Laser welding of electrode external tabs to internal terminals of battery cells

Abstract

A method for manufacturing a battery cell includes: providing a stack including C cathode electrodes, each cathode electrode including a cathode current collector, a cathode active layer, and an external tab extending from the cathode current collector; a anode electrodes including an anode current collector, an anode active layer, and an external tab extending from the anode current collector; and S diaphragms. The method includes providing a terminal including a first portion connected to a second portion at a predetermined angle less than or equal to 100 DEG; positioning an external tab of one of the A anode electrodes and the C cathode electrodes in contact with one of the inner surface and the outer surface of the first portion of the terminal; and laser welding an end portion of the external tab to one of the inner surface and the outer surface of the first portion of the terminal.

Description

Technical Field

[0001] The present disclosure relates to battery cells, and more particularly to external tabs laser welded to electrodes of internal terminals of battery cells. Background Art

[0002] The information provided in this section is for the purpose of generally presenting the background of the present disclosure. To the extent described in this section, the work of the presently named inventors, and aspects of the description that may not otherwise constitute prior art at the time of filing, are neither explicitly nor implicitly admitted as prior art to the present disclosure.

[0003] Electric vehicles (EVs), such as battery electric vehicles (BEVs), hybrid vehicles, and / or fuel cell vehicles, include one or more motors and a battery system including one or more battery cells, modules, and / or battery packs. A power control system is used to control the charging and / or discharging of the battery system during charging and / or driving. Summary of the invention

[0004] A method for manufacturing a battery cell includes providing a stack including C cathode electrodes, each cathode electrode including a cathode current collector, a cathode active layer disposed on the cathode current collector, and an external tab extending from the cathode current collector; A anode electrodes including an anode current collector, an anode active layer disposed on the anode current collector, and an external tab extending from the anode current collector; and S separators, wherein C, S, and A are integers greater than 1. The method includes providing a terminal including a first portion connected to a second portion at a predetermined angle less than or equal to 100°; positioning the external tab of one of the A anode electrodes and the C cathode electrodes to contact one of an inner surface and an outer surface of the first portion of the terminal; and laser welding an end of the external tab to one of the inner surface and the outer surface of the first portion of the terminal.

[0005] In other features, the predetermined angle is in the range of 80° to 100°. The predetermined angle is in the range of 15° to 75°. The predetermined angle is in the range of 35° to 55°. The height of the first portion of the terminal is greater than or equal to the height of the stack.

[0006] In other features, the method includes disposing a gas release channel on the second portion and on one of the support surfaces disposed below the stack and the terminal. The gas release channel is disposed below an external tab of one of the A anode electrodes and the C cathode electrodes. The external tab of one of the A anode electrodes and the C cathode electrodes is laser welded to an outer surface of the terminal. The external tab of one of the A anode electrodes and the C cathode electrodes is laser welded to an inner surface of the terminal.

[0007] In other features, the second portion is "U" shaped, and the terminal further includes a third portion extending from the second portion. The second portion includes a gas release channel. The method includes cutting an external tab of one of the A anode electrodes and the C cathode electrodes at a predetermined angle prior to laser welding. The predetermined angle is within + / - 10° of an angle formed between the first portion and the second portion of the terminal.

[0008] In other features, laser welding is performed through a first portion of the terminal. The laser welding forms a butt weld between the terminal and an external tab of one of the A anode electrodes and the C cathode electrodes. The method includes pressing the external tab of one of the A anode electrodes and the C cathode electrodes against the terminal before laser welding. The method includes pressing the external tab of one of the A anode electrodes and the C cathode electrodes against the terminal, and clamping the stack to at least one of the terminal and a support surface during laser welding.

[0009] The battery cell includes a stack including C cathode electrodes, each cathode electrode including a cathode current collector, a cathode active layer disposed on the cathode current collector, and an external tab extending from the cathode current collector; A anode electrodes including an anode current collector, an anode active layer disposed on the anode current collector, and an external tab extending from the anode current collector; and S separators, wherein C, S, and A are integers greater than 1. The battery cell includes a terminal including a first portion connected to a second portion at a predetermined angle less than or equal to 100°. The external tab of one of the A anode electrodes and the C cathode electrodes is laser welded to one of the inner surface and the outer surface of the first portion of the terminal.

