Composite current collector, electrode plate and battery

Abstract

The utility model discloses a composite current collector, an electrode plate and a battery, and belongs to the technical field of batteries. The composite current collector comprises a high-molecular polymer layer and two conductive layers, conductive layers are arranged on the two opposite sides of the high-molecular polymer layer in the first direction respectively, in the second direction, each conductive layer comprises a connecting part and an extending part which are connected, the connecting parts are used for being connected with the high-molecular polymer layer in an attached mode, the extending parts extend out of the edge of the high-molecular polymer layer, and the two opposite extending parts in the first direction are connected. According to the composite current collector, the two oppositely arranged extension parts are directly connected to realize the electric connection between the two conductive layers, so that the electric connection between the two conductive layers is relatively simple and convenient, the processing and manufacturing difficulty of the composite current collector is reduced, the production efficiency of the composite current collector, an electrode plate and the whole battery can be improved, and the production cost is reduced. And the cost can be reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to battery technology field especially relates to composite current collector, electrode sheet and battery. BACKGROUND

[0002] The composite current collector is the key auxiliary material in the lithium ion battery, and the main role is to conduct electricity, and the current generated by the active material layer is collected to generate greater output current, therefore, the ideal composite current collector often needs to have the comprehensive performance of high conductivity, good stability, good mechanical strength and lower cost.

[0003] Specifically, the composite current collector includes two conductive layers and a high molecular polymer layer, the two conductive layers are connected to opposite sides of the thickness direction of the high molecular polymer layer respectively, and a notch is formed on the high molecular polymer layer, and a conductive structure is arranged in the notch, so that the opposite ends of the conductive structure are connected with the conductive layers on the two sides of the high molecular polymer layer respectively, to realize the electrical connection between the two conductive layers through the conductive structure. Wherein, the conductive structure can be any structure capable of conducting electricity.

[0004] However, due to the electrical connection mode of opening the notch and arranging the conductive structure in the notch, the processing technology is complex and tedious, time-consuming and laborious, which leads to low production efficiency of the composite current collector, the electrode sheet and the whole lithium ion battery, and due to the need of processing the notch and arranging the conductive structure, the cost of the composite current collector, the electrode sheet and the whole battery is high.

[0005] In view of the above problems, a composite current collector, an electrode sheet and a battery are needed to solve the above problems. Utility model content

[0006] The utility model aims at providing a composite current collector, an electrode sheet and a battery, so that the electrical connection between the two conductive layers is relatively simple and convenient, the manufacturing difficulty of the composite current collector is reduced, so that the production efficiency of the composite current collector, the electrode sheet and the whole battery can be improved, and the cost can be reduced.

[0007] In order to achieve this purpose, the utility model adopts the following technical scheme:

[0008] The composite current collector comprises:

[0009] A high molecular polymer layer;

[0010] The conductive layer is provided with the conductive layer on opposite sides along the first direction, and along the second direction, the conductive layer comprises a connecting part and an extending part connected with each other, the connecting part is used for being connected with the high polymer layer, the extending part extends to the edge of the high polymer layer, and the extending parts on opposite sides along the first direction are connected.

[0011] As an option, along the second direction, the opposite ends of the connecting part are connected with the extending part respectively.

[0012] As an option, along the first direction, the thickness of the connecting part is the same as the thickness of the extending part, and both are H1=3um-6um.

[0013] As an option, the conductive layer is a prefabricated thin conductive layer, and the connecting part is bonded to one side of the high polymer layer.

[0014] As an option, along the second direction, the length L of the extending part is 5mm-30mm.

[0015] As an option, the connecting part and the extending part are integrally formed.

[0016] As an option, along the first direction, the thickness H2 of the high polymer layer is 2um-5um.

[0017] The electrode sheet comprises an active material layer and a composite current collector as described above, the active material layer is coated on the side of the connecting part away from the high polymer layer, and along the third direction, the width of the active material layer is the same as the width of the connecting part, and the third direction is perpendicular to the first direction and the second direction.

[0018] The battery comprises a plurality of separators and a plurality of electrode sheets as described above, each of the electrode sheets is alternately stacked, and the polarities of two adjacent electrode sheets are different, and the separators are arranged between the two adjacent electrode sheets.

