present disclosure will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0017] Figure 1 Some existing battery cells are shown in the top view schematic diagram;

[0018] Figure 2 A side view schematic of some existing cells is shown;

[0019] Figure 3a An exemplary side view of a shaping mechanism for cell tabs of some embodiments of the present disclosure is shown;

[0020] Figure 3b An exemplary perspective view of a shaping mechanism for cell tabs of some embodiments of the present disclosure is shown; Figure 3a A partial enlarged view of section A in the middle is shown;

[0021] Figure 4 An exemplary perspective view of a shaping mechanism for cell tabs of some embodiments of the present disclosure is shown;

[0022] Figure 5 A partial enlarged view of the first shaping surface and the second shaping surface of a shaping mechanism of some embodiments of the present disclosure is shown;

[0023] Figure 6 A partial enlarged view of the first shaping surface and the second shaping surface of a shaping mechanism of some embodiments of the present disclosure is shown;

[0024] Figure 7 A partial enlarged view of the first shaping surface and the second shaping surface of a shaping mechanism of some embodiments of the present disclosure is shown;

[0025] Figure 8 An exemplary side view of a welding apparatus for cell tabs of some embodiments of the present disclosure is shown.

[0026] BRIEF DESCRIPTION OF DRAWINGS

[0027] 10 - fixing assembly; 100 - shaping mechanism; 20 - shaping assembly; 200 - welding device; 21 - first shaping part; 211 - first shaping curved surface; 2110 - first clearance space; 2111 - first bending section; 2111a - first horizontal positioning section; 2111b - third vertical limiting section; 2112 - second bending section; 2112a - first clearance section; 2112b - second horizontal positioning section; 2113 - first vertical limiting section; 2114 - third bending section; 2115 - upper positioning section; 2116 - upper guiding section; 2120 - second clearance space; 22 - second shaping part; 221 - second shaping curved surface; 2211 - first lower bending section; 2211a - fourth horizontal positioning section; 2211b - second clearance section; 2212 - second lower bending section; 2212a - fourth vertical limiting section; 2212b - third horizontal positioning section; 2213 - second vertical limiting section; 2214 - third lower bending section; 2215 - lower positioning section; 2216 - lower guiding section; 2230 - third clearance space; 2240 - fourth clearance space; 23 - driving mechanism; 70 - fixing frame; 80 - welding machine; 90 - battery cell; 91 - battery cell body; 911 - tab; 92 - tab; 920 - bending buffer; 921 - foil tab; L - tab thickness; R1 - radius of circular-arc profile of first bending section; R2 - radius of circular-arc profile of second bending section. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present disclosure will be described clearly and completely below in combination with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present disclosure.

[0029] It should be understood that the terms "comprise" and "include" used in the specification and claims of the present disclosure indicate the presence of the described features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0030] It should also be understood that the terms used in the specification of the present disclosure are only for the purpose of describing specific embodiments, and are not intended to limit the present disclosure. As used in the specification and claims of the present disclosure, the singular forms "a", "an" and "the" are intended to include the plural forms, unless the context clearly indicates otherwise. It should be further understood that the term "and / or" used in the specification and claims of the present disclosure means any combination of one or more of the associated listed items and all possible combinations thereof, and includes these combinations.

[0031] As used in the specification and claims, the term "if' can be interpreted as meaning "when," or "as soon as," or "in response to a determination," or "in response to a detection" depending on the context. Similarly, the phrase "if it is determined" or "if [the recited condition or event] is detected" can be interpreted as meaning "as soon as it is determined" or "in response to the determination" or "as soon as [the recited condition or event] is detected" or "in response to the detection [of the recited condition or event]" depending on the context.

[0032] In the existing lithium battery production process, a step of combining and packaging a plurality of pole pieces stacked in the thickness direction is included. Among them, the positive and negative pole tab materials of the plurality of pole pieces need to be led out respectively, and the positive and negative pole tab materials of the plurality of pole pieces are welded by means of ultrasonic welding or the like respectively to form an overall cell tab. In this production step, the plurality of tab materials after welding are fixed as a whole and can be used to continue to be combined with other cells to form the final finished battery.