[0010] In other features, the predetermined angle is in the range of 15° to 100°.

[0011] In other features, the gas release channel is arranged on the second portion. The gas release channel is arranged below an external tab of one of the A anode electrodes and the C cathode electrodes. The external tab of one of the A anode electrodes and the C cathode electrodes is cut at a predetermined angle, and the predetermined angle is within + / - 10° of an angle formed between the first portion and the second portion of the terminal.

[0012] The present invention provides the following technical solutions:

[0013] 1. A method for manufacturing a battery cell, comprising:

[0014] Provides stacking including:

[0015] C cathode electrodes, each cathode electrode comprising a cathode current collector, a cathode active layer disposed on the cathode current collector, and an external tab extending from the cathode current collector;

[0016] A anode electrode, the anode electrode comprising an anode current collector, an anode active layer disposed on the anode current collector, and an external tab extending from the anode current collector; and

[0017] S diaphragms, where C, S, and A are integers greater than 1; and

[0018] providing a terminal including a first portion connected to a second portion at a predetermined angle less than or equal to 100°;

[0019] positioning an external tab of one of the A anode electrodes and the C cathode electrodes in contact with one of the inner surface and the outer surface of the first portion of the terminal; and

[0020] An end of the external tab is laser welded to one of the inner and outer surfaces of the first portion of the terminal.

[0021] 2. The method according to Scheme 1, wherein the predetermined angle is in the range of 80° to 100°.

[0022] 3. The method according to claim 1, wherein the predetermined angle is in the range of 15° to 75°.

[0023] 4. The method according to scheme 1, wherein the predetermined angle is in the range of 35° to 55°.

[0024] 5. The method according to claim 1, wherein the first portion of the terminal has a height greater than or equal to a height of the stack.

[0025] 6. The method according to claim 1, further comprising:

[0026] Arranging a gas release channel on the second portion and on one of the support surfaces arranged below the stack and the terminal,

[0027] The gas release channel is arranged below the external terminal of one of the A anode electrodes and the C cathode electrodes.

[0028] 7. The method according to claim 1, wherein an external tab of one of the A anode electrodes and the C cathode electrodes is laser welded to an outer surface of the terminal.

[0029] 8. The method of claim 1, wherein an external tab of one of the A anode electrodes and the C cathode electrodes is laser welded to an inner surface of the terminal.

[0030] 9. The method according to claim 1, wherein:

[0031] The second part is "U" shaped, and

[0032] The terminal also includes a third portion extending from the second portion.

[0033] 10. A method according to Option 9, wherein the second portion includes a gas release channel.

[0034] 11. The method according to Option 1 further includes cutting an external tab of one of the A anode electrodes and the C cathode electrodes at a predetermined angle before laser welding.

[0035] 12. The method according to claim 11, wherein the predetermined angle is within + / - 10° of an angle formed between the first portion and the second portion of the terminal.

[0036] 13. The method according to claim 11, wherein the laser welding is performed through a first portion of the terminal.

[0037] 14. The method of claim 1, wherein the laser welding forms a butt weld between the terminal and an external tab of one of the A anode electrodes and the C cathode electrodes.

[0038] 15. The method according to Option 1 further includes pressing an external tab of one of the A anode electrodes and the C cathode electrodes against the terminal before laser welding.

[0039] 16. The method of claim 1 further comprising pressing an external tab of one of the A anode electrodes and the C cathode electrodes against the terminal and clamping the stack to at least one of the terminal and a support surface during laser welding.

[0040] 17. A battery cell comprising:

[0041] A stack, the stack comprising:

[0042] C cathode electrodes, each cathode electrode comprising a cathode current collector, a cathode active layer disposed on the cathode current collector, and an external tab extending from the cathode current collector;

[0043] A anode electrode, the anode electrode comprising an anode current collector, an anode active layer disposed on the anode current collector, and an external tab extending from the anode current collector; and

[0044] S diaphragms, where C, S, and A are integers greater than 1; and

[0045] a terminal comprising a first portion connected to a second portion at a predetermined angle less than or equal to 100°,

[0046] An external tab of one of the A anode electrodes and the C cathode electrodes is laser welded to one of the inner surface and the outer surface of the first portion of the terminal.

