Pole piece, battery cell and battery
By designing a composite liquid collecting structure of the non-folded area and the folded area in the 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
- CN202421803157.3
- 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 leads to problems such as waste of materials and low energy density of the battery cell.
An electrode sheet structure is designed, in which the empty foil area of the composite liquid collecting divides the non-folded area and the folded area, and the first and second folded parts are formed by two folds, so that the first conductive layer and the second conductive layer are electrically conductive, and the electrode ears are welded to at least one conductive layer to realize the charging and discharging function of the two conductive layers.
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 CN223066186U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of lithium batteries, and particularly relates to an electrode sheet, a battery cell 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, leading to waste of materials and occupation of space, and low energy density of the battery cell. 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 occupation of space, and low energy density of the battery cell.
[0005] To achieve the above object, 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 to the tab;
[0009] Wherein, the bare foil area is at least divided into a non-folding area and a folding area located at one end of the non-folding area. The folding area forms a first folding part and a second folding part connected to the first folding part through two folds from one end of the non-folding area. The second folding part extends into the folding space of the first folding part and at least partially overlaps with the non-folding area. The first conductive layer of the second folding part is connected to the second conductive layer at the non-folding area, so that the first conductive layer and the second conductive layer are electrically connected.
[0010] In some embodiments, the folding area is located at the end area of the end of the empty foil area away from the coating area.
[0011] In some embodiments, the folding area is located between the two ends of the empty foil area and is formed by cutting on the empty foil area.
[0012] In some embodiments, the length of the folding area is less than 1 / 4 of the width of the composite current collector.
[0013] In some embodiments, the empty foil area is further divided into a welding area, and the welding area is located on one side of the folding area away from the non-folding area or on one side of the non-folding area away from the folding area;
[0014] One tab is provided, and the tab is located in the welding area; alternatively, at least two tabs are provided, and at least one tab is located in the welding area.
[0015] In some embodiments, after cutting the folding area on the empty foil area, a cutting hole is formed, and the cutting hole has a plurality of inner corners, and all of the plurality of inner corners are chamfered.
[0016] In some embodiments, the tensile force value of the welding of the tab to the first conductive layer is greater than the peeling force value of the first conductive layer from the substrate layer; and / or,
[0017] The tensile force value of the welding of the tab to the second conductive layer is greater than the peeling force value of the second conductive layer from the substrate layer; and / or,
[0018] The peeling force value of the first conductive layer from the substrate layer at the second folding part and the peeling force value of the second conductive layer from the substrate layer at the non-folding area are both less than the welding tensile force value of the first conductive layer at the second folding part and the second conductive layer at the non-folding area.
[0019] In some embodiments, the thickness of the tab and the thickness of the active material layer are both greater than the sum of the thicknesses of the first folding part and the second folding part; and / or,
[0020] The thickness of the tab is greater than or equal to the thickness of the composite current collector; and / or,
[0021] The thicknesses of the first conductive layer and the second conductive layer are both less than or equal to the thickness of the substrate layer.
[0022] The present utility model provides an electric core, which 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;
[0023] Wherein, at least one of the positive electrode plate and the negative electrode plate adopts the electrode plate as described above.
[0024] The present utility model also provides a battery, which includes a housing and the battery cell as described above, and the battery cell is disposed in the housing.