[0019] As an option, the battery is a square shell battery, the square shell battery further comprises a transition sheet and a pole, the extending part is cut to form a first tab, the first tab is welded to one end of the transition sheet, and the other end of the transition sheet is welded to the pole; or,

[0020] The battery is a soft package battery, the soft package battery further comprises an aluminum plastic film, the extending part is welded with a second tab, the aluminum plastic film is used for packaging the electrode sheet, and at least part of the second tab extends out of the aluminum plastic film.

[0021] The utility model discloses the beneficial effect that:

[0022] Through being provided with the conductive layer respectively along the opposite two sides of the high molecular polymer layer in the first direction, along the second direction, the conductive layer includes the connecting portion and the extension portion who links, the connecting portion is used for with the high molecular polymer layer and is connected, and the extension portion extends to the edge of the high molecular polymer layer, so that the opposite two extension portions along the first direction are connected, can realize the conduction between two conductive layers through the connection between two extension portions, need not set the notch on each conductive layer and set the conductive structure in the notch, make the electric connection between two conductive layers more simple and convenient, reduce the processing and manufacturing difficulty of composite current collector, can improve the production efficiency of composite current collector, electrode sheet and whole battery, and because no longer need to process the notch and need not set the conductive structure, make the cost of composite current collector, electrode sheet and whole battery lower. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is the structure schematic diagram of the composite current collector provided in the utility model.

[0024] BRIEF DESCRIPTION OF DRAWINGS:

[0025] 10-composite current collector;11-high molecular polymer layer;12-conductive layer;121-connecting portion;122-extension portion;

[0026] H1-thickness of connecting portion / thickness of extension portion;

[0027] L-length of extension portion;

[0028] H2-thickness of high molecular polymer layer. DETAILED DESCRIPTION

[0029] All features disclosed in this specification, and all methods or processes disclosed in this specification, can be combined in any manner, except where features or steps are mutually exclusive.

[0030] Any feature disclosed in this specification, unless stated otherwise, can be replaced by any equivalent or similar feature. That is, unless stated otherwise, each feature is one example only of a generic series of equivalent or similar features. Throughout this specification the same reference numerals refer to the same elements in the various figures.

[0031] In order to make the technical problems solved by the utility model, the technical scheme adopted and the technical effects reached more clear, the following further illustrates the technical scheme of the utility model through specific implementation mode and combining with the drawings.

[0032] Embodiment one

[0033] Currently, the composite current collector includes two conductive layers and a polymer layer, the two conductive layers are respectively connected to opposite sides of the polymer layer in the thickness direction, a notch is formed on the polymer layer, and a conductive structure is arranged in the notch, so that the opposite ends of the conductive structure are respectively connected with the conductive layers on the two sides of the polymer layer to realize the electrical connection between the two conductive layers through the conductive structure; however, due to the electrical connection mode of forming a notch and arranging a conductive structure in the notch, the processing technology is complex and tedious, time-consuming and laborious, resulting in low production efficiency of the composite current collector, the electrode sheet and the entire lithium ion battery; and due to the need to process the notch and arrange the conductive structure, the cost of the composite current collector, the electrode sheet and the entire battery is high.

[0034] Therefore, as shown in the drawings, Figure 1 the embodiment proposes a composite current collector 10, the manufacturing process of the composite current collector 10 is simple and convenient, time-saving and labor-saving, so as to ensure that the production efficiency of the composite current collector 10 is high; and the cost of the composite current collector 10 is low. Wherein, the working principle of the composite current collector 10 can refer to the working principle of the composite current collector 10 in the prior art, which will not be described in detail here.

[0035] Specifically, as shown in the drawings, Figure 1 the composite current collector 10 includes a polymer layer 11 and two conductive layers 12; wherein the polymer layer 11 is connected with the conductive layers 12 on opposite sides in the first direction, and in the second direction, the conductive layer 12 includes a connecting part 121 and an extension part 122 connected with each other, the connecting part 121 is used for adhering and connecting with the polymer layer 11, the extension part 122 extends to the edge of the polymer layer 11 outside in the second direction, and the opposite extension parts 122 in the first direction are connected. Wherein, the first direction is parallel to the thickness direction of the polymer layer 11, the first direction is specifically shown as an arrow A in Figure 1 , the second direction is perpendicular to the first direction, that is, the second direction is parallel to the length direction of the polymer layer 11, and the second direction is specifically shown as an arrow B in Figure 1 .

