Battery

Abstract

The utility model relates to the technical field of batteries, and discloses a battery, which comprises a pole piece, and the pole piece comprises a pole piece body and a pole lug formed by extending a local area of the pole piece body towards a direction far away from the pole piece body; the pole post is provided with a welding surface which is in welding connection with the tab; the welding face is provided with a first protruding part and a second protruding part, the orthographic projection of the first protruding part on the welding face is annular, and the second protruding part is located in the first protruding part. The maximum thickness of the non-welding area of the tab is D, and the maximum thickness of the welding area of the tab is W; the height H1 of the first protruding part protruding from the welding face meets the condition that (D-W) / H1 is larger than or equal to 0.0013 and smaller than or equal to 5.33. According to the battery provided by the utility model, the first lug boss is arranged outside the second lug boss, so that the first lug boss can play a supporting role, the thickness difference generated after the second lug boss is welded is reduced, and the welding of the second lug boss is reinforced.

Description

TECHNICAL FIELD

[0001] The utility model relates to battery technology field, concretely relates to a battery. BACKGROUND

[0002] In the related art, some pole pieces adopt a composite current collector form. Since the composite current collector contains a non-conductive base film layer, when the lug also adopts a composite current collector, the base film layer melts during welding of the lug and the pole, resulting in a thickness of the welded area that is significantly smaller than a thickness of the unwelded area, and a large thickness difference exists.

[0003] Furthermore, the connection point between the welded area and the adjacent unwelded area is prone to tearing due to vibration, resulting in connection failure. SUMMARY

[0004] Therefore, the utility model provides a battery to solve the problem that the connection point between the welded area and the unwelded area after the base film layer melts is prone to tearing due to vibration.

[0005] The utility model provides a battery, comprising:

[0006] A pole piece includes a pole piece body and a lug extending from a local area of the pole piece body in a direction away from the pole piece body.

[0007] A pole is used to electrically connect with the pole piece and has a welding surface for welding connection with the lug. The welding surface is provided with a first protruding part and a second protruding part. The first protruding part is annular in orthographic projection on the welding surface, and the second protruding part is located inside the first protruding part.

[0008] The maximum thickness of the non-welded area of the lug is D, and the maximum thickness of the welded area of the lug is W. The height of the first protruding part protruding from the welding surface is H1, and the following is satisfied: 0.0013≤(D-W) / H1≤5.33.

[0009] Advantages: the first protruding part is arranged outside the second protruding part, and the first protruding part is annular in orthographic projection on the welding surface. The first protruding part can play a supporting role, and the thickness difference caused by welding of the second protruding part is reduced. The welding of the second protruding part is strengthened.

[0010] By controlling the upper limit of the ratio of (D-W) / H1, the first protruding part can have a certain thickness at least. The first protruding part plays a supporting role, and the thickness difference caused by welding of the second protruding part is reduced. By controlling the lower limit of the ratio of (D-W) / H1, that is, avoiding H1 being too large, the situation that the first protruding part is too high and the supporting effect is poor can be avoided. The first protruding part plays a supporting role on the surrounding area of the second protruding part, the thickness difference caused by welding of the second protruding part is reduced, and the welding of the second protruding part is strengthened. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0012] Figure 1 The cross section of the pole piece of the utility model Figure 1 ;

[0013] Figure 2 The cross section of the pole piece of the utility model Figure 2 ;

[0014] Figure 3A This is the cross section of the base film layer after melting during the welding of the tab of the utility model. Figure 1 ;

[0015] Figure 3B This is the cross section of the base film layer after melting during the welding of the tab of the utility model. Figure 2 ;

[0016] Figure 4 A schematic diagram of a pole of the utility model;

[0017] Figure 5 This is a front view of the pole of the utility model;

[0018] Figure 6 It is a side view of the pole of the utility model;

[0019] Figure 7 for Figure 6 Schematic diagram of the AA section;

[0020] Figure 8 FIG. 4 is a schematic diagram of a cross section of a pole in another embodiment.

[0021] Description of reference numerals:

[0022] 1. Pole piece; 11. Conductive layer; 12. Base film layer; 13. Welding recess;

[0023] 2. Pole; 21. Welding surface; 22. First raised portion; 23. Second raised portion. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described in the utility model embodiments in combination with the drawings, obviously, the described embodiments are part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by the person skilled in the art without creative labor belong to the protection scope of the utility model.

