Combined trimming and welding of electrode foil

Abstract

A method for manufacturing a battery cell having electrode foils protruding from a cell pouch includes positioning the cell pouch in a fixture such that a distal segment of the foils extends outwardly from the fixture. The method includes clamping the distal segment in a curvilinear guide clamp to taper the distal segment into an electrode foil stack and then translating the clamp toward the fixture a predetermined distance to displace the distal segment the predetermined distance. The method also includes trimming the distal segment using a trimming tool, positioning an ultrasonic welding horn and an anvil adjacent opposing surfaces of the stack, and ultrasonically welding the stack to a conductive lead tab using the ultrasonic welding horn to form a weld joint within the battery cell. The ultrasonic welding horn can be multi-faceted with different knurl patterns for performing different welding processes.

Description

Technical Field

[0001] This invention relates to a comprehensive trimming and welding of electrode foil. Background Technology

[0002] Electrochemical battery cells and battery packs constructed from these cells are used as direct current (DC) power sources in large-scale, high-power battery power systems. For example, electric vehicles include high-voltage propulsion battery packs with a suitable number of cylindrical, prismatic, or pouch-shaped battery cells. The battery pack is connected to a DC voltage bus and, during battery discharge mode, ultimately powers one or more electric propulsion motors and associated power electronics. During battery charging mode, charging current is supplied to the constituent battery cells of the battery pack, for example, from an external charging station or via onboard regeneration. Rechargeable lithium-ion batteries are specifically operated by allowing lithium ions to reversibly pass back and forth between separators and electrodes in this construction. The grouped battery cells can be connected in series or parallel using an electrical interconnect assembly that contains various electrical buses, cell sensing hardware, and the power electronics required to operate the battery pack.

[0003] Propulsion battery packs suitable for use with electric vehicles and other high-power battery power systems typically utilize the aforementioned lithium-ion battery chemistry, or other suitable chemistry such as nickel metal hydride, to generate the necessary electricity to power (or more) propulsion motors and other electrical components. A standard pouch-type lithium-ion cell typically consists of working electrode foils and a permeable separator, surrounded by an electrolyte material. The various battery components are collectively enclosed within an electrically insulating outer pouch. The corresponding positive and negative electrodes serve as the cathode and anode of the assembled battery cell. In a typical construction, stacks of thin electrode foils can be arranged within the enclosed cell body inside the outer pouch. These electrode foils are then internally soldered to conductive leads protruding from the pouch and ultimately soldered to busbars or other interconnecting components during battery pack construction. Summary of the Invention

[0004] This document discloses methods and systems for manufacturing electrochemical cell units for battery packs. In a possible embodiment, the cell unit has an outer bag containing a cell body, which in turn encloses and protects a thin metal electrode foil. The ends of the electrode foil protrude from the edges of the cell body. In particular, this technology relates to methods and systems for forming internal welds between various electrode foils and conductive lead sheets within this cell unit. Thus, the contemplated internal weld is "internal" in the sense that it is entirely within the volume of the outer bag, that is, the opposite of the "external weld" of lead sheets to the conductive busbars or interconnecting components of the battery pack as understood in the art. This teaching contemplates the improved execution of multiple conventionally sequential processes at a single workstation. For example, embodiments of the disclosed method combine clamping, optional pre-welding, electrode foil trimming, lead sheet placement, and main welding processes in one or more embodiments, wherein this single-station method is implemented by hardware innovations described below.

[0005] Specifically, optional hardware implementations include: (1) a one-step internal welding process that integrates the main welding and electrode foil trimming processes while eliminating the pre-welding process; and (2) a two-step welding process that integrates the pre-welding and electrode foil trimming processes followed by the main welding process. Hardware options for optimizing the above processes are also disclosed herein, including direct and / or indirect heating of various metals, i.e., lead sheets and / or electrode foils, of the anvil and / or the workpiece; using a “soft-touch” guide fixture with an optional integral air duct for gently guiding the electrode foil to the anvil and the accompanying welding corner or ultrasonic welding electrode; and actuators for removing the electrode foil a predetermined distance to reduce tension on the electrode foil.

[0006] This disclosure includes a method for manufacturing a battery cell having a plurality of electrode foils protruding from a cell body. The method may include positioning the cell body in a fixture such that distal segments of the electrode foils extend outward from the fixture, and clamping the distal segments of the electrode foils between the elastic polymer surfaces of a curved guide jig, thereby tapering the distal segments into an electrode foil stack. The method may further include translating the curved guide jig toward the fixture a predetermined distance, thereby displacing the distal segments a predetermined distance. As part of this embodiment, the method includes trimming a portion of the distal segments using a trimming tool, positioning an ultrasonic welding electrode and an anvil as opposing surfaces adjacent to the electrode foil stack, and ultrasonically welding the electrode foil stack to conductive lead sheets using the ultrasonic welding electrode, thereby forming a weld joint within the battery cell.

[0007] In one or more embodiments, the predetermined distance is less than about 1.0 millimeter (mm) and greater than about 0.10 mm.

[0008] The relative sections of the curved guide clamp can define corresponding airways, in which case the method can include guiding pressurized airflow through the corresponding airways and onto the distal section.

[0009] Another aspect of this disclosure includes heating the electrode foil stack, conductive lead sheet, and / or anvil via a heat source at a predetermined time before and / or simultaneously with ultrasonic welding of the electrode foil stack.