[0033] In actual production and use, the active material on each pole piece in the cell will undergo corresponding physical and chemical changes during charging and discharging, and these changes on each pole piece will cause the size of the pole piece to change. Referring to Figure 1 and Figure 2 , Figure 1 shows a top view schematic diagram of some existing cells 90, Figure 2 shows a side view schematic diagram of some existing cells 90, in which the direction of the size change of the cell 90 is shown by an arrow, and the outline of the cell 90 after the size change is shown by a dashed line. As shown in the figure, the cell 90 generally includes a cell body 91 and a tab 92, the cell body 91 includes a plurality of pole pieces 911, and the tab 92 is formed by welding the pole tab 921 of the plurality of pole pieces 911. After the gradual accumulation of the size change of each pole piece 911, it will cause the overall cell 90 to change significantly in size, such as a significant increase in thickness and width, etc. After the overall size of the cell 90 changes, the plurality of pole pieces 911 of the cell 90 deviate from the original position, and the tab 92 of the cell 90 fixed by welding will be pulled by the pole tab 921 of the plurality of pole pieces 911, causing an undesirable internal stress in the tab 92 of the cell 90. If the internal stress exceeds the limit of the structural strength of the tab 92, it will cause the tab 92 of the cell 90 to tear or deform, causing the battery to fail, and even possibly causing the aluminum plastic film to tear, causing the risk of electrolyte leakage. However, in the existing design scheme, there are few corresponding solutions to such pulling stress.

[0034] Therefore, the shaping mechanism for the tab of the battery cell provided by the embodiments of the present disclosure can pre-shape the tab of the battery cell before welding by providing the first shaping surface with two bending sections having opposite bending directions, so that the non-welding part of the tab of the battery cell forms a bending buffer part, and when the size of the battery cell changes, the internal stress is offset by the deformation of the bending buffer part, thereby reducing the risk of tearing.

[0035] The embodiments of the shaping mechanism for the tab of the battery cell of the present disclosure are described below with reference to the accompanying drawings. For the sake of clarity and convenience of understanding, in the following, the side of the tab away from the main body of the battery cell is referred to as the distal end of the tab, and the side of the tab close to the main body of the battery cell is referred to as the proximal end of the tab. It should be understood by those skilled in the art that the description is only exemplary and does not limit the specific structure and positional relationship of the embodiments of the present disclosure.

[0036] Referring to Figure 3a and Figure 4 , Figure 3a an exemplary side view of the shaping mechanism 100 for the tab 92 of the battery cell 90 according to some embodiments of the present disclosure is shown, Figure 4 an exemplary perspective view of the shaping mechanism 100 for the tab 92 of the battery cell 90 according to some embodiments of the present disclosure is shown, wherein the fixing assembly 10 is shown in dashed lines to represent the connection part of the battery cell 90 and the shaping assembly 20. In some embodiments, the shaping mechanism 100 for the tab 92 of the battery cell 90 comprises a fixing assembly 10 and a shaping assembly 20. The fixing assembly 10 is a clamping mechanism for clamping and fixing the battery cell 90 along the stacking direction of the plurality of tabs 911 of the battery cell 90. The shaping assembly 20 comprises a driving mechanism 23 and a first shaping part 21 and a second shaping part 22 driven by the driving mechanism 23 to move relative to each other. The first shaping part 21 and the second shaping part 22 are oppositely arranged along the thickness direction of the tab 92. The first shaping part 21 has a first shaping surface 211 curved relative to the extension direction of the tab 92. The first shaping surface 211 of the first shaping part 21 abuts against the upper side surface of the tab 92, and the second shaping part 22 abuts against the lower side surface of the tab 92, so that the first shaping part 21 and the second shaping part 22 abut against the tab 92 along the thickness direction of the tab 92, causing the tab 92 to be deformed and bent according to the shape of the first shaping surface 211, thereby forming a bending buffer part 920.

