Current collector assembly, electrode plate, and battery

Abstract

A current collector assembly, an electrode plate, and a battery. The current collector assembly comprises a welding area (5), an extension area (15), and tabs. The welding area (5) is formed on a blank area (4), and the width of the welding area (5) is greater than the width of the blank area (4). One end of the extension area (15) is connected to the welding area (5), and the other end of the extension area (15) extends along a first direction. Tabs are disposed on conductive layers on each of two sides of an insulating layer (9), one end of each tab being in an insulating region (3), and the other end thereof passing through the welding area (5) and extending to the extension area (15) in the first direction; the lengths of the tabs on the conductive layers on both sides of the insulating layer (9) in the elongated region (15) are different. Conduction between a first conductive layer (6) and a second conductive layer (8) is ensured, and a relatively low number of tab layers is also ensured, thereby improving energy density.

Description

Current collector assembly, pole piece and battery

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application with application number CN202322590055.X and title “Current Collector Assembly, Pole Sheet and Battery” filed with the China Patent Office on September 21, 2023, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the technical field of lithium batteries, and in particular to a current collector assembly, a pole piece, and a battery. Background Art

[0004] The energy density of existing lithium-ion batteries cannot meet the growing demand for power batteries. Compared to the winding process, the lamination process can effectively increase the volumetric energy density of the battery cell. Considering the mass energy density, the metal-based current collector component accounts for a large proportion of the battery mass.

[0005] The industry is gradually exploring the possibility of using composite current collector assemblies to replace metal-based current collector assemblies. Composite current collector assemblies are sandwich structures consisting of an insulating polymer intermediate layer and metal layers plated on both sides of the insulating layer. Due to the presence of the intermediate insulating layer, the front and back sides of the composite current collector assembly cannot achieve electronic conductivity. Therefore, transfer welding is required during the application of composite current collector assemblies to conduct current.

[0006] At present, external metal tabs are used for composite current collector assemblies to guide current on both the front and back sides of the composite current collector assembly. However, the existing external metal tabs have the same size, which increases the number of tab layers and affects the subsequent bending and shell insertion of the battery. In addition, the increase in the number of tab layers will also reduce the energy density of the battery cell.

[0007] Therefore, there is an urgent need for a current collector assembly, a pole piece, and a battery that can solve the technical problems existing in the prior art to a certain extent.

[0008] Application Contents

[0009] In view of this, the purpose of the present application is to provide a current collector assembly, a pole piece and a battery, so as to improve the energy density of the battery cell to a certain extent without increasing the number of tab layers.

[0010] In a first aspect, the present application provides a current collector assembly, comprising an insulating layer and a conductive layer; the conductive layers are respectively provided on both sides of the insulating layer; the conductive layers can be formed with active material regions, insulating regions, and blank regions along a first direction; the current collector assembly further comprises a welding region, an extension region, and a tab;

[0011] The welding area is formed on the blank area, and the width of the welding area is greater than the width of the blank area, so that the welding area can cover the blank area; one end of the extension area is connected to the welding area and the other end extends along the first direction;

[0012] The tabs are respectively arranged on the conductive layers on both sides of the insulating layer, one end of the tab is arranged in the insulating area and the other end passes through the welding area and extends to the extension area along the first direction, and the tabs on the conductive layers on both sides of the insulating layer have different lengths in the extension area.

[0013] Beneficial effect: The energy density of the battery cell can be increased without increasing the number of tab layers.

[0014] In an optional embodiment, the conductive layer includes a first conductive layer and a second conductive layer, and the tab includes a first tab and a second tab;

[0015] The first electrode tab is disposed on the first conductive layer, and the second electrode tab is disposed on the second conductive layer.

[0016] In an optional embodiment, one end of the first pole lug and the second pole lug are both arranged on the insulating layer, and the other end extends along the first direction, passes through the welding area and extends to the extension area; and the length of the first pole lug located in the extension area is greater than the length of the second pole lug located in the extension area.

[0017] In an optional embodiment, the welding area exceeds the blank area at one end close to the extension area.