[0010] In some embodiments, the ultrasonic welding electrode is a multifaceted ultrasonic welding electrode with different knurling patterns on each respective side. In this case, positioning the ultrasonic welding electrode and the anvil as opposing surfaces of adjacent electrode foil stacks includes rotating the multifaceted ultrasonic welding electrode to present a predetermined one of the different knurling patterns of the adjacent electrode foil stacks.

[0011] In some implementations, the method is characterized by the absence of pre-welding of the electrode foils before the electrode foil stacks are ultrasonically welded to the conductive lead sheet.

[0012] Trimming a portion of the distal segment using a trimming tool can occur simultaneously or sequentially with the ultrasonic welding electrode foil being stacked onto the conductive lead sheet. Furthermore, the trimming tool can optionally be attached to the ultrasonic welding electrode. In this configuration, the method may include trimming a portion of the distal segment using the trimming tool while moving the ultrasonic welding electrode toward the anvil.

[0013] This document also discloses a workstation for manufacturing a battery cell having multiple electrode foils protruding from a cell body. The workstation includes: a fixing device configured to position the cell body in a predetermined orientation such that a distal segment of the electrode foil extends outward from the fixing device; and a curved guide jig configured to clamp the distal segment of the electrode foil therebetween, thereby tapering the distal segment into an electrode foil stack. The curved guide jig includes an elastic polymer surface. An actuator is configured to translate the curved guide jig towards the fixing device a predetermined distance of approximately 0.10 mm to approximately 1 mm, thereby displacing the distal segment by a predetermined distance. As part of this configuration, a trimming tool is operable to trim a portion of the distal segment. The workstation also includes an ultrasonic electrode and an anvil positioned opposite the ultrasonic electrode on adjacent opposing surfaces of the electrode foil stack. The ultrasonic electrode is configured to ultrasonically weld the electrode foil stack to conductive lead sheets, thereby forming a weld joint within the battery cell.

[0014] Another aspect of this disclosure includes a method for manufacturing a battery pack having multiple battery cells. Each respective battery cell has an electrode foil protruding from a cell pouch. The method according to an exemplary embodiment includes positioning the cell pouch in a fixing device such that a distal segment of the electrode foil extends outward from the fixing device, and then clamping the distal segment of the electrode foil between the elastic polymer surfaces of a curved guide jig, thereby tapering the distal segment into an electrode foil stack. The curved guide jig defines an air passage therein. The method may include guiding a pressurized airflow through the respective air passage and directing it onto the distal segment to maintain a planar arrangement of the electrode foil stack, and translating the curved guide jig toward the fixing device a predetermined distance, thereby displacing the distal segment by a predetermined distance, wherein the predetermined distance is configured to reduce tension on the electrode foil.

[0015] The method further includes trimming a portion of the distal section using a trimming tool, positioning the ultrasonic welding electrode and anvil as opposing surfaces adjacent to the electrode foil stack, such that the double-sided knurling pattern of the ultrasonic welding electrode is adjacent to the electrode foil stack, and ultrasonically welding the electrode foil stack to the conductive lead sheet using the ultrasonic welding electrode, thereby forming a weld joint within the battery cell. Multiple battery cells are then connected together to construct a battery pack.

[0016] The present invention also includes the following solutions:

[0017] Option 1. A method for manufacturing a battery cell having a plurality of electrode foils protruding from a cell body, the method comprising:

[0018] The unit body is positioned in the fixing device such that the distal segment of the electrode foil extends outward from the fixing device;

[0019] The distal segment of the electrode foil is clamped between the elastic polymer surfaces of the curved guide clamp, thereby causing the distal segment to gradually shrink into a stack of electrode foils.

[0020] The curved guide clamp is translated toward the fixing device by a predetermined distance, thereby displacing the distal segment by the predetermined distance;

[0021] Use trimming tools to trim a portion of the distal segment;

[0022] Position the ultrasonic welding electrode and the anvil adjacent to the opposing surfaces of the electrode foil stack; and

[0023] The electrode foils are ultrasonically welded to the conductive lead sheet using the ultrasonic welding electrode, thereby forming a weld joint within the battery cell.

[0024] Option 2. The method according to Option 1, wherein the predetermined distance is less than about 1.0 millimeter (mm) and greater than about 0.10 mm.

[0025] Option 3. The method according to Option 1, wherein the relative segments of the curved guide clamp define corresponding airways, the method further comprising:

[0026] The pressurized airflow is guided through the corresponding air passage and directed to the distal section.

[0027] Option 4. The method described in Option 1 further includes:

[0028] The electrode foil stack, the conductive lead sheet, and / or the anvil are heated via a heating source at a predetermined time, wherein the predetermined time is before and / or simultaneously with the ultrasonic welding of the electrode foil stack.

[0029] Option 5. The method according to Option 1, wherein the ultrasonic welding electrode is a multifaceted ultrasonic welding electrode with different knurling patterns on each corresponding side, and wherein positioning the ultrasonic welding electrode and the anvil adjacent to the opposing surfaces of the electrode foil stack includes rotating the multifaceted ultrasonic welding electrode to present a predetermined one of the different knurling patterns adjacent to the electrode foil stack.

[0030] Option 6. The method according to Option 1, wherein the method is characterized in that there is no pre-welding of the electrode foil before the electrode foil is ultrasonically welded to the conductive lead sheet.