[0047] 18. The battery cell according to claim 17, wherein the predetermined angle is in the range of 15° to 100°.

[0048] 19. The battery cell according to claim 17, further comprising:

[0049] A gas release channel is provided on the second part,

[0050] The gas release channel is arranged below the external contact of one of the A anode electrodes and the C cathode electrodes.

[0051] 20. The battery cell according to claim 17, wherein:

[0052] The outer tab of one of the A anode electrodes and the C cathode electrodes is cut at a predetermined angle, and

[0053] The predetermined angle is within + / - 10° of an angle formed between the first portion and the second portion of the terminal.

[0054] Further areas of applicability of the present disclosure will become apparent from the detailed description, claims and drawings.The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The present disclosure will be more fully understood from the detailed description and accompanying drawings, in which:

[0056] Figure 1A is a side cross-sectional view of an example of a battery cell including a cathode electrode, an anode electrode, and a separator according to the present disclosure;

[0057] Figure 1B is a side view of an example of a pouch battery cell according to the present disclosure;

[0058] Figure 1C is a perspective view of an example of a square battery according to the present disclosure;

[0059] Figure 1D is a side cross-sectional view of an example of an internal terminal and an external terminal of a square battery cell according to the present disclosure;

[0060] FIG. 2A to FIG. 2C is a perspective view of an example of an electrode stack arranged on and laser welded to an internal terminal according to the present disclosure;

[0061] FIG. 3A to FIG. 3B is a perspective view of another example of an electrode stack arranged on and laser welded to an internal terminal according to the present disclosure;

[0062] FIG. 4A to FIG. 4Bis a perspective view of another example of an electrode stack arranged on and laser welded to an internal terminal having a gas release channel according to the present disclosure;

[0063] FIG. 5A to FIG. 5E is a perspective view of another example of an electrode stack arranged on and laser welded to an internal terminal according to the present disclosure, the internal terminal including a first portion forming an acute angle with respect to a second portion;

[0064] Figure 6 is a side view of an example of an electrode stack having one end trimmed to an acute angle according to the present disclosure; and

[0065] Figure 7 is a side view of an example of an internal terminal having a first portion forming a predetermined angle relative to a second portion of the internal terminal and an electrode stack trimmed at substantially the same angle according to the present disclosure.

[0066] Among the drawings, reference numerals may be repeated to identify similar and / or identical elements. DETAILED DESCRIPTION

[0067] Although battery cells according to the present disclosure are illustrated in the context of electric vehicles, the battery cells may be used in stationary applications and / or other applications.

[0068] The present disclosure solves the quality problem of welding between the external tabs extending from the current collectors of the anode and / or cathode electrodes and the terminals of the battery cell. In some examples, the battery cell includes a soft pack battery cell, which includes a terminal that is laser welded to the external tabs and extends through the pouch-shaped housing. In some examples, in a square battery cell, the internal terminals of the battery cell are in contact with the external terminals of the battery cell. In other words, the external terminals are in contact with the internal terminals of the external tabs that are laser welded to the cathode electrode and / or the anode electrode. It is understood that the respective internal terminals are used to connect to the cathode electrode and the anode electrode.

[0069] When welding multiple layers of external tabs (e.g., external tabs extending from a current collector made of foil) in a lap joint, the weld may be porous and separation may occur at the fusion boundary. The present disclosure relates to connecting external tabs of current collectors of anode electrodes and / or cathode electrodes to internal terminals using laser welding with improved weld quality. In some examples, laser welding is performed without the need to use ultrasonic welding.

[0070] Reference now Figure 1A, the battery cell 10 includes C cathode electrodes 20, A anode electrodes 40, and S separators 32, which are arranged in a predetermined order in a stack 12 arranged in a housing 50. The cathode electrodes 20-1, 20-2, ..., and 20-C (where C is an integer greater than 1) include a cathode active layer 24 arranged on one side or both sides of a cathode current collector 26. The anode electrodes 40-1, 40-2, ..., and 40-A (where A is an integer greater than 1) include an anode active layer 42 arranged on one side or both sides of an anode current collector 46. The external tab corresponds to a portion of the current collector that extends beyond the active material layer.