[0018] In an optional embodiment, the length of one of the pole tabs on the conductive layer located on both sides of the insulating layer in the extension area is set between 0.1mm-100mm, and the length of one of the pole tabs on the conductive layer located on both sides of the insulating layer in the extension area is set between 0.1mm-2mm.

[0019] In an optional embodiment, the lengths of the tabs on the conductive layer on both sides of the insulating layer on the insulating region are both set between 0.1 mm and 2 mm.

[0020] In an optional embodiment, the width of the blank area is set between 1 mm and 10 mm, and the width of the welding area is set between 2 mm and 11 mm.

[0021] In an optional embodiment, the tabs on the conductive layer on both sides of the insulating layer can form a contact area of ​​1 mm to 10 mm on the welding area.

[0022] In an optional embodiment, the width of the insulating area is set between 0.5 mm and 10 mm.

[0023] In an optional embodiment, the thickness of the insulating layer is set between 0.5 μm and 10 μm.

[0024] In an optional embodiment, the thickness of the conductive layers on both sides of the insulating layer is set between 0.2 μm and 5 μm.

[0025] In a second aspect, the present application provides a pole piece, comprising the above-mentioned current collector assembly;

[0026] The welding area includes a tab area and a non-tab area arranged along the first direction;

[0027] Assuming the width of the non-tab area is L22, the width of the welding area is L2, the width of the blank area is L23, and the width of the tab area is L21, then L21, L23, L22 and L2 satisfy the following relationship:

[0028] In a third aspect, the present application provides a battery comprising the above-mentioned current collector assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0030] FIG1 is a plan view of a current collector assembly provided in Example 1 of the present application;

[0031] FIG2 is a cross-sectional view of a current collector assembly provided in Example 1 of the present application;

[0032] FIG3 is a plan view of the pole piece provided in the second embodiment of the present application.

[0033] Reference numerals:

[0034] 1-first direction; 2-active material area; 3-insulating area; 4-blank area; 5-welding area; 6-first conductive layer; 8-second conductive layer; 9-insulating layer; 10-first tab; 14-second tab; 15-extension area; 16-contact area; 17-tab area; 18-non-tab area. DETAILED DESCRIPTION

[0035] To make the purpose, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of this application.

[0036] 1 and 2 , a current collector assembly provided by the present application is described in detail.

[0037] In this embodiment, the current collector assembly includes an insulating layer 9 , a first conductive layer 6 , and a second conductive layer 8 .

[0038] Specifically, the first conductive layer 6 and the second conductive layer 8 are respectively disposed on both sides of the insulating layer 9 .

[0039] Furthermore, the thickness of the insulating layer 9 is set between 0.5 μm and 10 μm, preferably 0.8 μm.

[0040] Furthermore, the thickness of the first conductive layer 6 and the second conductive layer 8 are both set between 0.2 μm and 5 μm, preferably 0.3 μm.

[0041] Specifically, the active material is coated on the surface of the first conductive layer 6 and the second conductive layer 8, so that the first conductive layer 6 and the second conductive layer 8 form an active material area 2, an insulating area 3 and a blank area 4 along a first direction 1, where the first direction 1 is shown in Figure 1.

[0042] Furthermore, the width of the insulating region 3 is set between 0.5 mm and 10 mm, preferably 0.8 mm.

[0043] Furthermore, the width of the blank area 4 is set between 1 mm and 10 mm, and transfer welding is performed in the blank area 4 to achieve conduction between the first conductive layer 6 and the second conductive layer 8 .

[0044] Specifically, the current collector assembly further includes a welding area 5, an extension area 15, and a tab. The welding area 5 is formed on the blank area 4 and the width of the welding area 5 is greater than the width of the blank area 4. That is, when the blank area 4 is aligned with the welding area 5 at one end close to the insulating area 3, the other end of the welding area 5 is higher than (exceeds) the blank area 4. In other words, the area of ​​the welding area 5 is greater than the area of ​​the blank area 4, and the welding area 5 can cover the blank area 4 (the portion of the welding area 5 that exceeds the blank area 4 is the contact area 16 (the contact area 16 refers to the position where the first tab 10 and the second tab 14 can be welded and contacted, and the contact area 16 is described below)); one end of the extension area 15 is connected to the welding area 5 and the other end extends along the first direction 1.