[0031] Option 7. The method according to Option 6, wherein the trimming of the distal segment using the trimming tool occurs simultaneously or sequentially with the ultrasonic welding of the electrode foil stack to the conductive lead sheet.

[0032] Option 8. The method according to Option 7, wherein the trimming tool is connected to the ultrasonic welding electrode, the method further comprising:

[0033] As the ultrasonic welding electrode moves toward the anvil, the trimming tool is used to trim the portion of the distal section.

[0034] Option 9. A workstation for manufacturing a battery cell having multiple electrode foils protruding from a cell body, the workstation comprising:

[0035] A fixing device configured to position the unit body in a predetermined orientation, such that the distal segment of the electrode foil extends outward from the fixing device;

[0036] A curved guide clamp is configured to hold the distal segment of the electrode foil therebetween and thereby cause the distal segment to taper into a stack of electrode foils, wherein the curved guide clamp includes an elastic polymer surface.

[0037] An actuator configured to translate the curved guide clamp toward the fixing device by a predetermined distance of about 0.10 mm to about 1 mm, thereby displacing the distal segment by the predetermined distance;

[0038] A trimming tool operable for trimming a portion of the distal segment;

[0039] Ultrasonic welding electrode; and

[0040] An anvil is positioned relative to the ultrasonic welding electrode on the adjacent opposing surface of the electrode foil stack, wherein the ultrasonic welding electrode is configured to ultrasonically weld the electrode foil stack to a conductive lead sheet, thereby forming a weld joint within the battery cell.

[0041] Option 10. The workstation according to Option 9, wherein the ultrasonic welding electrode is a rotatable multi-faceted ultrasonic welding electrode, and the working surface of the multi-faceted ultrasonic welding electrode has a corresponding knurled pattern.

[0042] Option 11. The workstation according to Option 9, wherein the relative sections of the curved guide clamp define corresponding air passages, which are configured to guide pressurized airflow onto the distal section to maintain the alignment of the electrode foil stack.

[0043] Option 12. The workstation according to Option 11 further includes:

[0044] A pressurized air source is connected to the curved guide clamp and configured to provide the pressurized airflow.

[0045] Option 13. The workstation according to Option 9 further includes:

[0046] A heating source operable to heat the conductive lead sheet, the electrode foil stack, and / or the anvil.

[0047] Option 14. The workstation according to Option 13, wherein the heating source includes a laser positioned outside the conductive lead sheet and operable to directly heat the conductive lead sheet.

[0048] Option 15. The workstation according to Option 9, wherein the trimming tool is connected to the ultrasonic welding electrode such that movement of the ultrasonic welding electrode toward the anvil causes the trimming tool to move together with the ultrasonic welding electrode toward the anvil.

[0049] Option 16. A method for manufacturing a battery pack having a plurality of battery cells, each respective battery cell having an electrode foil protruding from a cell pouch, the method comprising:

[0050] Position the unit bag in the fixing device such that the distal section of the electrode foil extends outward from the fixing device;

[0051] The distal segment of the electrode foil is clamped between the elastic polymer surfaces of a curved guide clamp, thereby tapering the distal segment into an electrode foil stack, wherein the curved guide clamp defines an air passage therein.

[0052] The pressurized airflow is guided through the corresponding air passage and directed to the distal section to maintain the planar alignment of the electrode foil stack;

[0053] The curved guide clamp is translated toward the fixing device by a predetermined distance, thereby displacing the distal segment by the predetermined distance, wherein the predetermined distance is configured to reduce the tension on the electrode foil;

[0054] Use trimming tools to trim a portion of the distal segment;

[0055] The ultrasonic welding electrode and the anvil are positioned on opposite surfaces adjacent to the electrode foil stack, such that the double-sided knurling pattern of the ultrasonic welding electrode is adjacent to the electrode foil stack.

[0056] The electrode foils are ultrasonically welded to the conductive lead sheet using the ultrasonic welding electrode, thereby forming a weld joint within the battery cell; and

[0057] The battery pack is constructed by connecting multiple battery cells together.

[0058] Option 17. The method according to Option 16 further includes:

[0059] Before ultrasonically welding the electrode foil stack, the conductive lead sheet, the electrode foil stack, and / or the anvil are heated via a heat source.

[0060] Option 18. The method according to Option 16, wherein the ultrasonic welding electrode is the multifaceted ultrasonic welding electrode having a different knurling pattern on each respective side of the multifaceted ultrasonic welding electrode, and wherein positioning the ultrasonic welding electrode and the anvil adjacent to the opposing surfaces of the electrode foil stack includes rotating the multifaceted ultrasonic welding electrode to present a predetermined one of the different knurling patterns adjacent to the electrode foil stack.

[0061] Option 19. The method according to Option 16, wherein the predetermined distance is less than about 1.0 millimeter (mm) and greater than about 0.10 mm.

[0062] Option 20. The method according to Option 18, wherein the trimming tool is connected to the ultrasonic welding electrode, the method further comprising:

[0063] While ultrasonically welding the electrode foil stack to the conductive lead sheet using the ultrasonic welding electrode, the electrode foil stack is trimmed using the trimming tool.

