Pole piece, battery cell and battery
By designing a folded structure of the empty foil area of the composite fluid in the lithium battery electrode sheet, the conductive layer is electrically conductive, solving the problem of low conductive layer utilization, and achieving efficient material utilization and improving the energy density of the battery cell.
Patent Information
- Application Number
- CN202421796767.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-26
- Publication Date
- 2025-07-04
- Estimated Expiration
- 2034-07-26
AI Technical Summary
The low utilization rate of the conductive layer of the composite fluid collector in existing lithium batteries leads to problems such as waste of materials and low energy density of the battery cell.
An electrode sheet structure is designed, wherein the empty foil area of the composite liquid collector is divided into a non-cut area, a first cutting area and a second cutting area. The first folded part and the second folded part are formed by folding, so that the first conductive layer and the second conductive layer are electrically conductive, and the electrode ears are welded and connected to at least one to achieve full utilization of the conductive layer.
The utilization rate of the conductive layer of the composite fluid collector is improved, material waste is avoided, and the energy density of the battery cell is improved.
Smart Images
Figure CN223066184U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of lithium batteries, and particularly relates to an electrode sheet, an electric core and a battery. Background Art
[0002] As a new type of current collector, the composite current collector mainly has a sandwich structure of an inner polymer layer (such as polymer materials like PP / PET / PI, etc.) and two outer conductive layers (such as Al or Cu). This structure enables it to have good application scenarios in lithium batteries.
[0003] In a lithium battery cell, the tab is usually arranged on one side of the electrode sheet, and the conductive layer of the composite current collector on the corresponding side is welded to the tab and cooperates with the tab to perform charge and discharge. However, the conductive layer on the other side of the composite current collector is not electrically connected to the tab, resulting in the "idle" of the non-conductive conductive layer on this side, which is not fully utilized, causing waste of materials and occupying space, and the energy density of the cell is low. Summary of the Utility Model
[0004] The main purpose of the utility model is to propose an electrode sheet, aiming to solve the technical problems of low utilization rate of the conductive layer of the composite current collector in the current electrode sheet, resulting in waste of materials and occupying space, and low energy density of the cell.
[0005] To achieve the above purpose, the utility model proposes an electrode sheet, which includes:
[0006] A composite current collector, the composite current collector has a coating area and a bare foil area arranged in sequence along its length direction, and both the coating area and the bare foil area include a first conductive layer, a substrate layer and a second conductive layer arranged in a stacked manner;
[0007] An active material layer, the active material layer is arranged on the first conductive layer and / or the second conductive layer of the coating area;
[0008] A tab, at least one of the first conductive layer of the bare foil area, the second conductive layer of the bare foil area, the first conductive layer of the coating area and the second conductive layer of the coating area is welded and connected with the tab;
[0009] Wherein, the bare foil area is at least divided into a non-cutting area, a first cutting area and a second cutting area. The first cutting area and the second cutting area are respectively folded inwards from both ends of the non-cutting area to correspondingly form a first folding part and a second folding part. The first folding part extends into the folding space of the second folding part and at least partially overlaps with the second folding part. The first conductive layer at the first folding part is connected to the second conductive layer at the second folding part, so that the first conductive layer and the second conductive layer are electrically connected.
[0010] In some embodiments, the empty foil area is further divided into a welding area, which is located on the side of the first cutting area away from the non-cutting area or on the side of the second cutting area away from the non-cutting area;
[0011] One tab is provided, and the tab is located in the welding area; alternatively, at least two tabs are provided, and at least one of the tabs is located in the welding area.
[0012] In some embodiments, the width of the folded part of the first folding part and the width of the folded part of the second folding part are both smaller than the width of the non-cutting area.
[0013] In some embodiments, the positive projection of the end of the first folding part in the thickness direction of the composite current collector is located within the non-cutting area;
[0014] The positive projection of the end of the second folding part in the thickness direction of the composite current collector is located within the non-cutting area.