[0045] Specifically, two pole tabs are provided, namely a first pole tab 10 and a second pole tab 14. The first pole tab 10 is provided on the first conductive layer 6, and the second pole tab 14 is provided on the second conductive layer 8. Furthermore, one end of the first pole tab 10 and the second pole tab 14 are both provided on the insulating layer 9, and the other end extends along the first direction 1, passes through the welding area 5 and extends to the extension area 15, and the length of the first pole tab 10 located in the extension area 15 is not the same as the length of the second pole tab 14 located in the extension area 15. Combined with Figure 2, taking the example that the length of the first pole tab 10 located in the extension area 15 is greater than the length of the second pole tab 14 located in the extension area 15 as an example, detailed explanation is given.

[0046] First, the welding area 5 is able to cover the blank area 4, that is to say, a portion of the welding area 5 completely overlaps with the blank area 4, and another portion of the welding area 5 is extra (exceeds) the blank area 4. As shown in Figure 1, the welding area 5 exceeds the blank area 4 at the end close to the extension area 15 (the exceeding portion is the contact area 16).

[0047] Then, one end of the first pole ear 10 and the second pole ear 14 are both arranged in the insulating area 3, and the other end extends to the extension area 15. That is to say, the first pole ear 10 and the second pole ear 14 both pass through the welding area 5 (while passing through the welding area 5, they will inevitably pass through the blank area 4), and a part of the first pole ear 10 and the second pole ear 14 overlaps with the blank area 4. At this time, it is equivalent to the first pole ear 10 and the second pole ear 14 being blocked by the blank area 4, so this part of the first pole ear 10 and the second pole ear 14 cannot contact each other. This part of the first pole ear 10 realizes welding with the first conductive layer 6, and this part of the second pole ear 14 realizes welding with the second conductive layer 8.

[0048] Then, because the width of the welding area 5 is greater than the width of the blank area 4, that is to say, there is still a part of the first pole tab 10 and the second pole tab 14 that does not overlap with the blank area 4, and is beyond the blank area 4. In other words, there is no obstacle between the first pole tab 10 and the second pole tab 14 at this time, so the first pole tab 10 and the second pole tab 14 of this part can be contacted by welding, and when the first pole tab 10 and the second pole tab 14 of this part are welded, the first conductive layer 6 and the second conductive layer 8 will be conductive.

[0049] Finally, since the height of the first pole tab 10 in the extension region 15 is greater than the height of the second pole tab 14 in the extension region 15, the first pole tab 10 can be bent when forming the pole piece so that the first pole tab 10 forms the positive or negative pole of the battery cell, and the second pole tab 14 does not need to be bent.

[0050] In summary, the conduction between the first conductive layer 6 and the second conductive layer 8 is ensured, and a smaller number of tab layers is ensured (in this application, for a current collector, one layer of tabs is ultimately formed; while in the prior art, for a current collector, two layers of tabs are ultimately formed), thereby improving the energy density.

[0051] In addition, the present application can achieve one-time welding in the process steps without the need for secondary welding; as shown in Figure 2, the present application can directly achieve welding of the first pole ear 10 and the first conductive layer 6, the second pole ear 14 and the second conductive layer 8, and the first pole ear 10 and the second pole ear 14 in the welding area 5, which can be welded in one time and the process is simple.

[0052] In this embodiment, the length of the first electrode tab 10 in the extension region 15 is set between 0.2 mm and 100 mm, and the length of the second electrode tab 14 in the extension region 15 is set between 0.1 mm and 2 mm.

[0053] Optionally, the length of the first tab in the extension region 15 is 100 mm, and the length of the second tab 14 in the extension region 15 is 2 mm.