[0036] The composite current collector 10 in the embodiment changes the electrical connection mode between the two conductive layers 12 relative to the prior art; by arranging the conductive layers 12 on the opposite sides of the polymer layer 11 along the first direction, along the second direction, the conductive layer 12 includes the connecting part 121 connected and the extension part 122 extending out of the edge of the polymer layer 11, so that the two extension parts 122 along the first direction are connected, and the conduction between the two conductive layers 12 can be realized by the contact connection between the two extension parts 122, without the need to additionally arrange a notch on the conductive layer 12 and arrange a conductive structure in the notch, so that the electrical connection between the two conductive layers 12 is relatively simple and convenient, and the processing and manufacturing difficulty of the composite current collector 10 is reduced, thereby the production efficiency of the composite current collector 10 can be improved; and because the notch does not need to be processed and the conductive structure does not need to be arranged, the cost of the composite current collector 10 is relatively low.

[0037] It is worth noting that the two extension parts 122 along the first direction are connected by welding, so that the connection stability is good, thereby ensuring the reliability and stability of the conduction between the two conductive layers 12; the conductive layer 12 can be formed of a copper foil or an aluminum foil, which needs to be determined according to the polarity of the composite current collector 10, which is not limited here. For example, when the composite current collector 10 is a positive electrode composite current collector, the conductive layer 12 is formed of an aluminum foil; when the composite current collector 10 is a negative electrode composite current collector, the conductive layer 12 is formed of a copper foil.

[0038] Further, as shown in Figure 1 , along the second direction, the opposite ends of the connecting part 121 are respectively connected with the extension parts 122, that is, each conductive layer 12 is connected and formed by one connecting part 121 and two extension parts 122.

[0039] By connecting the extension parts 122 on the opposite ends of the connecting part 121, two groups of oppositely arranged extension parts 122 can be formed along the first direction, so that the electrical connection between the two conductive layers 12 can be better realized by the welding connection between the two groups of oppositely arranged extension parts 122, thereby ensuring the stability and reliability of the electrical connection between the two conductive layers 12.

[0040] Specifically, along the first direction, the thickness of the connecting part 121 is the same as the thickness of the extension part 122, that is, the bottom end surface and the top end surface of the entire conductive layer 12 are located on a horizontal plane, so that the appearance of the entire conductive layer 12 is relatively flat and beautiful, and it is beneficial to the welding connection of the two oppositely arranged extension parts 122.

[0041] Further, as shown in Figure 1As shown, the thickness of the connecting portion 121 and the thickness of the extension portion 122 are both H1 = 3um to 6um, so that the thickness of the entire conductive layer 12 is suitable and there is no problem of the thickness being too thin. This ensures that the surface resistance of the electrode sheet is small, and that the structural strength and support effect of the entire conductive layer 12 are good, thereby ensuring the stability of the connection portion 121 between the connecting portion 121 and the extension portion 122.

[0042] Currently, a conductive layer (aluminum or copper) is deposited onto a polymer layer using magnetron sputtering to achieve electrical connection between the polymer layer and the conductive layer. However, the conductive layer prepared by the magnetron sputtering method is relatively thin. On the one hand, this results in a high surface resistance of the electrode sheet. On the other hand, due to the thinness of the conductive layer, the extension extending beyond the edge of the polymer layer in the second direction is unsupported, meaning it is suspended. Therefore, in a thin conductive layer, the suspended extension is prone to breakage between itself and the connection.

[0043] To solve the above problems, such as Figure 1 As shown, the conductive layer 12 in this embodiment is a pre-pressed thin conductive layer manufactured by a roll forming process. That is, the pre-pressed thin conductive layer can be directly bonded to the polymer layer 11, ensuring that the conductive layer 12 achieves a suitable thickness. Specifically, the thickness of both the connecting portion 121 and the extension portion 122 is H1 = 3µm to 6µm. This approach helps reduce the surface resistance of the electrode sheet. Furthermore, because the thickness of the pre-pressed thin conductive layer is suitable, the extension portion 122 extending beyond the edge of the polymer layer 11 along the second direction will not break off from the connecting portion 121 due to lack of support, thus ensuring a stable connection between the connecting portion 121 and the suspended extension portion 122. Here, the specific thickness of the connecting portion 121 and the extension portion 122 is not limited, as long as H1 = 3µm to 6µm is satisfied.

