Battery cell capable of preventing inverted insertion of tabs

Abstract

The utility model provides a battery cell capable of preventing a tab from being reversely inserted, and belongs to the field of new energy batteries. The battery cell capable of preventing the tabs from being inversely inserted comprises a connecting piece and a core bag, the connecting piece is strip-shaped and is provided with a welding part, and the welding part is arranged on one side face of the connecting piece in a protruding mode and is arranged in the length direction of the connecting piece. A plurality of tabs are led out of the top of the core package, the tabs are fixed through middle auxiliary welding so as to be stacked to form a first tab bundle and a second tab bundle, the tail ends of the first tab bundle and the second tab bundle are welded to the two ends of a welding part in the length direction respectively, and the second tab bundle is bent in an arc shape in the direction away from the first tab bundle; and the first tab bundle is bent towards the direction close to the second tab bundle and is attached to the second tab bundle. The technical problem of short service life caused by inverted insertion of a lead tab in a battery cell in the prior art can be solved.

Description

Technical Field

[0001] The utility model relates to the field of new energy batteries, in particular to a battery core capable of preventing a tab from being inverted. Background Art

[0002] As one of the current mainstream energy storage devices, lithium-ion batteries are widely used in new energy vehicles, various portable electronic devices and communication equipment. With the continuous progress in the field of lithium-ion batteries, especially the explosive development of the new energy vehicle industry, in order to ensure endurance, people have put forward higher requirements for the overall service life of lithium-ion batteries.

[0003] In the related technology, lithium-ion batteries usually use multiple cells stacked to form a module, and put them into a battery box to work together. A single cell usually includes a cover plate, a shell and a winding core arranged inside. The top of the internal winding core leads to the pole ear. As an important component of the battery cell, the pole ear is connected to the winding core pole piece inside and the pole column outside. It is an important bridge for current transmission. The pole ear is usually welded to the pole column on the cover plate through a connecting piece.

[0004] For traditional battery cells in related technologies, the length of the internal tabs is still a great challenge. Tabs that are too long are prone to bending during the rolling process, and tabs that are too short are affected by the vibration of the battery cell after welding, causing the tabs to break. In order to maximize the capacity of current batteries, the gap between the internal winding core and the top cover is very small, which means that there is very little space to accommodate the tabs. After the tabs are folded and welded to the connecting sheet, they are easily compressed when the battery cell vibrates up and down, and inserted into the winding core below, causing a short circuit, which affects the service life of the battery cell. Utility Model Content

[0005] The embodiment of the utility model provides a battery cell that prevents the lead tab from being inverted, which can solve the technical problem of short service life caused by the lead tab being inverted in the battery cell in the prior art. The technical solution is as follows:

[0006] The utility model provides a battery cell for preventing the tab from being inverted, comprising: a connecting piece and a core package.

[0007] The connecting piece is in the shape of an elongated strip and is provided with a welding portion, wherein the welding portion is protrudingly provided on a side surface of the connecting piece and arranged along the length direction of the connecting piece;

[0008] A plurality of pole tabs are led out from the top of the core package, and the plurality of pole tabs are fixed by auxiliary welding in the middle to be stacked to form a first pole tab bundle and a second pole tab bundle, wherein the end of the first pole tab bundle is welded to one end of the welding portion in the length direction, and the end of the second pole tab bundle is welded to the other end of the welding portion in the length direction, and the second pole tab bundle is bent in an arc shape away from the first pole tab bundle, and the first pole tab bundle is bent in a direction close to the second pole tab bundle and is in contact with the second pole tab bundle.

[0009] Optionally, a first auxiliary weld mark is formed by welding in the middle of the first tab bundle, and a second auxiliary weld mark is formed by welding in the middle of the second tab bundle, and the thickness of the first auxiliary weld mark and the second auxiliary weld mark is greater than the thickness of the tab.

[0010] Optionally, ends of the first electrode tab bundle and the second electrode tab bundle are pre-welded and fixed.

[0011] Optionally, the length of the pole lug ranges from 10 to 60 mm, and the width of the pole lug ranges from 15 to 85 mm.

