Tab and pouch cell

Abstract

The application relates to the technical field of batteries, and provides a tab and a soft package battery cell. The tab comprises a first tab section connected with a pole group, a second tab section used for being connected with an external conductive component, and a soft connection section connecting the first tab section and the second tab section, the soft connection section can be bent to change the inclination angle alpha of the second tab section relative to the first tab section under external operation. The tab has good bendability, compared with the tab with a hard material and poor bendability in the prior art, the tab does not affect the space utilization of the subsequent soft package battery module assembly, and can improve the energy density of the module.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a tab and a pouch cell. Background Technology

[0002] In related technologies, pouch cells are currently the most common form of lithium-ion battery. The conventional pouch lithium-ion cell process involves welding external tabs to the electrode assembly, placing it within a perforated aluminum-plastic film, and then sealing it with negative pressure to fix the electrode assembly within the film's recesses before proceeding with capacity testing and other processes. To ensure overcurrent and tab strength, and to meet welding requirements, 0.3-0.6mm thick aluminum tabs and nickel-plated copper tabs are typically used. The tab material is relatively hard and not easily bent, affecting the space utilization of subsequent pouch cell module assembly and hindering the improvement of module energy density. Utility Model Content

[0003] In view of this, this application aims to propose a tab that is beneficial to improving the energy density of pouch cell modules.

[0004] To achieve the above objectives, the technical solution of this application is implemented as follows:

[0005] A tab, used in a pouch cell, includes a first tab segment connected to a pole group, a second tab segment for connecting to an external conductive component, and a flexible connection segment connecting the first tab segment and the second tab segment. The flexible connection segment is capable of bending under external operation to change the tilt angle α of the second tab segment relative to the first tab segment.

[0006] Furthermore, the tab is a positive tab, and the flexible connection segment is made of multiple layers of aluminum foil stacked together.

[0007] Furthermore, the cross-sectional area S of the flexible connection segment satisfies: 20 ≤ S ≤ 50 mm. 2 .

[0008] Furthermore, the tab is a negative tab; the flexible connection section is made of multiple layers of copper foil stacked together, or the flexible connection section is made of copper-nickel composite strip, or the flexible connection section is made of braided copper wire bundle.

[0009] Furthermore, the cross-sectional area S of the flexible connection segment satisfies 15 ≤ S ≤ 40 mm². 2 .

[0010] Furthermore, along the thickness direction of the tab, the thickness t1 of the flexible connecting section satisfies: 0.2≤t1≤3.5mm; and / or, along the width direction of the tab, the width W1 of the flexible connecting section satisfies: 5≤W1≤15mm.

[0011] Furthermore, along the length direction of the electrode tab, the length L1 of the flexible connection segment satisfies: 10≤L1≤30mm; and / or, the length L2 of the second electrode tab segment satisfies: 3≤L2≤15mm.

[0012] Furthermore, the tilt angle α satisfies: 90≤α≤180°; and / or, the flexible connecting segment is welded together with the first electrode segment, and the flexible connecting segment is welded together with the second electrode segment.

[0013] Compared with related technologies, this application has the following advantages:

[0014] (1) The tab described in this application can change the tilt angle α of the second tab section relative to the first tab section by setting a soft connection section, that is, to achieve the bending of the tab. Compared with the tabs in traditional technology that are harder and less flexible, it will not affect the space utilization of the subsequent soft-pack battery cell module assembly, but can help improve the energy density of the module.

[0015] (2) The tab is a positive tab, and the soft connection section can be made of multiple layers of aluminum foil stacked together. It has low cost, good conductivity, and strong bendability.

[0016] (3) Ensure that the cross-sectional area S of the flexible connection section satisfies: 20≤S≤50mm 2 This can help meet the current density requirements and thermal management needs of the positive electrode tab.

[0017] (4) The tab is a negative tab, and the flexible connection section is made of multiple layers of copper foil to improve bending performance, while also having good conductivity and oxidation resistance. In addition, the flexible connection section can also be made of copper-nickel composite strip, which can balance good conductivity and welding stability. At the same time, the flexible connection section can also be made of braided copper wire bundle, which has the advantages of high flexibility and strong fatigue resistance, and can meet the requirements of high vibration environment.