[0015] In some embodiments, after the first cutting area is folded, a first cutting hole is formed in the empty foil area. The first cutting hole has a plurality of first inner corners, and all of the plurality of first inner corners are chamfered; and / or,
[0016] After the second cutting area is folded, a second cutting hole is formed in the empty foil area. The second cutting hole has a plurality of second inner corners, and all of the plurality of second inner corners are chamfered.
[0017] In some embodiments, the first cutting area, the non-cutting area, and the second cutting area are located at the edge position of the empty foil area along the length direction of the composite current collector; or,
[0018] The first cutting area, the non-cutting area, and the second cutting area are located at the edge position of the empty foil area along the width direction of the composite current collector; or,
[0019] The first cutting area, the non-cutting area, and the second cutting area are located at a non-edge position of the empty foil area.
[0020] In some embodiments, when the tab is welded to the first conductive layer, the tensile force value of the welding between the tab and the first conductive layer is greater than the peel force value between the first conductive layer and the substrate layer; and / or,
[0021] When the tab is welded to the second conductive layer, the tensile force value of the welding between the tab and the second conductive layer is greater than the peel force value between the second conductive layer and the substrate layer.
[0022] In some embodiments, the thickness of the tab is greater than or equal to the thickness of the composite current collector.
[0023] The present utility model also provides an electrode core, which includes a positive electrode tab, a negative electrode tab, and a separator disposed between the positive electrode tab and the negative electrode tab;
[0024] Wherein, at least one of the positive electrode tab and the negative electrode tab is the electrode tab as described above.
[0025] The present utility model also provides a battery, which includes a housing and the electrode core as described above, and the electrode core is disposed in the housing.
[0026] In the electrode tab of the present utility model, the composite current collector has a coating area and a bare foil area arranged in sequence along its length direction. Both the coating area and the bare foil area include a first conductive layer, a substrate layer, and a second conductive layer arranged in a stacked manner. The active material layer is disposed on the first conductive layer and / or the second conductive layer of the coating area. At least one of the first conductive layer of the bare foil area, the second conductive layer of the bare foil area, the first conductive layer of the coating area, and the second conductive layer of the coating area is connected with a tab; wherein, the bare foil area is at least divided into a non-cutting area, a first cutting area, and a second cutting area, and the first cutting area and the second cutting area are folded from both ends of the non-cutting area towards each other to correspondingly form a first folding part and a second folding part. The first folding part extends into the folding space of the second folding part and at least partially overlaps with the second folding part. By connecting the first conductive layer at the first folding part with the second conductive layer at the second folding part, the first conductive layer and the second conductive layer are electrically connected, so that both the first conductive layer and the second conductive layer of the composite current collector cooperate with the tab to perform charge and discharge, improving the utilization rate of the conductive layer of the composite current collector, thereby avoiding waste of materials and occupation of space, and improving the energy density of the electrode core. Description of the Drawings
[0027] Figure 1 It is a schematic structural diagram of an electrode tab in an embodiment of the present utility model;
[0028] Figure 2 It is a schematic structural diagram of an electrode tab in another embodiment of the present utility model;
[0029] Explanation of the Reference Numerals in the Drawings:
[0030] Label Name Label Name 100 Composite current collector 200 Active material layer 300 Tab 110 Coating area 120 Empty foil area 101 First conductive layer 102 Substrate layer 103 Second conductive layer 121 Non-cutting area 122 First cutting area 123 Second cutting area 122F First folding part 123F Second folding part K1 First cutting hole K2 Second cutting hole 124 Welding area
[0031] The realization, functional characteristics, and advantages of the object of the present utility model will be further described with reference to the embodiments and the accompanying drawings. Detailed Embodiments
[0032] Next, the solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the protection scope of the present utility model.
[0033] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present utility model are only used to explain the relative position relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If this specific posture changes, the directional indication will also change accordingly.
