Pole piece, secondary battery and electronic device

Abstract

The embodiment of the utility model provides a pole piece, a secondary battery and an electronic device. The pole piece comprises a pole piece main body; the pole lug extends out from the pole piece main body along a first direction, a reinforcing rib is arranged on the surface of the pole lug, the reinforcing rib at least comprises a first part and a second part, the first part and the second part are connected through a bending part, and an angle a formed by the first part and the second part is greater than or equal to 28 degrees and less than or equal to 45 degrees. According to the technical scheme, at least a more effective strengthening effect can be provided for the tabs, and the tabs are effectively prevented from being fractured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, and more particularly, to a tab, a secondary battery and an electronic device. BACKGROUND

[0002] For secondary batteries in the field of new energy power batteries, copper foil and aluminum foil are generally used as current collectors of tabs. With the thinning of the foil, the bending strength of the foil itself is extremely low, and the tab ear folding phenomenon easily occurs, which greatly affects the production efficiency and yield of the battery.

[0003] The existing technology improves the bending strength of the tab ear by setting a reinforcing rib on the surface of the tab ear. Compared with the tab ear without the reinforcing rib, the strength of the tab ear can be improved, and the possibility of tab ear bending can be reduced. However, the existing reinforcing rib structure still has the problem of insufficient strengthening effect. CONTENT OF THE UTILITY MODEL

[0004] In view of the problems in the related art, the purpose of the present application is to provide a tab, a secondary battery and an electronic device, which can at least provide more effective strengthening effect for the tab ear and effectively avoid tab ear cracking.

[0005] To achieve the above-mentioned purpose, the embodiments of the present application provide a tab, which comprises: a tab body; and a tab ear extending out from the tab body along a first direction, a reinforcing rib being arranged on the surface of the tab ear, wherein the reinforcing rib at least comprises a first part and a second part, the first part and the second part are connected by a bending part, and the angle formed by the first part and the second part is a, 28°≤a≤45°. The above-mentioned technical solution of the present application can at least provide more effective strengthening effect for the tab ear and effectively avoid tab ear cracking.

[0006] In some embodiments, 30°≤a≤35°.

[0007] In some embodiments, the bending part has an inner fillet part connecting the inner side edges of the first part and the second part opposite to each other, and the circular arc radius of the inner fillet part is Rn, Rn≥0.5mm.

[0008] In some embodiments, the bending part has an outer fillet part connecting the outer side edges of the first part and the second part, and the circular arc radius of the outer fillet part is Ro, Ro≥1.5mm.

[0009] In some embodiments, Ro>Rn.

[0010] In some embodiments, the width of the first part is w, and the recess depth of the first part in the thickness direction relative to one surface of the tab ear is h, then 1.1≤w / h≤6.67.

[0011] In some embodiments, 1.15 ≤ w / h ≤ 2.4.

[0012] In some embodiments, the reinforcing rib comprises a plurality of first portions and a plurality of second portions, the first portions and the second portions are arranged alternately along a second direction and are connected by the bending portions, and the second direction is perpendicular to the first direction.

[0013] Embodiments of the present application also provide a secondary battery, comprising an electrode assembly, the electrode assembly comprising a positive electrode tab, a negative electrode tab, and a separator between the positive electrode tab and the negative electrode tab, wherein at least one of the positive electrode tab and the negative electrode tab is the electrode tab of any one of the above.

[0014] Embodiments of the present application also provide an electronic device comprising the secondary battery of any one of the above.

[0015] The above technical solutions of the present application can provide more effective reinforcement for the tab by configuring the angle a between the first portion and the second portion of the reinforcing rib on the tab to be 28° ≤ a ≤ 45°, and effectively avoid tab cracking at the same time. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0017] Figures 1A-1F is a schematic diagram showing different manufacturing stages of manufacturing an electrode tab according to an embodiment of the present application.

[0018] Figure 2 shows a partial enlarged view of a part of the reinforcing rib in Figure 1F

[0019] Figure 3A shows a partial enlarged view of a part of the reinforcing rib in Figure 1F

[0020] Figure 3B is a cross-sectional view of the reinforcing rib on the tab.

[0021] Figures 4A-4B is a schematic diagram showing different manufacturing stages of manufacturing an electrode tab according to another embodiment of the present application.

[0022] Figure 5 shows a schematic diagram of an electrode tab according to yet another embodiment of the present application.