[0018] (5) The cross-sectional area S of the flexible connection section satisfies 15≤S≤40mm 2 This helps to meet the current density requirements and thermal management needs of the negative electrode tab.

[0019] (6) Along the thickness direction of the tab, the thickness t1 of the flexible connection section satisfies: 0.2≤t1≤3.5mm, which can meet the current carrying capacity requirements of different ratios. At the same time, along the width direction of the tab, the width W1 of the flexible connection section satisfies: 5≤W1≤15mm, which can avoid the current carrying capacity from being too small and the current carrying capacity from being too large and the space layout from being affected.

[0020] (7) Along the length of the tab, the length L1 of the flexible connection section satisfies: 10≤L1≤30mm, to ensure that the flexible connection section has sufficient bending length to meet the purpose of a large bending angle of the tab. In addition, the length L2 of the second tab section satisfies: 3≤L2≤15mm, to ensure that the welding area is far away from the root of the tab, reduce stress concentration, improve connection reliability, and avoid cracks caused by fretting of the tab.

[0021] (8) The tilt angle α satisfies: 90≤α≤180°, which can help meet the requirements of different tab bending angles when the module is assembled, improve the space utilization of the soft-pack cell module assembly, and thus help improve the energy density of the module.

[0022] This application also proposes a pouch cell, including an electrode assembly and tabs as described above connected to the electrode assembly.

[0023] Furthermore, it also includes tab adhesive covering the tab; along the length direction of the tab, the distance L3 between the flexible connecting section and the tab adhesive satisfies: 3≤L3≤15mm.

[0024] The pouch cell described in this application has the aforementioned tabs, which have the same beneficial effects as traditional technologies, and will not be elaborated further here.

[0025] In addition, along the length of the tab, the distance L3 between the flexible connecting section and the tab adhesive is made to satisfy: 3≤L3≤15mm, which can avoid interference with the top sealing edge, leave space for thermal expansion, and prevent the tab from deforming under stress. Attached Figure Description

[0026] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0027] Figure 1 This is a schematic diagram of the structure of the tabs assembled in the pouch cell according to an embodiment of this application;

[0028] Figure 2 This is a schematic diagram of the assembly of the electrode tab and electrode tab adhesive as described in the embodiments of this application;

[0029] Figure 3 for Figure 2 A schematic diagram of the structure shown from another perspective;

[0030] Figure 4 This is a schematic diagram of the flexible connector segment under bending conditions as described in the embodiments of this application;

[0031] Explanation of reference numerals in the attached figures:

[0032] 100. Electrode; 101. First electrode segment; 102. Second electrode segment; 103. Soft connector segment;

[0033] 200, tab adhesive; 300, aluminum-plastic film;

[0034] t1, thickness of the flexible connecting section; W1, width of the flexible connecting section; L1, length of the flexible connecting section; L2, length of the second electrode tab section; L3, distance between the flexible connecting section and the electrode tab adhesive; S, cross-sectional area of ​​the flexible connecting section; α, tilt angle. Detailed Implementation

[0035] To make the technical solution and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0036] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0037] Furthermore, it should be noted that in the description of this application, if terms such as "upper," "lower," "inner," or "outer" appear, indicating orientation or positional relationship, these are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this application 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 on this application. In addition, if terms such as "first" or "second" appear, they are also used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0038] Furthermore, in the description of this application, unless otherwise expressly defined, the terms "installation," "connection," "joining," and "connector" 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 connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application in light of the specific circumstances.

[0039] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0040] The present application will now be described in detail through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0041] An embodiment of the first aspect of this application provides a tab 100, which is applied in a pouch cell, and is beneficial to improving the space utilization of the pouch cell module assembly, thereby increasing the energy density of the module.

[0042] In related technologies, pouch cells are currently the most common form of lithium-ion battery. The conventional pouch lithium-ion cell process involves welding the electrode assembly to external tabs 100, then placing it within a perforated aluminum-plastic film 300, and sealing it with negative pressure to fix the electrode assembly within the recesses of the aluminum-plastic film 300, followed by capacity testing and other processes. To ensure overcurrent protection and the strength of the tabs 100, and to meet welding requirements, 0.3-0.6mm thick aluminum tabs 100 and nickel-plated copper tabs 100 are typically used. The tabs 100 are relatively hard and not easily bent, affecting the space utilization of subsequent pouch cell module assembly and hindering the improvement of module energy density.