[0025] In the description of the utility model, it needs to be explained that the orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the utility model. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0026] In the description of the utility model, it needs to be explained that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected, it can be mechanically connected, or it can be electrically connected, it can be directly connected, or it can be indirectly connected through an intermediate medium, it can be the communication inside two elements. For the person skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific situation.

[0027] In addition, the technical features involved in the different embodiments of the utility model described below can be combined with each other as long as there is no conflict between them.

[0028] In the related art, some pole pieces adopt a composite current collector form, since the composite current collector contains a non-conductive base film layer, when the lug also adopts a composite current collector, during welding of the lug and the pole, the base film layer melts, resulting in that the thickness of the welding area is obviously smaller than the thickness of the non-welding area, and there is a large thickness difference.

[0029] When the thickness difference is large, at the connecting point between the welding area and the non-welding area next to it, since there is a large layer error, stress is easily concentrated, and tearing is easily caused by vibration, resulting in connection failure.

[0030] The embodiments of the utility model will be described below in combination with Figures 1 to 8 , the embodiments of the utility model.

[0031] According to the embodiments of the utility model, a battery is provided, comprising:

[0032] Pole piece 1, comprising a pole piece body and a pole ear formed by extending from a local area of ​​the pole piece body in a direction away from the pole piece body;

[0033] The electrode 2 is used to electrically connect to the electrode piece 1 and has a welding surface 21 welded to the electrode tab; the welding surface 21 is provided with a first raised portion 22 and a second raised portion 23, the orthographic projection of the first raised portion 22 on the welding surface 21 is annular, and the second raised portion 23 is located inside the first raised portion 22;

[0034] The maximum thickness of the non-welded area of ​​the tab is D, and the maximum thickness of the welded area of ​​the tab is W. The height of the first protrusion 22 protruding from the welded surface 21 is H1, which satisfies the following: 0.0013≤(DW) / H1≤5.33.

[0035] In some embodiments, the electrode 1 includes a positive electrode, a negative electrode, and a composite current collector arranged between the positive electrode and the negative electrode; the composite current collector is suitable for separating the positive electrode and the negative electrode; and prevents electrons in the battery from freely passing through the composite current collector, but allows ions in the electrolyte to pass freely between the positive and negative electrodes.

[0036] The composite current collector includes a base film layer 12 and a conductive layer 11 disposed on at least one side surface of the base film layer 12 .

[0037] In this embodiment, at least one side of the composite current collector has a conductive layer, and further, both sides of the composite current collector have a conductive layer.

[0038] Figure 1 The composite current collector of the electrode 1 comprises a base film layer 12, and a conductive layer 11 is provided on both sides of the base film layer 12; Figure 2 The composite current collector of the electrode 1 includes a base film layer 12 , and a conductive layer 11 is provided on one side surface of the base film layer 12 .

[0039] The pole piece 1 of this embodiment includes a composite current collector, which includes a base film layer 12 and a conductive layer 11 disposed on at least one surface of the base film layer 12. Since a local area of ​​the pole piece 1 forms a pole tab, in this embodiment, the pole tab also includes a composite current collector, and the composite current collector of the pole tab also includes a base film layer 12 and a conductive layer 11 disposed on at least one surface of the base film layer 12.

[0040] by Figure 1 Taking the example of the conductive layer 11 being provided on both sides of the base film layer 12 as shown, the composite current collector includes a first conductive layer, a base film layer 12 and a second conductive layer stacked in sequence; during the welding process, the high heat generated by the welding will cause the base film layer 12 to melt, and the base film layer 12 will be combined with the attached conductive layer. Figure 3A or Figure 3BAs shown, the first conductive layer and the second conductive layer are in a bonded state. At this time, in the area of ​​the tab corresponding to the welding position, due to the melting of the base film layer 12, the conductive layers 11 on both sides will move closer to the middle position or even bond together, thereby forming a welding recess 13 on the outer surface of the tab. The maximum thickness of the non-welding area of ​​the tab is D, that is, the thickness of the first conductive layer, base film layer 12 and second conductive layer bonded in sequence in the non-welding area is D. The maximum thickness of the welding area of ​​the tab is W, that is, the thickness of the first conductive layer and the second conductive layer when bonded after the base film layer 12 in the welding area melts is W.

[0041] In addition, combined with the Figure 3A or Figure 3B As shown, if the two sides of the tab are subjected to pressure during the welding process between the tab and the pole 2, it will appear Figure 3A The double-sided concave welding concave portion 13 shown in FIG. If the pole tab is subjected to pressure on one side during the welding process between the pole tab and the pole post 2, a Figure 3B The welding depression 13 shown is recessed on one side.