[0064] The foregoing features and advantages, as well as other features and incidental advantages of this disclosure, will become apparent from the following detailed description of illustrative examples and models for carrying out this disclosure, taken in conjunction with the accompanying drawings and appended claims. Furthermore, this disclosure explicitly includes combinations and sub-combinations of the elements and features set forth above and below. Attached Figure Description

[0065] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0066] Figure 1 This is a diagram illustrating the integrated process of internal welding for forming an electrochemical cell cell according to the present disclosure.

[0067] Figure 2 yes Figure 1 The illustration shows a portion of the workstation, illustrating a possible configuration in which a soft-touch guide clamp is used to guide a thin electrode foil of a battery cell to a mating anvil and ultrasonic welding electrode, wherein the guide clamp may define optional air passages for directing pressurized airflow onto the electrode foil.

[0068] Figure 3A and Figure 3B An optional tension relief mechanism is shown, which displaces the electrode foil by a small, predetermined distance to reduce tension on the electrode foil during the described synthesis process.

[0069] Figure 4 yes Figure 1 A diagram illustrating the comprehensive process.

[0070] Figure 5 This is a diagram of an optional multifaceted ultrasonic welding electrode according to aspects of this disclosure.

[0071] The accompanying drawings are not necessarily drawn to scale and may present slightly simplified representations of various preferred features of this disclosure, as disclosed herein, including, for example, specific dimensions, orientations, positions, and shapes. Details associated with these features will be determined in part by the particular intended application and context of use. Detailed Implementation

[0072] This disclosure allows for many different forms of embodiments. Representative examples of this disclosure are shown in the accompanying drawings and are described in detail herein as non-limiting examples of the disclosed principles. Therefore, elements and limitations described in the abstract, background, summary, and detailed description sections, but not expressly set forth in the claims, should not be incorporated into the claims individually or collectively by implication, reasoning, or otherwise.

[0073] For the purposes of this description, unless specifically denied, the use of the singular includes the plural, and vice versa; the terms “and” and “or” should be both conjunctions and adversative conjunctions; and the words “including,” “contains,” “comprising,” “having,” etc., should mean “including but not limited to.” Furthermore, approximate words such as “approximately,” “almost,” “basically,” “generally,” “about,” etc., may be used herein to mean “reaching, approaching, or nearly reaching,” or “within 0-5% of,” or “within acceptable manufacturing tolerances,” or logical combinations thereof. As used herein, a component “configured” to perform a specified function is capable of performing the specified function without alteration, and not merely potentially capable of performing the specified function after further modification. In other words, the described hardware, when explicitly configured to perform the specified function, is specifically selected, created, implemented, utilized, programmed, and / or designed for the purpose of performing the specified function.

[0074] Referring to the accompanying drawings, similar reference numerals in several views denote similar features. Figure 1 An integrated workstation 10 is depicted, configured to perform integrated trimming and internal soldering processes during the manufacture of electrochemical cell 12. As described above, this teaching envisions the improved execution of multiple traditionally separate or sequential processes at a single workstation. For example, embodiments of the disclosed method combine clamping, optional pre-soldering, electrode foil trimming, lead sheet placement, and main soldering processes in one or more embodiments, wherein this single-station approach is implemented by the hardware innovations described below. Therefore, the solutions provided below can be used to manufacture cell 12 in a more efficient manner, particularly in terms of manufacturing space and process time.

[0075] The battery cell 12 envisioned herein, for example, a lithium-ion battery cell, includes a cell body 14 and a casing or pouch 16 constructed of laminated foil or another suitable component. However, this teaching is not limited to batteries having a lithium-ion chemistry, and therefore a lithium-ion battery is merely one possible configuration of the battery cell 12. Figure 1In a representative configuration, the battery cell 12 has positive and negative external electrode plates 15 protruding from the peripheral edge 160 of the pouch 16. The electrode plates 15 may be constructed of copper, aluminum, or another metal suitable for the application, allowing several of the battery cells 12 to be arranged in a stack and electrically joined together in a series or parallel arrangement, for example, using one or more busbars or interconnecting members (not shown) when constructing a battery pack with an output voltage suitable for the application.

[0076] In representative use cases, multiple battery cells 12 can be joined together to form a propulsion battery pack 18 for an electrified powertrain system 20, for example, a motor vehicle 22 having a vehicle body 200 connected to one or more road wheels 24. The motor vehicle 22 can optionally be embodied as a battery electric vehicle as shown, or as a hybrid electric vehicle. Alternatively, the electrified powertrain system 20 can be used as part of another mobility system, such as, but not limited to, railway vehicles, aircraft, ships, robots, agricultural equipment, etc. Similarly, the electrified powertrain system 20 can also be stationary, such as in the case of an electric power unit, crane, drive belt, or transmission system. Therefore, Figure 1 The electrified powertrain system 20 in the representative vehicle embodiment is intended to illustrate this teaching and is not intended to limit it.

[0077] As those skilled in the art will understand, when the propulsion battery pack 18 is used to power one or more single-phase or multi-phase / AC devices (such as typical propulsion or traction motors), the propulsion battery pack 18 is connected to a power inverter (not shown) such that the voltage and current from the discharging battery cells 12 of the propulsion battery pack 18 are ultimately supplied to the power inverter. A set of semiconductor switches residing within the power inverter is controlled via pulse width modulation, pulse density modulation, or other suitable switching control techniques to convert the DC input voltage into an AC output voltage suitable for energizing the motor. Therefore, the high-speed switching of the resident semiconductor switches of the power inverter ultimately causes (multiple) motors to... Figure 1 The illustrated vehicle embodiment delivers motor drive torque to one or more of the road wheels 24, or in other embodiments, delivers motor drive torque to another coupled mechanical load.

