Electrode assembly, battery cell, battery monomer and battery pack

Abstract

The invention relates to the technical field of batteries, and provides an electrode assembly, a battery cell, a battery monomer and a battery pack. The electrode assembly comprises a current collector, a main tab and at least one auxiliary tab, the current collector is provided with an empty foil area, one end of the auxiliary tab is connected with the main tab, the other end of the auxiliary tab is connected with the empty foil area of the current collector, and the main tab is connected with the empty foil area of the current collector. And a gap is formed between the joint of the main tab and the empty foil area and the joint of the auxiliary tab and the empty foil area. As the gap is formed between the joint of the main tab and the empty foil area and the joint of the auxiliary tab and the empty foil area, namely, the main tab and the auxiliary tab can be regarded as two independent parts and are independently welded with the empty foil area of the current collector, even if the joint of the main tab and the current collector is broken, the main tab and the auxiliary tab can be independently welded with the empty foil area of the current collector. In addition, the electrode assembly can output or input current through the auxiliary tabs, so that the service life of the single battery adopting the electrode assembly can be effectively prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and more particularly to an electrode assembly, an electrode core, a battery cell and a battery pack. Background Art

[0002] Generally, an electrode assembly includes a positive electrode sheet, a separator and a negative electrode sheet. The positive electrode sheet, the separator and the negative electrode sheet form the aforementioned electrode assembly through a stacking process or a winding process. Both the positive electrode sheet and the negative electrode sheet include a current collector and a tab. Usually, the current collector includes a coated area and a bare foil area. The coated area is coated with an active material layer, and the tab is welded to the bare foil area. The tab is used to connect with an external structural component.

[0003] Chinese Patent with application number CN201822215767.2 discloses a welding structure of a positive tab of a cylindrical lithium-ion battery, which includes a positive tab plate. A main tab is welded at the center position of the positive tab plate. Auxiliary tabs are evenly distributed on both sides of the main tab, and the number of auxiliary tabs is several. Among them, the main tab and the auxiliary tabs are arranged at intervals, and the several auxiliary tabs are arranged at intervals. During welding, each auxiliary tab is welded to the main tab by ultrasonic welding respectively, and the main tab is then welded to the cap alone. However, the total thickness of the main tab and several auxiliary tabs is relatively large. During welding, problems such as poor welding or over-welding are likely to occur, thereby reducing the welding reliability of the battery cell, resulting in the battery cell being unable to be used continuously, and greatly shortening the service life of the battery cell. Summary of the Invention

[0004] The purpose of the present invention is to provide an electrode assembly, an electrode core, a battery cell and a battery pack, aiming to solve the technical problem of the relatively low service life of existing battery cells.

[0005] In a first aspect, the present application provides an electrode assembly, including a current collector, a main tab and at least one auxiliary tab. The current collector has a bare foil area. One end of the auxiliary tab is connected to the main tab, and the other end of the auxiliary tab is connected to the bare foil area. The main tab is connected to the bare foil area. There is a gap between the connection of the main tab and the bare foil area and the connection of the auxiliary tab and the bare foil area.

[0006] The beneficial effects of the electrode assembly provided by the present invention are as follows:

[0007] First of all, since there is a gap between the connection of the main tab and the bare foil area and the connection of the auxiliary tab and the bare foil area, that is, the main tab and the auxiliary tab can be regarded as two independent parts. The main tab and the auxiliary tab are welded to the bare foil area of the current collector separately. Even when the main tab breaks at its connection with the current collector, the electrode assembly can output or input current through the auxiliary tab, greatly reducing the possibility of problems such as poor welding during the welding process of the main tab. In this way, the service life of the battery cell using this electrode assembly can be effectively improved.

[0008] Secondly, the secondary tab provided by the present invention can also play a role in shunt balancing when a large current is transmitted in the electrode assembly.

[0009] Furthermore, the electrode assembly can effectively control the length of the welding mark. It can be understood that when the lengths of the tabs are the same, in this electrode assembly, since there is a gap between the connection between the main tab and the empty foil area and the connection between the secondary tab and the empty foil area, then during welding, the welding equipment does not need to perform welding operations on the aforementioned gap, which can effectively shorten the length of the welding mark, thereby reducing the heat accumulation generated during welding, and further improving the overall sealing effect of the battery cell.

[0010] Optionally, multiple secondary tabs are respectively distributed at both ends of the main tab in the length extension direction.