[0042] by Figure 3B For example, in this embodiment, DW reflects the depth of the welding recess 13. From another perspective, when the base film layer 12 is completely melted, DW reflects the thickness of the base film layer 12.

[0043] This embodiment further includes a pole 2, which is used to be welded to the tab to achieve conductive connection between the electrode group inside the battery and the pole 2, so as to be connected to an external circuit.

[0044] The pole 2 has a welding surface 21 welded to the tab; by providing a second protrusion 23 on the welding surface 21, the second protrusion 23 can be more tightly combined with the welding recess 13 by utilizing the cooperation between the protrusion and the recess, thereby optimizing the welding firmness of the pole 2 and the tab and preventing the occurrence of cold welding.

[0045] However, when the electrode tab and the electrode post 2 are welded, the base film layer 12 of the composite current collector melts, resulting in the thickness of the welded area being significantly smaller than the thickness of the unwelded area. There is a large thickness difference, and the connection point between the welded area and the non-welded area is prone to tearing. The second raised portion 23 is combined with the welding recessed portion 13, while the area outside the second raised portion 23 and the area corresponding to the pole piece form a non-welded area. That is, there is a thickness difference between the pole piece corresponding to the second raised portion 23 and the area adjacent to the second raised portion 23, which makes it easy to tear at this position.

[0046] The first protruding part 22 is arranged outside the second protruding part 23, and the first protruding part 22 has a ring-shaped orthographic projection on the welding surface 21. The first protruding part 22 can play a supporting role, reduce the thickness difference caused by welding of the second protruding part 23, and strengthen the welding of the second protruding part 23.

[0047] By controlling the upper limit of the ratio of (D-W) / H1, the first protruding part 22 has a certain thickness, plays a supporting role, reduces the thickness difference caused by welding of the second protruding part 23, and controls the lower limit of the ratio of (D-W) / H1, that is, avoids that H1 is too large, avoids that the first protruding part 22 is too high and the supporting effect is poor, thereby the first protruding part 22 plays a supporting role on the surrounding area of the second protruding part 23, reduces the thickness difference caused by welding of the second protruding part 23, and strengthens the welding of the second protruding part 23.

[0048] For example, the value of (D-W) / H1 can be 0.0013, 0.003, 0.005, 0.01, 0.03, 0.08, 0.1, 0.5, 1.1, 1.5, 2.3, 4.2, 5.33, or an interval range formed by any two of the above values.

[0049] In some embodiments, the first protruding part 22 is arranged on the welding surface 21. Figure 7 As shown in the figure, the height H1 of the first protruding part 22 protruding from the welding surface 21 satisfies: 0.3mm≤H1≤3.0mm.

[0050] When the height H1 of the first protruding part 22 protruding from the welding surface 21 is less than the lower limit, the height of the first protruding part 22 protruding from the welding surface 21 is too low, and cannot play a good role in reducing the height difference, thereby causing poor supporting effect and failing to reduce the thickness difference caused by welding of the second protruding part 23. When the height H1 of the first protruding part 22 protruding from the welding surface 21 is greater than the upper limit, a large gap is easily formed between the welding surface 21 of the tab and the tab, the fitting degree is poor, the overcurrent is affected, and the first protruding part 22 and the welding surface 21 can also be easily torn due to the large thickness difference and vibration, thereby causing connection failure.

[0051] For example, the value of H1 can be 0.3mm, 0.5mm, 0.8mm, 1.5mm, 1.9mm, 2.3mm, 2.5mm, 3mm, or an interval range formed by any two of the above values.

[0052] In some embodiments, the maximum thickness D of the non-welding area of the tab satisfies: 0.04mm≤D≤3.2mm.

[0053] Exemplarily, the value of D can be 0.04 mm or 0.08 mm or 0.1 mm or 0.3 mm or 0.5 mm or 1 mm or 1.5 mm or 1.9 mm or 2.3 mm or 2.5 mm or 3 mm or 3.2 mm, etc., or an interval range formed by any two of the above values.

[0054] In some embodiments, the maximum thickness W of the welding area of the tab satisfies: 0.02 mm≤D≤2.9 mm.

[0055] Exemplarily, the value of W can be 0.02 mm or 0.04 mm or 0.08 mm or 0.1 mm or 0.3 mm or 0.5 mm or 0.8 mm or 1.5 mm or 1.9 mm or 2.3 mm or 2.9 mm, etc., or an interval range formed by any two of the above values.