[0044] Furthermore, such as Figure 1 As shown, the connecting part 121 is bonded to one side of the polymer layer 11. That is, the opposite sides of the polymer layer 11 along the first direction are respectively adhesive, so that the conductive layer 12 can be directly bonded to one side of the polymer layer 11, thereby realizing that the conductive layer 12 is connected to the opposite sides of the polymer layer 11 along the first direction.

[0045] The connection between the polymer layer 11 and the connecting part 121 is achieved by bonding, which makes the connection simple, convenient, time-saving, and labor-saving, further improving the production efficiency of the entire composite current collector 10. Here, the specific connection method between the polymer layer 11 and the connecting part 121 is not limited.

[0046] Furthermore, such as Figure 1 As shown, along the second direction, the length L of the extension 122 is 5mm to 30mm, ensuring that the extension 122 is sufficiently long. This arrangement facilitates welding operations between the two opposing extensions 122. Furthermore, the longer extension 122 provides sufficient welding space for the external first electrode, allowing for easy welding of the first electrode onto the extension 122 and ensuring the welding length of the first electrode on the extension 122. Alternatively, the longer length of the extension 122 allows for the direct cutting of the second electrode from the extension 122. The composite current collector 10 can achieve external conductivity through either the external first electrode or the directly cut second electrode from the extension 122. Both the external first electrode and the cut second electrode are common electrode structures in the prior art; the only difference between the first and second electrodes is their manufacturing process. Moreover, the arrangement of the first and second electrodes does not affect the welding connection between the two extensions 122. Here, the specific length of the extension 122 is not limited, as long as L = 5mm to 30mm is satisfied.

[0047] Specifically, such as Figure 1 As shown, the connecting part 121 and the extension part 122 are integrally formed. On the one hand, this makes the processing and manufacturing of the entire conductive layer 12 simpler and more convenient. On the other hand, it ensures the stability of the connection between the connecting part 121 and the extension part 122, and better avoids the problem of breakage in the connection between the extension part 122 and the connecting part 121.

[0048] Furthermore, such as Figure 1 As shown, along the first direction, the thickness H2 of the polymer layer 11 is 2µm to 5µm, which results in good structural strength and support of the entire polymer layer 11, which is beneficial to ensuring the stability and reliability of the connection between the polymer layer 11 and the connecting part 121. In this embodiment, the polymer layer 11 is a common polymer structure in existing composite current collectors. Here, the working principle of the polymer layer 11 will not be described in detail. Here, the specific thickness of the polymer layer 11 is not limited, as long as H2 = 2µm to 5µm is satisfied.

[0049] The composite current collector 10 in the embodiment can realize the electrical connection between the two conductive layers 12 by adopting the welding connection mode of the two oppositely arranged extension portions 122 by changing the electrical connection mode between the two conductive layers 12, so that the production efficiency of the composite current collector 10 can be improved, and the connection mode is simple and convenient, time and labor are saved, and the cost of the composite current collector 10 can be reduced.

[0050] Embodiment two

[0051] The electrode sheet in the embodiment comprises an active material layer and the composite current collector 10 in the above-mentioned embodiment one, and the active material layer is coated on the side of the connecting portion 121 away from the polymer layer 11, that is, the active material layer is not coated on the extension portion 122, so that the first tab can be directly welded on the extension portion 122 or the second tab can be directly cut on the extension portion 122.

[0052] Further, along the third direction, the width of the active material layer is the same as the width of the connecting portion 121, so that the active material layer can fully cover the connecting portion 121 along the third direction, and the energy density of the whole electrode sheet can be ensured to be high. The third direction is parallel to the width direction of the polymer layer 11, and the first direction, the second direction and the third direction are perpendicular to each other.

[0053] It is worth noting that the electrode sheet can be a positive electrode sheet or a negative electrode sheet, which needs to be determined according to the specific polarity of the electrode sheet, and here, no specific limitation is made. For example, when the electrode sheet is a positive electrode sheet, the composite current collector 10 is a positive composite current collector; when the electrode sheet is a negative electrode sheet, the composite current collector 10 is a negative composite current collector.

[0054] The electrode sheet in the embodiment comprises the composite current collector 10 in the above-mentioned embodiment one, so that the production efficiency of the whole electrode sheet can be high, and the cost of the whole electrode sheet can be low.

[0055] Embodiment three

[0056] The battery in the embodiment comprises a plurality of separators and a plurality of electrode sheets as in the above-mentioned embodiment two, each electrode sheet is alternately stacked, and the polarity of adjacent two electrode sheets is different, and a separator is arranged between the adjacent two electrode sheets with different polarities.

