Bipolar group tab welding structure, bipolar group, soft package battery and energy storage device

Abstract

The utility model relates to the technical field of soft package batteries, in particular to a bipolar pack tab welding structure, a bipolar pack, a soft package battery and an energy storage device.The bipolar pack tab welding structure is used for connecting a first pole pack and a second pole pack and comprises a first tab bundle, a second tab bundle and connecting tabs, and the first tab bundle is formed on the first pole pack; the second tab bundle is formed on the second pole group, and the second tab bundle and the first tab bundle are oppositely arranged; the connecting tab is arranged between the first tab bundle and the second tab bundle and is provided with a first welding surface and a second welding surface which are oppositely arranged, the first welding surface is used for being welded with the first tab bundle, and the second welding surface is used for being welded with the second tab bundle. By adopting the bipolar group tab welding structure disclosed by the invention, soft package bipolar group welding can be realized, the number of layers of a tab bundle welded at a time can be reduced, the problems of insufficient welding, tearing, wrinkling and the like caused by excessive layers of tab welding are avoided, and the welding yield is improved while the battery capacity is improved.

Description

Technical Field

[0001] This application relates to the technical field of soft-pack batteries, and particularly to a bipolar group tab welding structure, a bipolar group, a soft-pack battery, and an energy storage device. Background Art

[0002] Taking the bipolar group battery cell as an example in the multi-pole group process, two battery cells are placed in a single housing after being connected in parallel. The multi-pole group structure makes more reasonable use of space, increases the battery capacity, and enhances the battery life accordingly, meeting the increasing demand of future customers for the battery life of lithium-ion new energy. Currently, multi-pole group processes such as two-pole groups and four-pole groups have been realized for square lithium batteries.

[0003] However, due to the limitations of the current welding process conditions, soft-pack batteries still exist in the single-pole group battery mode. Some soft-pack batteries meet the high-capacity requirements by connecting traditional batteries in parallel, but problems such as inconsistent parallel connection of batteries are likely to occur, and the material consumption is also higher than that of bipolar group batteries, making them less competitive in terms of cost. Some soft-pack batteries meet the high-capacity requirements by increasing the battery thickness (relying on the aluminum-plastic film forming process and packaging process). However, the current tab welding process can reach a maximum of 100 layers (positive electrode + negative electrode), and multi-layer tab welding not only easily causes safety problems such as metal spatter, but also reduces the welding quality, and problems such as false welding, welding wrinkles, and increased internal resistance are inevitable. Summary of the Utility Model

[0004] This application provides a bipolar group tab welding structure, a bipolar group, a soft-pack battery, and an energy storage device to solve the problem of low welding quality caused by easy occurrence of false welding, tearing, and wrinkles in multi-layer tab welding in the prior art.

[0005] On the one hand, this application provides a bipolar group tab welding structure for connecting a first pole group and a second pole group. The welding structure includes:

[0006] A first tab bundle formed on the first pole group;

[0007] A second tab bundle formed on the second pole group, arranged opposite to the first tab bundle;

[0008] Connecting tabs are arranged between the first tab bundle and the second tab bundle, having a first welding surface and a second welding surface arranged opposite to each other. The first welding surface is used for welding with the first tab bundle, and the second welding surface is used for welding with the second tab bundle.

[0009] In a possible design, the welding structure further includes:

[0010] A first protective sheet arranged on the side of the first tab bundle away from the connecting tabs;

[0011] A second protective sheet arranged on the side of the second tab bundle away from the connecting tabs.

[0012] In a possible design,

[0013] the thickness of the first tab bundle is equal to the thickness of the second tab bundle;

[0014] and / or, the thickness of the first protective sheet is equal to the thickness of the second protective sheet.

[0015] In a possible design, the first tab bundle is formed at a position on the end face of the first electrode group close to the connecting tab; the second tab bundle is formed at a position on the end face of the second electrode group close to the connecting tab.