[0012] Optionally, the width of the first auxiliary weld mark and the second auxiliary weld mark ranges from 0.05 to 0.5 mm.

[0013] Optionally, the number of pole tabs in the first pole tab bundle and the second pole tab bundle is greater than or equal to 5.

[0014] Optionally, it further comprises a shell and a cover plate, wherein the core package is installed in the shell, the cover plate is covered on the shell, a pole is arranged on the cover plate, and the connecting piece is connected to the pole.

[0015] Optionally, an insulating plastic part is provided on the cover plate, a limit block is protruding from one side of the insulating plastic part close to the core package, a through groove is provided on the limit block along the length direction of the connecting piece, and the second pole lug bundle is passed through the through groove.

[0016] The beneficial effects brought by the technical solution provided by the embodiment of the utility model include at least:

[0017] The battery cell with anti-inverted tab insertion provided by the embodiment of the utility model improves the connection structure between the tabs led out from the core package in the traditional battery cell and the connecting piece. The multiple tabs led out from the top of the core package are pre-welded, and after the multiple tabs are evenly distributed, they are ultrasonically welded respectively, so that the two tabs are stacked into a first tab bundle and a second tab bundle, and are preliminarily fixed by the middle. After that, the first tab bundle and the second tab bundle are over-current welded to the connecting piece, and the two ends of the welding part of the single connecting piece are respectively connected, so that there is a certain interval between the first tab bundle and the second tab bundle. After the core package is put into the shell, the connecting piece will produce downward extrusion on the first tab bundle and the second tab bundle. Before entering the shell, the first tab bundle and the second tab bundle are pre-bent to a certain extent. After bending, the first tab bundle is embedded in the inner side of the bending opening of the second tab bundle and adheres to it. When the battery cell is working subsequently, when it is subjected to the pressure of longitudinal vibration, the second pole ear bundle located on the outside can provide support force to the bottom of the first pole ear bundle nested on the inside, and support its bent middle section, which is located directly below the welding part and is mainly under pressure, to avoid the bent multiple pole ears from tilting downward as a whole and contacting and inverting with the bottom core package, which can solve the technical problem of low service life caused by inverted insertion of the lead ears inside the battery cell in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 This is a schematic diagram of the internal structure of a battery cell that prevents inverted tab insertion provided by an embodiment of the utility model;

[0020] Figure 2 It is a schematic diagram of preparing a battery cell for preventing inverted tab insertion provided by an embodiment of the utility model;

[0021] Figure 3 It is a schematic diagram of the connection structure between the first tab bundle and the connecting sheet on the core package provided by an embodiment of the utility model;

[0022] Figure 4 It is a schematic diagram of the connection structure between the second tab bundle and the connecting sheet on the core package provided by an embodiment of the utility model.

[0023] In the figure: 1-connecting piece; 2-core package; 3-shell; 4-cover plate; 11-welding part; 21-ear; 211-first ear bundle; 212-second ear bundle; 41-insulating plastic part; 411-limiting block; 2111-first auxiliary welding mark; 2121-second auxiliary welding mark; 4111-through groove; a-first auxiliary welding head; b-second auxiliary welding head. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention more clear, the implementation mode of the present invention will be further described in detail below with reference to the accompanying drawings.

[0025] In the related technology, lithium-ion batteries usually use multiple cells stacked to form a module, and put them into a battery box to work together. A single cell usually includes a cover plate, a shell and a winding core arranged inside. The top of the internal winding core leads to the pole ear. As an important component of the battery cell, the pole ear is connected to the winding core pole piece inside and the pole column outside. It is an important bridge for current transmission. The pole ear is usually welded to the pole column on the cover plate through a connecting piece.

[0026] For traditional battery cells in related technologies, the length of the internal tabs is still a great challenge. Tabs that are too long are prone to bending during the rolling process, and tabs that are too short are affected by the vibration of the battery cell after welding, causing the tabs to break. In order to maximize the capacity of current batteries, the gap between the internal winding core and the top cover is very small, which means that there is very little space to accommodate the tabs. After the tabs are folded and welded to the connecting sheet, they are easily compressed when the battery cell vibrates up and down, and inserted into the winding core below, causing a short circuit, which affects the service life of the battery cell.