[0037] In particular, referring to Figure 3a and Figure 4In this embodiment, the shaping assembly 20 comprises a driving mechanism 23 arranged in vertical direction, which is a cylinder comprising a cylinder body and a cylinder rod movable relative to the cylinder body in vertical direction. The cylinder body of the driving mechanism 23 is fixedly connected with a fixed frame (not shown), and the end of the extending end of the cylinder rod is fixedly connected with the first shaping part 21. The first shaping part 21 is generally cuboid, and its upper side is fixedly connected with the cylinder rod of the driving mechanism 23, and its lower side is arranged to have a first shaping curved surface 211 facing the second shaping part 22. In some embodiments not shown, the driving mechanism 23 can also comprise two cylinders arranged opposite in vertical direction to drive the first shaping part 21 and the second shaping part 22 to approach or move away from each other, respectively.

[0038] The second shaping part 22 has a second shaping curved surface 221 which is generally complementary to the shape of the first shaping curved surface 211 of the first shaping part 21, so that after the first shaping curved surface 211 abuts against the tab 92, the material of the tab 92 can be deformed and uniformly fill the gap between the two shaping curved surfaces. Thus, when the first shaping part 21 is driven by the driving mechanism 23 to extend towards the second shaping part 22, the first shaping curved surface 211 can abut against the upper surface of the tab 92, and further abut against the tab 92 to make it bend downwards, and the lower surface of the tab 92 contacts the second shaping curved surface 221. Further, the first shaping curved surface 211 and the second shaping curved surface 221 abut against the upper and lower sides of the tab 92, respectively, to further deform the tab 92, until the upper surface of the tab 92 is in contact with the first shaping curved surface 211, and the lower surface of the tab 92 is in contact with the second shaping curved surface 221. At this time, the first shaping part 21 and the second shaping part 22 can complete the shaping of the tab 92. Since the first shaping curved surface 211 and the second shaping curved surface 221 have generally complementary shapes relative to each other, the distance between them in the direction perpendicular to the cross-sectional profile of the tab 92 remains unchanged. During the deformation of the tab 92, the upper and lower surfaces of the tab 92 can be integrally in contact with the first shaping curved surface 211 and the second shaping curved surface 221, so that the abutting force of the tab 92 in the gap is more evenly distributed, which strengthens the plastic deformation of the tab 92 and reduces the amount of elastic deformation after contact.

[0039] Referring to Figure 3b , Figure 3b It is shown that Figure 3aA partial enlarged view of the middle A part. The first shaping surface 211 includes a first bending section 2111 and a second bending section 2112. The first bending section 2111 is a quarter circular arc-shaped recess facing the second shaping part 22, and the second bending section 2112 is a quarter circular arc-shaped protrusion facing the second shaping part 22. Similar to the first shaping part 21, the second shaping surface 221 of the second shaping part 22 includes a first lower bending section 2211 and a second lower bending section 2212. The first lower bending section 2211 is a quarter circular arc-shaped protrusion facing the first bending section 2111, and the second lower bending section 2212 is a quarter circular arc-shaped recess facing the second bending section 2112. In this embodiment, the arc-shaped profiles of the first bending section 2111 and the first lower bending section 2211 are concentrically arranged, and the arc-shaped profiles of the second bending section 2112 and the second lower bending section 2212 are concentrically arranged, so that the radial distance between the corresponding two arc-shaped profiles is always consistent.

[0040] Through comprehensive consideration of the material strength of the tab 92 and the actual use, for a common tab 92 with a thickness of 0.3 mm, the radius R1 of the circular arc profile of the first bending section 2111 is preferably in the range of 0.5 mm to 2 mm, and more preferably 1 mm. For the second bending section 2112 abutting the inner side of the bending part of the tab 92, the radius R2 is preferably in the range of 0.2 mm to 1.7 mm, and more preferably 0.7 mm. Further, the preferred ratio of the tab thickness L of the tab 92 to the radius R1 of the circular arc cross-sectional profile of the first bending section 2111 should satisfy 0.15≤L / R1≤0.6, and the preferred ratio of the tab thickness L of the tab 92 to the radius R2 of the circular arc cross-sectional profile of the second bending section 2112 should satisfy 0.17≤L / R2≤1.5.