[0034] It should also be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there may be an intermediate element at the same time. When an element is referred to as "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time.
[0035] In addition, the descriptions involving "first", "second", etc. in the present utility model are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present utility model.
[0036] An electrode tab is proposed in the embodiments of the present utility model. Referring to Figure 1 and Figure 2 , the electrode tab includes: a composite current collector 100, an active material layer 200, and a tab 300. The composite current collector 100 has a coating area 110 and a bare foil area 120 arranged in sequence along its length direction. Both the coating area 110 and the bare foil area 120 include a first conductive layer 101, a substrate layer 102, and a second conductive layer 103 arranged in a stacked manner; the active material layer 200 is disposed on the first conductive layer 101 and / or the second conductive layer 103 of the coating area 110; at least one of the first conductive layer 101 of the bare foil area 120, the second conductive layer 103 of the bare foil area 120, the first conductive layer 101 of the coating area 110, and the second conductive layer 103 of the coating area 110 is welded and connected to the tab 300;
[0037] Among them, the empty foil area 120 is at least divided into a non-cutting area 121, a first cutting area 122, and a second cutting area 123. The first cutting area 122 and the second cutting area 123 are respectively folded from both ends of the non-cutting area 121 towards each other to correspondingly form a first folding part 122F and a second folding part 123F. The first folding part 122F extends into the folding space of the second folding part 123F and at least partially overlaps with the second folding part 123F. The first conductive layer 101 at the first folding part 122F is connected to the second conductive layer 103 at the second folding part 123F, so that the first conductive layer 101 and the second conductive layer 103 are electrically connected.
[0038] The electrode sheet involved in this embodiment can be a positive electrode sheet or a negative electrode sheet, and there is no limitation in this regard. The electrode sheet is applied to the battery cell, and the electrode sheet, another electrode sheet with the opposite polarity thereto, and a separator, etc. are combined to form the battery cell.
[0039] In this electrode sheet, the composite current collector 100 has a coating area 110 and an empty foil area 120. Taking the length direction of the composite current collector 100 as the reference direction, the coating area 110 and the empty foil area 120 are arranged in sequence, and the empty foil area 120 is located on one side of the coating area 110. Moreover, the composite current collector 100 has a multi-layer structure. Both the coating area 110 and the empty foil area 120 of the composite current collector 100 include a first conductive layer 101, a substrate layer 102, and a second conductive layer 103. The substrate layer 102 therein is a polymer layer, such as a PE polyethylene polymer layer or a PP polypropylene polymer layer, etc. The first conductive layer 101 and the second conductive layer 103 are metal conductive layers, such as metal layers like an aluminum layer, a copper layer, a nickel layer, etc., or other alloy layers, etc. Moreover, the first conductive layer 101 and the second conductive layer 103 can be the same metal or different metals.
[0040] The active material layer 200 is disposed on the coating area 110 of the composite current collector 100. Correspondingly, the empty foil area 120 of the composite current collector 100 is not coated with the active material. Among them, the active material layer 200 can be disposed in one layer, and this active material layer 200 is coated on the first conductive layer 101 of the coating area 110 or coated on the second conductive layer 103 of the coating area 110; or, the active material layer 200 can be disposed in two layers, one active material layer 200 is coated on the first conductive layer 101 of the coating area 110, and the other active material layer 200 is coated on the second conductive layer 103 of the coating area 110.
[0041] The tab 300 is welded to the composite current collector 100, which can be welded to the empty foil area 120 of the composite current collector 100 or to the coated area 110 of the composite current collector 100. Specifically, one, or more, or all of the first conductive layer 101 of the empty foil area 120, the second conductive layer 103 of the empty foil area 120, the first conductive layer 101 of the coated area 110, and the second conductive layer 103 of the coated area 110 are welded to the tab 300. Among them, when the first conductive layer 101 and / or the second conductive layer 103 of the empty foil area 120 are welded to the tab 300, the tab 300 can be directly welded to the corresponding conductive layer; when the first conductive layer 101 and / or the second conductive layer 103 of the coated area 110 are welded to the tab 300, if an active material layer 200 is provided at the corresponding conductive layer, a part of the active material layer 200 can be cleaned to expose the conductive layer, so as to form a welding slot for the tab 300, and the tab 300 is correspondingly welded at the welding slot. The tab 300 can be one or at least two, and the specific number of the tabs 300 can be set according to functional requirements.