[0078] Regardless of the end use or application of the battery cell 12, the internal welding within it can be constructed using the integrated workstation 10 shown. In possible embodiments, the integrated workstation 10 can be used to perform a one-step welding process that integrates the main welding and electrode foil trimming processes while eliminating the pre-welding process, or to perform a two-step welding process that integrates the pre-welding and electrode foil trimming processes followed by the main welding process. Each option will be described in turn below.

[0079] like Figure 1As shown, unit body 14 surrounds electrode foil 28 protruding from edge 240 of unit body 14. Unit body 14 is arranged between corresponding upper section 26U and lower section 26L of clamping and fixing device 26, wherein clamping and fixing device 26 is configured to position unit body 14 in a predetermined orientation. In this orientation, distal end 280 of electrode foil 28 extends outward from clamping and fixing device 26. For example, electromechanical, hydraulic or pneumatic actuators (not shown) can apply clamping force (arrow F) to upper section 26U and lower section 26L of clamping and fixing device 26. C The clamping and fixing device 26 thus smoothly and securely holds and retains the unit 14 in the indicated orientation. Figure 1 In a representative orientation, the longitudinal central axis 140 of unit 14 is arranged in a generally horizontal manner relative to the factory floor surface (not shown).

[0080] In the orientation shown for unit 14, electrode foil 28 is oriented as shown below (reference). Figures 2 to 4 The curved guide fixture 30 constructed as described is presented. For example, in Figure 2 In an exemplary configuration, the curved guide clamp 30 includes opposing segments 30A and 30B configured to gently clamp the electrode foil 28 therebetween and to smoothly taper the electrode foil 28 into an electrode foil stack 27. Figure 1 The text also depicts a trimming tool 32, such as a laser beam or a hard blade, like a sharpened blade, operable to trim the distal end 280 of the electrode foil 28 during the trimming process. Figure 1 The integrated workstation 10 also includes a vibration welding corner or ultrasonic welding electrode 34 and an anvil 36, the anvil 36 being connected to, integrally formed with, or placed adjacent to the trimming block 36B. In the illustrated configuration, the anvil 36 is positioned opposite the ultrasonic welding electrode 34 on a proximal opposing surface of the electrode foil stack 27 and can optionally be heated via a heating source 38, as referenced below. Figure 4 Described.

[0081] As is understood in the art, Figure 1 The ultrasonic welding electrode 34 is configured to vibrate at ultrasonic or higher frequencies, thereby welding the electrode foil stack 27 to the conductive lead sheet 40 of the battery cell 12. In this way, the integration station 10 is configured to form a weld joint within the battery cell 12, i.e., internal welding. In possible configurations, the ultrasonic welding electrode 34 may have a multi-faceted knurled pattern for use in heat pressing, ultrasonic pre-welding, and final welding. Further details will be provided below. Figure 5This describes an exemplary method for implementing a representative multifaceted variant of the ultrasonic welding electrode 34. Furthermore, the conductive lead sheet 40 can be fixed between the robotic fingers 42 of a robot (not shown), or within a suitable fixing device, and positioned adjacent to the oriented electrode foil stack 27. A portion of the conductive lead sheet 40 can be wrapped or coated in a film 43, for example, for handling and protection, wherein the uncoated portion 41 is used to form the aforementioned weld joint via method 100.

[0082] Now for reference Figure 2 In one or more embodiments, opposing segments 30A and 30B of the curved guide jig 30 move together via a clamping actuator 39. The clamping actuator 39, schematically shown for simplicity, can be embodied as an electrical, electromechanical, hydraulic, or pneumatic device as known in the art. The radial surface 35 of the curved guide jig 30 gently contacts the electrode foil 28 projecting from the edge 240 of the unit body 14. The electrode foil 28 is very thin, for example, about 6 micrometers to about 15 micrometers (6-15 μm), and therefore quite fragile and easily damaged during the manufacturing process. Therefore, to protect the electrode foil 28, the radial surface 35 of the curved guide jig 30 can be constructed of a soft, elastic polymer material, such as an open-cell polymer or a foam material. As used herein, "elastic" requires the ability to gently press against the electrode foil 28 and then return to an uncompressed state when the electrode foil 28 is released. In other words, when the clamping actuator 39 translates the relative sections 30A and 30B into contact with the electrode foil 28, the material of the radial surface 35 will be gently compressed or yielded, thereby protecting the electrode foil 28 from damage during this part of the process.

[0083] Furthermore, the curved guide clamp 30 may optionally define a corresponding air passage 33, for example, through one or more tubular openings in opposite sections 32A and 32B, as shown. In this embodiment, a blower 44 (such as a motorized fan assembly) is coupled to the air passage 33 and configured to introduce pressurized airflow (arrow AA) into the fluid inlet 330 of the air passage 33, through the air passage 33, and through the fluid outlet 430. The pressurized airflow (arrow AA) ultimately contacts the distal end 280 of the electrode foil 28. Using pressurized airflow (arrow AA) in this manner is intended to help maintain the desired arrangement of the electrode foil stack 27. That is, the escaping airflow through the fluid outlet 430 is gently blown onto and through the electrode foil 28 at sufficient pressure to gently align the electrode foil 28 and ensure that the top / bottom foils of the presented electrode foil stack 27 are unfolded and substantially flat or aligned.

