Electrode assembly and battery cell

Abstract

The utility model provides a kind of electrode assembly and battery, the electrode assembly of utility model embodiment includes composite foil current collector, composite foil current collector includes substrate layer, first conductive layer located substrate layer one side and second conductive layer located substrate layer other side, composite foil current collector includes current collector body and folding piece, composite foil current collector has empty foil area, folding piece is torn from the part of composite foil current collector located empty foil area and forms, folding piece is folded from the one side of current collector body to the other side of current collector body, to make first conductive layer and second conductive layer between electric connection. Therefore, the electrode assembly of utility model embodiment can make the effective conduction between the conductive layer of both sides of composite foil current collector.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to an electrode assembly and a battery cell. Background Technology

[0002] In the new energy consumer market, lithium-ion batteries have rapidly occupied the 3C digital consumer market, the new energy vehicle market, and the energy storage application market due to their high energy density. With the development of the industry, the requirements for the electrical energy stored per unit mass of lithium-ion batteries are also getting higher and higher, that is, the requirements for the energy density of batteries are getting higher and higher.

[0003] To improve the energy density of lithium-ion batteries, composite foil current collectors are often used instead of traditional metal foil current collectors. Composite foil current collectors have a lower areal density, which reduces the weight of the current collector and thus increases the energy density of the battery. On the other hand, because polymer materials have high ductility, when a lithium-ion battery is impacted by a foreign object, the polymer material can wrap the fracture surface, thereby preventing the fracture from piercing the separator and causing a short circuit, reducing the risk of thermal runaway and improving the safety performance of the lithium-ion battery. However, due to the low conductivity of polymer materials, effective conductivity cannot be achieved between the conductive layers on both sides of the polymer material.

[0004] Therefore, the composite foil current collector in the related technology has the problem that the conductive layers on both sides cannot conduct electricity effectively. Utility Model Content

[0005] This utility model provides an electrode assembly to solve the problem in related technologies where the conductive layers on both sides of the composite foil current collector cannot conduct electricity effectively.

[0006] The electrode assembly of this utility model embodiment includes a composite foil current collector, which includes a substrate layer, a first conductive layer located on one side of the substrate layer, and a second conductive layer located on the other side of the substrate layer.

[0007] The composite foil current collector includes a current collector body and a folded sheet. The composite foil current collector has an empty foil area, and the folded sheet is formed by tearing a portion of the composite foil current collector.

[0008] The folded sheet is folded from one side of the current collector body to the other side of the current collector body to make the first conductive layer and the second conductive layer electrically connected.

[0009] The electrode assembly of this utility model provides a folded piece formed by tearing part of the composite foil current collector in the empty foil area of ​​the composite foil current collector, and folds the folded piece from one side of the current collector body to the other side of the current collector body, thereby achieving the effect of electrical connection between the first conductive layer and the second conductive layer, and thus enabling effective electrical connection between the first conductive layer and the second conductive layer.

[0010] Therefore, the electrode assembly of this utility model embodiment enables effective conductivity between the conductive layers on both sides of the composite foil current collector.

[0011] In some embodiments, a U-shaped cut is provided on the empty foil area, the folded piece is formed in the U-shaped cut, one end of the folded piece is a fixed end connected to the current collector body, and the other end of the folded piece is a free end that can be folded. When the folded piece is folded, a through hole is formed in the U-shaped cut.

[0012] In some embodiments, the folded sheet includes a first folded segment located on one side of the current collector body, the first folded segment and the current collector body having a first overlapping region that coincides in the thickness direction of the current collector body, and the first folded segment and the current collector body being electrically connected through the first overlapping region.

[0013] In some embodiments, the first folded segment extends in the width direction of the current collector body, and the first overlapping area has a size range of 2-50 mm in the length direction of the current collector body.

[0014] The first overlapping area has a dimension ranging from 2 to 70 mm in the width direction of the current collector body;

[0015] The ratio between the dimension of the first overlapping area in the width direction of the current collector body and the width of the current collector body is 5%-40%.