[0023] Figure 6 ​​A schematic view of a reinforcing rib on a tab is shown according to another embodiment of the present application.

[0024] Figure 7 A perspective schematic view of a secondary battery is shown according to an embodiment of the present application.

[0025] Figure 8 A cross-sectional schematic view of a secondary battery is shown according to an embodiment of the present application.

[0026] Figure 9 is Figure 8 A cross-sectional schematic view of an electrode assembly of a secondary battery in

[0027] Figure 10 A schematic view of an electronic device according to an embodiment of the present application is shown when the electronic device is a vehicle. DETAILED DESCRIPTION

[0028] For a better understanding of the spirit of the embodiments of the present application, reference will be made to the following portions of the present application in connection with the preferred embodiments thereof.

[0029] Embodiments of the present application will be described in detail below. Throughout the specification, like or similar components and components having like or similar functions are denoted by like reference numerals. The embodiments described herein with reference to the accompanying drawings are illustrative in nature, diagrammatic and are provided to give an overall understanding of the present application. The embodiments of the present application should not be construed as limiting the present application.

[0030] As used herein, the terms "approximately," "substantially," "about," and "generally" are used to describe and account for small variations. When utilized in connection with an event or circumstance, such terms can refer to instances in which the event or circumstance is exact, and instances in which the event or circumstance is close enough to the exact event or circumstance.

[0031] In this specification, unless specifically specified or limited, relative terms such as "central," "longitudinal," "lateral," "forward," "rearward," "rightward," "leftward," "internal," "external," "lower," "upper," "horizontal," "vertical," "higher," "lower," "above," "below," "top," "bottom," and derivatives thereof (e.g., "horizontally," "downwardly," "upwardly," etc.) should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms are for convenience of description only and do not require that the apparatus be constructed or operated in a particular orientation unless specifically specified.

[0032] For ease of description, "first," "second," "third," and so on can be used herein to distinguish different components of one figure or a series of figures. The "first," "second," "third," and so on are not intended to describe the corresponding components.

[0033] A secondary battery refers to a battery that can be used continuously by activating active materials through charging after discharging. The types of secondary batteries can include a nickel-hydrogen battery, a nickel-cadmium battery, a lead-acid battery, a lithium-ion battery, a polymer lithium-ion battery, and the like. The electrode assembly of a secondary battery mainly includes a positive electrode tab and a negative electrode tab, and the positive electrode tab and the negative electrode tab are separated by a separator. The positive electrode tab, the negative electrode tab, and the separator are formed into an electrode assembly in a winding or stacking manner, and the electrode assembly is sealed in a case to form a secondary battery.

[0034] The positive electrode tab can include a positive electrode current collector and a positive electrode active material layer, and the positive electrode active material layer is coated on part of the surface of the positive electrode current collector. The negative electrode tab can include a negative electrode current collector and a negative electrode active material layer, and the negative electrode active material layer is coated on part of the surface of the negative electrode current collector. In some embodiments, for example, in a lithium-ion battery, the material of the positive electrode current collector can be aluminum, and the thickness can be 10-12 microns. The positive electrode active material layer can include a positive electrode active material, and the positive electrode active material can be lithium cobaltate, lithium iron phosphate, ternary lithium, or lithium manganate, etc. For high-nickel ternary lithium batteries, the positive electrode active material can be a ternary material composed of nickel, cobalt, manganese (or aluminum). The material of the negative electrode current collector can be copper, and the thickness can be 4.5-6 microns. The negative electrode active material layer can include a negative electrode active material, and the negative electrode active material can be carbon or silicon, etc. The material of the separator can be, for example, PP (polypropylene) or PE (polyethylene), etc.

[0035] Figures 1A-1F is a schematic diagram showing different manufacturing stages of manufacturing a tab according to an embodiment of the present application. First, referring to Figure 1AAs shown, the active material layer 130 is coated on both side surfaces of the current collector 110 in the thickness direction thereof. The active material layer 130 can be coated on the current collector 110 by a coating device. The edge portion 110e of the current collector 110 in the width direction thereof is not coated with the active material layer 130 to form a blank foil region. In some embodiments in which the electrode tab 100 forms a negative electrode tab, the current collector 110 is a negative current collector and the active material layer 130 is a negative active material layer. In some embodiments, the material of the negative current collector can be, for example, copper, and the thickness can be 4.5-6 microns. In some embodiments in which the electrode tab 100 forms a positive electrode tab, the current collector 110 is a positive current collector and the active material layer 130 is a positive active material layer. In some embodiments, the material of the positive current collector can be aluminum, and the thickness can be 10-12 microns. After the active material layer 130 is coated, the current collector 110 and the active material layer 130 can be cut along the dashed line L1 to obtain a single electrode assembly 200. Figure 1B The single electrode tab 100 shown in FIG. 1A is used to form a single electrode assembly.