[0011] Optionally, multiple secondary tabs are distributed at the same end of the main tab in the length extension direction.

[0012] Optionally, multiple secondary tabs located at one end of the main tab in the length extension direction are connected in sequence and then connected to the main tab.

[0013] Optionally, multiple secondary tabs located at one end of the main tab in the length extension direction are arranged in sequence along the width extension direction of the main tab.

[0014] In a second aspect, the present application provides a battery cell, including the above-mentioned electrode assembly, and the secondary tab is encapsulated in the battery cell.

[0015] Since the battery cell provided by the present invention adopts the above-mentioned electrode assembly, on the one hand, the service life of the battery cell can be extended. On the other hand, since the secondary tab is encapsulated in the battery cell, the influence of the secondary tab from the external environment and external working conditions can be effectively reduced, which is beneficial to extending the service life of the secondary tab.

[0016] Optionally, tab glue is provided on the main tab.

[0017] Optionally, the battery cell is a stacked battery cell or a wound battery cell.

[0018] In a third aspect, the present application provides a battery monomer, including the above-mentioned battery cell.

[0019] In a fourth aspect, the present application provides a battery pack, including the above-mentioned battery monomer. Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0021] Figure 1 Schematic diagram of the electrode assembly provided by an embodiment of the present invention;

[0022] Figure 2 Another schematic diagram of the electrode assembly provided by an embodiment of the present invention;

[0023] Figure 3 Exploded view of the electrode assembly provided by an embodiment of the present invention;

[0024] Figure 4 Another exploded view of the electrode assembly provided by an embodiment of the present invention;

[0025] Figure 5 Another exploded view of the electrode assembly provided by an embodiment of the present invention;

[0026] Figure 6 Another exploded view of the electrode assembly provided by an embodiment of the present invention;

[0027] Figure 7 Another exploded view of the electrode assembly provided by an embodiment of the present invention;

[0028] Figure 8 Another exploded view of the electrode assembly provided by an embodiment of the present invention.

[0029] Among them, each reference numeral in the figure:

[0030] 100, electrode assembly; 10, current collector; 20, main tab;

[0031] 30, secondary tab; 11, empty foil area; 111, first welding mark area;

[0032] 112, second welding mark area; 21, tab glue; 22, main welding mark area;

[0033] 31, connecting part; 32, welding part; 321, secondary welding mark area. Detailed implementation manners

[0034] The embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0035] References throughout this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Thus, the appearances of the phrases "in another embodiment of the present application" or "in an embodiment" or "in some embodiments" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0036] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0037] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0038] In the present invention, unless otherwise clearly specified and defined, the terms "mounted", "connected", "connected to", "fixed" and the like should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] Please refer to Figures 1 to 8 , and now the electrode assembly 100, the battery cell, the battery monomer and the battery pack in the embodiments of the present invention will be described.

[0040] Please refer to Figure 1 , wherein the X-axis is the length direction of the main pole tab 20, the Y-axis is the width direction of the main pole tab 20, and the Z-axis is the thickness direction of the main pole tab 20.

[0041] Please refer to Figures 1 to 5, an electrode assembly 100 provided by the present application includes a current collector 10, a main tab 20, and at least one secondary tab 30. The current collector 10 has an empty foil area 11. One end of the secondary tab 30 is connected to the main tab 20, and the other end of the secondary tab 30 is connected to the empty foil area 11. The main tab 20 is connected to the empty foil area 11, and there is a gap between the connection between the main tab 20 and the empty foil area 11 and the connection between the secondary tab 30 and the empty foil area 11.

[0042] Specifically, the secondary tab 30 includes a connected connection portion 31 and a welding portion 32. One end of the connection portion 31 is connected to the main tab 20, and the other end of the connection portion 31 is connected to the welding portion 32. Both the main tab 20 and the welding portion 32 are welded to the empty foil area 11, and the welding portion 32 and the main tab 20 are arranged at intervals.

[0043] First, since there is a gap between the connection between the main tab 20 and the empty foil area 11 and the connection between the secondary tab 30 and the empty foil area 11, that is, the main tab 20 and the secondary tab 30 can be regarded as two independent parts, and the main tab 20 and the secondary tab 30 are separately welded to the empty foil area 11 of the current collector 10. Even when the main tab 20 breaks at its connection with the current collector 10, the electrode assembly 100 can still output or input current through the secondary tab 30, greatly reducing the possibility of problems such as poor soldering during the welding process of the main tab 20. Thus, the service life of the battery cell using the electrode assembly 100 can be effectively improved.