[0016] In some embodiments, the folded sheet further includes a second folded segment connected to the first folded segment and located on the other side of the current collector body, the second folded segment and the current collector body having a second overlapping region that coincides in the thickness direction of the current collector body, and the second folded segment and the current collector body being electrically connected through the second overlapping region.

[0017] In some embodiments, the second folded segment extends in the width direction of the current collector body, and the second overlapping area has a size range of 2-50 mm in the length direction of the current collector body;

[0018] The second overlapping area has a dimension ranging from 2 to 70 mm in the width direction of the current collector body;

[0019] The ratio between the dimension of the second overlapping area in the width direction of the current collector body and the width of the current collector body is 5%-29%.

[0020] In some embodiments, the connection between the first folded segment and the second folded segment is spaced apart from the side edge corresponding to the current collector body.

[0021] In some embodiments, the connection between the first folded segment and the second folded segment abuts against the side edge corresponding to the current collector body.

[0022] In some embodiments, an adapter tab is further included, which is electrically connected to the folded plate.

[0023] This utility model also provides a battery cell.

[0024] The battery cell of this utility model embodiment includes the electrode assembly described in the above embodiment. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the electrode assembly according to an embodiment of the present invention;

[0027] Figure 2 This is a cross-sectional view of the electrode assembly according to an embodiment of the present utility model;

[0028] Figure 3 This is a cross-sectional view of an electrode assembly according to another embodiment of the present invention;

[0029] Figure 4 This is one of the enlarged partial views of the electrode assembly according to an embodiment of the present utility model;

[0030] Figure 5 This is a second enlarged view of the electrode assembly according to an embodiment of the present utility model;

[0031] Figure 6 This is a schematic diagram of the installation of the adapter tab of the electrode assembly according to an embodiment of the present invention;

[0032] Figure 7 A schematic diagram of the cutout structure of the electrode assembly in this embodiment of the present invention.

[0033] In the picture:

[0034] 1. Composite foil current collector; 101. Substrate layer; 102. First conductive layer; 103. Second conductive layer; 104. Empty foil area; 105. Current collector body;

[0035] 2. Folding piece; 201. First folding section; 202. Second folding section;

[0036] 3. First overlapping area;

[0037] 4. Second overlapping area;

[0038] 5. Adapter tabs;

[0039] 6. U-shaped cut;

[0040] 7. Through hole. Detailed Implementation

[0041] To make the technical problems solved, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0042] In the description of this utility model, it should be understood that the terms "longitudinal," "radial," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0043] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal encapsulation of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0044] In order to solve the problem that the conductive layers on both sides of the composite foil current collector 1 cannot conduct electricity effectively.

[0045] This invention provides an electrode assembly.

[0046] As shown in Figures 1-7, the electrode assembly of this utility model embodiment includes a composite foil current collector 1. The composite foil current collector 1 includes a substrate layer 101, a first conductive layer 102 located on one side of the substrate layer 101, and a second conductive layer 103 located on the other side of the substrate layer 101. The composite foil current collector 1 includes a current collector body and a folded sheet 2. The composite foil current collector 1 has an empty foil area 104. The folded sheet 2 is formed by tearing a portion of the composite foil current collector 1 located in the empty foil area 104. The folded sheet 2 is folded from one side of the current collector body to the other side of the current collector body so that the first conductive layer 102 and the second conductive layer 103 are electrically connected.

[0047] The electrode assembly of this utility model provides a folded piece 2 formed by tearing part of the composite foil current collector 1 at the empty foil area 104 of the composite foil current collector 1, and folds the folded piece 2 from one side of the current collector body 105 to the other side of the current collector body 105, thereby achieving the effect of electrical connection between the first conductive layer 102 and the second conductive layer 103, and thus enabling effective electrical connection between the first conductive layer 102 and the second conductive layer 103.