[0025] In the pole piece 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 base material 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 in the coating area. At least one of the first conductive layer in the bare foil area, the second conductive layer in the bare foil area, the first conductive layer in the coating area, and the second conductive layer in the coating area is welded and connected with a tab; wherein, the bare foil area is at least divided into a non-folded area and a folded area. The folded area forms a first folded portion and a second folded portion through two folds from one end of the non-folded area. The second folded portion extends into the folding space of the first folded portion and at least partially overlaps with the non-folded area. By connecting the first conductive layer at the second folded portion with the second conductive layer at the non-folded area, the first conductive layer and the second conductive layer are electrically conducted, 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 battery cell. Description of the Drawings
[0026] Figure 1 It is a schematic structural diagram of a pole piece in an embodiment of the present utility model;
[0027] Figure 2 It is a schematic structural diagram of a pole piece in another embodiment of the present utility model;
[0028] Figure 3 It is a schematic structural diagram of a pole piece in yet another embodiment of the present utility model;
[0029] Description 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-folding area 122 Folding area 1221 First folding part 1222 Second folding part 123 Welding area K Cutting hole
[0031] The realization, functional features, and advantages of the object of the present utility model will be further described with reference to the embodiments and the drawings. Detailed Embodiments
[0032] Next, the solutions in the embodiments of the present utility model will be clearly and completely described with reference to the 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 of 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 shall 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 positional relationship and movement conditions between components in a certain specific posture (as shown in the attached drawings). If this specific posture changes, the directional indications 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 should not be construed as indicating or implying their relative importance or implicitly specifying 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 fact that those of ordinary skill in the art can implement them. When the combination of technical solutions results in contradictions 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 embodiment of the present utility model provides a pole piece. Referring to Figure 1 and Figure 2 , the pole piece 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 to the tab 300;
[0037] Among them, the empty foil area 120 is at least divided into a non-folding area 121 and a folding area 122 located at one end of the non-folding area 121. The folding area 122 forms a first folding portion 1221 and a second folding portion 1222 connected to the first folding portion 1221 through two folds from one end of the non-folding area 121. The second folding portion 1222 extends into the folding space of the first folding portion 1221 and at least partially overlaps with the non-folding area 121. The first conductive layer 101 of the second folding portion 1222 is connected to the second conductive layer 103 at the non-folding area 121, 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 a battery cell, and the electrode sheet, another electrode sheet with the opposite polarity thereto, and a separator, etc. are combined to form a 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 aluminum layer, copper layer, 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, and it 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 a non-folded area 121 and a folded area 122 are divided. The folded area 122 is located at one end of the non-folded area 121. Optionally, the folded area 122 can be located at one end of the non-folded area 121 away from the coated area 110. In addition to this, the folded area 122 can also be located at one end of the non-folded area 121 close to the coated area 110. Within the area of the empty foil area 120, in addition to the divided non-folded area 121 and folded area 122, other areas can also be included, and no restrictions are imposed on this. The folded area 122 is folded from one end of the non-folded area 121 through two folds to form a first folded portion 1221 and a second folded portion 1222, and the second folded portion 1222 is connected to the first folded portion 1221. And, the second folded portion 1222 extends into the folding space of the first folded portion 1221 and has an overlapping relationship with the non-folded area 121 that is at least partially overlapped. Specifically, the first folded portion 1221 is formed by the first fold of the folded area 122 towards the other end of the non-folded area 121, and the second folded portion 1222 is formed by the second fold of the folded area 122 into the folding space of the first folded portion 1221 on the basis of the already folded first folded portion 1221.
[0043] On this basis, the first conductive layer 101 at the second folding part 1222 is connected to the second conductive layer 103 at the non-folding area 121, 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, it 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 layer of the composite current collector 100, thus avoiding waste of materials and occupation of space, and improving the energy density of the battery cell. Optionally, the connection manner between the first conductive layer 101 at the second folding part 1222 and the second conductive layer 103 at the non-folding area 121 may be a welding connection, including but not limited to this.
[0044] 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.
[0045] There can be various situations for the setting position of the folding area 122 divided by the empty foil area 120. For example:
[0046] In some embodiments, referring to Figure 3 , the folding area 122 is located at the end area of the empty foil area 120 far from the coating area 110. By setting the folding area 122 at the end area of the empty foil area 120, the height of the folding area 122 is equal to the height of the electrode sheet. Therefore, the folding area 122 can be directly folded from the end area of the empty foil area 120 to form the first folding part 1221 and the second folding part 1222, without the need to perform processing operations such as cutting on the folding area 122 in advance, which saves time and effort. Moreover, the burrs on the end edge of the empty foil area 120 after folding are wrapped in the folding space of the first folding part 1221, realizing hidden setting, which can reduce the risk of the edge burrs piercing the diaphragm and is beneficial to improving the safety of the battery cell.