[0054] Alternatively, the length of the first tab in the extension region 15 is 50 mm, and the length of the second tab 14 in the extension region 15 is 1 mm.

[0055] In another embodiment, the length of the first tab in the extension region 15 is 0.2 mm, and the length of the second tab 14 in the extension region 15 is 0.1 mm.

[0056] In summary, in the actual welding process, considering that welding may have certain errors or deviations caused by other uncertain factors, the second electrode tab 14 is set to a certain length in the extension zone 15, and the overlapping part of the second electrode tab 14 and the extension zone 15 can be called a buffer zone.

[0057] In this embodiment, the length of the first electrode tab 10 on the insulating region 3 is set between 0.1 mm and 2 mm, and the length of the second electrode tab 14 on the insulating region 3 is set between 0.1 mm and 2 mm.

[0058] Optionally, the length of the first electrode tab 10 on the insulating region 3 is 0.1 mm, and the length of the second electrode tab 14 on the insulating region 3 is 0.1 mm.

[0059] Alternatively, the length of the first electrode tab 10 on the insulating region 3 is 2 mm, and the length of the second electrode tab 14 on the insulating region 3 is 2 mm.

[0060] In another embodiment, the length of the first electrode tab 10 on the insulating region 3 is 1 mm, and the length of the second electrode tab 14 on the insulating region 3 is 1 mm.

[0061] In summary, in the actual welding process, considering that there will be certain errors or deviations caused by other uncertain factors in welding, the first pole tab 10 and the second pole tab 14 are set to a certain length in the insulating area 3, and the overlapping part of the first pole tab 10 and the insulating area 3 and the overlapping part of the second pole tab 14 and the insulating area 3 can be called a buffer zone.

[0062] In this embodiment, the width of the blank area 4 is set between 1 mm and 10 mm, and the width of the welding area 5 is set between 2 mm and 11 mm.

[0063] Alternatively, the width of the blank area 4 is 1 mm, and the width of the welding area 5 is set to 2 mm. Then the width of the welding area 5 exceeding the blank area 4 is 1 mm (2 mm - 1 mm).

[0064] Alternatively, the width of the blank area 4 is 1 mm, and the width of the welding area 5 is set to 11 mm. Then the width of the welding area 5 exceeding the blank area 4 is 10 mm (11 mm-1 mm).

[0065] Specifically, the portion of the welding area 5 that exceeds the blank area 4 is called the contact area 16. Within the contact area 16, the first electrode tab 10 and the second electrode tab 14 are not blocked by the blank area 4, that is, welding can be performed. After welding, electrical conductivity between the first electrode tab 10 and the second electrode tab 14 is achieved, thereby achieving electrical conductivity between the first conductive layer 6 and the second conductive layer 8. In addition, by setting the width of the blank area 4 and the welding area 5, it can be seen that the width of the contact area 16 is set between 1 mm and 10 mm.

[0066] In summary, the width of the welding area 5 of the present application is greater than the width of the blank area 4, and the length of the first pole tab 10 in the extension area 15 is greater than the length of the second pole tab 14 in the extension area 15, so the conductivity of the transfer welding can be effectively improved and the number of pole tab layers can be reduced.

[0067] As shown in FIG3 , a pole piece is also provided in this embodiment, including the above-mentioned current collector assembly.

[0068] Specifically, the welding area 5 can be divided into a tab area 17 and a non-tab area 18 , and the tab area 17 and the non-tab area 18 are arranged along the first direction 1 .

[0069] Specifically, assuming that the width of the non-tab area 18 is L22, the width of the welding area 5 is L2, the width of the blank area 4 is L23, and the width of the tab area 17 is L21, then L21, L23, L22 and L2 satisfy the following relationship:

[0070] In summary, the pole piece can be formed in one step during the die-cutting process, greatly improving production efficiency. And because each pole piece can serve as a minimum unit of the battery cell, the yield rate of composite current collector laminate production can be effectively improved.