[0042] Among them, as Figure 1 and Figure 2 shown, the empty foil area 120 is divided into regions, and at least divided into a non-cutting area 121, a first cutting area 122, and a second cutting area 123. The non-cutting area 121 is located between the first cutting area 122 and the second cutting area 123, and the first cutting area 122 and the second cutting area 123 are separated by the middle non-cutting area 121. Within the area of the empty foil area 120, in addition to the divided non-cutting area 121, first cutting area 122, and second cutting area 123, other areas may also be included, and there is no limitation on this. The cutting methods of the first cutting area 122 and the second cutting area 123 can be, for example, knife cutting, laser cutting, etc., and there is no limitation on this. The first cutting area 122 is folded from one end of the non-cutting area 121 to correspondingly form a first folding part 122F, and the second cutting area 123 is folded from the other end of the non-cutting area 121 to correspondingly form a second folding part 123F. Among them, the first cutting area 122 and the second cutting area 123 are folded towards each other, that is, the first cutting area 122 is folded towards the direction where the second cutting area 123 is located, and the second cutting area 123 is folded towards the direction where the first cutting area 122 is located, so that the formed first folding part 122F and the second folding part 123F are overlapped in alignment.
[0043] Specifically, the first folding portion 122F extends into the folding space of the second folding portion 123F and at least partially overlaps with the second folding portion 123F. That is, the first cutting area 122 is first folded to form the first folding portion 122F, one side of the first folding portion 122F faces the non-cutting area 121, and the second cutting area 123 is then folded to form the second folding portion 123F and covers the first folding portion 122F. The other side of the first folding portion 122F faces the second folding portion 123F, so that the first folding portion 122F extends into the folding space of the second folding portion 123F and is in an overlapping relationship with the second folding portion 123F where they at least partially overlap each other.
[0044] On this basis, the first conductive layer 101 at the first folding portion 122F is connected to the second conductive layer 103 at the second folding portion 123F, so that the first conductive layer 101 and the second conductive layer 103 are electrically connected. In this way, when the tab 300 is welded to one of the first conductive layer 101 and the second conductive layer 103, since the first conductive layer 101 and the second conductive layer 103 are electrically connected, the tab 300 will be electrically connected to both the first conductive layer 101 and the second conductive layer 103 at the same time. Both the first conductive layer 101 and the second conductive layer 103 cooperate with the tab 300 to perform charge and discharge, improving the utilization rate of the conductive layers of the composite current collector 100, thereby avoiding waste of materials and occupation of space and increasing the energy density of the battery cell. Optionally, the connection manner between the first conductive layer 101 at the first folding portion 122F and the second conductive layer 103 at the second folding portion 123F can be welding connection, including but not limited to this.
[0045] It should be noted that the so-called electrical connection between the first conductive layer 101 and the second conductive layer 103 means that the first conductive layer 101 and the second conductive layer 103 in the coating area 110 and the first conductive layer 101 and the second conductive layer 103 in the empty foil area 120 are all electrically connected.
[0046] In some embodiments, referring to Figure 1 and Figure 2 , the empty foil area 120 is further divided into a welding area 124. The welding area 124 is located on the side of the first cutting area 122 away from the non-cutting area 121 or on the side of the second cutting area 123 away from the non-cutting area 121;
[0047] One tab 300 is provided, and the tab 300 is located in the welding area 124; or, at least two tabs 300 are provided, and at least one tab 300 is located in the welding area 124.