[0047] In addition to the above setting positions, it can also be that, in some embodiments, referring to Figure 1 and Figure 2, the folding area 122 is located between the two ends of the empty foil area 120 and is formed by cutting on the empty foil area 120. Specifically, when the folding area 122 is located between the two ends of the empty foil area 120, the folding area 122 can be located at the edge position extending along the length direction of the composite current collector 100 of the empty foil area 120; alternatively, the folding area 122 can be located at a non-edge position of the empty foil area 120, and the non-edge position of the empty foil area 120 can be the middle position of the empty foil area 120, etc. And, in order to achieve folding, the folding area 122 is obtained by cutting, and the cutting method can be, for example, knife cutting, laser cutting, etc., which is not limited thereto. Among them, when the folding area 122 is arranged at the edge position of the empty foil area 120, the folding area 122 is cut inward from the edge line of the empty foil area 120.
[0048] In some embodiments, referring to Figure 2 , the length of the folding area 122 is less than 1 / 4 of the width of the composite current collector 100. The length direction of the folding area 122 is the same as the width direction of the composite current collector 100. In this embodiment, by setting the length of the folding area 122 to be less than 1 / 4 of the width of the composite current collector 100, that is, in the width direction of the composite current collector 100, the cutting length of the folding area 122 is correspondingly limited to be smaller, so as to avoid the folding area 122 affecting the structural strength of the composite current collector 100 due to too large a cutting length and prevent the pole piece from breaking.
[0049] In some embodiments, referring to Figure 1 and Figure 2 , the empty foil area 120 is further divided into a welding area 123, and the welding area 123 is located on the side of the folding area 122 away from the non-folding area 121 or on the side of the non-folding area 121 away from the folding area 122;
[0050] One pole ear 300 is provided, and the pole ear 300 is located in the welding area 123; or, at least two pole ears 300 are provided, and at least one pole ear 300 is located in the welding area 123.
[0051] In this embodiment, according to the number of the provided pole ears 300, the welding positions of the pole ears 300 are correspondingly arranged. Among them, the empty foil area 120 is further divided into a welding area 123, and the welding area 123 is other partial areas in the empty foil area 120 different from the non-folding area 121 and the folding area 122. For example, the welding area 123 is located in the direction of the side of the folding area 122 away from the non-folding area 121, and the welding area 123 is spaced from the non-folding area 121. The first folding part 1221 and the second folding part 1222 formed by the folding area 122 are stacked and covered on the non-folding area 121, and the provided welding area 123 is used for welding the pole ear 300. By separating the welding area 123 from the non-folding area 121, the thickness concentration of the battery cell can be avoided.
[0052] Such as Figure 1 andFigure 2 As 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 123 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 123 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 123 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.
[0053] In some embodiments, referring to Figure 1 and Figure 2 , after the cutting and folding area 122, a cutting hole K is formed in the empty foil area 120. The cutting hole K has a plurality of inner corners, and all of the plurality of inner corners are chamfered. The cutting hole K penetrates through the empty foil area 120 and has the same contour shape as the folding area 122. For example, the cutting hole K is a square hole and has four inner corners, and the four inner corners are respectively distributed at the four corner positions of the cutting hole K and are all chamfered. Among them, the chamfer can be a rounded chamfer or the like. By chamfering each inner corner of the cutting hole K, it is beneficial to reduce the stress concentration at the inner corner position of the cutting hole K, and the stress can be better dispersed and balanced.