[0027] Figure 1 This is a schematic diagram of the internal structure of a battery cell that prevents inverted tab insertion provided by an embodiment of the utility model; Figure 2 It is a schematic diagram of preparing a battery cell for preventing inverted tab insertion provided by an embodiment of the utility model;

[0028] Figure 3 It is a schematic diagram of the connection structure between the first tab bundle and the connecting sheet on the core package provided by an embodiment of the utility model; Figure 4 Schematic diagram of the connection structure between the second tab bundle and the connecting sheet on the core package provided by the embodiment of the utility model. Figures 1 to 4 A battery cell for preventing inverted tab insertion is shown, comprising a connecting piece 1 and a core package 2.

[0029] The connecting piece 1 is in the shape of an elongated strip and is provided with a welding portion 11 . The welding portion 11 is protrudingly provided on a side surface of the connecting piece 1 and is arranged along the length direction of the connecting piece 1 .

[0030] Multiple tabs 21 are led out from the top of the core package 2, and the multiple tabs 21 are fixed by auxiliary welding in the middle to stack and form a first tab bundle 211 and a second tab bundle 212. The end of the first tab bundle 211 is welded to one end of the welding portion 11 in the length direction, and the end of the second tab bundle 212 is welded to the other end of the welding portion 11 in the length direction. The second tab bundle 212 is curved in an arc shape away from the first tab bundle 211, and the first tab bundle 211 is bent in a direction close to the second tab bundle 212 and is attached to the second tab bundle 212.

[0031] In the embodiment of the utility model, the cell structure improves the connection structure between the tabs 21 led out from the core pack 2 in the traditional cell and the connecting sheet 1. The top of the core pack 2 is led out, and the multiple tabs 21 to be connected to the same pole are pre-welded, wherein the multiple tabs 21 are divided into two groups due to the large number of tabs 21. For example, in the embodiment of the utility model, based on the size of the core pack 2 and the tabs 21 in the conventional cell, combined with the time, power and energy of the auxiliary ultrasonic welding, the tabs 21 used to connect to the same pole are usually set to be greater than or equal to 10 layers under the consideration and test of ensuring the quality and stability of the auxiliary welding, that is, the number of tabs 21 through auxiliary welding in the first tab bundle 211 and the second tab bundle 212 is greater than or equal to 5 layers. After the multiple tabs 21 are evenly distributed, the first auxiliary welding head a is used to press down and ultrasonically weld the two groups of tabs 21 from both sides of the multiple tabs, close to the lead-out root to the middle section, so that the two groups of tabs 21 are stacked into the first tab bundle 211 and the second tab bundle 212, and are initially fixed from the middle. After the two groups of tabs 21 are respectively bundled, the second auxiliary welding head b is used to pre-weld and fix the ends of the first tab bundle 211 and the second tab bundle 212, so as to pre-treat the ends of the first tab bundle 211 and the second tab bundle 212 for subsequent welding with the connecting piece 1, so as to avoid being in a loose state and improve the subsequent welding efficiency and welding stability. Then, the first pole lug bundle 211 and the second pole lug bundle 212 are over-current welded to the connecting piece 1, wherein the ends of the first pole lug bundle 211 and the second pole lug bundle 212 are respectively connected to the two ends of the welding portion 11 of a single connecting piece 1 by single-sided ultrasonic welding, so that there is a certain interval between the first pole lug bundle 211 and the second pole lug bundle 212. After the other side of the connecting piece 1 is welded to the pole on the battery cover 4, the core package 2 is put into the shell, and the cover 4 is covered, the connecting piece 1 follows the cover 4 to be pressed down, which will produce downward extrusion on the first pole lug bundle 211 and the second pole lug bundle 212. Before entering the shell, the first pole lug bundle 211 and the second pole lug bundle 212 are pre-bent to a certain extent, wherein the second pole lug bundle 212 is bent in an arc shape in the direction away from the first pole lug bundle 211. Here, the second pole lug bundle 212 is close to the side edge of the battery shell, and is biased toward the side of the core package 2 close to the shell. After bending, the second pole lug bundle 212 is in a "C" shape as a whole, and the opening of the "C" after bending faces the first pole lug bundle 211. The first pole lug bundle 211 is bent in the direction close to the second pole lug bundle 212. Here, since the top of the first pole lug bundle 211 is connected to the other end of the welding part 11, there is a certain distance between it and the top of the second pole lug bundle 212. In the bending process, there are two arc-shaped bending sections as a whole, which are in an "S" shape as a whole. After bending, the first pole lug bundle 211 is embedded in the inner side of the opening of the second pole lug bundle 212 and is attached to it.When the battery cell is working subsequently, when it is subjected to the pressure of longitudinal vibration, the second pole ear bundle 212 located on the outside can provide support force for the bottom of the first pole ear bundle 211 nested on the inside and bent twice, and support the bent middle section, that is, the part directly below the welding part 11, which is mainly under pressure, to prevent the bent pole ear 21 from tilting downward as a whole and contacting and inverting with the bottom core package 2, which can solve the technical problem of low service life caused by inverted insertion of the lead ear inside the battery cell in the prior art.