[0071] In some examples, the anode active layer 42 and / or the cathode active layer 24 comprises a coating comprising one or more active materials, one or more conductive fillers / additives, and / or one or more binder materials. In some examples, the battery cell and / or electrode is manufactured by applying a slurry to coat the current collector in a roll-to-roll manufacturing process. In some examples, the cathode current collector 26 and the anode current collector 46 comprise a foil layer. In some examples, the current collector is made of one or more materials selected from the group consisting of copper, stainless steel, brass, bronze, zinc, aluminum, and alloys thereof.

[0072] Reference now Figure 1B , the soft pack battery cell 52 includes a pouch-shaped housing 53, which includes a stack 56. As will be further described below, external tabs 57 of the anode and cathode electrodes are laser welded to terminals 54 and 55 extending through the pouch-shaped housing 53, respectively.

[0073] Reference now Figure 1C , the square battery cell 58 includes a housing 60. Although a square battery cell is shown for illustrative purposes, other battery cell form factors may be used. In some examples, the housing 60 has a rectangular cross-section in the x-axis, y-axis, and z-axis planes. The square battery cell 58 includes external terminals 62 and 64 and a vent cover 66. A stack 12 of C cathode electrodes 20, A anode electrodes 40, and S separators 32 is arranged in the housing 60. As will be further described below, the external tabs of the anode current collector and / or cathode current collector are laser welded to the corresponding internal terminals. The internal terminals are arranged to contact the external terminals 62 and 64 of the battery cell 10.

[0074] Reference now Figure 1D , internal terminals 84 and 86 are shown in housing 60. Stack 12 of A anode electrodes and C cathode electrodes includes external tabs 88 laser welded to internal terminals 84 and 86, respectively, as will be further described below.

[0075] Reference now FIG. 2A to FIG. 2C, shows an example of a method of attaching external tabs of anode and / or cathode electrodes to internal terminals. Figure 2A In the embodiment, the stack 110 (eg, A anode electrodes, C cathode electrodes, and S separators) is arranged in an adjacent position relative to the internal terminal 114. The external tabs 120 of the anode and / or cathode electrodes are laser welded to the internal terminal 114.

[0076] In some examples, the internal terminal 114 includes a first portion 116 and a second portion 118. In some examples, the first portion 116 is attached to the second portion 118 at a predetermined angle in the range of 80° to 100° (e.g., 90°). In some examples, the first portion 116 has a height extending generally transverse to the longitudinal direction of the second portion 118. In some examples, the height of the first portion 116 is greater than or equal to the height of the stack 110. The longitudinal length of the second portion can be longer or shorter than the length of the stack 110.

[0077] In some examples, the A anode electrodes or C cathode electrodes in the stack 110 include one or more external tabs 120 (extending from the current collector beyond the active material layer 124). In some examples, the external tabs 120 extend the entire width of the electrode, current collector, and / or internal terminal. In other examples, the external tabs 120 extend only partially along the width of the electrode, current collector, and / or internal terminal. In other examples, each current collector includes two or more external tabs that are separated or notched (e.g., separated by a gap) and are laser welded to the internal terminal to provide redundant connections as described below.

[0078] exist Figure 2B and 2C In FIG. 1 , laser 130 is used to weld external tab 120 to inner surface 131 of first portion 116. Figure 2C In the embodiment shown in FIG. 1 , a butt weld 134 is formed between the outer tab 120 and the inner surface 131 of the first portion 116 .

[0079] Reference now FIG. 3A to FIG. 3B , the internal terminals may have other configurations and / or the external tabs 120 may be welded to the internal terminals in other orientations. Figure 3A , the internal terminal 144 includes a first portion 146 and a second portion 148. In some examples, the first portion 146 is attached to the second portion 148 at a predetermined angle in the range of 80° to 100° (e.g., 90°). In some examples, the height of the first portion 146 is greater than or equal to the height of the stack 110. The longitudinal length of the second portion 148 can be longer or shorter than the length of the stack 110.