[0084] refer to Figure 3A and Figure 3B In execution Figure 1During method 100, it is desirable to minimize the tension on the electrode foil 28. Therefore, in possible embodiments, the method described herein may include clamping the electrode foil 28 in a curved guide jig 30 as described above. Figure 3A The shape, profile, and material of the curved guide fixture 30 help reduce the likelihood of bent foil problems and other manufacturing issues as described above. Aspects of the method envisioned herein may further include translating the curved guide fixture 30 toward the clamping fixture 26 or unit 14 by a predetermined distance (ΔX), such as... Figure 3B As best illustrated, for example, a linear actuator 50 is used, whose range of motion is limited to a predetermined distance (ΔX). In this way, the linear actuator 50 applies force (arrow F). T An amount of material is applied to the curved guide clamp 30, sufficient to displace the distal end 280 and the electrode foil 28 by a predetermined distance (ΔX).

[0085] Representative embodiments include a predetermined distance (ΔX) of less than or equal to about 1.0 mm and greater than or equal to about 0.10 mm in possible embodiments, or from about 0.2 mm to about 0.5 mm, or from about 0.3 mm to about 0.4 mm in different embodiments. This minute movement will tend to reduce the tension on the fragile electrode foil 28, especially in the middle layer of the electrode stack 27, thus minimizing the possibility of damage to the electrode foil 28 during the subsequent ultrasonic welding process.

[0086] Now for reference Figure 4 In one or more embodiments of the integrated workstation 10, the trimming tool 32 briefly mentioned above can be connected to the ultrasonic welding electrode 34, such that the trimming tool 32, in conjunction with the movement of the ultrasonic welding electrode 34, moves toward the anvil 36, or more specifically... Figure 1 The trimming block 36B moves. This movement occurs in... Figure 4 The arrow BB indicates this. While in other configurations, the trimming tool 32 does not need to be connected to the ultrasonic welding electrode 34, but... Figure 1 When this method is performed during the manufacturing of the battery cell 12, the trimming tool 32 is attached to the ultrasonic welding electrode 34, which can be more efficient in terms of movement economy. Therefore, the trimming tool 32 is used to perform a trimming process in which the unused portion 380 of the electrode foil 28 is cleanly cut to form the distal end 280. The unused portion 380 is then disposed of as waste material.

[0087] In addition, the integrated workstation 10 may include an optional heating source 38 (e.g., a resistive heating element, such as a conductive wire or coil), a fluid heating source (such as oil circulating through an internal channel (not shown) in the anvil 36), or another suitable embodiment that allows internal heating of the anvil 36 and thus indirect heating of the metal forming the workpiece. It can be operatively connected to or integrated with the anvil 36 (e.g., Figure 4 The heating source 36 (illustrated schematically) is thus operable to heat the anvil 36, particularly around its working surface. Heating the anvil 36 to about 175 degrees Celsius (°C) to about 225°C, or to about 200°C, helps reduce the force or energy required to ultrasonically pre-weld the electrode foils 28 together to form the electrode stack 27. That is, the “pre-welding” contemplated herein involves forming the electrode foils 28 into the electrode stack 27 prior to welding the electrode stack to the lead sheet 40 (“final welding”). Using the applied heat in this manner further reduces the tendency of the electrode foils 28 to break, particularly near the ultrasonic welding electrode 34.

[0088] Those skilled in the art will recognize that the above method can be performed without heating the anvil 36, for example, by using an external heating source 138 instead of heating one or more of the conductive lead sheet 40 and / or electrode foil 28. In this embodiment, the external heating source 138, for example, a laser or hot lamp operable to emit thermal energy (HH) toward the conductive lead sheet 40 and / or distal end 280, may be located close to the main sheet 40 and electrode foil 28, as shown. The external heating source 138 may be used alone or in conjunction with the heating source 38 of the anvil 36. As described above, the working surface of the ultrasonic welding electrode 34 may have a knurled pattern 340 to enhance the heating of the pre-welding and final welding, for example, by helping to distribute heat to the affected surface of the electrode foil 28. In some embodiments, the anvil 36 may have a similar knurled pattern 360 to achieve the same purpose.

[0089] Brief Reference Figure 5 In forming various ultrasonic welds, such as during pre-welding and main welding, the use of multi-faceted weld corners can be advantageous. This welding may require different knurling patterns. In the context of this disclosure, running two welding processes on the same welding machine would require rotating the welding machine and using separate ultrasonic welding electrodes 34 and anvils 36, or using a specialized welding machine with two different anvils 36 and multi-faceted ultrasonic welding electrodes. In some embodiments, the latter solution can be used to implement this integrated strategy at a single integrated workstation.