[0016] In a possible design, the first tab bundle and the second tab bundle each include a plurality of tab pieces, and each tab piece includes a bent section and a welding section. The width of the welding section of the tab piece far from the connecting tab is greater than the width of the corresponding first protective sheet / second protective sheet.

[0017] In a possible design,

[0018] the first protective sheet and the second protective sheet are each a nickel strip;

[0019] and / or, the thicknesses of the first protective sheet and the second protective sheet are each 0.05 - 0.3 mm;

[0020] and / or, the thickness of the connecting tab is 0.2 - 0.8 mm.

[0021] In a possible design, the connecting tab includes:

[0022] a metal strip for welding with the first tab bundle and the second tab bundle;

[0023] a first film provided on one side of the metal strip;

[0024] a second film provided on the other side of the metal strip.

[0025] On the other hand, the present application also provides a bipolar group including the bipolar group tab welding structure as described above.

[0026] On another aspect, the present application also provides a soft-pack battery including the bipolar group as described above.

[0027] On yet another aspect, the present application also provides an energy storage device including the soft-pack battery as described above.

[0028] The beneficial effects of the present application are as follows:

[0029] The bipolar group tab welding structure of the present application makes the first tab bundle formed on the first pole group and the second tab bundle formed on the second pole group be arranged oppositely, and uses the connecting tab to connect the first tab bundle and the second tab bundle. Specifically, the connecting tab has a first welding surface and a second welding surface. By welding the first welding surface to the first tab bundle and the second welding surface to the second tab bundle, the welding of the first tab bundle and the second tab bundle is realized, thereby connecting the two pole groups and realizing the welding of the soft-pack bipolar group. Thus, the maximum forming depth of the aluminum-plastic film can be effectively utilized, and the battery capacity can be increased. At the same time, by increasing the connecting tab, the number of tab bundles welded at one time can be reduced, avoiding problems such as false soldering, tearing and wrinkling caused by too many layers of tab welding, and improving the welding yield while increasing the battery capacity. Compared with the traditional battery parallel structure, the bipolar group battery cell can save a set of positive and negative Tab sheets and a set of aluminum-plastic film on the straight material, and synchronously save a corresponding set of manufacturing processes, reducing the consumable cost on the basis of realizing the same-capacity battery.

[0030] The bipolar group provided by the present application includes all the above advantages of the bipolar group tab welding structure because it includes the bipolar group tab welding structure of the present application.

[0031] The soft-pack battery provided by the present application includes all the above advantages of the bipolar group because it includes the bipolar group of the present application.

[0032] The energy storage device provided by the present application includes all the above advantages of the soft-pack battery because it includes the soft-pack battery of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0034] Figure 1 It is a schematic structural diagram of the bipolar group tab welding structure provided by the embodiment of the present application;

[0035] Figure 2 It is a schematic structural diagram of the connecting tab of the bipolar group tab welding structure provided by the embodiment of the present application;

[0036] Figure 3 It is a front view of the connecting tab of the bipolar group tab welding structure provided by the embodiment of the present application;

[0037] Figure 4A schematic structural diagram of a first pole group of a bipolar group pole tab welding structure provided in an embodiment of the present application;

[0038] Figure 5 A schematic diagram of the structure of the first pole lug bundle of the first pole group of the bipolar group pole lug welding structure provided in an embodiment of the present application after being folded.

[0039] Reference numerals:

[0040] 100, first pole group; 110, first pole lug bundle; 200, second pole group; 210, second pole lug bundle; 300, connecting pole lug; 310, first welding surface; 320, second welding surface; 330, metal strip; 340, first film; 350, second film; 410, first protective sheet; 420, second protective sheet; 500, pole lug sheet; 510, bending section; 520, welding section. DETAILED DESCRIPTION

[0041] The technical solution of the present application will be described clearly and completely below in conjunction with the embodiments. 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 ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0042] Combine the following Figures 1 - 5 , describing the bipolar group tab welding structure provided in the embodiments of the present application.