[0041] Those skilled in the art can understand that, although the above describes a scheme in which the first shaping surface 211 and the second shaping surface 221 are arranged to include a plurality of circular arc profiles complementary in shape, the present disclosure does not limit the specific shape of the first shaping surface 211 and the second shaping surface 221.

[0042] For example, see Figure 5 , Figure 5A partial enlarged view of the first shaping surface 211 and the second shaping surface 221 of the shaping mechanism 100 of some embodiments of the present disclosure is shown, and the electrode tab 92 is clamped between the first shaping portion 21 and the second shaping portion 22. In this embodiment, in addition to the plurality of bending sections arranged correspondingly, the first shaping surface 211 further comprises a first vertical limiting section 2113 arranged in the vertical direction, and the second shaping surface 221 also comprises a corresponding second vertical limiting section 2213, the first vertical limiting section 2113 connects the bottom side of the first bending section 2111 and the upper side of the second bending section 2112, and is tangent to the cross-sectional profile of both, and the second vertical limiting section 2213 connects the bottom side of the first lower bending section 2211 and the upper side of the second lower bending section 2212, and is also tangent to the cross-sectional profile of both. By arranging the first vertical limiting section 2113 and the second vertical limiting section 2213, the distance between the two adjacent bending sections on the same shaping surface is lengthened, thereby increasing the moment acting on the bending portion when the second bending section 2112 and the second lower bending section 2212 abut against the distal end of the tab 92. Thus, it is easier to cause the tab 92 to plastically deform, and the amount of elastic rebound after deformation is smaller.

[0043] Referring to Figure 6 , Figure 6 A partial enlarged view of the first shaping surface 211 and the second shaping surface 221 of the shaping mechanism 100 of some embodiments of the present disclosure is shown, and the electrode tab 92 is clamped between the first shaping portion 21 and the second shaping portion 22. In this embodiment, the first shaping surface 211 comprises a horizontally arranged upper positioning section 2115, a first bending section 2111 in the shape of a quarter circle arc, and a second bending section 2112 tangent to the first bending section 2111 and curved in the opposite direction to the first bending section 2111, and the second bending section 2112 has a semicircular arc-shaped cross-sectional profile shape. On the side of the second bending section 2112 away from the battery body 91, a third bending section 2114 tangent to the second bending section 2112 is further provided, the third bending section 2114 has a cross-sectional profile in the shape of a quarter circle arc, and is opposite in curvature direction to the second bending section 2112, and the third bending section 2114 is also arranged mirror symmetrically about the second bending section 2111 with the first bending section 2111. On the side of the third bending section 2114 away from the battery body 91, a horizontally arranged upper guide section 2116 tangent to the third bending section 2114 is further provided.

[0044] Similarly, the second shaping surface 221 includes, in sequence from the side close to the cell body 91 to the side away from the cell body 91, a lower positioning segment 2215, a first lower bending segment 2211, a second lower bending segment 2212, a third lower bending segment 2214, and a lower guiding segment 2216. The first lower bending segment 2211 and the third lower bending segment 2214 have a quarter-arc cross-sectional profile shape, the second lower bending segment 2212 has a half-arc cross-sectional profile shape, and the first lower bending segment 2211 and the third lower bending segment 2214 are mirror-symmetrically arranged about the second lower bending segment 2212.