[0048] Therefore, the electrode assembly of this utility model embodiment enables effective conductivity between the conductive layers on both sides of the composite foil current collector 1.

[0049] In some embodiments, such as Figure 7 As shown, a U-shaped cutout 6 is provided on the empty foil area 104, and a folded piece 2 is formed in the U-shaped cutout 6. One end of the folded piece 2 is a fixed end connected to the current collector body 105, and the other end of the folded piece 2 is a free end that can be folded. When the folded piece 2 is folded, a through hole 7 is formed in the U-shaped cutout 6.

[0050] Thus, the folded piece 2 can be folded from one side of the current collector body 105 to the other side of the current collector body 105, thereby achieving the effect of electrical connection between the first conductive layer 102 and the second conductive layer 103, and thus enabling effective electrical connection between the first conductive layer 102 and the second conductive layer 103.

[0051] In some embodiments, the folded sheet 2 includes a first folded segment 201 located on one side of the current collector body 105. The first folded segment 201 and the current collector body 105 have a first overlapping region 3 that overlaps in the thickness direction of the current collector body 105. The first folded segment 201 and the current collector body 105 are electrically connected through the first overlapping region 3.

[0052] The electrode assembly of this utility model provides a first overlapping area 3 between the first folded section 201 and the current collector body 105, enabling the first folded section 201 of the adapter to form an effective electrical connection with the first conductive layer 102. A welding device can be used to weld the portion of the first folded section 201 corresponding to the first overlapping area 3 and the portion of the current collector body 105 corresponding to the first overlapping area 3, preventing the first folded section 201 from detaching from the first conductive layer 102 and improving the connection quality between the first folded section 201 and the first conductive layer 102.

[0053] In some embodiments, the first folded segment 201 extends in the width direction of the current collector body 105, and the size of the first overlapping area 3 in the length direction of the current collector body 105 ranges from 2 to 50 mm.

[0054] The first overlapping area 3 has a size range of 2-70 mm in the width direction of the current collector body 105;

[0055] It is understandable that the size range of the first overlapping region 3 in the length direction of the current collector body 105 and the size range of the first overlapping region 3 in the width direction of the current collector body 105 determine the flow area between the folded piece 2 and the current collector body 105. The larger the flow area, the stronger the current carrying capacity of the electrode assembly of this utility model embodiment. However, the larger the flow area, the larger the volume of the folded piece 2 will inevitably be increased, that is, the volume of the electrode assembly of this utility model embodiment will be increased. On the one hand, it will reduce the energy density of the battery after assembly, and on the other hand, it will increase the manufacturing cost.

[0056] Therefore, by setting the dimensions of the first overlapping region 3 in the length direction and the width direction of the current collector body 105 to the aforementioned ranges, the electrode assembly of this utility model can, while meeting the current carrying capacity requirements of the electrode assembly, minimize the increase in the volume of the electrode assembly. The ratio between the dimension of the first overlapping region 3 in the width direction of the current collector body 105 and the width of the current collector body 105 is 5%-40%.

[0057] Similarly, the ratio between the dimension of the first overlapping region 3 in the width direction of the current collector body 105 and the width of the current collector body 105 determines the flow area between the folded piece 2 and the current collector body 105. The larger the flow area, the stronger the current carrying capacity of the electrode assembly in this embodiment of the present invention. However, the larger the flow area, the larger the volume of the folded piece 2 will inevitably be, that is, the larger the volume of the electrode assembly in this embodiment of the present invention. On the one hand, this will reduce the energy density of the battery after assembly, and on the other hand, it will increase the manufacturing cost.

[0058] Therefore, by setting the ratio between the dimension of the first overlapping region 3 in the width direction of the current collector body 105 and the width of the current collector body 105 to the above-mentioned range, the electrode assembly of this utility model can meet the current carrying requirements of the electrode assembly while minimizing the increase in the volume of the electrode assembly of this utility model.