[0043] In view of this, in order to overcome the shortcomings of the related technology, the tab 100 in this embodiment combines... Figures 1 to 4 In terms of overall design, it includes a first tab section 101 connected to the electrode group, a second tab section 102 for connecting to an external conductive component, and a flexible connection section 103 connecting the first tab section 101 and the second tab section 102. The flexible connection section 103 can be bent to withstand external operation, thereby changing the tilt angle α of the second tab section 102 relative to the first tab section 101.

[0044] Therefore, by setting the soft connection section 103, the tilt angle α of the second tab section 102 relative to the first tab section 101 can be changed, that is, the tab 100 can be bent. Compared with the tab 100 of traditional technology which is made of harder material and not easy to bend, it will not affect the space utilization of subsequent soft-pack battery module assembly, but can help improve the energy density of the module.

[0045] Based on the above general introduction, specifically, in some exemplary embodiments, the combination of the first tab segment 101, the second tab segment 102, and the soft connection segment 103 in this embodiment is equivalent to embedding a soft connection segment 103 in the tab 100, so that the tab 100 has better bending performance, which is suitable for improving the grouping space utilization when pouch cells are grouped, thereby achieving the purpose of improving energy density.

[0046] Furthermore, the external conductive component connected to the second tab section 102 may be, for example, a busbar connecting each pouch cell when they are grouped together. Meanwhile, in some exemplary embodiments, the flexible connection section 103 is welded together with the first tab section 101, and also with the second tab section 102, to ensure the overall connection stability and conductivity reliability of the tabs 100.

[0047] Moreover, in this application Figures 1 to 4 The purpose is to show the general structure of the tabs and the soft-pack battery cell. The specific dimensions, proportions and shapes of the components such as the first tab section 101, the second tab section 102, the soft connection section 103, the tab adhesive 200, and the aluminum-plastic film 300 are not limited. That is, the specific dimensions, proportions and shapes of the above components can be adaptively adjusted and set according to the actual application. They will not be described in detail here.

[0048] In some exemplary embodiments, the tab 100 is a positive tab, and the flexible connection section 103 is made of multiple layers of aluminum foil stacked together. In this way, the overall cost of the tab 100 can be reduced, while also having good conductivity and flexibility.

[0049] Furthermore, in some exemplary embodiments, when the tab 100 is a positive tab, the cross-sectional area S of the flexible connection section 103 satisfies: 20 ≤ S ≤ 50 mm. 2 And for example, it can be specifically set to 20mm 2 30mm 2 40mm 2 Or 50mm 2 The main advantage of this design is that it helps to meet the current density requirements and thermal management needs of the positive electrode, ensuring that the electrode 100 has sufficient conductivity.

[0050] Furthermore, in some exemplary embodiments, the tab 100 is a negative tab, and the flexible connection segment 103 is made of multiple layers of copper foil stacked together to improve bending performance, while also having good conductivity and oxidation resistance.

[0051] Of course, in addition to being made of multiple layers of stacked copper foil, the aforementioned flexible connection section 103 can also be made of copper-nickel composite strip, which can balance good conductivity and welding stability. At the same time, the flexible connection section 103 can also be made of braided copper wire bundle, which has the advantages of high flexibility and strong fatigue resistance, and can meet the requirements of high vibration environment.

[0052] In some exemplary embodiments, the aforementioned tab 100 is a negative tab, in which case the cross-sectional area S of the flexible connection section 103 satisfies 15 ≤ S ≤ 40 mm. 2 And for example, it can be specifically set to 15mm 2 20mm2 25mm 2 30mm 2 Or 40mm 2 This allows for meeting the current density requirements and thermal management needs of the negative electrode tab, ensuring that the tab 100 can meet the negative electrode conductivity requirements.

[0053] In addition, continue to combine Figures 2 to 4 As shown, in some exemplary embodiments, along the thickness direction of the tab 100, the thickness t1 of the flexible connection section 103 satisfies: 0.2≤t1≤3.5mm, and can be specifically set to 0.2mm, 1mm, 2mm, 3mm or 3.5mm, etc. This setting can not only meet the current carrying capacity requirements of different rates, but also have a higher upper limit current carrying capacity.