[0032] Optionally, the middle part of the first tab bundle 211 is welded to form a first auxiliary weld mark 2111, and the middle part of the second tab bundle 212 is welded to form a second auxiliary weld mark 2121, and the thickness of the first auxiliary weld mark 2111 and the second auxiliary weld mark 2121 is greater than the thickness of the tab 21. Exemplarily, in the embodiment of the utility model, when the auxiliary welding of the first tab bundle 211 and the second tab bundle 212 is performed to achieve the pre-fixation of the middle section, the first auxiliary weld mark 2111 and the second auxiliary weld mark 2121, which are thicker than the single-piece tab 21, are left. When bending subsequently, they can serve as the bending part of the first tab bundle 211 toward the second tab bundle 212, and the bending part of the second tab bundle 212 away from the outer side of the first tab bundle 211, to guide the pre-bending process and improve the preparation efficiency. After bending and sticking together, the first auxiliary weld mark 2111 and the second auxiliary weld mark 2121 located at the bending position will respectively give the first pole ear bundle 211 and the second pole ear bundle 212 an internal stress F1 and F2 along the bending direction, and the direction of the internal stress follows the main direction of the bending, and the whole is horizontally toward the outside of the core package 2, so that the multiple pole ears 21 as a whole remain bent to one side in the horizontal direction, avoiding downward tilting and inverted insertion due to longitudinal vibration, and further improving the anti-inverted insertion capability.

[0033] Optionally, the length of the pole lug 21 ranges from 10 to 60 mm, and the width of the pole lug 21 ranges from 15 to 85 mm.

[0034] Optionally, the width of the first auxiliary weld mark 2111 and the second auxiliary weld mark 2121 ranges from 0.05 to 0.5 mm.

[0035] Optionally, the battery cell that prevents the inverted pole lug insertion also includes a shell 3 and a cover plate 4, the core package 2 is installed in the shell 3, the cover plate 4 is covered on the shell 3, the cover plate 4 is provided with a pole, and the connecting piece 1 is connected to the pole. The battery cell that prevents the inverted pole lug insertion provided by the embodiment of the utility model cooperates with the traditional battery cell shell structure, and after the connecting piece 1 and the pole on the cover plate 4 are connected to each other through current flow and sealed in the shell, when the battery cell is subsequently working, when it is subjected to the pressure of longitudinal vibration, the second pole lug bundle 211 located on the outside can provide support force to the bottom of the first pole lug bundle 211 nested inside and bent twice, and support the bent middle section, that is, the part directly below the welding part 11, which is mainly subjected to pressure, to prevent the bent pole lug 21 from tilting downward as a whole and contacting and inverting with the bottom core package 2, which is enough to solve the technical problem of low service life caused by the inverted insertion of the lead pole lug inside the battery cell in the prior art.