[0036] Referring to Figure 1C As shown, the side of the current collector 110 of the electrode tab 100 that is not coated with the active material can be cut according to the dashed line L2, which can be referred to as tab ear cutting. After the cutting, referring to Figure 1D As shown, a plurality of tab ears 150 are formed at intervals along the length direction of the electrode tab 100. The uncut portions of the current collector 110 and the active material layer 130 can be referred to as a tab body 160. The tab body 160 includes the current collector 110 and the active material layer 130, wherein the active material layer 130 covers both side surfaces of the current collector 110 in the thickness direction thereof.

[0037] The tab ear 150 extends from the tab body 160 in a first direction D1. The first direction D1 is parallel to the width direction of the electrode tab 100, and a second direction D2 is perpendicular to the first direction D1 and parallel to the length direction of the electrode tab 100. Specifically, in the present embodiment, the tab ear 150 can include a tab ear blank foil region 152 formed by the current collector 110 that is not covered by the active material layer 130. The tab ear 150 can also include a tab ear coating region 154 connected between the tab ear blank foil region 152 and the tab body 160. The tab ear coating region 154 protrudes from the edge 160e of the tab body 160 perpendicular to the first direction D1. Moreover, the active material layer 130 is also coated on the tab ear coating region 154. The tab ear described in the present application is formed by cutting the current collector coated with the active material, and the tab ear described in the present application can also be connected to the tab body 160 by other means such as welding.

[0038] Referring to Figure 1E and Figure 1F As shown, wherein Figure 1F isFigure 1E A local enlarged view of the region S1 of the pole piece 100 is shown. A reinforcing rib 190 is formed on the surface of each tab 150. In some embodiments, the reinforcing rib can be formed before or after the tab is cut. Preferably, the reinforcing rib is formed on the tab by rolling the tab with a reinforcing rib roller before the tab is cut.

[0039] In the present embodiment, the reinforcing rib 190 extends to the tab coating region 154 but not to the pole piece body 160. By extending the reinforcing rib 190 to the tab coating region 154, the bending resistance provided by the reinforcing rib 190 to the tab can be increased. In other embodiments, the reinforcing rib 190 can not extend to the tab coating region 154.

[0040] Specifically, referring to Figure 1F The reinforcing rib 190 can include a first portion 192 and a second portion 194, which are connected by a bending portion 196. The first portion 192 and the second portion 194 form an angle a. In some embodiments, the angle a formed by the first portion 192 and the second portion 194 is in the range of 28°-45°, i.e., 28°≤a≤45°. In some embodiments, the first portion 192 and the second portion 194 extend in different directions on the tab, and the two portions can have the same shape and structure except for the difference in the extension direction. In other embodiments, the first portion 192 and the second portion 194 extend in different directions on the tab, and the two portions can have slightly different shape and structure except for the difference in the extension direction.

[0041] The first portion 192 and the second portion 194 form an angle a. Since a triangle has good stability, the stable structure formed by the first portion 192 and the second portion 194 in a triangular shape can provide good reinforcement to the tab. However, if the angle a is too small, the distance between the adjacent first portion 192 and the second portion 194 will be too close. On the one hand, this will cause the tab between the adjacent first portion 192 and the second portion 194 to be over-pressed and stress concentration will occur, which can eventually lead to tab cracking and other conditions. On the other hand, after the distance is too close, the effect of the first portion 192 and the second portion 194 is similar to that of a single strip-shaped reinforcing rib, which will reduce the stability of the triangle. If the angle a is too large, the region of the tab between the first portion 192 and the second portion 194 will be widened. At this time, the first portion 192 and the second portion 194 are not enough to effectively reinforce the region of the tab between them, and the tab is prone to fold down to the pole piece body region.