[0080] exist Figure 3A, the internal terminal 144 is arranged on the support surface 149, wherein the second portion 148 extends away from the stack 110. The external tab 120 is arranged in contact with the outer surface 147 of the first portion 146. The external tab 120 is butt welded to the outer surface 147 of the first portion 146 using a laser.

[0081] exist Figure 3B , the internal terminal 150 includes a first portion 152, a second portion 154, and a third portion 156. In some examples, the first portion 152 is attached to the second portion 154 at a predetermined angle in the range of 80° to 100° (e.g., 90°). The second portion 154 is in a "U" shape. In other words, the second portion 154 folds back on itself to form a "U" shape with minimal or no gap between its sides. One end of the second portion 154 extends from the first portion 152. The third portion 156 extends from the other end of the second portion 154. The first portion 152 forms an angle relative to one side of the second portion 154. The second portion 154 extends a first predetermined distance, bends 180°, extends a second predetermined distance, and is connected to the third portion 156. The longitudinal length of the third portion 156 may be longer or shorter than the length of the stack 110. In some examples, during laser welding, the stack 110 may be arranged on a support surface 157.

[0082] Reference now FIG. 4A to FIG. 4B The gas release channel can be used to release welding gases generated during laser welding. In some examples, the gas release channel includes a concave channel extending under the internal terminal and / or the external tab to allow welding gases to escape during laser welding. Figure 4A middle, Figure 3A The internal terminal 144 of the stack 110 is welded to the external tab 120 of the stack 110. The support surface 180 includes a gas release channel 184 disposed below the external tab 120 and adjacent to the outer surface of the first portion 146.

[0083] exist Figure 4B In the embodiment, the internal terminal 200 includes a first portion 202, a second portion 204 and a third portion 206 (e.g., similar to Figure 3B The second portion 204 further includes a gas release channel 208 disposed below the external tab 120 and adjacent to the outer surface of the first portion 202 .

[0084] Reference now FIG. 5A to FIG. 5E , the internal terminal 220 includes a first portion 222 that forms an acute angle relative to the second portion 224. In some examples, the acute angle is within a predetermined range between 15° and 75°. In some examples, the acute angle is within a predetermined range between 35° and 55° (e.g., 45°). Figure 5AIn the embodiment, the stack 110 is arranged on the second portion 224 and is laterally pressed against the inner surface of the first portion 222 as shown by arrow 221. The lateral pressure on the stack 110 on the first portion 202 causes the electrodes higher in the stack to bend and creates spaces between the layers of the stack. The excess length of the upper electrode layers compensates for welding shrinkage. The spaces created between the upper electrode layers of the stack also provide a path for welding gases to escape during laser welding. Alternatively, a gas release channel can be created in the second portion of the internal terminal and / or on the support surface.

[0085] In some examples, during laser welding, after applying lateral pressure to hold the stack against the inner terminals, a clamp 226 may be used to apply pressure to the stack 110, such as Figure 5B and 5C shown.

[0086] exist Figure 5D In the embodiment, the internal terminal 250 includes a first portion 252, a second portion 254 and a third portion 256 (e.g., similar to Figure 3B ). In some examples, the first portion 252 is attached to the second portion 254 at a predetermined angle in the range of 15° to 75°. In other examples, the predetermined angle is in the range of 35° to 55° (e.g., 45°). The second portion 254 folds back on itself to form a "U" shape with minimal or no gap between its sides. One end of the second portion 254 extends from the first portion 252. The third portion 256 extends from the second portion 254. The longitudinal length of the third portion 256 can be longer or shorter than the length of the stack 110. In some examples, the stack 110 can be arranged on the support surface 157 during laser welding.

[0087] exist Figure 5E , the second portion 254 of the inner terminal 250 includes a gas release channel 270 disposed below the outer tab 120 and adjacent to the outer surface of the first portion 202 .

[0088] Reference now Figure 6 , stack 310 includes an anode electrode or a cathode electrode having an external tab 312 extending from a corresponding current collector. The external tab 312 is trimmed at one end to an acute angle. In some examples, the external tab 312 is trimmed to an acute angle that is approximately the same as the angle formed between the first and second portions of the internal terminal. As used herein, approximately the same acute angle means within + / -5° or + / -10°.

