Electrode and separator stacker for high speed battery production

Abstract

Embodiments of battery stackers, including z-fold stackers, are disclosed that are shaped to transfer battery layers in a rolling manner in order to reduce wear. In some embodiments, the battery layer is bent onto an arcuate surface using a vacuum or other force. The arcuate surface is then rotated to release the battery layer at the desired transfer location. For example, the desired transfer position may be on the top of the stack, or on another arcuate gripper surface.

Description

Technical Field

[0001] The present disclosure generally relates to a battery stacking machine for stacking an anode, a cathode, and a separator. The present disclosure also relates to methods and grippers for battery stacking. In particular, the present disclosure relates to the rolling transfer of battery layers. Background Art

[0002] Prismatic batteries are formed by interleaving alternating layers of cathodes, insulating separators, and anodes. Thus, to form a stack, the separator is a continuous layer that is folded back and forth (Z-folded) between alternating anode and cathode layers. The battery design itself impedes aligning the edges of the individual layers with a common reference. To avoid malfunctions, there should be no electrical contact between the anode and the adjacent cathode. For this purpose, the sizes of the anode and the cathode generally do not match and are centered relative to each other, such that there is a physical boundary of 1 mm to 2 mm between adjacent anode and cathode layers.

[0003] Conventional Z-fold stacking machine mechanisms are limited in production volume because the system architecture follows a repetitive placement / clamping / folding sequence. With a transfer device for each electrode, these previous attempts included various clamping and retention techniques to hold the stack in place while placing another electrode on top, which reduced the production volume. In addition, synchronizing each transfer device and the separator feeding device has been challenging.

[0004] The patent application publication No. US2006 / 0051652A1 of Samuels describes an example of previous attempts. The '652 publication describes an interleaving machine for forming a stack. Samuels' Figure 1 shows a first pick-and-place device for handling a cathode stack, a second pick-and-place device for handling an anode stack, and a centrally positioned elevator for interleaving a separator between alternating cathode and anode layers. In one embodiment, Samuels describes a Bernoulli pick-and-place device for handling electrodes. A carriage facilitates the horizontal movement of the pick-and-place device.

[0005] Another example is Korean Patent No. 101220981, which also describes a stacking device having a first vacuum transfer device for an anode and a second vacuum transfer device for a cathode. Each vacuum transfer device can pivot to fold a separator down onto the stack. Summary of the Invention

[0006] In one aspect, a method for forming a battery electrode and separator stack is implemented by a battery stacker or a gripper of a battery stacker. The method includes applying a force to a battery layer via an arcuate surface, causing the battery layer to move from a first position and bend onto a conforming position on the arcuate surface. The method further includes rotating the arcuate surface together with the battery layer to a second position while the force keeps the battery layer bent in the conforming position. The method further includes transferring the battery layer from the conforming position on the arcuate surface to a receiving surface, wherein the transfer includes releasing the force applied via the arcuate surface.

[0007] In some embodiments, the receiving surface is another arcuate surface, and wherein the transfer includes applying a force using the arcuate receiving surface to bend the layer onto a conforming position on the receiving surface.

[0008] In some embodiments, the receiving surface is a battery electrode and separator stack including a substantially flat surface, and wherein the transfer includes transferring the battery stack to an unbent position.

[0009] The method may further include eccentrically rotating the arcuate surface to laterally and vertically displace the arcuate surface relative to the receiving surface.

[0010] The method may further include applying a force by evacuating a vacuum in a hole of the arcuate surface.

[0011] The method may further include having the battery layer with discrete electrodes located on top of a continuous separator sheet.

[0012] The method may further include having the battery layer with discrete electrodes located on top of discrete separator sheets.

[0013] The method may further include applying a force by evacuating a vacuum through holes in a laterally reciprocating gripper.

[0014] The method may further include gradually applying a positive pressure through holes in the arcuate surface according to a change in the lateral position.

[0015] The method may further include a first position, the first position being a vertically oriented material transfer position defined by the arcuate surface facing another arcuate surface used as a pick-and-place device.

[0016] The method may further include applying, rotating, and transferring the force in combination with a first laterally reciprocating roller on a first side of the battery stacker, and the method further includes repeating the application, rotation, and transfer of the force in combination with a second laterally reciprocating roller on a second side of the battery stacker.

[0017] The method may further include applying a force by evacuating a vacuum through pores in a continuous separator sheet to bend the battery layer.

[0018] In one aspect, a battery stacker is disclosed. The stacker includes: an arcuate surface configured to apply a force to pull a battery layer out of a first position and bend it to a conforming position on the arcuate surface; an axis about which the arcuate surface is rotatable while the force holds the battery layer bent in the conforming position to rotate the battery layer to a second position; and a receiving surface for receiving the battery layer in response to the release of the force to transfer the battery layer from the conforming position on the arcuate surface to the receiving surface.