[0048] In this embodiment, according to the number of the tabs 300 provided, the welding positions of the tabs 300 are arranged correspondingly. Among them, the empty foil area 120 is further divided into a welding area 124, and the welding area 124 is the other partial area in the empty foil area 120 that is different from the non-cutting area 121, the first cutting area 122, and the second cutting area 123. For example, the welding area 124 is located on the side of the first cutting area 122 away from the second cutting area 123, and the welding area 124 is arranged at intervals with the first cutting area 122.
[0049] As Figure 1 and Figure 2 shown, when one tab 300 is provided, the tab 300 is welded to the empty foil area 120. Specifically, the tab 300 is located in the welding area 124 of the empty foil area 120. When at least two tabs 300 are provided, at least one tab 300 is welded to the empty foil area 120. Specifically, at least one tab 300 is located in the welding area 124 of the empty foil area 120. As for the other tabs 300, they can be welded to the coating area 110. Exemplarily, when two tabs 300 are provided, one tab 300 is located in the welding area 124 of the empty foil area 120 and is welded to the empty foil area 120, and the other tab 300 can be welded to the coating area 110.
[0050] In some embodiments, referring to Figure 1 and Figure 2 , the width of the folded part of the first folding part 122F and the width of the folded part of the second folding part 123F are both smaller than the width of the non-cutting area 121. In this embodiment, the width direction of the folded part of the first folding part 122F, the width direction of the folded part of the second folding part 123F, and the width direction of the non-cutting area 121 are the same as the length direction of the composite current collector 100.
[0051] The width of the folded part of the first folding part 122F is smaller than the width of the non-cutting area 121. In this way, the extending position of the first folding part 122F extending into the folding space of the second folding part 123F is limited, and a distance is formed between the outer end of the folded first folding part 122F and the corner position of the folded second folding part 123F, so as to avoid structural interference with the second folding part 123F. Moreover, the width of the folded part of the second folding part 123F is smaller than the width of the non-cutting area, so that the folding position of the second folding part 123F is limited, and a relatively wide folding space is formed inside, so as to arrange the first folding part 122F, and a distance is formed between the corner position of the folded second folding part 123F and the outer end of the folded first folding part 122F, so as to avoid structural interference with the first folding part 122F.
[0052] In some embodiments, referring to Figure 1 and Figure 2, the orthographic projection of the end of the first folding portion 122F in the thickness direction of the composite current collector 100 is located within the non-cutting area 121;
[0053] The orthographic projection of the end of the second folding portion 123F in the thickness direction of the composite current collector 100 is located within the non-cutting area 121.
[0054] In this embodiment, the orthographic projection of the end of the first folding portion 122F in the thickness direction of the composite current collector 100 is located within the non-cutting area 121, that is, the extending position of the end of the first folding portion 122F in the folding space of the second folding portion 123F does not exceed the area where the non-cutting area 121 is located. A spacing is formed between the end of the first folding portion 122F and the inner corner of the second folding portion 123F, thereby avoiding structural interference with the second folding portion 123F. At the same time, the orthographic projection of the end of the second folding portion 123F in the thickness direction of the composite current collector 100 is located within the non-cutting area 121, that is, the extending position of the end of the second folding portion 123F does not exceed the area where the non-cutting area 121 is located, thereby forming a relatively wide folding space inside itself for arranging the first folding portion 122F, so that a spacing is formed between the inner corner of the second folding portion 123F and the end of the first folding portion 122F, thereby avoiding structural interference with the first folding portion 122F.