[0056] In some embodiments, in combination Figure 7 As shown, the height of the second protruding part 23 protruding from the welding surface 21 is H2, satisfying: 0 mm≤H2-H1≤0.5 mm.

[0057] In the present embodiment, the height H2 of the second protruding part 23 protruding from the welding surface 21 can be greater than the height H1 of the first protruding part 22 protruding from the welding surface 21. In a direction parallel to the welding surface 21 and along the second protruding part 23 towards the first protruding part 22, by gradually reducing the height of the protruding part, the first protruding part 22 can play a supporting role, reduce the thickness difference after welding of the second protruding part 23, strengthen the welding of the second protruding part 23, ensure the connection effect, and reduce the possibility of tearing.

[0058] Exemplarily, the value of H2-H1 can be 0 mm or 0.1 mm or 0.15 mm or 0.2 mm or 0.3 mm or 0.4 mm or 0.5 mm, etc., or an interval range formed by any two of the above values.

[0059] In some embodiments, in combination Figure 8 As shown, in a direction perpendicular to the welding surface 21, the cross-sectional width of the first protruding part 22 away from the welding surface 21 is smaller than the cross-sectional width close to the welding surface 21.

[0060] Since the composite current collector contains the non-conductive base film layer 12, when resistance welding is applied to the composite current collector, the protruding part needs to be designed to be relatively sharp or sharp, and by pressing the pole and the tab before welding, the protruding part can pierce the tab, and the protruding part can be in contact with the conductive layer in the composite current collector to conduct electricity, thereby improving the connection tightness and ensuring the connection effect.

[0061] The first protruding part 22 is designed as a blade shape with a narrow upper part and a wide lower part, so that the tab can be pierced before welding, and after welding, the sharp tip of the first protruding part 22 away from the welding surface 21 is melted into a flat surface, so that the first protruding part 22 forms a table shape with gradually increasing width from top to bottom, ensuring the contact area of the first protruding part 22 with the tab after welding.

[0062] In some embodiments, in combination Figure 8 As shown, the cross-sectional width of the first protruding part 22 away from the welding surface 21 is M1, and the cross-sectional width of the first protruding part 22 close to the welding surface 21 is M2, satisfying: 0mm≤M2-M1≤2mm.

[0063] The greater the difference between M2-M1, the relatively greater the sharpness of the first protruding part 22 away from the welding surface 21, so that it is easier to pierce the composite current collector.

[0064] By limiting the lower limit of the difference between M2-M1, it can be ensured that the tab is pierced when the pole is pressed against the tab before welding. And by limiting the upper limit of the difference between M2-M1, it can avoid the insufficient strength caused by the too narrow cross-sectional width of the first protruding part 22 away from the welding surface 21, and ensure a certain flow area after welding.

[0065] For example, the value of M2-M1 can be 0mm or 0.1mm or 0.5mm or 0.8mm or 1mm or 2mm, or an interval range formed by any two of the above values.

[0066] In some embodiments, in combination Figure 7 As shown, in the direction parallel to the welding surface 21, the shortest distance between the first protruding part 22 and the second protruding part 23 is F, satisfying: 0.5mm≤F≤5mm.

[0067] The first protruding part 22 and the second protruding part 23 should be at a suitable distance to effectively reduce the height difference of the tab after welding.

[0068] To ensure the continuity of the weld pool, improve the flow capacity, and ensure sufficient weld tensile strength, the distance between the first protruding part 22 and the second protruding part 23 cannot be too large; but if the distance between the first protruding part 22 and the second protruding part 23 is too small, it cannot reduce the height difference.

[0069] For example, the value of F can be 0.5mm or 0.8mm or 1mm or 1.5mm or 2.5mm or 3.5mm or 4mm or 5mm, or an interval range formed by any two of the above values.

[0070] In some embodiments, the maximum thickness D of the non-welding area of the tab and the height H1 of the first protruding portion 22 protruding from the welding surface 21 satisfy: 0.013≤D / H1≤10.67.

[0071] Since the tab contains a composite current collector, the composite current collector contains the base film layer 12, and only after the first protruding portion 22 pierces the tab can a good welding effect be ensured. By limiting the range of D / H1, it can be ensured that when the tab is pressed against the tab before welding, the first protruding portion 22 can smoothly pierce the tab.