[0019] In some embodiments, the receiving surface can be another arcuate surface of the battery stacker, and the stacker can include a device for applying a force to the battery layer. In some embodiments, the receiving surface can be the same as or substantially the same as the arcuate surface from which the battery layer is transferred. In some embodiments, the receiving surface is a battery electrode and separator stack including a substantially flat surface.

[0020] The battery stacker can also include a rotatable multi-faceted gripper including the arcuate surface. The rotatable multi-faceted gripper can be rotatable eccentrically.

[0021] The battery stacker can also include left and right eccentric rotatable multi-faceted grippers as pick-and-place devices.

[0022] The battery stacker can also be a Z-fold stacker.

[0023] The battery stacker can also include a force as a vacuum force applied through a hole in the arcuate surface.

[0024] The battery stacker can also include a force as a first force, and wherein the arcuate surface is configured to apply a second force as a positive pressure applied through a hole in the arcuate surface.

[0025] In one aspect, a rotatable multi-faceted gripper for conveying a battery layer is disclosed. The gripper includes a body including three angularly spaced-apart arcuate gripper surfaces and three angularly spaced-apart frustoconical sides. Each arcuate gripper surface includes a device for applying a force to a battery layer positioned on the gripper surface to hold the battery layer in a conforming position on the arcuate surface.

[0026] In some embodiments, each arcuate gripper surface further includes a device for applying a second force as a positive pressure to the battery layer to release the battery layer and / or transfer the battery layer to the receiving surface.

[0027] The disclosed embodiments utilize the physical flexibility of the materials to be stacked in order to effect material transfer by rolling action. There are four rolling transfer scenarios in which the disclosed techniques can be utilized: (1) transfer from a moving roller to a stationary plane; (2) transfer from a stationary plane to a moving roller; (3) transfer from a stationary roller to a moving plane; or (4) transfer from a moving plane to a stationary roller. The disclosed material transfer is wear-free, i.e., the relative movement between the roller and the plane is minimal.

[0028] Conventional Z-fold stacking machine techniques typically utilize reciprocating motion (e.g., pick and place) to build stacks from discrete electrodes. Thus, in some embodiments, it is also desirable to use continuous rotational motion in place of reciprocating motion.

[0029] Other aspects and advantages will become apparent from the following detailed description of the embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] To facilitate identification of the discussion of any particular element or act, one or more of the most significant (or leading) digits in the reference numeral refers to the figure number of the drawing in which the element was first introduced.

[0031] Figure 1 is an isometric view of a Z-fold stacking machine according to one embodiment.

[0032] Figure 2 is a sequence of side views according to one embodiment, which shows Figure 1 a sequence of different lateral material transfer positions during counterclockwise eccentric rotation of the multi-faceted gripper of

[0033] Figure 3 is an isometric view of an eccentrically rotatable multi-faceted gripper assembly according to one embodiment.

[0034] Figure 4 is an isometric view of a Z-fold stacking machine according to one embodiment having separate stacks for each electrode type.

[0035] Figure 5 is during a stacking sequence Figure 4 a set of detailed views of a Z-fold stacking machine of

[0036] Figure 6 is an isometric view of a Z-fold stacking machine according to another embodiment.

[0037] Figure 7 is a side view of a Reuleaux triangle according to one embodiment.

[0038] Figure 8 is a diagram showing Figure 7 scrubbing varying with the angular position of the Reuleaux triangle shown in

[0039] Figure 9 is Figure 7 a side view of the centroid of the Reuleaux triangle shown.

[0040] Figure 10 is an annotated side view of a portion of a centroid circular and non-circular orbital path according to an embodiment.

[0041] Figure 11 shows inscribed in Figure 9 and Figure 10 the centroid non-circular orbital path of Figure 10 a side view of a full view of the centroid circular orbital path of

[0042] Figure 12 is Figure 7 a side view of the Reuleaux triangle in Figure 11 where angular position lines are marked for experimentally determining a non-worn and having

[0043] Figure 13 is a side view showing in more detail Figure 12 the position lines in

[0044] Figure 14 is a side view showing in more detail Figure 12 and Figure 13 the intersection of the position lines shown in

[0045] Figure 15 is a side view showing in more detail Figure 14 the angle formed at the intersection shown in

[0046] Figure 16 is a side view of a modified arcuate surface obtained experimentally using the Figures 9 to 15 technique shown.