[0042] Therefore, the inventors have found through experimental verification research that by setting the first portion 192 and the second portion 194 to form an angle a, and configuring the range of the angle a to be 28°≤a≤45°, a more effective reinforcement effect can be provided for the tab, and at the same time, the tab cracking can be effectively avoided. Preferably, the range of the angle a is 30°-35°, i.e., 30°≤a≤35°. This range of the angle a can further provide a more effective reinforcement effect for the tab, and effectively avoid the tab cracking.

[0043] Figure 2 A partial enlarged view of a portion of the reinforcing rib 190 in Figure 1F is shown. Referring to Figure 2 , the reinforcing rib 190 can include a first portion 192 and a second portion 194. The first portion 192 extends longitudinally from one end 192a thereof to the other end 192b thereof. The second portion 194 extends longitudinally from one end 194a thereof to the other end 194b thereof. The one end 192a of the first portion 192 and the one end 194a of the second portion 194 are connected to each other by a bending portion 196. The angle a formed by the first portion 192 and the second portion 194 can be an angle defined between the inner side edge 1921 of the first portion 192 and the inner side edge 1941 of the second portion 194 opposite to each other.

[0044] More specifically, the bending portion 196 has an inner fillet An located at the inner side of the bending portion 196. The inner fillet An connects the inner side edge 1921 of the first portion 192 and the inner side edge 1941 of the second portion 194 opposite to each other. The inner fillet An has a circular arc radius Rn and a corresponding center O1. In some embodiments, the circular arc radius Rn of the inner fillet An≥0.5mm. For the range of the corresponding angle a of 28°-45°, the apex (at the bending portion 196) is prone to become a stress concentration area. By setting the inner side of the bending portion 196 as the inner fillet An, and controlling the circular arc radius Rn of the inner fillet An to be not less than 0.5mm, the stress concentration problem at the inner side of the bending portion 196 can be effectively alleviated.

[0045] In addition, the bending portion 196 further has an outer fillet Ao located on the outer side of the bending portion 196. The outer fillet Ao connects the outer side edge 1922 of the first portion 192 and the outer side edge 1942 of the second portion 194 away from each other. The radius of the arc of the outer fillet Ao is Ro, and the corresponding center is O2. In some embodiments, the radius of the arc Ro of the outer fillet Ao is ≥1.5 mm. As described above, for the value range of the corresponding angle a 28°-45°, the vertex angle (at the bending portion 196) is prone to be a stress concentration area. By setting the outer side of the bending portion 196 as the outer fillet Ao and controlling the radius of the arc Ro of the outer fillet Ao to be not less than 1.5 mm, the stress concentration problem of the outer side of the bending portion 196 can be effectively alleviated.

[0046] Further, in some embodiments, the radius of the arc Ro of the outer fillet Ao of the bending portion 196 is greater than the radius of the arc Rn of the inner fillet An, i.e., Ro>Rn. Due to the stress concentration at the bending portion 196, by setting the radius of the arc Ro as Ro>Rn, the outer fillet Ao can be increased, and the foil cracking of the bending portion 196 when forming the reinforcing rib can be avoided.

[0047] The axis Lx extending through the centers O1, O2 can be perpendicular to the second direction D2. The first portion 192 and the second portion 194 can be symmetrical relative to the axis Lx, and the bending portion 196 can be symmetrical relative to the axis Lx. The included angle between the first portion 192 or the second portion 194 and the axis Lx is 1 / 2 of the angle a. For example, Figure 2 As shown in FIG. 1B, the angle a' between the inner side edge 1941 of the second portion 194 and the axis Lx is 1 / 2 of the angle a. The bending portion 196 connected to the other end 194b of the second portion 194 has an end point Eb in the opposite direction of the first direction D1. The end point Eb and the centers O1, O2 of the corresponding inner fillet An and outer fillet Ao can be located on the same straight line extending in the first direction D1.

[0048] In some embodiments in which the reinforcing rib 190 extends to the tab coating area 154, the bending portion 196 of the reinforcing rib 190 facing the tab body 160 can extend to the active material layer 130. Since the bending portion 196 is prone to be a stress concentration area, the active material layer 130 can be peeled off. By controlling the radius of the arc Rn of the inner fillet An of the bending portion 196 to be not less than 0.5 mm and / or the radius of the arc Ro of the outer fillet Ao to be not less than 1.5 mm, the stress concentration problem of the inner side and / or the outer side of the bending portion 196 can be effectively alleviated, so that the active material can be prevented from being peeled off.