[0072] For example, the value of D / H1 can be 0.013 or 0.05 or 0.1 or 0.8 or 2 or 5 or 8 or 10 or 10.67, etc. It can also be an interval range formed by any two of the above values.

[0073] In some embodiments, the orthographic projection of the first protruding portion 22 on the welding surface 21 is a discontinuous ring (not shown in the figure).

[0074] By setting the first protruding portion 22 as a discontinuous ring, the overcurrent area during welding can be reduced on the basis of ensuring the welding effect, the required welding power can be appropriately lowered, thereby improving production efficiency and ensuring safety.

[0075] In some embodiments, in combination Figure 4 As shown, the orthographic projection of the second protruding portion 23 on the welding surface 21 is a ring.

[0076] By setting the second protruding portion 23 as a continuous ring, the welding process can be more continuous, and the connection of each area of the tab and the tab is more stable, and the overcurrent is more uniform.

[0077] In some embodiments, the orthographic projection of the second protruding portion 23 on the welding surface 21 is a discontinuous ring (not shown in the figure).

[0078] By setting the second protruding portion 23 as a discontinuous ring, the overcurrent area during welding can be reduced on the basis of ensuring the welding effect, the required welding power can be appropriately lowered, thereby improving production efficiency and ensuring safety.

[0079] Obviously, the above embodiments are only examples for the sake of clarity, and are not a limitation on the embodiments. Although the embodiments of the present application are described in conjunction with the drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present application, and such modifications and variations fall within the scope of the present application.

Claims

1. A battery, characterized by, Comprise: a pole piece (1) comprising a pole piece body and a tab formed by a local area of the pole piece body extending away from the pole piece body; a pole post (2) for electrically connecting with the pole piece (1), having a welding surface (21) welded with the tab; the welding surface (21) is provided with a first protruding part (22) and a second protruding part (23), the first protruding part (22) is annular in the orthographic projection of the welding surface (21), and the second protruding part (23) is located inside the first protruding part (22); the maximum thickness of the non-welding area of the tab is D, the maximum thickness of the welding area of the tab is W; the height of the first protruding part (22) protruding from the welding surface (21) is H1, and 0.0013≤(D-W) / H1≤5.33 is satisfied.

2. The battery of claim 1, wherein, The height H1 of the first protruding part (22) protruding from the welding surface (21) satisfies: 0.3mm≤H1≤3.0mm.

3. The battery of claim 1, wherein, The maximum thickness D of the non-welding area of the tab satisfies: 0.04mm≤D≤3.2mm.

4. The battery of claim 1, wherein, The maximum thickness W of the welding area of the tab satisfies: 0.02mm≤D≤2.9mm.

5. The battery of claim 1, wherein, The pole piece (1) comprises a positive pole piece, a negative pole piece, and a composite current collector arranged between the positive pole piece and the negative pole piece; the composite current collector is adapted to separate the positive pole piece and the negative pole piece; The composite current collector comprises a base film layer (12) and a conductive layer (11) arranged on at least one side surface of the base film layer (12).

6. The battery of claim 1, wherein, The height H2 of the second protruding part (23) protruding from the welding surface (21) satisfies: 0mm≤H2-H1≤0.5mm.

7. The battery of claim 1, wherein, In the direction perpendicular to the welding surface (21), the cross-sectional width of the first protruding part (22) away from the welding surface (21) side is smaller than the cross-sectional width close to the welding surface (21) side.

8. The battery of claim 7, wherein, The cross-sectional width of the first protruding part (22) away from the welding surface (21) side is M1, and the cross-sectional width of the first protruding part (22) close to the welding surface (21) side is M2, satisfying: 0mm≤M2-M1≤2mm.

9. The battery of claim 1, wherein, In the direction parallel to the welding surface (21), the shortest distance F between the first protruding part (22) and the second protruding part (23) satisfies: 0.5mm≤F≤5mm.

10. The battery of claim 1, wherein, The maximum thickness D of the non-welding area of the tab and the height H1 of the first protruding part (22) protruding from the welding surface (21) satisfy: 0.013≤D / H1≤10.

67.

11. The battery of claim 1, wherein, The orthographic projection of the first protruding part (22) on the welding surface (21) is a discontinuous annular shape.

12. The battery of claim 1, wherein, The orthographic projection of the second protruding part (23) on the welding surface (21) is an annular shape.

13. The battery of claim 12, wherein, The orthographic projection of the second protruding part (23) on the welding surface (21) is a discontinuous annular shape.

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