[0055] In some embodiments, referring to Figure 1 and Figure 2 , after the first cutting area 122 of the empty foil area 120 is folded, a first cutting hole K1 is formed. The first cutting hole K1 has a plurality of first inner corners, and all the first inner corners are chamfered. The first cutting hole K1 penetrates through the empty foil area 120 and has the same contour shape as the first cutting area 122. For example, the first cutting hole K1 is a square hole with four first inner corners, and the four first inner corners are respectively distributed at the four corners of the first cutting hole K1 and are all chamfered. Among them, the chamfer can be a rounded corner, etc. By chamfering each first inner corner of the first cutting hole K1, it is beneficial to reduce the stress concentration at the inner corner position of the first cutting hole K1, and the stress can be better dispersed and balanced. And / or, in some embodiments, after the second cutting area 123 of the empty foil area 120 is folded, a second cutting hole K2 is formed. The second cutting hole K2 has a plurality of second inner corners, and all the second inner corners are chamfered. The second cutting hole K2 penetrates through the empty foil area 120 and has the same contour shape as the second cutting area 123. For example, the second cutting hole K2 is a square hole with four second inner corners, and the four second inner corners are respectively distributed at the four corners of the second cutting hole K2 and are all chamfered. Among them, the chamfer can be a rounded corner, etc. By chamfering each second inner corner of the second cutting hole K2, it is beneficial to reduce the stress concentration at the inner corner position of the second cutting hole K2, and the stress can be better dispersed and balanced.
[0056] In some embodiments, with reference to Figure 2 , the first cutting area 122, the non-cutting area 121, and the second cutting area 123 are located at the edge positions of the empty foil area 120 along the length direction of the composite current collector 100; or,
[0057] the first cutting area 122, the non-cutting area 121, and the second cutting area 123 are located at the edge positions of the empty foil area 120 along the width direction of the composite current collector 100; or,
[0058] the first cutting area 122, the non-cutting area 121, and the second cutting area 123 are located at non-edge positions of the empty foil area 120.
[0059] In the empty foil area 120, the positions of the first cutting area 122, the non-cutting area 121, and the second cutting area 123 can be set in multiple places. For example, the first cutting area 122, the non-cutting area 121, and the second cutting area 123 can be set at the edge positions of the empty foil area 120 along the length direction of the composite current collector 100. Also, for example, the first cutting area 122, the non-cutting area 121, and the second cutting area 123 can be set at the edge positions of the empty foil area 120 along the width direction of the composite current collector 100. Further, for example, the first cutting area 122, the non-cutting area 121, and the second cutting area 123 can be set at non-edge positions of the empty foil area 120, and the non-edge positions of the empty foil area 120 can be the middle positions of the empty foil area 120, etc. Among them, when the first cutting area 122, the non-cutting area 121, and the second cutting area 123 are set at the edge positions of the empty foil area 120, the first cutting area 122 and the second cutting area 123 are cut inwards from the edge line of the empty foil area 120.
[0060] As a preferred solution, as Figure 2 shown, the first cutting area 122, the non-cutting area 121, and the second cutting area 123 can be set at the edge positions of the empty foil area 120 along the length direction of the composite current collector 100, and compared with being set at other positions, it has less influence on the tensile strength of the pole piece.