[0044] Second, the secondary tab 30 provided by the present invention can also play a role in shunting and balancing during large current transmission of the electrode assembly.

[0045] Furthermore, the electrode assembly 100 can effectively control the length of the welding mark. It can be understood that in the case of the same tab length, in the electrode assembly 100, since there is a gap between the connection between the main tab 20 and the empty foil area 11 and the connection between the secondary tab 30 and the empty foil area 11, then during welding, the welding equipment does not need to perform welding operations on the aforementioned gap, which can effectively shorten the length of the welding mark, thereby reducing the heat accumulation generated during welding, and further improving the overall sealing effect of the battery cell.

[0046] For convenience of illustration, please refer to Figures 3 to 5 , the main tab 20 is provided with a main welding mark area 22, the welding portion 32 is provided with a secondary welding mark area 321, and the empty foil area 11 is provided with a first welding mark area 111 and a second welding mark area 112. Among them, the first welding mark area 111 and the second welding mark area 112 are arranged at intervals, the first welding mark area 111 corresponds to the main welding mark area 22, and the second welding mark area 112 corresponds to the secondary welding mark area 321, that is, the main tab 20 and the empty foil area 11 are connected at the main welding mark area 22 and the first welding mark area 111, and the welding portion 32 and the empty foil area 11 are connected at the secondary welding mark area 321 and the second welding mark area 112.

[0047] It is understandable that in addition to the empty foil area 11, the current collector 10 also has a coating area. Generally, the current collector 10 is a metal foil. The coating area on the current collector 10 is used to carry the active material. When the current collector 10 is used to carry the positive active material, the current collector 10 is the positive current collector. When the current collector 10 is used to carry the negative active material, the current collector 10 is the negative current collector. The empty foil area 11 refers to the area on the current collector 10 where the slurry is not coated.

[0048] In addition, the secondary tab 30 can be welded to the main tab 20 or integrally formed with the main tab 20, which is not limited herein.

[0049] The electrode assembly 100 provided in this application can be applied to blade battery cells, soft-pack battery cells, square shell battery cells, etc.

[0050] In another embodiment of this application, please refer to Figure 3 , the number of secondary tabs 30 is multiple, and the multiple secondary tabs 30 are respectively distributed at both ends of the main tab 20 in the length extension direction. As an example, in one embodiment, the number of secondary tabs 30 is two, and the two secondary tabs 30 are respectively at both ends of the main tab 20 in the length direction.

[0051] It should be noted that in this application, multiple means two or more (including two).

[0052] In another embodiment of this application, please refer to Figure 4 , the number of secondary tabs 30 is multiple, and the multiple secondary tabs 30 are distributed at the same end of the main tab 20 in the length extension direction. As an example, in one embodiment, the number of secondary tabs 30 is two, and the two secondary tabs 30 are both located at one end of the main tab 20 in the length direction.

[0053] In another embodiment of this application, please refer to Figure 4 , the multiple secondary tabs 30 located at one end of the main tab 20 in the length extension direction are connected in sequence and then connected to the main tab 20. Specifically, the multiple secondary tabs 30 are connected in sequence along the length direction of the main tab 20, and the secondary tab 30 closest to the main tab 20 is connected to the main tab 20.

[0054] In another embodiment of this application, please refer to Figure 5 , the multiple secondary tabs 30 located at one end of the main tab 20 in the length extension direction are arranged in sequence along the width extension direction of the main tab 20. Specifically, in the length direction of the main tab 20 and along the direction away from the length direction of the main tab 20, the connecting portion 31 of each secondary tab 30 gradually approaches the empty foil area 11. With such a setting, to a certain extent, it can effectively reduce the degree of sagging of the tab due to its excessive length, so that the main tab 20 remains flat, thereby improving the feasibility of cell packaging.

[0055] In another embodiment of the present application, please refer to Figures 3 to 5 , the length of the main tab 20 is greater than the length of the secondary tab 30. The main tab 20 is the main tab for inputting or outputting current, while the secondary tab 30 is the secondary tab. The main function of the secondary tab 30 is that when the main tab 20 breaks at its connection with the empty foil area 11, the electrode assembly 100 can still work. Therefore, configuring the length of the main tab 20 to be greater than the length of the secondary tab 30 can ensure the overcurrent capacity of the electrode assembly 100.