[0049] In addition, in some embodiments, a portion of the first portion 192 and the second portion 194 can extend to the active material layer 130 (for example,Figure 1F (As shown). By configuring the range of angle a to 28°≤a≤45°, the stress concentration problem between adjacent first part 192 and second part 194 can be alleviated, thereby preventing the active material from falling off.

[0050] also, Figure 3A It shows Figure 1F A partially enlarged schematic diagram of the reinforcing rib 190 in the diagram. (See attached diagram.) Figure 3A As shown, the reinforcing rib 190 may include multiple first portions 192 and multiple second portions 194. Figure 3A The diagram shows two first portions 192 and two second portions 194 as examples. Along the second direction D2, the first portions 192 and second portions 194 are alternately arranged and connected by a bend 196. Thus, the first portions 192, second portions 194, and bends 196 form a W-shaped, continuously extending reinforcing rib 190 on the electrode tab 150. Due to the good stability of triangles, the triangular-like stability structure between each adjacent first portion 192 and second portion 194 provides excellent reinforcement for the electrode tab.

[0051] See again Figure 2 As shown, the first part 192 extends longitudinally from one end 192a to the other end 192b. Let the width of the first part 192 be w, and the direction of the width w of the first part 192 is perpendicular to the direction of its longitudinal extension. The overall width w of the first part 192 can be uniform and consistent. Figure 3B This is a schematic cross-sectional view of the reinforcing rib 190 on the tab 150. This cross-section is perpendicular to the thickness direction of the tab 150 and passes through the tab 150 along the length of the electrode sheet. (Reference) Figure 3B Along the thickness direction of the tab 150, the recess depth of the first portion 192 relative to one surface (the recessed side) of the tab 150 is h. In one embodiment, the reinforcing rib 190 can be formed by roll forming, and h can be the recess depth of the area where the first portion 192 is located relative to the roll-formed surface of the tab 150. In some embodiments, the value of w / h ranges from 1.1 to 6.67, that is, 1.1 ≤ w / h ≤ 6.67. If the ratio of w / h is less than the lower limit of the above range of 1.1, then w is relatively too narrow, the edge stress points are more concentrated, and cracking problems are prone to occur. If the ratio of w / h is greater than the upper limit of the above range of 6.67, then the depth h of the first portion 192 is relatively too small, and after the first portion 192 is formed, the recess depth of the first portion 192 cannot meet the tab reinforcement requirements. Preferably, the range of w / h is 1.15-2.4, that is, 1.15 ≤ w / h ≤ 2.4. This can further alleviate the problem of concentrated stress points at the edges, which makes them prone to cracking, and ensure that the depth of the depression in the first part 192 meets the requirements.

[0052] Similarly, the second portion 194 extends longitudinally from one end 194a to the other end 194b, and the second portion 194 has a width w, which is perpendicular to the longitudinal direction of the second portion 194. The width w of the second portion 194 is uniform and consistent throughout. It should be understood that although the first portion 192 and the second portion 194 are both provided with w, the widths of the first portion 192 and the second portion 194 can be the same or different. Referring to Figure 3B , the second portion 194 has a recessed depth h relative to one surface (the recessed side surface) of the tab 150. It should be understood that although the first portion 192 and the second portion 194 are both provided with h, the recessed depths of the first portion 192 and the second portion 194 can be the same or different. In some embodiments, for the second portion 194, 1.1≤w / h≤6.67. If the ratio of w / h is less than the lower limit of the above range of 1.1, w is relatively too narrow, the edge stress point is relatively concentrated, and the problem of cracking is prone to occur. If the ratio of w / h is greater than the upper limit of the above range of 6.67, the depth h of the second portion 194 is relatively too small, and after the second portion 194 is formed, the recessed depth of the second portion 194 cannot meet the tab strengthening requirement. Preferably, for the second portion 194, 1.15≤w / h≤2.4. In this way, the problem of cracking caused by the relatively concentrated edge stress point can be further alleviated, and the recessed depth of the second portion 194 can meet the requirement.