[0054] In some embodiments, the tensile value of the welding 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. Herein, the so-called tensile value of the welding between the tab 300 and the first conductive layer 101 refers to 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 value of the welding 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 value of the welding 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 refers to 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 value of the welding 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, when 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, thus ensuring the welding strength of the tab 300. And / or, in some embodiments, the tensile value of the welding 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. Herein, the so-called tensile value of the welding between the tab 300 and the second conductive layer 103 refers to 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 value of the welding 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 value of the welding 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 refers to the force value at which the second conductive layer 103 and the substrate layer 102 are peeled off. When the peeling force applied to the second conductive layer 103 reaches this force value, the second conductive layer 103 will be peeled off from the substrate layer 102. In this embodiment, by setting the tensile value of the welding between the tab 300 and 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, when the external force is large, first, the second conductive layer 103 and the substrate layer 102 will be peeled off, and the tab 300 will not detach from the second conductive layer 103, thus ensuring the welding strength of the tab 300.Moreover, and / or, the peel force value between the first conductive layer 101 and the substrate layer 102 at the second folding portion 1222 and the peel force value between the second conductive layer 103 and the substrate layer 102 at the non-folding area 121 are both smaller than the tensile force value of the welding between the first conductive layer 101 at the second folding portion 1222 and the second conductive layer 103 at the non-folding area 121. The so-called tensile force value of the welding between the first conductive layer 101 at the second folding portion 1222 and the second conductive layer 103 at the non-folding area 121 refers to the maximum tensile force that the first conductive layer 101 at the second folding portion 1222 and the second conductive layer 103 at the non-folding area 121 can withstand after welding. When the tensile force applied by the outside world to the first conductive layer 101 at the second folding portion 1222 or the second conductive layer 103 at the non-folding area 121 is smaller than the tensile force value of the welding between the first conductive layer 101 at the second folding portion 1222 and the second conductive layer 103 at the non-folding area 121, the first conductive layer 101 at the second folding portion 1222 and the second conductive layer 103 at the non-folding area 121 will not separate; while when the tensile force applied by the outside world to the first conductive layer 101 at the second folding portion 1222 or the second conductive layer 103 at the non-folding area 121 is greater than the tensile force value of the welding between the first conductive layer 101 at the second folding portion 1222 and the second conductive layer 103 at the non-folding area 121, the first conductive layer 101 at the second folding portion 1222 and the second conductive layer 103 at the non-folding area 121 will separate. The peel force value between the first conductive layer 101 and the substrate layer 102 at the second folding portion 1222 refers to the force value at which the first conductive layer 101 at the second folding portion 1222 peels off from the substrate layer 102. When the peeling force acting on the first conductive layer 101 at the second folding portion 1222 reaches this force value, the first conductive layer 101 will peel off from the substrate layer 102. The peel force value between the second conductive layer 103 and the substrate layer 102 at the non-folding area 121 refers to the force value at which the second conductive layer 103 at the non-folding area 121 peels off from the substrate layer 102. When the peeling force acting on the second conductive layer 103 at the non-folding area 121 reaches this force value, the second conductive layer 103 will peel off from the substrate layer 102.In this embodiment, by setting the peel strength value of the first conductive layer 101 and the substrate layer 102 at the second folding portion 1222 and the peel strength value of the second conductive layer 103 and the substrate layer 102 in the non-folding area 121 to be both less than the tensile strength value of the welding between the first conductive layer 101 at the second folding portion 1222 and the second conductive layer 103 in the non-folding area 121, when an external force acts on the first conductive layer 101 at the second folding portion 1222 or the second conductive layer 103 in the non-folding area 121, when the external force is large, it will also cause the first conductive layer 101 at the second folding portion 1222 to peel from the substrate layer 102, or the second conductive layer 103 in the non-folding area 121 to peel from the substrate layer 102, and the first conductive layer 101 at the second folding portion 1222 and the second conductive layer 103 in the non-folding area 121 will not separate, thus ensuring the welding strength between the two.
[0055] In some embodiments, the thickness of the tab 300 and the thickness of the active material layer 200 are both greater than the sum of the thicknesses of the first folding portion 1221 and the second folding portion 1222. Specifically, by setting the thickness of the tab 300 and the thickness of the active material layer 200 to be both greater than the sum of the thicknesses of the first folding portion 1221 and the second folding portion 1222, so that the stacked thickness of the first folding portion 1221 and the second folding portion 1222 formed by folding the folding area 122 does not exceed the thicknesses of the tab 300 and the active material layer 200, avoiding the local over-thickness of the electrode due to the protruding stacked first folding portion 1221 and second folding portion 1222, and ensuring the uniform thickness of the electrode. And / or, in some embodiments, the thickness of the tab 300 is greater than or equal to the thickness of the composite current collector 100. Specifically, by setting the thickness of the tab 300 to be greater than or less than the thickness of the composite current collector 100, to ensure sufficient strength when the electrode is welded to the composite current collector 100 and improve the welding stability of the tab 300. And / or, in some embodiments, the thicknesses of the first conductive layer 101 and the second conductive layer 103 are both less than or equal to the thickness of the substrate layer 102. Specifically, by setting the thicknesses of the first conductive layer 101 and the second conductive layer 103 to be both less than or equal to the thickness of the substrate layer 102, further ensuring that the substrate layer 102 is relatively thick, so that it can better isolate and protect the internal structure of the battery, reduce the occurrence of safety risks such as short circuits and overheating, and effectively improve the overall safety of the battery cell. Moreover, setting a thicker substrate layer 102 can reduce the demand for expensive metal materials while ensuring the performance of the battery cell, thereby reducing production costs and improving economic benefits.