[0036] Optionally, an insulating plastic part 41 is provided on the cover plate 4, and a limit block 411 is protrudingly provided on one side of the insulating plastic part 41 close to the core package 2, and a through groove 4111 is provided on the limit block 411 along the length direction of the connecting piece 1, and the second pole lug bundle 212 is passed through the through groove 4111. Exemplarily, in the embodiment of the utility model, an insulating plastic part 41 is protrudingly provided below the cover plate 4, and its bottom end face abuts against the top of the core package 2 after the cover is closed to limit and fix the core package 2. At the same time, a limiting block 411 with a through groove 4111 is also provided near the connection between the second pole ear bundle 212 and the connecting plate 1. The section between the middle bending part and the top end of the second pole ear bundle 212 bent in a "C" shape can be inserted into the through groove 4111 while bending, so that the top of the second pole ear bundle 212 is limited, fixed and supported by the limiting block 411, further avoiding the overall downward deformation and inverted insertion of multiple pole ears 21 due to vibration, and further improving the anti-inverted insertion performance.

[0037] Unless otherwise defined, the technical terms or scientific terms used herein shall have the usual meanings understood by persons with ordinary skills in the field to which the utility model belongs. The words "first", "second" and similar words used in the specification and claims of the utility model patent application do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "one" do not indicate a quantity limitation, but indicate the existence of at least one. Words such as "include" or "comprise" mean that the elements or objects appearing before "include" or "comprise" include the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0038] The above description is only an optional embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A battery cell that prevents tab inversion, characterized in that: include: Connecting piece (1) and core package (2), The connecting piece (1) is in the shape of an elongated strip and is provided with a welding portion (11), wherein the welding portion (11) is protrudingly arranged on a side surface of the connecting piece (1) and is arranged along the length direction of the connecting piece (1); A plurality of pole lugs (21) are led out from the top of the core package (2), and the plurality of pole lugs (21) are fixed by auxiliary welding in the middle to be stacked to form a first pole lug bundle (211) and a second pole lug bundle (212); the end of the first pole lug bundle (211) is welded to one end of the welding portion (11) in the length direction, and the end of the second pole lug bundle (212) is welded to the other end of the welding portion (11) in the length direction; the second pole lug bundle (212) is bent in an arc shape in a direction away from the first pole lug bundle (211), and the first pole lug bundle (211) is bent in a direction close to the second pole lug bundle (212) and is in contact with the second pole lug bundle (212).

2. The battery cell for preventing the tab from being inverted according to claim 1, characterized in that: A first auxiliary weld mark (2111) is formed by welding in the middle of the first pole lug bundle (211), and a second auxiliary weld mark (2121) is formed by welding in the middle of the second pole lug bundle (212), and the thickness of the first auxiliary weld mark (2111) and the second auxiliary weld mark (2121) is greater than the thickness of the pole lug (21).

3. The battery cell for preventing the tab from being inverted according to claim 2, characterized in that: The ends of the first electrode tab bundle (211) and the second electrode tab bundle (212) are pre-welded and fixed.

4. The battery cell for preventing inverted tab insertion according to claim 2, characterized in that: The length of the pole lug (21) ranges from 10 to 60 mm, and the width of the pole lug (21) ranges from 15 to 85 mm.

5. The battery cell for preventing the tab from being inverted according to claim 4, characterized in that: The width of the first auxiliary weld mark (2111) and the second auxiliary weld mark (2121) ranges from 0.05 to 0.5 mm.

6. The battery cell for preventing inverted tab insertion according to claim 4, characterized in that: The number of the pole tabs (21) in the first pole tab bundle (211) and the second pole tab bundle (212) are both greater than or equal to 5.

7. The battery cell for preventing the tab from being inverted according to any one of claims 1 to 6, characterized in that: It also comprises a shell (3) and a cover plate (4), the core package (2) being installed in the shell (3), the cover plate (4) being arranged on the shell (3), a pole being arranged on the cover plate (4), and the connecting piece (1) being connected to the pole.

8. The battery cell for preventing tab inversion according to claim 7, characterized in that: An insulating plastic part (41) is provided on the cover plate (4), a limit block (411) is protruding from one side of the insulating plastic part (41) close to the core package (2), a through groove (4111) is provided on the limit block (411) along the length direction of the connecting piece (1), and the second pole lug bundle (212) is inserted into the through groove (4111).

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