[0043] Reference Figure 1 As shown, in the embodiment provided in the present application, the bipolar group tab welding structure is used to connect the first pole group 100 and the second pole group 200, and the welding structure includes a first tab bundle 110, a second tab bundle 210 and a connecting tab 300, wherein the first tab bundle 110 is formed on the first pole group 100; the second tab bundle 210 is formed on the second pole group 200, and the second tab bundle 210 is arranged opposite to the first tab bundle 110; the connecting tab 300 is arranged between the first tab bundle 110 and the second tab bundle 210, and the connecting tab 300 has a first welding surface 310 and a second welding surface 320 arranged opposite to each other, the first welding surface 310 is used to weld with the first tab bundle 110, and the second welding surface 320 is used to weld with the second tab bundle 210. Specifically, the first welding surface 310 is welded with the first tab bundle 110 by ultrasonic welding, and the second welding surface 320 is welded with the second tab bundle 210 by ultrasonic welding. In some specific embodiments, the thickness of the connecting tab 300 is 0.2-0.8 mm, for example, the thickness of the connecting tab 300 is 0.5 mm, 0.6 mm, etc. Figure 2 , Figure 3As shown, in some specific embodiments, the connecting tab 300 includes a metal strip 330, a first film 340, and a second film 350. The metal strip 330 is used for welding with the first tab bundle 110 and the second tab bundle 210. The first film 340 is disposed on one side of the metal strip 330. The second film 350 is disposed on the other side of the metal strip 330. Specifically, the first film 340 and the second film 350 respectively cover the middle positions of the metal strip 330, and both ends of the metal strip 330 are respectively exposed outside the first film 340 and the second film 350. The metal strip 330 is made of a metal material. One end of the metal strip 330 is used for welding with the first tab bundle 110 and the second tab bundle 210 respectively, and the other end of the metal strip 330 extends outside the aluminum-plastic film for the pole group to conduct electricity with the outside. The first film 340 and the second film 350 are respectively PP adhesives, which are used for bonding with the aluminum-plastic film after the connecting tab 300 is welded to the pole group.

[0044] Using the technical solution provided by the above embodiments, by arranging the first tab bundle 110 and the second tab bundle 210 oppositely, and connecting the first tab bundle 110 and the second tab bundle 210 with the connecting tab 300, by welding the first welding surface 310 with the first tab bundle 110 and the second welding surface 320 with the second tab bundle 210, the first tab bundle 110 and the second tab bundle 210 are respectively welded to the connecting tab 300, so as to connect two pole groups and realize the welding of the soft-pack double pole groups. Thus, the maximum forming depth of the aluminum-plastic film can be effectively utilized, and the battery capacity can be increased. At the same time, by adding the connecting tab 300, the number of tab bundles welded at one time can be reduced, and problems such as false soldering, tearing, and wrinkling caused by too many layers of tab welding can be avoided, and the welding yield can be improved while increasing the battery capacity. Compared with the traditional battery parallel structure, the bipolar cell can save a set of positive and negative Tab sheets and a set of aluminum-plastic film on the straight material, and simultaneously save a corresponding set of manufacturing processes, reducing the consumable cost on the basis of realizing the same-capacity battery.

[0045] Refer to Figure 1As shown, in some embodiments provided by the present application, the welding structure further includes a first protection sheet 410 and a second protection sheet 420. The first protection sheet 410 is disposed on a side of the first tab bundle 110 away from the connecting tab 300; the second protection sheet 420 is disposed on a side of the second tab bundle 210 away from the connecting tab 300. In some specific embodiments, the first protection sheet 410 and the second protection sheet 420 are nickel strips respectively; before welding the first tab bundle 110 or the second tab bundle 210 to the connecting tab 300, spot welding is first performed between the first tab bundle 110 and the first protection sheet 410, and between the second tab bundle 210 and the second protection sheet 420 respectively, so that the relative positions between the first protection sheet 410 and the first tab bundle 110, and between the second tab bundle 210 and the second protection sheet 420 are pre-fixed respectively, and then the first tab bundle 110 or the second tab bundle 210 is ultrasonically welded to the connecting tab 300; by performing electric welding between the first tab bundle 110 / the second tab bundle 210 and the corresponding first protection sheet 410 / second protection sheet 420 respectively, it can be ensured that the first tab bundle 110 and the second tab bundle 210 do not shift during subsequent ultrasonic welding with the connecting tab 300. At the same time, the first protection sheet 410 and the second protection sheet 420 can also reduce the friction generated by the vibration of the first tab bundle 110 and the second tab bundle 210 during the welding process, thereby reducing the probability of tearing of the first tab bundle 110 and the second tab bundle 210, improving the welding effect, and enhancing the welding quality and welding consistency.