[0061] In some embodiments, when the first conductive layer 101 is welded to the tab 300, the tensile force value of the weld between the tab 300 and the first conductive layer 101 is greater than the peel force value between the first conductive layer 101 and the substrate layer 102. The first conductive layer 101 involved in this embodiment may be the first conductive layer 101 in the coating area 110 or the first conductive layer 101 in the empty foil area 120, and there is no limitation thereto. When the tab 300 is welded to the first conductive layer 101, the tensile force value of the weld between the two is greater than the peel force value between the first conductive layer 101 and the substrate layer 102. Among them, the so-called tensile force value of the weld between the tab 300 and the first conductive layer 101 is the maximum tensile force that the tab 300 and the first conductive layer 101 can withstand after welding. When the external tensile force applied to the tab 300 is less than the tensile force value of the weld between the tab 300 and the first conductive layer 101, the tab 300 will not detach from the first conductive layer 101; when the external tensile force applied to the tab 300 is greater than the tensile force value of the weld between the tab 300 and the first conductive layer 101, the tab 300 will detach from the first conductive layer 101. The peel force value between the first conductive layer 101 and the substrate layer 102 is the force value at which the first conductive layer 101 and the substrate layer 102 are peeled off. When the peeling force applied to the first conductive layer 101 reaches this force value, the first conductive layer 101 will be peeled off from the substrate layer 102. In this embodiment, by setting the tensile force value of the weld between the tab 300 and the first conductive layer 101 to be greater than the peel force value between the first conductive layer 101 and the substrate layer 102, when the tab 300 is subjected to an external force and the external force is large, first, the first conductive layer 101 and the substrate layer 102 will be peeled off, and the tab 300 will not detach from the first conductive layer 101, thereby ensuring the welding strength of the tab 300. And / or, when the second conductive layer 103 is welded to the tab 300, the tensile force value of the weld between the tab 300 and the second conductive layer 103 is greater than the peel force value between the second conductive layer 103 and the substrate layer 102. The second conductive layer 103 involved in this embodiment may be the second conductive layer 103 in the coating area 110 or the second conductive layer 103 in the empty foil area 120, and there is no limitation thereto. When the tab 300 is welded to the second conductive layer 103, the tensile force value of the weld between the two is greater than the peel force value between the second conductive layer 103 and the substrate layer 102. Among them, the so-called tensile force value of the weld between the tab 300 and the second conductive layer 103 is the maximum tensile force that the tab 300 and the second conductive layer 103 can withstand after welding. When the external tensile force applied to the tab 300 is less than the tensile force value of the weld between the tab 300 and the second conductive layer 103, the tab 300 will not detach from the second conductive layer 103; when the external tensile force applied to the tab 300 is greater than the tensile force value of the weld between the tab 300 and the second conductive layer 103, the tab 300 will detach from the second conductive layer 103.The peel force value between the second conductive layer 103 and the substrate layer 102, that is, the force value at which the second conductive layer 103 peels off from the substrate layer 102. When the peeling force applied to the second conductive layer 103 reaches this force value, the second conductive layer 103 will peel off from the substrate layer 102. In this embodiment, by setting the tensile force value of welding the tab 300 to the second conductive layer 103 to be greater than the peel force value between the second conductive layer 103 and the substrate layer 102, when the tab 300 is subjected to an external force and the external force is large, first, the second conductive layer 103 will peel off from the substrate layer 102, and the tab 300 will not break away from the second conductive layer 103, thus ensuring the welding strength of the tab 300.
[0062] In some embodiments, the thickness of the tab 300 is greater than or equal to the thickness of the composite current collector 100. By setting the thickness of the tab 300 to be greater than or less than the thickness of the composite current collector 100, sufficient strength can be ensured when the electrode tab is welded to the composite current collector 100, and the welding stability of the tab 300 can be improved.
[0063] An embodiment of the present invention further provides an electric core, which includes a positive electrode tab, a negative electrode tab, and a separator disposed between the positive electrode tab and the negative electrode tab;
[0064] Among them, at least one of the positive electrode tab and the negative electrode tab is an electrode tab as described in the foregoing embodiments.
[0065] Specifically, it may be that the positive electrode tab uses the foregoing electrode tab, or the negative electrode tab uses the foregoing electrode tab, or both the positive electrode tab and the negative electrode tab use the foregoing electrode tab.
[0066] For the specific structure of this electrode tab, refer to the above embodiments. Since this electric core adopts all the technical solutions of the above embodiments, it at least has all the technical effects brought by the technical solutions of the above embodiments, which will not be elaborated here one by one.
[0067] An embodiment of the present invention further provides a battery, which includes a housing and an electric core as described in the foregoing embodiments, and the electric core is disposed in the housing. For the specific structure of this electric core, refer to the above embodiments. Since this battery adopts all the technical solutions of the above embodiments, it at least has all the technical effects brought by the technical solutions of the above embodiments, which will not be elaborated here one by one. Among them, the type of the battery can be a lithium battery.