[0090] Specifically, an integrated workstation 10A is shown, comprising a welding machine 60, a rotatable multifaceted ultrasonic welding electrode 134, and a first anvil 136A and a second anvil 136B. The ultrasonic welding electrode 134 has a rotation axis 234 about which the welding machine 60 is operable to rotate the ultrasonic welding electrode 134 to present: (1) a first anvil 136A and a first knurling pattern 340A, or (2) a second anvil 136B and a second knurling pattern 340B. The corresponding first knurling pattern 340A and second knurling pattern 340B are configured for a given welding process; for example, the second knurling pattern 340B may be used for pre-welding and thus may be less prominent, more textured, or more penetrating than the first knurling pattern 340A. Similarly, the first knurling pattern 340A may be configured to perform the main welding process and thus may have larger, more textured, or more penetrating knurling relative to the second knurling pattern 340B. Therefore, Figure 5 One side of the ultrasonic welding electrode 134 can be rotatably positioned and used for a pre-welding process, after which the ultrasonic welding electrode 134 is rotated before performing the main welding process. Then, the ultrasonic welding electrode 134 is removed from the stack before the dressing tool 32 is moved into position. Therefore, positioning the ultrasonic welding electrode 134 and the anvil 136A or 136B adjacent to the opposing surfaces of the electrode foil stack 27 can include rotating the multi-faceted ultrasonic welding electrode 134 to present a predetermined one of different knurling patterns 340A or 340B adjacent to the electrode foil stack 27. Alternatively, a single-faceted ultrasonic welding electrode 34 (see...) can be used. Figure 1 This may require separating and replacing the ultrasonic welding electrode 34 and possibly the anvil 36 during the transition between the pre-welding and main welding processes. Although in Figure 5 Two sides are shown, but those skilled in the art will recognize that additional sides will be provided, for example, to reduce wear.

[0091] Return to Figure 1 The integrated workstation 10 is therefore suitable for performing a method for manufacturing a battery cell 12, which in turn has a plurality of electrode foils 28 protruding from a cell body 14. Embodiments of this method may include positioning the cell body 14 in a clamping fixture 26 such that the distal ends 280 of the electrode foils 28 extend outward from the fixture 26, and then gently clamping or positioning the distal ends 280 of the electrode foils 28 between opposing sections 30A and 30B of a curved guide jig 30. In this manner, the curved guide jig 30 smoothly bends or tapers the distal ends 280 into an electrode foil stack 27. Possible embodiments of this teaching include translating the curved guide jig 30 toward the clamping fixture 26 a predetermined distance (ΔX) to slightly displace the distal ends 280, and trimming the unused portion 380 of the distal ends 280 using the trimming tool 32 described above in its various embodiments. Figure 4 ).

[0092] As part of method 100, the ultrasonic welding electrode 34 and the anvil 36 are positioned adjacent to the opposing surfaces of the electrode foil stack 27. The disclosed method in this embodiment may include trimming the electrode foil 28 using a trimming tool 32 to form a distal end 280. This may occur simultaneously or sequentially with the ultrasonic welding of the electrode foil stack 27 to the conductive lead sheet 40. Therefore, this method may include ultrasonically welding the electrode foil stack 27 to the conductive lead sheet 40 using the ultrasonic welding electrode 34, thereby forming a weld joint within the battery cell 12, which may optionally occur simultaneously with or sequentially with the trimming process described above.

[0093] In the configuration of the curved guide fixture 30, where opposing sections 30A and 30B define air passages 33, method 100 may require the guided pressurized airflow (arrow AA) to pass through the respective air passages 33 and be directed onto the distal section 280. Similarly, method 100 may include heating the anvil 36 or electrode foil 28 via a heat source 38 and / or 380 before and / or during ultrasonic welding of the electrode foil stack 27.

[0094] The methods described in this article can be applied to a single workstation, for example... Figure 1 The process is performed at 10 integrated workstations. A key feature of this method is that there is no pre-welding of the electrode foils 28 to each other prior to the ultrasonic welding of the electrode foil stack 27 to the conductive lead sheet 40. In other words, the main welding and finishing of the electrode foils 28 can occur in a one-step implementation. Alternatively, the pre-welding and finishing can be integrated, and the main welding performed as a separate subsequent step. These and other incidental benefits will be readily apparent to those skilled in the art in light of the foregoing disclosure.

[0095] The detailed description and accompanying drawings or figures are intended to support and describe this teaching, but the scope of this teaching is defined only by the claims. While some of the best modes and other embodiments for carrying out this teaching have been described in detail, various alternative designs and embodiments exist to practice the teaching as defined in the appended claims. Furthermore, this disclosure explicitly includes combinations and sub-combinations of the elements and features set forth above and below.

Claims

1. A method for manufacturing a battery cell having a plurality of electrode foils protruding from a cell body, the method comprising: The unit body is positioned in the fixing device such that the distal segment of the electrode foil extends outward from the fixing device; The distal segment of the electrode foil is clamped between the elastic polymer surfaces of the curved guide clamp, thereby causing the distal segment to gradually shrink into a stack of electrode foils. The curved guide clamp is translated toward the fixing device by a predetermined distance, thereby displacing the distal segment by the predetermined distance; Use trimming tools to trim a portion of the distal segment; Position the ultrasonic welding electrode and the anvil adjacent to the opposing surfaces of the electrode foil stack; and The electrode foils are ultrasonically welded to the conductive lead sheet using the ultrasonic welding electrode, thereby forming a weld joint within the battery cell. The relative segments of the curved guide clamp define corresponding airways, and the method further includes: The pressurized airflow is guided through the corresponding air passage and directed to the distal section.

2. The method according to claim 1, wherein the predetermined distance is less than 1.0 mm and greater than 0.10 mm.

3. The method according to claim 1, further comprising: The electrode foil stack, the conductive lead sheet, and / or the anvil are heated via a heating source at a predetermined time, wherein the predetermined time is before and / or simultaneously with the ultrasonic welding of the electrode foil stack.