[0071] The present application also provides a battery including the above-mentioned current collector assembly, which has all the beneficial effects of the current collector assembly and will not be elaborated on in detail here.

[0072] Although the embodiments of the present application have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present application, and such modifications and variations shall fall within the scope defined by the appended claims. Industrial Applicability

[0073] The current collector assembly provided in the present application includes an insulating layer and a conductive layer; the conductive layer is disposed on both sides of the insulating layer; the conductive layer can be formed with an active material region, an insulating region, and a blank region along a first direction, and also includes a welding region, an extension region, and a tab; the welding region is formed on the blank region and has a width greater than that of the blank region; one end of the extension region is connected to the welding region and the other end extends along the first direction; the tabs are disposed on the conductive layer on both sides of the insulating layer, one end of the tab is disposed in the insulating region and the other end extends through the welding region along the first direction to the extension region, and the tabs on the conductive layer on both sides of the insulating layer have different lengths in the extension region. The present application ensures conductivity between the first and second conductive layers and a reduced number of tab layers, thereby improving energy density.

Claims

1. A current collector assembly, comprising an insulating layer and a conductive layer; the conductive layers are disposed on both sides of the insulating layer; the conductive layer can form an active material area, an insulating area and a blank area along a first direction, characterized in that: The current collector assembly also includes a welding area, an extension area and a tab; The welding area is formed on the blank area, and the width of the welding area is greater than the width of the blank area, so that the welding area can cover the blank area; one end of the elongated area is connected to the welding area and the other end extends along the first direction; The pole tabs are respectively arranged on the conductive layers on both sides of the insulating layer, one end of the pole tab is arranged in the insulating area and the other end passes through the welding area and extends to the extension area along the first direction, and the pole tabs on the conductive layers on both sides of the insulating layer have different lengths in the extension area.

2. The current collector assembly according to claim 1, characterized in that: The conductive layer includes a first conductive layer and a second conductive layer, and the tab includes a first tab and a second tab; The first electrode tab is disposed on the first conductive layer, and the second electrode tab is disposed on the second conductive layer.

3. The current collector assembly according to claim 2, characterized in that: One end of the first pole lug and the second pole lug are both arranged on the insulating layer, and the other end extends along the first direction, passes through the welding area and extends to the extension area; and the length of the first pole lug located in the extension area is greater than the length of the second pole lug located in the extension area.

4. The current collector assembly according to claim 1, characterized in that: The welding area exceeds the blank area at one end close to the extension area.

5. The current collector assembly according to claim 3, characterized in that: The length of the first pole tab in the extension region is set between 0.1 mm and 100 mm, and the length of the second pole tab in the extension region is set between 0.1 mm and 2 mm.

6. The current collector assembly according to claim 1, characterized in that: The lengths of the tabs on the conductive layer on both sides of the insulating layer on the insulating region are both set between 0.1 mm and 2 mm.

7. The current collector assembly according to claim 1, characterized in that: The width of the blank area is set between 1 mm and 10 mm, and the width of the welding area is set between 2 mm and 11 mm.

8. The current collector assembly according to claim 7, characterized in that: The tabs on the conductive layer at both sides of the insulating layer can form a contact area between 1 mm and 10 mm on the welding area.

9. The current collector assembly according to claim 1, characterized in that: The width of the insulating area is set between 0.5 mm and 10 mm.

10. The current collector assembly according to claim 1, characterized in that: The thickness of the insulating layer is set between 0.5 μm and 10 μm.

11. The current collector assembly according to claim 1, characterized in that: The thickness of the conductive layer located on both sides of the insulating layer is set between 0.2 μm and 5 μm.

12. A pole piece, characterized in that: A current collector assembly comprising any one of claims 1 to 11; The welding area includes a tab area and a non-tab area arranged along the first direction; Assuming the width of the non-tab area is L22, the width of the welding area is L2, the width of the blank area is L23, and the width of the tab area is L21, then L21, L23, L22 and L2 satisfy the following relationship:

13. A battery, characterized in that: A current collector assembly comprising any one of claims 1-11.

Images