[0068] The above are only partial or preferred embodiments of the present utility model. Neither the text nor the drawings can limit the scope of protection of the present utility model. Any equivalent structural transformation made by using the content of the specification and drawings of the present utility model under the overall concept of the present utility model, or any direct / indirect application in other related technical fields, is included in the scope of protection of the present utility model.
Claims
1. A pole piece, characterized in that, Comprising: A composite current collector, the composite current collector having a coated area and a bare foil area arranged in sequence along its length direction, both the coated area and the bare foil area including a first conductive layer, a substrate layer, and a second conductive layer arranged in a stacked manner; An active material layer, the active material layer being disposed on the first conductive layer and / or the second conductive layer of the coated area; A tab, at least one of the first conductive layer of the bare foil area, the second conductive layer of the bare foil area, the first conductive layer of the coated area, and the second conductive layer of the coated area being welded to the tab; Wherein, the bare foil area is at least divided into a non-cutting area, a first cutting area, and a second cutting area, the first cutting area and the second cutting area are respectively folded from both ends of the non-cutting area towards each other to correspondingly form a first folding portion and a second folding portion, the first folding portion extends into the folding space of the second folding portion and at least partially overlaps with the second folding portion, and the first conductive layer at the first folding portion is connected to the second conductive layer at the second folding portion, so that electrical conduction is achieved between the first conductive layer and the second conductive layer.
2. The pole piece according to claim 1, characterized in that, The bare foil area is further divided into a welding area, the welding area being located on one side of the first cutting area away from the non-cutting area or on one side of the second cutting area away from the non-cutting area; One tab is provided, and the tab is located in the welding area; or, at least two tabs are provided, and at least one of the tabs is located in the welding area.
3. The electrode tab according to claim 1, wherein The width of the folded part of the first folding portion and the width of the folded part of the second folding portion are both smaller than the width of the non-cutting area.
4. The pole piece according to claim 1, wherein The projection of the end of the first folding portion in the thickness direction of the composite current collector is located within the non-cutting area; The projection of the end of the second folding portion in the thickness direction of the composite current collector is located within the non-cutting area.
5. The pole piece according to claim 1, characterized in that, When the first cutting area of the bare foil area is folded, a first cutting hole is formed, the first cutting hole having a plurality of first inner corners, and all of the plurality of first inner corners are chamfered; and / or, When the second cutting area of the bare foil area is folded, a second cutting hole is formed, the second cutting hole having a plurality of second inner corners, and all of the plurality of second inner corners are chamfered.
6. The pole piece according to claim 1, characterized in that, The first cutting area, the non-cutting area, and the second cutting area are located at the edge position of the bare foil area along the length direction of the composite current collector; or, The first cutting area, the non-cutting area, and the second cutting area are located at the edge position of the bare foil area along the width direction of the composite current collector; or, The first cutting area, the non-cutting area, and the second cutting area are located at a non-edge position of the bare foil area.
7. The pole piece according to claim 1, characterized in that, When the tab is welded to the first conductive layer, the tensile force value of the welding between the tab and the first conductive layer is greater than the peeling force value between the first conductive layer and the substrate layer; and / or, When the tab is welded to the second conductive layer, the tensile force value of the welding between the tab and the second conductive layer is greater than the peeling force value between the second conductive layer and the substrate layer.
8. The electrode tab according to claim 1, characterized in that, The thickness of the tab is greater than or equal to the thickness of the composite current collector.
9. A battery cell, characterized in that, It includes a positive electrode plate, a negative electrode plate and a separator, and the separator is disposed between the positive electrode plate and the negative electrode plate; Wherein, at least one of the positive electrode plate and the negative electrode plate adopts the electrode plate described in any one of claims 1 to 8.
10. A battery, characterized in that, It includes a housing and the battery cell described in claim 9, and the battery cell is disposed in the housing.