[0045] Thus, when the first shaping portion 21 and the second shaping portion 22 abut the tab 92 in the vertical direction, the upper positioning segment 2115 and the lower positioning segment 2215 respectively position the proximal end of the tab 92 from the upper and lower sides of the tab 92, and the upper guiding segment 2116 and the lower guiding segment 2216 respectively position the distal end of the tab 92 from the upper and lower sides of the tab 92. The first bending segment 2111, the second bending segment 2112, and the third bending segment 2114 of the first shaping surface 211 respectively abut the upper surface of the tab 92, bend the tab 92 downward, and abut the corresponding first lower bending segment 2211, the second lower bending segment 2212, and the third lower bending segment 2214. Thus, the tab 92 forms a substantially "U"-shaped bending buffer portion 920 after shaping, and the height difference between the proximal end and the distal end remains substantially the same, thereby avoiding a shift in the position of the distal end of the tab 92 caused by shaping, and eliminating the need for adaptive special processing of the tab 92 that has shifted in position.

[0046] For example, in some embodiments, the first shaping surface 211 and the second shaping surface 221 do not completely conform to the tab 92, but only have corresponding contact portions at the points of action where the bending action is required to be applied to the tab 92. Referring to FIG. 6, the first shaping surface 211 and the second shaping surface 221 have a first contact portion 2113 and a second contact portion 2213, respectively, at the points of action where the bending action is required to be applied to the tab 92. Figure 7 , Figure 7 FIG. 6 shows a partial enlarged view of the first shaping surface 211 and the second shaping surface 221 of the shaping mechanism 100 according to some embodiments of the present disclosure. In this embodiment, the first shaping surface 211 includes, in sequence from the side close to the cell body 91 to the side away from the cell body 91, a first horizontal positioning segment 2111a, a third vertical limiting segment 2111b, a first emptying segment 2112a, and a second horizontal positioning segment 2112b.

[0047] Specifically, the first horizontal positioning segment 2111a is arranged along a horizontal direction for abutting against the upper surface of the tab 92 to position the tab 92. The third vertical limiting segment 2111b extends downward from the first horizontal positioning segment 2111a along a vertical direction for abutting against and bending the tab 92 in a horizontal direction toward the main body 91 of the battery cell. Thus, the first horizontal positioning segment 2111a and the third vertical limiting segment 2111b jointly form the first bending segment 2111. The first clearance segment 2112a extends from the third vertical limiting segment 2111b along a downwardly inclined direction toward a side away from the main body 91 of the battery cell. The second horizontal positioning segment 2112b extends from the first clearance segment 2112a along a horizontal direction away from the main body 91 of the battery cell to form a distal end of the tab 92 for abutting against and positioning the tab 92. Thus, the first clearance segment 2112a and the second horizontal positioning segment 2112b jointly form the second bending segment 2112. The inclined portion of the first clearance segment 2112a toward one side of the tab 92 forms a first clearance space 2110 for avoiding interference with the bent portion of the tab 92, and the first horizontal positioning segment 2111a and the third vertical limiting segment 2111b toward one side of the tab 92 form a second clearance space 2120.

[0048] The second shaping curved surface 221 is arranged in a manner that is substantially rotationally symmetrical with the first shaping curved surface 211. The second shaping curved surface 221 includes the third horizontal positioning segment 2212b, the fourth vertical limiting segment 2212a, the second clearance segment 2211b, and the fourth horizontal positioning segment 2211a arranged in sequence from a side of the second shaping curved surface 221 away from the main body 91 of the battery cell to a side of the second shaping curved surface 221 close to the main body 91 of the battery cell. The third horizontal positioning segment 2212b extends in a horizontal direction toward the main body 91 of the battery cell, and the fourth vertical limiting segment 2212a extends upward from the third horizontal positioning segment 2212b along a vertical direction. The second clearance segment 2211b extends along an upwardly inclined direction toward the side of the second shaping curved surface 221 close to the main body 91 of the battery cell. The fourth horizontal positioning segment 2211a extends from the second clearance segment 2211b along a horizontal direction toward the main body 91 of the battery cell. The inclined portion of the second clearance segment 2211b toward one side of the tab 92 forms a third clearance space 2230 for avoiding interference with the bent portion of the tab 92, and the third horizontal positioning segment 2212b and the fourth vertical limiting segment 2212a toward one side of the tab 92 form a fourth clearance space 2240. The fourth horizontal positioning segment 2211a abuts against the tab 92 from below to position and clamp the tab 92, similar to the first horizontal positioning segment 2111a. Similarly, the second horizontal positioning segment 2112b and the third horizontal positioning segment 2212b abut against and position the distal end of the tab 92 from above and below, respectively.