[0056] In another embodiment of the present application, the material of the current collector 10, the material of the main tab 20, and the material of the secondary tab 30 are the same. With this setting, while facilitating the welding between the three, the overcurrent capacity is improved.

[0057] In another embodiment of the present application, please refer to Figure 1 , the number of current collectors 10 is multiple, and the multiple current collectors 10 are stacked along the thickness direction of the electrode assembly 100. The main tab 20 and the secondary tab 30 are both arranged in the empty foil area 11 located at the uppermost layer or the lowermost layer. Among them, the thickness direction of the electrode assembly 100 is parallel to the thickness direction of the main tab 20.

[0058] In another embodiment of the present application, please refer to Figure 2 , the current collector 10 has multiple empty foil areas 11, and the multiple empty foil areas 11 are arranged at intervals. The total number of empty foil areas 11 on the current collector 10 is A, and the total number of the main tab 20 and the secondary tab 30 is B, satisfying the relationship A = B. In this embodiment, the main tab 20 corresponds to one empty foil area 11, and each secondary tab 30 corresponds to one empty foil area 11 respectively. With this setting, during welding, the heat transferred from one empty foil area 11 to another can be reduced, thereby improving the overall welding quality and welding reliability.

[0059] The present application also provides a battery cell, including the above-mentioned electrode assembly 100, wherein the secondary tab 30 is encapsulated in the battery cell. In this way, on the one hand, the service life of the battery cell can be extended; on the other hand, since the secondary tab 30 is encapsulated in the battery cell, external physical collisions and other interferences are isolated, the influence of the secondary tab 30 from the external environment and external working conditions can be effectively reduced, and the secondary tab 30 does not need to be folded and is not easily damaged, which is beneficial to extending the service life of the secondary tab 30.

[0060] In another embodiment of the present application, please refer to Figures 6 to 8 , the main tab 20 is provided with tab glue 21 to facilitate the encapsulation of the battery cell. Specifically, the tab glue 21 is located on the side of the secondary tab 30 away from the empty foil area 11, so that after the battery cell is encapsulated, the secondary tab 30 is located inside the battery cell.

[0061] The battery cell provided by this application is a stacked battery cell or a wound battery cell. That is to say, the electrode assembly 100 provided by this application can be applied to both stacked battery cells and wound battery cells.

[0062] This application also provides a battery monomer, including the above-mentioned battery cell.

[0063] This application also provides a battery pack, including the above-mentioned battery monomer. When the battery pack contains multiple battery monomers, the multiple battery monomers are connected in series, parallel or in a hybrid connection through a busbar component.

[0064] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. An electrode assembly, characterized in that: It includes a current collector (10), a main tab (20) and at least one auxiliary tab (30). The current collector (10) has an empty foil area (11). One end of the auxiliary tab (30) is connected to the main tab (20), and the other end of the auxiliary tab (30) is connected to the empty foil area (11). The main tab (20) is connected to the empty foil area (11). There is a gap between the connection of the main tab (20) and the empty foil area (11) and the connection of the auxiliary tab (30) and the empty foil area (11).

2. The electrode assembly according to claim 1, wherein: A plurality of the auxiliary tabs (30) are respectively distributed at both ends in the length extension direction of the main tab (20).

3. The electrode assembly according to claim 1, wherein: A plurality of the auxiliary tabs (30) are distributed at the same end in the length extension direction of the main tab (20).

4. The electrode assembly according to any one of claims 1 to 3, characterized in that: A plurality of the auxiliary tabs (30) located at one end in the length extension direction of the main tab (20) are connected in sequence and then connected to the main tab (20).

5. The electrode assembly according to claim 4, wherein: A plurality of the auxiliary tabs (30) located at one end in the length extension direction of the main tab (20) are arranged in sequence along the width extension direction of the main tab (20).

6. A battery cell, characterized in that: It includes the electrode assembly (100) according to any one of claims 1 to 5, and the auxiliary tab (30) is encapsulated in the battery cell.

7. The battery cell according to claim 6, wherein: There is tab glue (21) on the main tab (20).

8. The battery cell according to claim 6, wherein: The battery cell is a laminated battery cell or a wound battery cell.

9. A battery cell, characterized in that: It includes the battery cell according to any one of claims 6 to 8.

10. A battery pack, characterized in that: It includes the battery monomer according to claim 9.

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