[0046] Referring to Figure 1 As shown, in some embodiments provided by the present application, the thickness of the first tab bundle 110 is equal to the thickness of the second tab bundle 210. In this way, it is possible to reduce the number of layers of the tab sheets 500 corresponding to each pole group as much as possible, reduce the welding difficulty, and improve the welding quality; at the same time, by making the thickness of the first tab bundle 110 equal to the thickness of the second tab bundle 210, it is beneficial to make the forces on the first welding surface 310 and the second welding surface 320 of the connecting tab 300 equal, and it is beneficial to maintain a good connection strength after welding. In some of these embodiments, the thickness of the first protection sheet 410 is equal to the thickness of the second protection sheet 420, and the thicknesses of the first protection sheet 410 and the second protection sheet 420 are 0.05 - 0.3 mm respectively; for example, the thicknesses of the first protection sheet 410 and the second protection sheet 420 are 0.1 mm and 0.2 mm respectively. By making the thickness of the first protection sheet 410 equal to the thickness of the second protection sheet 420, it is beneficial to make the forces between the first protection sheet 410 and the first tab bundle 110, and between the second protection sheet 420 and the second tab bundle 210 balanced, and it is beneficial to maintain a good connection strength after welding.

[0047] It should be noted that the first tab bundle 110 and the second tab bundle 210 respectively include a plurality of tab sheets 500, and the tab sheets 500 are foils made of metal materials, and may be aluminum foil or copper foil according to the positive and negative electrode positions. Figure 4 As shown, multiple pole tabs 500 are arranged parallel to each other at the end of the pole group. Before welding, the multiple pole tabs 500 are first gathered to form a pole tab bundle, and then welded to the first protection sheet 410 / the second protection sheet 420 and the connecting pole tab 300 respectively.

[0048] Reference Figure 1 As shown, in some embodiments provided in the present application, the first pole tab bundle 110 is formed at a position of the end surface of the first pole group 100 close to the connecting pole tab 300; the second pole tab bundle 210 is formed at a position of the end surface of the second pole group 200 close to the connecting pole tab 300. In this way, when the first pole group 100 and the second pole group 200 are stacked up and down, the first pole tab bundle 110 and the second pole tab bundle 210 can just overlap with the connecting pole tab 300, which is conducive to welding the first pole tab bundle 110 and the second pole tab bundle 210 with the connecting pole tab 300.

[0049] Reference Figure 5 As shown, in some embodiments provided in the present application, the first tab bundle 110 and the second tab bundle 210 respectively include a plurality of tab sheets 500, and the plurality of tab sheets 500 are formed into two sections in the process of being pressed into the tab bundle, so that each tab sheet 500 includes a bending section 510 and a welding section 520, wherein the width of the welding section 520 of the tab sheet 500 away from the connecting tab 300 is greater than the width of the corresponding first protection sheet 410 / second protection sheet 420. By making the width of the outermost tab sheet 500 greater than the width of the corresponding first protection sheet 410 / second protection sheet 420, the first protection sheet 410 / second protection sheet 420 can be completely contacted with the outermost tab sheet 500 for spot welding, thereby improving the firmness of the connection between the first protection sheet 410 / second protection sheet 420 and the tab sheet 500, so that the protection sheet is not easily offset.