[0059] In some embodiments, the folded piece 2 further includes a second folded piece 202 connected to the first folded piece 201 and located on the other side of the current collector body 105. The second folded piece 202 and the current collector body 105 have a second overlapping region 4 that coincides in the thickness direction of the current collector body 105. The second folded piece 202 and the current collector body 105 are electrically connected through the second overlapping region 4.

[0060] The electrode assembly of this utility model provides a second overlapping area 4 between the second folded section 202 and the current collector body 105, enabling the second folded section 202 of the adapter to form an effective electrical connection with the second conductive layer 103. A welding device can be used to weld the portion of the second folded section 202 corresponding to the second overlapping area 4 and the portion of the current collector body 105 corresponding to the second overlapping area 4, preventing the second folded section 202 from detaching from the second conductive layer 103 and improving the connection quality between the second folded section 202 and the second conductive layer 103.

[0061] In some embodiments, the second folded segment 202 extends in the width direction of the current collector body 105, and the second overlapping area 4 has a size range of 2-50 mm in the length direction of the current collector body 105.

[0062] The second overlapping area 4 has a size range of 2-70 mm in the width direction of the current collector body 105;

[0063] It is understandable that the size range of the second overlapping region 4 in the length direction of the current collector body 105 and the size range of the second overlapping region 4 in the width direction of the current collector body 105 determine the flow area between the folded piece 2 and the current collector body 105. The larger the flow area, the stronger the current carrying capacity of the electrode assembly of this utility model embodiment. However, the larger the flow area, the larger the volume of the folded piece 2 will inevitably be increased, that is, the volume of the electrode assembly of this utility model embodiment will be increased. On the one hand, it will reduce the energy density of the battery after assembly, and on the other hand, it will increase the manufacturing cost.

[0064] Therefore, by setting the size range of the second overlapping region 4 in the length direction of the current collector body 105 and the size range of the second overlapping region 4 in the width direction of the current collector body 105 to the above range, the electrode assembly of this utility model can meet the current carrying requirements of the electrode assembly while avoiding excessive increase in the volume of the electrode assembly of this utility model.

[0065] The ratio between the dimension of the second overlapping region 4 in the width direction of the current collector body 105 and the width of the current collector body 105 is 5%-29%;

[0066] Similarly, the ratio between the dimension of the second overlapping region 4 in the width direction of the current collector body 105 and the width of the current collector body 105 determines the flow area between the folded piece 2 and the current collector body 105. The larger the flow area, the stronger the current carrying capacity of the electrode assembly in this embodiment of the present invention. However, the larger the flow area, the larger the volume of the folded piece 2 will inevitably be, that is, the larger the volume of the electrode assembly in this embodiment of the present invention. On the one hand, it will reduce the energy density of the battery after assembly, and on the other hand, it will increase the manufacturing cost.

[0067] Therefore, by setting the ratio between the dimension of the second overlapping region 4 in the width direction of the current collector body 105 and the width of the current collector body 105 within the aforementioned range, the electrode assembly of this utility model can, while meeting the current carrying requirements of the electrode assembly, avoid excessively increasing the volume of the electrode assembly of this utility model. In some embodiments, the connection between the first folded segment 201 and the second folded segment 202 is spaced apart from the side edge corresponding to the current collector body 105.

[0068] The electrode assembly of this utility model increases the contact area between the folded piece 2 and the external component by setting the connection between the first folded segment 201 and the second folded segment 202 at a distance from the side edge corresponding to the current collector body 105, thereby facilitating the connection area between the folded piece 2 and the external component.

[0069] In some embodiments, the connection between the first folded segment 201 and the second folded segment 202 is abutted against the side edge corresponding to the current collector body 105.

[0070] The electrode assembly of this utility model embodiment, by setting the connection between the first folded segment 201 and the second folded segment 202 to abut against the side edge corresponding to the current collector body 105, can avoid increasing the volume of the electrode assembly of this utility model embodiment while connecting the first conductive layer 102 and the second conductive layer 103.