[0049] When the first shaping part 21 and the second shaping part 22 are moved relative to each other in the vertical direction and abut against the tab 92, the second horizontal positioning segment 2112b pushes the distal end of the tab 92 to move downwardly and bend until it abuts against the third horizontal positioning segment 2212b, while the first horizontal positioning segment 2111a and the fourth horizontal positioning segment 2211a clamp and position the proximal end of the tab 92. At the same time, the third vertical limiting segment 2111b and the fourth vertical limiting segment 2212a abut against the middle portion of the tab 92 between the distal end and the proximal end relative to each other, so as to deform the middle portion of the tab 92 in the vertical direction, so as to bend relative to the horizontally fixed proximal end and distal end, and finally form a curved buffer portion 920 having a generally "S" shaped cross-sectional profile.

[0050] By arranging the horizontal positioning segments and the vertical limiting segments to abut against and position the tab 92, and arranging the first to fourth avoidance spaces to avoid the bending portion of the tab 92, the actual contact area between the first shaping surface 211 and the second shaping surface 221 and the tab 92 becomes smaller. Therefore, only the portions of the corresponding shaping surfaces that are in contact with the tab 92 need to be surface treated, without the need for precise control of the size and fine processing of the surfaces of all the flat surfaces, thereby reducing the production cost of the shaping mechanism 100. In addition, in the case where the tab 92 itself has local deformation due to machining errors, since the contact area with the tab 92 is reduced, the shaping surfaces only abut against a small number of target regions of the tab 92, thereby also improving the fault tolerance to local shape errors of the tab 92.

[0051] As can be understood by those skilled in the art, although several shape design schemes of the first shaping surface 211 and the second shaping surface 221 are described above, the several schemes above are not independent of each other, and the shape features in each embodiment can be combined for use according to actual conditions. For example, in some embodiments not shown, the first shaping surface 211 can include an upper bending segment having a semicircular profile that protrudes downwardly, and the second shaping surface 221 can include a lower bending segment corresponding in shape to the upper bending segment. At the same time, the first shaping surface 211 can further include two vertical limiting segments arranged on both sides of the upper bending segment and tangent to the upper bending segment, and a horizontal positioning segment arranged perpendicularly to the two vertical limiting segments and extending towards and away from the direction of the main body of the battery cell. The horizontal positioning segment and the vertical limiting segments form avoidance spaces on the side facing the tab for avoiding the bending portion of the tab. Thus, the shaping mechanism 100 of this embodiment can shape the tab to have a curved buffer portion with a generally "U" shaped profile, and due to the presence of the avoidance spaces, the contact area between the tab and the shaping mechanism 100 is smaller, thereby reducing the production cost and improving the fault tolerance.

[0052] The shaping mechanism 100 according to the embodiments of the present disclosure can bend the shape of the tab by setting the bending segments with two opposite bending directions and the driving assembly of the first shaping part 21 and the second shaping part 22 abutting against the tab, so that the tab forms a curved buffer part for unloading internal stress, and the anti-cracking performance of the battery cell is improved.

[0053] Further referring to Figure 8 , Figure 8 An exemplary side view of a welding device 200 for the tab 92 of the battery cell 90 according to some embodiments of the present disclosure is shown. The welding device 200 for the tab 92 of the battery cell 90 includes a fixed frame 70 and the shaping mechanism 100 for the tab 92 of the battery cell 90 according to the above embodiments disposed on the fixed frame 70. The fixed frame 70 further includes a welding machine 80 for welding the tab.