[0054] Meanwhile, in some exemplary embodiments, along the width direction of the tab 100, the width W1 of the flexible connection section 103 satisfies: 5≤W1≤15mm, and can be specifically set to 5mm, 7.5mm, 10mm, 12.5mm or 15mm, etc., thereby avoiding the current carrying capacity from being too small and the current carrying capacity from being too large, and the overall spatial layout when grouped.

[0055] Continue to combine Figures 2 to 4 As shown, in some exemplary embodiments, along the length direction of the tab 100, the length L1 of the flexible connection segment 103 satisfies: 10≤L1≤30mm, and can be specifically set to 10mm, 15mm, 20mm, 25mm or 30mm, etc., to ensure that the flexible connection segment 103 has sufficient bending length to meet the purpose of a large bending angle of the tab 100.

[0056] Furthermore, in some exemplary embodiments, the length L2 of the second tab section 102 satisfies: 3≤L2≤15mm, and can be specifically set to 3mm, 5mm, 7.5mm, 10mm, 12.5mm or 15mm, etc. The main advantage of this setting is that it can ensure that the welding area of ​​the second tab section 102 and the busbar is far away from the root of the tab 100, reduce stress concentration, improve the overall connection reliability of the tab 100, and avoid cracks at the connection due to the slight movement of the tab 100 after assembly.

[0057] In addition, continue to combine Figures 1 to 4 As shown, in some of the exemplary embodiments, the tilt angle α satisfies: 90 ≤ α ≤ 180°, and can be specifically set to 90°, 120°, 150° or 180°, etc., thereby facilitating the meeting of the 100° bending angle requirements of different tabs when assembling modules, improving the space utilization of soft-pack cell module assembly, and thus improving the energy density of the module.

[0058] It is worth noting that, regarding the tab 100 of this embodiment, based on the above exemplary implementations, in a specific implementation, as a preferred embodiment, it is still as shown in the figure, and is applied in a soft-pack battery cell, including a first tab section 101, a second tab section 102 and a soft connection section 103.

[0059] The first tab section 101 is connected to the electrode assembly, the second tab section 102 is used to connect to an external conductive component, and the flexible connection section 103 connects the first tab section 101 and the second tab section 102. Furthermore, the flexible connection section 103 can be bent to withstand external operation, thereby changing the tilt angle α of the second tab section 102 relative to the first tab section 101.

[0060] Among them, tab 100 is the positive tab, and flexible connection section 103 is composed of multiple layers of aluminum foil stacked together. Furthermore, in specific implementation, the cross-sectional area S of flexible connection section 103 satisfies: 20 ≤ S ≤ 50 mm². 2 .

[0061] Among them, the tab 100 is the negative tab, and the flexible connection section 103 is made of multiple layers of copper foil stacked together, or made of copper-nickel composite strip, or made of braided copper wire bundle. In specific implementation, the cross-sectional area S of the flexible connection section 103 satisfies 15 ≤ S ≤ 40 mm². 2 .

[0062] Wherein, along the thickness direction of the tab 100, the thickness t1 of the flexible connecting section 103 satisfies: 0.2≤t1≤3mm, and along the width direction of the tab 100, the width W1 of the flexible connecting section 103 satisfies: 5≤W1≤15mm.

[0063] Among them, along the length direction of the tab 100, the length L1 of the flexible connecting section 103 satisfies: 10≤L1≤30mm, and the length L2 of the second tab section 102 satisfies: 3≤L2≤15mm.

[0064] The tilt angle α satisfies the condition: 90 ≤ α ≤ 180°. Furthermore, the flexible connecting section 103 is welded together with the first electrode lug section 101, and also with the second electrode lug section 102.

[0065] In the preferred embodiment of the tab 100 above, the specific settings and arrangements of the first tab segment 101, the second tab segment 102, the flexible connection segment 103, etc., can still be referred to the descriptions in the above exemplary embodiments. Furthermore, in this preferred embodiment, the beneficial effects brought about by the design of the first tab segment 101, the second tab segment 102, the flexible connection segment 103, etc., can also be referred to the descriptions in the above exemplary embodiments.

[0066] In this embodiment, the tab 100 adopts the above design. Through the setting of the flexible connection section 103, the tab 100 as a whole has good bendability. On this basis, by improving and setting the dimensions of the flexible connection section 103, the first tab section 101 and the second tab section 102, the flexible connection section 103 can maintain good conductivity. This solves the problem that the material of the tab 100 in the traditional technology is too hard and not easy to bend, which affects the space utilization of subsequent soft-pack battery cell module assembly, so as to improve the energy density of the module.