[0053] Figures 4A-4B is a schematic diagram showing different manufacturing stages of manufacturing the tab 100A according to another embodiment of the present application. In this embodiment, as shown in Figure 4A , the side of the current collector 110 of the tab 100A which is not coated with the active material layer 130 can be cut according to the dashed line L3. After cutting, as shown in Figure 4B , a plurality of tabs 150' are formed which are arranged at intervals along the length direction of the tab 100A. The tabs 150' extend from the edge 160e of the tab body 160 in the direction D1. In the tab 100A of the present embodiment, the tabs 150' are only composed of tab empty foil areas, and the reinforcing ribs 190 on the tabs 150' can partially extend to the area of the tab body 160. In other embodiments, the reinforcing ribs 190 on the tabs 150' can not extend to the area of the tab body 160. In the present embodiment, the reinforcing ribs 190 on the tabs 150' can be similar to those described above with reference to Figures 1A-3B , and can have the benefits described above with reference to Figures 1A-3B .

[0054] Figure 5 is a schematic diagram showing a tab 100B according to yet another embodiment of the present application. Referring to Figure 5In the present embodiment, in the tab 100B of the present embodiment, the tab 150’ is composed of only the tab empty foil region. The interface between the active material layer 130 and the tab 150’ can be aligned with the edge 160e of the tab body 160 along the tab length direction. In the present embodiment, the reinforcing ribs 190 do not extend onto the active material layer 130. The reinforcing ribs 190 on the tab 150’ can be similar to those described above with reference to Figures 1A-3B and can have the benefits described above with reference to Figures 1A-3B .

[0055] Figure 6 A schematic view of reinforcing ribs on a tab 150’ according to another embodiment of the present application is shown. Reference is made to Figure 6 In the present embodiment, each reinforcing rib 190 is a continuous reinforcing rib formed by a first portion 192, a second portion 194 and a bent portion 196. And, a plurality of continuous reinforcing ribs 190 can be provided on the surface of the tab 150’, the plurality of continuous reinforcing ribs 190 being arranged in the first direction D1 so that the plurality of continuous reinforcing ribs 190 form a reinforcing rib array. By forming a reinforcing rib array on the tab using the continuous reinforcing ribs 190 described above, more effective reinforcement of the tab can be provided and the tab can be more effectively prevented from being crushed and folded over to the tab body region.

[0056] A portion of another reinforcing rib 190 can be provided between the first portion 192 and the second portion 194 of a continuous reinforcing rib 190. In this way, the portions of two adjacent continuous reinforcing ribs 190 in the first direction D1 can overlap in the second direction D2. This can allow the reinforcing ribs on the tab 150’ to be arranged more densely, which can provide more effective reinforcement of the tab and more effectively prevent the tab from being crushed and folded over to the tab body region.

[0057] In some embodiments, the tab 150’ has a lower edge 156 that interfaces with the tab body 160 and an upper edge 157 that is distal from the tab body 160. The reinforcing rib 190 of the plurality of continuous reinforcing ribs 190 that is closest to the lower edge 156 is a lower continuous reinforcing rib 198, and the area enclosed by the lower continuous reinforcing rib 198 and the lower edge 156 is filled with a truncated reinforcing rib 190S. The truncated reinforcing rib 190S can be a portion of a single continuous reinforcing rib 190, and can be understood to be conformal and identical in size to the portion of the single continuous reinforcing rib 190. In the present embodiment, two truncated reinforcing ribs 190S are arranged in the first direction D1. In other embodiments, other numbers of truncated reinforcing ribs 190S can be provided in the area between the lower continuous reinforcing rib 198 and the lower edge 156. In some embodiments, each adjacent reinforcing rib 190 and truncated reinforcing rib 190S is arranged at equal intervals in the first direction D1.

[0058] Similarly, in some embodiments, the continuous reinforcing rib closest to the upper edge 157 among the plurality of continuous reinforcing ribs 190 is the upper continuous reinforcing rib 199, and the area enclosed by the upper continuous reinforcing rib 199 and the upper edge 157 is filled with truncated reinforcing ribs 190S. By forming truncated reinforcing ribs 190S between the upper continuous reinforcing rib 199 and the lower continuous reinforcing rib 198 and the upper edge 157 and lower edge 156 corresponding to the tab 150', the area on the tab 150' where continuous reinforcing ribs cannot be provided can be further filled, thus avoiding stress junction points in the area where continuous reinforcing ribs cannot be provided, and further strengthening the support to reduce the possibility of the tab 150' bending. It is understandable that the cut-off reinforcing rib 190S in the area between the upper continuous reinforcing rib 199 and the upper edge 157 is not necessary, while the cut-off reinforcing rib 190S between the lower continuous reinforcing rib 198 and the lower edge 156 can strengthen the root area where the tab 150' connects to the electrode body 160, and has a stronger effect on the additional support of the tab 150'.