[0056] An embodiment of the present invention further provides a battery cell, which includes a positive electrode, a negative electrode, and a separator, and the separator is disposed between the positive electrode and the negative electrode;
[0057] Among them, at least one of the positive electrode plate and the negative electrode plate adopts the electrode plate described in the foregoing embodiments.
[0058] Specifically, it may be that the positive electrode plate adopts the foregoing electrode plate, or the negative electrode plate adopts the foregoing electrode plate, or both the positive electrode plate and the negative electrode plate adopt the foregoing electrode plate.
[0059] For the specific structure of this electrode plate, refer to the above embodiments. Since this battery cell adopts all the technical solutions of all the above embodiments, it has at least all the technical effects brought by the technical solutions of the above embodiments, which will not be elaborated here one by one.
[0060] An embodiment of the present invention also provides a battery, which includes a housing and a battery cell described in the foregoing embodiments, and the battery cell is disposed in the housing. For the specific structure of this battery cell, refer to the above embodiments. Since this battery adopts all the technical solutions of all the above embodiments, it has at least 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 may be a lithium battery.
[0061] The above are only partial or preferred embodiments of the present invention. Neither the text nor the drawings can limit the scope of protection of the present invention. Any equivalent structural transformation made by using the content of the specification and drawings of the present invention under the overall concept of the present invention, or direct / indirect application in other related technical fields is included in the scope of protection of the present invention.
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-folding area and a folding area located at one end of the non-folding area, the folding area being formed by folding twice from one end of the non-folding area to form a first folding portion and a second folding portion connected to the first folding portion, the second folding portion extending into the folding space of the first folding portion and at least partially overlapping with the non-folding area, and the first conductive layer of the second folding portion being connected to the second conductive layer at the non-folding area, such that electrical conduction is achieved between the first conductive layer and the second conductive layer.
2. The electrode tab according to claim 1, wherein The folding area is located at the end area of the bare foil area far from the coated area.
3. The pole piece according to claim 1, characterized in that, The folding area is located between the two ends of the bare foil area and is formed by cutting on the bare foil area.
4. The pole piece according to claim 3, characterized in that, The length of the folding area is less than 1 / 4 of the width of the composite current collector.
5. The pole piece according to claim 1, wherein The bare foil area is further divided into a welding area, the welding area being located on the side of the folding area far from the non-folding area or on the side of the non-folding area far from the folding 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 tab is located in the welding area.
6. The pole piece according to claim 1, characterized in that, After cutting the folding area on the bare foil area, a cutting hole is formed, and the cutting hole has a plurality of inner corners, and all the inner corners are chamfered.
7. The pole piece according to claim 1, characterized in that, The tensile strength value of the welding between the tab and the first conductive layer is greater than the peeling strength value between the first conductive layer and the substrate layer; and / or, The tensile strength value of the welding between the tab and the second conductive layer is greater than the peeling strength value between the second conductive layer and the substrate layer; and / or, The peeling strength values between the first conductive layer and the substrate layer at the second folding portion and between the second conductive layer and the substrate layer at the non-folding area are both less than the tensile strength value of the welding between the first conductive layer at the second folding portion and the second conductive layer at the non-folding area.
8. The pole piece according to claim 1, wherein The thickness of the tab and the thickness of the active material layer are both greater than the sum of the thicknesses of the first folding portion and the second folding portion; and / or, The thickness of the tab is greater than or equal to the thickness of the composite current collector; and / or, The thicknesses of the first conductive layer and the second conductive layer are both less than or equal to the thickness of the substrate layer.
9. A battery cell, characterized in that, Comprising a positive electrode tab, a negative electrode tab, and a separator, the separator being disposed between the positive electrode tab and the negative electrode tab; Wherein, at least one of the positive electrode tab and the negative electrode tab adopts the tab according to any one of claims 1 to 8.
10. A battery, characterized in that, Comprising a housing and the battery cell according to claim 9, the battery cell being disposed in the housing.