[0057] Specifically, a part of the above-mentioned electrode sheets can be positive electrode sheets, and another part of the above-mentioned electrode sheets can be negative electrode sheets, each positive electrode sheet and each negative electrode sheet are alternately stacked in sequence, and a separator for isolation is arranged between adjacent positive electrode sheets and negative electrode sheets. In the embodiment, the specific working principle of the battery can refer to the working principle of the existing battery, and here, the specific working principle of the battery is not described in detail.

[0058] Specifically, when the battery is a square cell, the square cell further comprises a tab and a pole, the extension 122 is cut to form a first tab, the first tab is directly welded to one end of the tab, and the other end of the tab is welded to the pole, so that the electrode sheet can be externally connected through the pole. Wherein, the tab and the pole are common structures in the existing square cell.

[0059] In other embodiments, a second tab is cut on the extension 122, and the second tab is welded to the tab, and the end of the tab away from the second tab is welded to the pole, so that the pole and the electrode sheet are externally connected.

[0060] In another embodiment, when the battery is a soft pack battery, the soft pack battery further comprises an aluminum plastic film, the second tab is directly welded on the extension 122, and the aluminum plastic film is used to package the electrode sheet, and at least part of the second tab extends out of the aluminum plastic film, so that the electrode sheet can be externally connected through the second tab. Wherein, the aluminum plastic film is a common structure in the existing soft pack battery.

[0061] The battery in the embodiment can make the processing difficulty of the positive and negative electrode sheets lower, so that the production efficiency of the whole battery is higher, and the cost of the whole battery is lower.

[0062] The above is only a preferred embodiment of the present application, and for those skilled in the art, according to the idea of the present application, the specific embodiment and application range can be changed, and the content of the specification should not be understood as a limitation of the present application.

Claims

1. A composite current collector, characterized by, The battery comprises: a high polymer layer (11); a conductive layer (12), the high polymer layer (11) is provided with the conductive layer (12) on opposite sides in a first direction, and the conductive layer (12) comprises a connecting part (121) and an extension part (122) connected in a second direction, the connecting part (121) is used for being connected with the high polymer layer (11), the extension part (122) extends out of the edge of the high polymer layer (11), the opposite extension parts (122) in the first direction are connected, the first direction is parallel to the thickness direction of the high polymer layer (11), and the second direction is perpendicular to the first direction.

2. The composite current collector of claim 1, wherein In the second direction, the opposite ends of the connecting part (121) are connected with the extension part (122) respectively.

3. The composite current collector of claim 1, wherein In the first direction, the thickness of the connecting part (121) is the same as the thickness of the extension part (122), and both are H1=3um-6um.

4. The composite current collector of claim 3, wherein The conductive layer (12) is a prefabricated thin conductive layer, and the connecting part (121) is bonded to one side of the high polymer layer (11).

5. The composite current collector of any one of claims 1-4, wherein, In the second direction, the length L of the extension part (122) is 5mm-30mm.

6. The composite current collector of any one of claims 1-4, wherein, The connecting part (121) and the extension part (122) are an integral structure.

7. The composite current collector of any one of claims 1-4, wherein, In the first direction, the thickness H2 of the high polymer layer (11) is 2um-5um.

8. An electrode tab, characterized by The battery comprises an active material layer and the composite current collector as claimed in any one of claims 1-7, the active material layer is coated on the side of the connecting part (121) away from the high polymer layer (11), and in a third direction, the width of the active material layer is the same as the width of the connecting part (121), and the third direction is perpendicular to the first direction and the second direction.

9. A battery characterized by The battery comprises a plurality of separators and a plurality of electrode sheets as claimed in claim 8, each of the electrode sheets is alternately stacked, the polarities of adjacent two electrode sheets are different, and the separators are arranged between the adjacent two electrode sheets.

10. The battery of claim 9, wherein the electrolyte comprises a lithium salt. The battery is a square cell, the square cell further comprises a transition sheet and a pole, the extension part (122) is cut to form a first tab, the first tab is welded to one end of the transition sheet, the other end of the transition sheet is welded to the pole; or, The battery is a soft package battery, the soft package battery further comprises an aluminum plastic film, the extension part (122) is welded with a second tab, the aluminum plastic film is used for packaging the electrode sheet, and at least part of the second tab extends out of the aluminum plastic film.

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