[0059] Furthermore, when the area between the continuous reinforcing rib 198 and the lower edge 156 is near the active material layer 130 of the electrode, if no reinforcing rib is provided in the area between the continuous reinforcing rib 198 and the lower edge 156, during the process of forming the reinforcing rib for the electrode tab, the continuous reinforcing rib 198 near the lower edge 156 usually has an end point (such as the aforementioned end point Eb) or a bend 196. During the formation of the reinforcing rib, stress concentration usually occurs, and the active material layer 130 adjacent to it may detach due to stress concentration. By filling the area between the continuous reinforcing rib 198 and the lower edge 156 with a truncated reinforcing rib 190S, the detachment of active material caused by stress concentration can be alleviated.

[0060] When Figure 6 The reinforcing rib array shown is applied to Figure 1E Electrode 100 or Figure 4B In the electrode 100A, a portion of the area between the lower continuous reinforcing rib 198 and the lower edge 156 can be located within the active material layer 130, and the truncated reinforcing rib 190S can extend from the tab empty foil area onto the active material layer 130. In this case, since the height of the truncated reinforcing rib 190S in the first direction D1 is limited, the same pressure may cause the active material to bear higher pressure. Thus, for a single reinforcing rib 190S in the truncated reinforcing rib, in the first direction D1, a portion of the pressure can be shared by the tab empty foil area, thereby reducing the pressure on the active material region and reducing the risk of overpressure in the active material region.

[0061] Figure 7 A perspective view of a secondary battery according to an embodiment of this application is shown. Figure 8A cross-sectional view of a secondary battery according to an embodiment of the present application is shown. Figure 8 A cross-sectional view of an electrode assembly of a secondary battery in Figure 7 A cross-sectional view of an electrode assembly of a secondary battery in

[0062] In conjunction with Figures 7-8 As shown in FIG. 1, the secondary battery 500 can include a case 200 including a peripheral side wall 109 and an end wall 111 connected to one end of the peripheral side wall 109, the other end of the peripheral side wall 109 opposite to the end wall 111 being provided with an opening 205. A top cover assembly 220 is covered on the opening 205 of the case 200 for defining a receiving cavity together with the case 200, and the electrode assembly 120 is located in the receiving cavity.

[0063] The direction from the end wall 111 to the top cover assembly 220 is the height direction Z of the secondary battery 500. The height direction Z can correspond to the first direction D1 described above. In the present embodiment, two electrode assemblies 120 are stacked in the case 200 along the thickness direction of the electrode assembly 120. In other embodiments, more than two electrode assemblies 120 can be provided in the case 200.

[0064] Figure 9 A cross-sectional view of an electrode assembly of a secondary battery in Figure 8 A cross-sectional view of an electrode assembly of a secondary battery in Figure 9 As shown in FIG. 1, the secondary battery 500 can include a case 200 including a peripheral side wall 109 and an end wall 111 connected to one end of the peripheral side wall 109, the other end of the peripheral side wall 109 opposite to the end wall 111 being provided with an opening 205. A top cover assembly 220 is covered on the opening 205 of the case 200 for defining a receiving cavity together with the case 200, and the electrode assembly 120 is located in the receiving cavity.

[0065] In conjunction with Figures 7-9As shown, the top cover assembly 220 includes a top cover body 221 and a first electrode terminal 223 and a second electrode terminal 224 disposed on the top cover body 221. The first electrode terminal 223 and the second electrode terminal 224 can pass through the top cover body 221 and be insulated from the top cover body 221. One of the first electrode terminal 223 and the second electrode terminal 224 is a positive electrode terminal, and the other is a negative electrode terminal. The electrode assembly 120 is provided with a tab at one end thereof, and in this embodiment, the first tab 121 and the second tab 122 at one end of the electrode assembly 120 are connected to the corresponding first electrode terminal 223 and the second electrode terminal 224, respectively. In some embodiments, the first tab 121 and the second tab 122 can be connected to the first electrode terminal 223 and the second electrode terminal 224, respectively, through a corresponding adapter piece 226. The first tab 121 and the second tab 122 can be welded to the adapter piece 226 after being bent.