4. The method of claim 1, wherein the ultrasonic welding electrode is a multifaceted ultrasonic welding electrode with different knurling patterns on each respective side of the multifaceted ultrasonic welding electrode, and wherein positioning the ultrasonic welding electrode and the anvil adjacent to the opposing surfaces of the electrode foil stack includes rotating the multifaceted ultrasonic welding electrode to present a predetermined one of the different knurling patterns adjacent to the electrode foil stack.

5. The method according to claim 1, wherein the method is characterized in that there is no pre-welding of the electrode foil before the electrode foil is ultrasonically welded to the conductive lead sheet.

6. The method of claim 5, wherein the trimming of the distal segment using the trimming tool occurs simultaneously or sequentially with the ultrasonic welding of the electrode foil stack to the conductive lead sheet.

7. The method of claim 6, wherein the trimming tool is connected to the ultrasonic welding electrode, the method further comprising: As the ultrasonic welding electrode moves toward the anvil, the trimming tool is used to trim a portion of the distal section.

8. A workstation for manufacturing a battery cell having a plurality of electrode foils protruding from a cell body, the workstation comprising: A fixing device configured to position the unit body in a predetermined orientation, such that the distal segment of the electrode foil extends outward from the fixing device; A curved guide clamp is configured to hold the distal segment of the electrode foil therebetween and thereby cause the distal segment to taper into a stack of electrode foils, wherein the curved guide clamp includes an elastic polymer surface. An actuator configured to translate the curved guide clamp toward the fixing device by a predetermined distance of 0.10 mm to 1 mm, thereby displacing the distal segment by the predetermined distance; A trimming tool operable for trimming a portion of the distal segment; Ultrasonic welding electrode; as well as An anvil, positioned opposite the ultrasonic welding electrode on a nearby opposing surface of the electrode foil stack, wherein the ultrasonic welding electrode is configured to ultrasonically weld the electrode foil stack to a conductive lead sheet, thereby forming a weld joint within the battery cell. The relative sections of the curved guide clamp define corresponding air passages, which are configured to direct pressurized airflow onto the distal section to maintain the alignment of the electrode foil stack.

9. The workstation according to claim 8, wherein the ultrasonic welding electrode is a rotatable multi-faceted ultrasonic welding electrode, and the working surface of the multi-faceted ultrasonic welding electrode has a corresponding knurled pattern.

10. The workstation according to claim 8, further comprising: A pressurized air source is connected to the curved guide clamp and configured to provide the pressurized airflow.

11. The workstation according to claim 8, further comprising: A heating source operable to heat the conductive lead sheet, the electrode foil stack, and / or the anvil.

12. The workstation of claim 11, wherein the heating source comprises a laser positioned outside the conductive lead sheet and operable to directly heat the conductive lead sheet.

13. The workstation of claim 8, wherein the trimming tool is connected to the ultrasonic welding electrode such that movement of the ultrasonic welding electrode toward the anvil causes the trimming tool to move together with the ultrasonic welding electrode toward the anvil.

14. A method for manufacturing a battery pack having a plurality of battery cells, each respective battery cell having an electrode foil protruding from a cell pouch, the method comprising: Position the unit bag in the fixing device such that the distal section of the electrode foil extends outward from the fixing device; The distal segment of the electrode foil is clamped between the elastic polymer surfaces of a curved guide clamp, thereby tapering the distal segment into an electrode foil stack, wherein the curved guide clamp defines an air passage therein. The pressurized airflow is guided through the corresponding air passage of the curved guide clamp and directed to the distal section to maintain the planar alignment of the electrode foil stack; The curved guide clamp is translated toward the fixing device by a predetermined distance, thereby displacing the distal segment by the predetermined distance, wherein the predetermined distance is configured to reduce the tension on the electrode foil; Use trimming tools to trim a portion of the distal segment; The ultrasonic welding electrode and the anvil are positioned on opposite surfaces adjacent to the electrode foil stack, such that the double-sided knurling pattern of the ultrasonic welding electrode is adjacent to the electrode foil stack. The electrode foils are ultrasonically welded to the conductive lead sheet using the ultrasonic welding electrode, thereby forming a weld joint within the battery cell. as well as The battery pack is constructed by connecting multiple battery cells together.

15. The method of claim 14, further comprising: Before ultrasonically welding the electrode foil stack, the conductive lead sheet, the electrode foil stack, and / or the anvil are heated via a heat source.

16. The method of claim 14, wherein the ultrasonic welding electrode is the multifaceted ultrasonic welding electrode having a different knurling pattern on each respective side of the multifaceted ultrasonic welding electrode, and wherein positioning the ultrasonic welding electrode and the anvil adjacent to the opposing surfaces of the electrode foil stack includes rotating the multifaceted ultrasonic welding electrode to present a predetermined one of the different knurling patterns adjacent to the electrode foil stack.

17. The method of claim 14, wherein the predetermined distance is less than 1.0 mm and greater than 0.10 mm.

18. The method of claim 16, wherein the trimming tool is connected to the ultrasonic welding electrode, the method further comprising: While ultrasonically welding the electrode foil stack to the conductive lead sheet using the ultrasonic welding electrode, the electrode foil stack is trimmed using the trimming tool.

Images