[0071] In some embodiments, the electrode assembly of this utility model further includes an adapter tab 5, which is electrically connected to the folded piece 2.

[0072] It is understandable that the adapter tab 5 can be electrically connected to other components. When the battery is a pouch battery, the adapter tab 5 can be electrically connected to external electrical devices. When the battery is a steel-cased battery, the adapter tab 5 can be electrically connected to the terminals on the battery casing.

[0073] This utility model also provides a battery cell.

[0074] The battery cell of this utility model embodiment includes the electrode assembly described in the above embodiment.

[0075] The above-described embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model, and should all be included within the protection scope of this utility model.

Claims

1. An electrode assembly, characterized in that, The composite foil current collector (1) includes a substrate layer (101), a first conductive layer (102) located on one side of the substrate layer (101), and a second conductive layer (103) located on the other side of the substrate layer (101). The composite foil current collector (1) includes a current collector body (105) and a folded sheet (2). The composite foil current collector (1) has an empty foil area (104). The folded sheet (2) is formed by tearing a portion of the composite foil current collector (1) located in the empty foil area (104). The folded piece (2) is folded from one side of the current collector body (105) to the other side of the current collector body (105) so that the first conductive layer (102) and the second conductive layer (103) are electrically connected.

2. The electrode assembly according to claim 1, characterized in that, A U-shaped cutout (6) is provided on the empty foil area (104). The folded piece (2) is formed in the U-shaped cutout (6). One end of the folded piece (2) is a fixed end connected to the current collector body (105), and the other end of the folded piece (2) is a free end that can be folded. When the folded piece (2) is folded, a through hole (7) is formed in the U-shaped cutout (6).

3. The electrode assembly according to claim 1, characterized in that, The folded piece (2) includes a first folded segment (201) located on one side of the current collector body (105). The first folded segment (201) and the current collector body (105) have a first overlapping area (3) that overlaps in the thickness direction of the current collector body (105). The first folded segment (201) and the current collector body (105) are electrically connected through the first overlapping area (3).

4. The electrode assembly according to claim 3, characterized in that, The first folded segment (201) extends in the width direction of the current collector body (105), and the first overlapping area (3) has a size range of 2-50 mm in the length direction of the current collector body (105). The first overlapping area (3) has a size range of 2-70 mm in the width direction of the current collector body (105); The first overlapping area (3) has a dimension in the width direction of the current collector body (105) that is 5%-40% of the width of the current collector body (105).

5. The electrode assembly according to claim 3, characterized in that, The folded piece (2) further includes a second folded piece (202) connected to the first folded piece (201) and located on the other side of the current collector body (105). The second folded piece (202) and the current collector body (105) have a second overlapping area (4) that coincides with the thickness direction of the current collector body (105). The second folded piece (202) and the current collector body (105) are electrically connected through the second overlapping area (4).

6. The electrode assembly according to claim 5, characterized in that, The second folded segment (202) extends in the width direction of the current collector body (105), and the second overlapping area (4) has a size range of 2-50 mm in the length direction of the current collector body (105). The second overlapping area (4) has a size range of 2-70 mm in the width direction of the current collector body (105); The ratio between the dimension of the second overlapping area (4) in the width direction of the current collector body (105) and the width of the current collector body (105) is 5%-29%.

7. The electrode assembly according to claim 5, characterized in that, The connection between the first folded segment (201) and the second folded segment (202) is spaced apart from the side edge corresponding to the current collector body (105).

8. The electrode assembly according to claim 5, characterized in that, The connection between the first folded segment (201) and the second folded segment (202) is abutted against the side edge corresponding to the current collector body (105).

9. The electrode assembly according to any one of claims 1-8, characterized in that, It also includes an adapter tab (5), which is electrically connected to the folded piece (2).

10. A battery cell, characterized in that, Includes the electrode assembly as described in any one of claims 1-9.

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