[0066] In some embodiments, one of the first tab 201 and the second tab 202 is a positive electrode tab, and the other is a negative electrode tab. In some embodiments, at least one of the positive electrode tab and the negative electrode tab of the electrode assembly 120 is the tab 100, the tab 100A or the tab 100B described above. Correspondingly, one of the first tab 121 and the second tab 122 is a positive electrode tab, and the other is a negative electrode tab. At least one of the positive electrode tab and the negative electrode tab of the electrode assembly 120 is the corresponding tab 150 or tab 150' of the tab 100, the tab 100A or the tab 100B described above. In some embodiments, the negative electrode tab of the electrode assembly 120 is the tab 100, the tab 100A or the tab 100B described above, and the negative electrode tab is the corresponding tab 150 or tab 150'.

[0067] It should be understood that Figures 7-9 The secondary battery is taken as a square cell as an example for illustration. The tab 100, the tab 100A or the tab 100B described above can also be used to form any other appropriate type of secondary battery, such as a soft pack battery, a cylindrical battery, etc.

[0068] Figure 10 A schematic diagram of the electronic device according to an embodiment of the present application is shown when the electronic device is a vehicle. Referring to FIG. 1, the electronic device according to an embodiment of the present application is a vehicle 1000. The vehicle 1000 includes a battery 1100, a motor 1200, a controller 1300, a power management system 1400, a power supply system 1500, a power distribution system 1600, a power conversion system 1700, a power storage system 1800, a power utilization system 1900, and a power supply system 2000. Figure 10In some embodiments, the electronic device 1000 can be a vehicle. The vehicle can be a fuel vehicle, a gas vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle, but is not limited thereto. The working part of the electronic device 1000 can be a vehicle body. The battery pack 1002 can be arranged at the bottom of the vehicle body and provide power support for driving of the vehicle or operation of electrical elements in the vehicle. However, in some other embodiments, the electronic device 1000 can also be a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy, an electric tool, or the like. The spacecraft includes an airplane, a rocket, a space shuttle, a spacecraft, or the like. The working part can obtain power from the battery pack 1002 and make corresponding working unit components, such as a fan blade rotating unit, a dust suction working unit of a dust collector, or the like. The electric toy includes a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, an electric airplane toy, or the like. The electric tool includes a metal cutting electric tool, a grinding electric tool, an assembling electric tool, and a railway electric tool, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact electric drill, a concrete vibrator, an electric planer, or the like. The battery pack 1002 can include a plurality of secondary batteries, such as the secondary battery 500 described above.

[0069] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, or the like within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A pole piece, characterized in that, The tab includes: a tab body; and a tab ear extending from the tab body in a first direction, a surface of the tab ear being provided with a reinforcing rib, wherein the reinforcing rib includes at least a first portion and a second portion, the first portion and the second portion being connected by a bend, wherein an angle formed by the first portion and the second portion is a, 28°≤a≤45°.

2. The tab of claim 1, wherein 3. The tab of claim 1, wherein 30°≤a≤35°。 the bend has an inner fillet connecting inner side edges of the first portion and the second portion opposite to each other, the inner fillet having a radius of curvature Rn, Rn≥0.5mm.

4. The tab of claim 3, wherein the bend has an outer fillet connecting outer side edges of the first portion and the second portion, the outer fillet having a radius of curvature Ro, Ro≥1.5mm.

5. The tab of claim 4, wherein Ro>Rn.

6. The tab of claim 1, wherein a width of the first portion is w; a depth of a recess of the first portion in a thickness direction relative to a surface of the tab ear is h, then, 1.1≤w / h≤6.

67.

7. The tab of claim 6, wherein 1.15≤w / h≤2.

4. the reinforcing rib includes a plurality of the first portions and a plurality of the second portions, the first portions and the second portions being alternately arranged in a second direction perpendicular to the first direction and being connected by the bends.

8. The pole piece of claim 1, wherein The electrode assembly includes:

9. A secondary battery characterized by comprising: a positive electrode tab, a negative electrode tab, and a separator between the positive electrode tab and the negative electrode tab, wherein at least one of the positive electrode tab and the negative electrode tab is the tab of any one of claims 1-8. The secondary battery includes the secondary battery of claim 9.

10. An electronic device, comprising: ​

Images