[0054] Further referring to Figure 3a and Figure 3b , and Figure 5 to Figure 7 The present disclosure further provides a battery cell 90 including a battery cell body and a tab, the shape of the tab of the battery cell 90 is made by the welding device 200 for the tab of the battery cell 90 and shaped by the shaping mechanism 100 for the tab of the battery cell 90 according to one of the above embodiments to form a curved buffer part in the extension direction of the tab. Thus, the internal stress generated by the deformation of the thickness and width of the battery cell can be unloaded by the curved buffer part, so that the anti-cracking performance of the battery cell is improved, and the safety of the battery cell is enhanced.

[0055] Although the embodiments of the present disclosure have been shown and described herein, it would be clear to those skilled in the art that such embodiments are provided by way of example only. Numerous modifications, changes, and alternatives can be conceived by those skilled in the art without departing from the spirit and principles of the present disclosure. It should be understood that various alternatives to the embodiments of the present disclosure described herein can be employed in practicing the present disclosure. The appended claims are intended to define the scope of protection of the present disclosure and thus cover equivalents or alternatives within the scope of the claims.

Claims

1. A shaping mechanism for battery cell tabs, characterized in that, include: Fixing component (10) for fixing the battery cell; The shaping component (20) includes a first shaping part (21) and a second shaping part (22) that are movable relative to each other along the thickness direction of the tab. The first shaping part (21) and the second shaping part (22) are disposed opposite to each other along the thickness direction of the tab. The first shaping part (21) has a first shaping surface (211) that is bent relative to the extension direction of the tab. The first shaping surface (211) has a first bending segment (2111) and a second bending segment (2112) with opposite bending directions.

2. The shaping mechanism according to claim 1, characterized in that, The second shaping part (22) has a second shaping surface (221) that is adapted to the shape of the first shaping surface (211).

3. The shaping mechanism according to claim 2, characterized in that, Along the thickness direction of the tab, both the first bent segment (2111) and the second bent segment (2112) have a quarter-circle arc cross-sectional profile.

4. The shaping mechanism according to claim 3, characterized in that, The ratio of the electrode thickness L to the radius R1 of the arc-shaped cross-sectional profile of the first bent segment (2111) satisfies 0.15≤L / R1≤0.6, and the ratio of the electrode thickness L to the radius R2 of the arc-shaped cross-sectional profile of the second bent segment (2112) satisfies 0.17≤L / R2≤1.

5.

5. The shaping mechanism according to claim 1, characterized in that, The first shaped surface (211) also includes a third bending segment (2114) connected to the second bending segment (2112), wherein the bending direction of the third bending segment (2114) is opposite to that of the second bending segment (2112).

6. The shaping mechanism according to claim 1, characterized in that, The second bending section (2112) includes a first clearance section (2112a), which is inclined to the extension direction of the electrode tab and forms a first clearance space (2110) on the side facing the electrode tab.

7. The shaping mechanism according to claim 1, characterized in that, The first bending section (2111) includes a first horizontal positioning section (2111a) and a third vertical limiting section (2111b) connected thereto. The first horizontal positioning section (2111a) is located close to the main body of the battery cell, and it and the third vertical limiting section (2111b) form a second clearance space (2120) on the side facing the electrode.

8. The shaping mechanism according to claim 1, characterized in that, The first bending segment (2111) and the second bending segment (2112) are spaced apart along the thickness direction of the electrode tab, and a first vertical limiting segment (2113) extending along the thickness direction of the electrode tab is provided between them.

9. The shaping mechanism according to any one of claims 1 to 8, characterized in that, It includes at least one drive mechanism (23) that drives at least one of the first shaping part (21) and the second shaping part (22) to move one of them relative to the other along the thickness direction of the tab.

10. A battery cell, characterized in that, It includes a battery cell body and a tab, the shape of which is formed by a shaping mechanism according to any one of claims 1 to 9.

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