[0067] An embodiment of the second aspect of this application provides a pouch cell, which includes an electrode assembly and the aforementioned tab 100 connected to the electrode assembly.

[0068] Continue to combine Figure 1 As shown, in some exemplary embodiments, the pouch cell further includes an aluminum-plastic film 300 wrapped around the electrode assembly and tab adhesive 200 covering the tabs 100. A portion of the first tab segment 101, the flexible connection segment 103, and the second tab segment 102 of the tab 100 extend beyond the aluminum-plastic film 300, and the tab adhesive 200 is sealed together with the aluminum-plastic film 300. As for any structures not mentioned in this pouch cell description, reference can be made to pouch cell products well-known to those skilled in the art, and they will not be elaborated upon here.

[0069] In some of the exemplary implementations, the combination continues Figures 2 to 4 As shown, along the length direction of the tab 100, the distance L3 between the flexible connection section 103 and the tab adhesive 200 satisfies: 3≤L3≤15mm, and can be specifically set to 3mm, 5mm, 7.5mm, 10mm, 12.5mm or 15mm, etc., to avoid interference with the top sealing edge of the soft-pack battery cell, leave space for thermal expansion, and prevent the tab 100 from deforming under stress.

[0070] In this embodiment, the pouch cell, by setting the aforementioned tab 100, not only improves the space utilization rate of the pouch cell module assembly, thereby increasing the energy density of the module, but also reduces the risk of damage to the tab 100 after assembly, thus achieving good performance.

[0071] The above descriptions are merely some embodiments of this application and are not intended to limit this application. The technical features or structures in the foregoing different embodiments can be arbitrarily combined to form other specific technical solutions as needed. For those skilled in the art, this application can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of the claims of this application.

Claims

1. A tab for use in a pouch cell, characterized in that: It includes a first tab segment connected to the electrode assembly, a second tab segment for connecting to an external conductive component, and a flexible connection segment connecting the first tab segment and the second tab segment. The flexible connection segment can be bent to withstand external operation to change the tilt angle α of the second tab segment relative to the first tab segment.

2. The electrode tab according to claim 1, characterized in that: The tab is a positive tab, and the flexible connection section is made of multiple layers of aluminum foil stacked together.

3. The electrode tab according to claim 2, characterized in that: The cross-sectional area S of the flexible connection segment satisfies: 20 ≤ S ≤ 50 mm 2 .

4. The electrode tab according to claim 1, characterized in that: The electrode tab is a negative electrode tab; The flexible connection segment is made of multiple layers of copper foil stacked together, or the flexible connection segment is made of copper-nickel composite strip, or the flexible connection segment is made of braided copper wire bundle.

5. The electrode tab according to claim 4, characterized in that: The cross-sectional area S of the flexible connection segment satisfies 15 ≤ S ≤ 40 mm. 2 .

6. The electrode tab according to claim 1, characterized in that: Along the thickness direction of the electrode tab, the thickness t1 of the flexible connecting section satisfies: 0.2 ≤ t1 ≤ 3.5 mm; and / or, Along the width direction of the tab, the width W1 of the flexible connection segment satisfies: 5≤W1≤15mm.

7. The electrode tab according to claim 1, characterized in that: Along the length direction of the electrode tab, the length L1 of the flexible connecting segment satisfies: 10 ≤ L1 ≤ 30 mm; and / or, The length L2 of the second pole ear segment satisfies: 3≤L2≤15mm.

8. The electrode tab according to any one of claims 1 to 7, characterized in that: The tilt angle α satisfies: 90 ≤ α ≤ 180°; and / or, The flexible connecting segment is welded together with the first electrode segment, and the flexible connecting segment is welded together with the second electrode segment.

9. A pouch cell, characterized in that: It includes an electrode assembly and a tab as described in any one of claims 1 to 8 connected to the electrode assembly.

10. The pouch cell according to claim 9, characterized in that: It also includes tab adhesive covering the tabs; Along the length direction of the electrode tab, the distance L3 between the flexible connecting section and the electrode tab adhesive satisfies: 3≤L3≤15mm.

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