[0089] Reference now Figure 7, the internal terminal 330 includes a first portion 332 and a second portion 334. In some examples, the internal terminal 330 and / or the stack 110 are arranged on a support surface 338. The first portion 332 forms an acute angle relative to the second portion 334. The stack 310 includes an external tab 312 trimmed at an acute angle. The laser 130 welds the external tab 312 to the first portion 332 through the first portion 332.

[0090] The foregoing description is merely illustrative in nature and is in no way intended to limit the present disclosure, its application or use. The broad teachings of the present disclosure can be implemented in a variety of forms. Therefore, although the present disclosure includes specific examples, the true scope of the present disclosure should not be so limited, because after studying the drawings, the specification and the appended claims, other modifications will become apparent. It should be understood that one or more steps in the method can be performed in different orders (or simultaneously) without changing the principles of the present disclosure. In addition, although each embodiment is described as having certain features above, any one or more of those features described with respect to any embodiment of the present disclosure can be implemented in any other embodiment and / or combined with the features of any other embodiment, even if the combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and the replacement of one or more embodiments with each other is still within the scope of the present disclosure.

[0091] The spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including "connected," "engaged," "coupled," "adjacent," "immediately adjacent," "on top of," "above," "below," and "disposed." Unless explicitly described as "direct," when describing a relationship between a first element and a second element in the above disclosure, the relationship may be a direct relationship in which no other intermediate elements exist between the first element and the second element, but may also be an indirect relationship in which one or more intermediate elements (spatially or functionally) exist between the first element and the second element. As used herein, the phrase at least one of A, B, and C should be interpreted to mean a logical (A or B or C) using a non-exclusive logical "or," and should not be interpreted to mean "at least one of A, at least one of B, and at least one of C."

[0092] In the drawings, the direction of the arrows (as indicated by the arrows) generally indicates the flow of information (such as data or instructions) of interest to the diagram. For example, when component A and component B exchange various information, but the information sent from component A to component B is relevant to the diagram, the arrow may point from component A to component B. This unidirectional arrow does not mean that no other information is sent from component B to component A. In addition, for information sent from component A to component B, component B may send a request for the information or a confirmation of receipt of the information to component A.

Claims

1. A method for manufacturing a battery cell, comprising: Provides stacking including: C cathode electrodes, each cathode electrode comprising a cathode current collector, a cathode active layer disposed on the cathode current collector, and an external tab extending from the cathode current collector; A anode electrode, the anode electrode comprising an anode current collector, an anode active layer disposed on the anode current collector, and an external tab extending from the anode current collector; and S diaphragms, where C, S, and A are integers greater than 1; and providing a terminal including a first portion connected to a second portion at a predetermined angle less than or equal to 100°; positioning an external tab of one of the A anode electrodes and the C cathode electrodes in contact with one of the inner surface and the outer surface of the first portion of the terminal; and An end of the external tab is laser welded to one of the inner and outer surfaces of the first portion of the terminal.

2. The method according to claim 1, wherein: The predetermined angle is in the range of 80° to 100°. The method according to claim 1 , wherein the predetermined angle is in the range of 15° to 75°. The method according to claim 1 , wherein the predetermined angle is in the range of 35° to 55°. The method of claim 1 , wherein the first portion of the terminal has a height greater than or equal to a height of the stack.

6. The method according to claim 1, further comprising: Arranging a gas release channel on the second portion and on one of the support surfaces arranged below the stack and the terminal, The gas release channel is arranged below the external terminal of one of the A anode electrodes and the C cathode electrodes. 7 . The method of claim 1 , wherein an external tab of one of the A anode electrodes and the C cathode electrodes is laser welded to an outer surface of the terminal.

8. The method of claim 1, wherein an external tab of one of the A anode electrodes and the C cathode electrodes is laser welded to an inner surface of the terminal.

9. The method according to claim 1, wherein: The second part is "U" shaped, and The terminal also includes a third portion extending from the second portion.

10. The method of claim 9, wherein the second portion comprises a gas release channel.

Images