[0050] The welding process of the bipolar group tab welding structure provided in the embodiment of the present application is as follows:

[0051] The tab sheets 500 on the first pole group 100 and the second pole group 200 are respectively bent toward one side and then flattened to form a first tab bundle 110 and a second tab bundle 210 that are gathered toward one side;

[0052] The first pole group 100 and the second pole group 200 are stacked up and down, so that the first pole tab bundle 110 and the second pole tab bundle 210 are arranged opposite to each other;

[0053] Spot weld the first protective sheet 410 to the side of the first tab bundle 110 away from the second electrode group 200, and spot weld the second protective sheet 420 to the side of the second tab bundle 210 away from the first electrode group 100;

[0054] Place the connecting tab 300 between the first tab bundle 110 and the second tab bundle 210. After ultrasonic welding the first welding surface 310 of the connecting tab 300 to the first tab bundle 110, then ultrasonic weld the second welding surface 320 of the connecting tab 300 to the second tab bundle 210.

[0055] An embodiment of the present application also provides a bipolar group, including the bipolar group tab welding structure in the above embodiment.

[0056] An embodiment of the present application also provides a soft-pack battery, including the bipolar group in the above embodiment.

[0057] An embodiment of the present application also provides an energy storage device, including the soft-pack battery in the above embodiment. Specifically, the energy storage device can be a vehicle, a working machine, etc.

[0058] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application 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 therefore should not be construed as a limitation to the present application.

[0059] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, the meaning of "plural" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0060] In this application, unless otherwise clearly specified and defined, terms such as "installed", "connected", "linked", "fixed", etc. shall 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, an electrical connection, or communicable with each other; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0061] In this application, terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of this application. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0062] Although the embodiments of this application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limitations on this application. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A bipolar group tab welding structure, characterized in that: Used to connect the first pole group and the second pole group, the welding structure includes: A first pole lug bundle is formed on the first pole group; A second pole lug bundle is formed on the second pole group and is arranged opposite to the first pole lug bundle; The connecting tab is arranged between the first tab bundle and the second tab bundle, and has a first welding surface and a second welding surface arranged opposite to each other, wherein the first welding surface is used for welding with the first tab bundle, and the second welding surface is used for welding with the second tab bundle.

2. The bipolar group tab welding structure according to claim 1, characterized in that: Also includes: A first protective sheet, arranged on a side of the first tab bundle away from the connecting tab; The second protection sheet is arranged on a side of the second pole tab bundle away from the connecting pole tab.

3. The bipolar group tab welding structure according to claim 2, characterized in that: The thickness of the first pole tab bundle is equal to the thickness of the second pole tab bundle; And / or, the thickness of the first protection sheet is equal to the thickness of the second protection sheet.

4. The bipolar group tab welding structure according to claim 3, characterized in that: The first pole tab bundle is formed at a position close to the connecting pole tab on the end surface of the first pole group; the second pole tab bundle is formed at a position close to the connecting pole tab on the end surface of the second pole group.

5. The bipolar group tab welding structure according to claim 4, characterized in that: The first pole tab bundle and the second pole tab bundle respectively include a plurality of pole tab sheets, each of the pole tab sheets respectively includes a bending section and a welding section, and the width of the welding section of the pole tab sheet away from the connecting pole tab is greater than the width of the corresponding first protective sheet / the second protective sheet.

6. The bipolar group tab welding structure according to any one of claims 2 to 5, characterized in that: The first protection sheet and the second protection sheet are nickel strips respectively; And / or, the thickness of the first protection sheet and the second protection sheet is 0.05-0.3 mm respectively; And / or, the thickness of the connecting tab is 0.2-0.8 mm.

7. The bipolar group tab welding structure according to any one of claims 1 to 5, characterized in that: The connecting tab comprises: A metal strip, used for welding with the first pole tab bundle and the second pole tab bundle; A first film is disposed on one side of the metal belt; The second film is arranged on the other side of the metal belt.

8. A bipolar group, characterized in that: The invention comprises the bipolar group tab welding structure according to any one of claims 1 to 7.

9. A soft pack battery, characterized in that: Comprising the bipolar group as claimed in claim 8.

10. An energy storage device, characterized in that: Including the soft pack battery as described in claim 9.

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