[0047] Figure 17 is an isometric view showing Figure 16 the modified arcuate surface in

[0048] Figure 18 is an isometric view of a Z-fold stacker with a reciprocating carriage according to another embodiment.

[0049] Figure 19 is a set of isometric views showing a reciprocating carriage and a vacuum roll in a stacking position sequence according to an embodiment.

[0050] Figure 20 is showing in a stacking position sequence according to an embodiment Figure 19A set of side views of the vacuum roll.

[0051] Figure 21 Is a set of isometric views showing a Z - fold stacking machine during a stacking sequence according to another embodiment.

[0052] Figure 22 Is a flowchart of a process according to an embodiment. Detailed Description

[0053] Figure 1 Shows a simplified view of a Z - fold stacking machine 100 according to an embodiment. The Z - fold stacking machine 100 includes: a first electrode delivery system 102 for providing a first type of electrode material 104 (e.g., a copper anode 106); a second electrode delivery system 108 that provides a second type of electrode material 110 (e.g., an aluminum cathode 112); and a central assembly system 114 that provides a separator 116 for Z - folding with the electrodes to form a battery stack 118. In the Z - fold configuration, the separator 116 is not monomerized into discrete layers but forms a single continuous layer that folds back and forth between alternating electrodes (anodes and cathodes).

[0054] In the battery stack 118, the copper anodes 106 and aluminum cathodes 112 typically have mismatched sizes and are centered (i.e., there is no common edge reference), such that there is a physical boundary of 1 mm to 2 mm between adjacent anode and cathode layers. The design of the Z - fold stacking machine 100 meets this centering specification, typically with an accuracy of about 0.25 mm. The Z - fold stacking machine 100 can accommodate a wide range of electrode sizes.

[0055] In an example of the Z - fold stacking machine 100, the first electrode delivery system 102 includes a first roll 120 of electrode material 104. As a conveyor 122 or other transport mechanism pulls the electrode material 104 from the first roll 120, a laser ablation device 124 cuts the electrode material 104 to form a first electrode 126 that is monomerized and separated from the first roll 120.

[0056] Similarly, the second electrode delivery system 108 includes a second roll 128 of electrode material 110. As the electrode material 110 is pulled from the second roll 128 by a conveyor 130 or other transport mechanism, a laser ablation device 132 cuts the electrode material 110 to form a second electrode 134 that is monomerized and separated from the second roll 128.

[0057] The central assembly system 114 includes three eccentric rotatable multi-faceted grippers, which will be explained in more detail below. However, initially, the longitudinal axis of each eccentric rotatable multi-faceted gripper is offset from the axis of rotation such that the eccentric rotatable multi-faceted gripper moves around an annular path while sequentially presenting different arcuate gripper surfaces to the lateral material transfer position.

[0058] In the example of this Z-fold stacker 100, the first eccentric rotatable multi-faceted gripper 136 and the second eccentric rotatable multi-faceted gripper 138 are used as pick-and-place devices that move the electrodes from a horizontal position on top of the respective transfer devices 122 and 130 to a vertical position at which the electrodes can be transferred to the central eccentric rotatable multi-faceted gripper 140, which also selectively engages the draping section 142 of the separator 116. The central eccentric rotatable multi-faceted gripper 140 then places the material on top of the battery stack 118.

[0059] In this embodiment, the separator 116 is fed along the same side as the first electrode 126 but at twice the speed of the first electrode 126, i.e., the length of the separator per unit length is twice the length of the electrode. The unconstrained portion of the separator (between the battery stack 118 and the picked-up electrode) is held taut by air pressure before being folded onto the battery stack 118 by the orbital motion of the central eccentric rotatable multi-faceted gripper 140. The inherent flexibility of the material enables pick-up and placement to be performed at a predetermined location with a rolling action while the central eccentric rotatable multi-faceted gripper 140 maintains a continuous orbital motion. Since the central assembly system 114 employs continuous rotational motion, the Z-fold stacker 100 is capable of achieving high production volumes, high efficiency, and reduced high forces and vibrations associated with reciprocating motion.

[0060] As explained below, loading and unloading layers from the arcuate gripper surface onto the battery stack 118 can be achieved with little wear. Wear occurs when a layer at the top of the stack is laterally pulled (i.e., dragged or slid) against the underlying layer. For example, in some embodiments, the change in distance from the initial contact point of the two layers to their final relative position is less than about 100 μm. However, those skilled in the art will understand that different wear tolerances can be achieved using different battery layer materials and production specifications.

[0061] The continuous motion of the rotating components at a constant rotational speed enables higher production volumes to be achieved. The target cycle time is 0.1 s (electrode to electrode), which is approximately six times faster than traditional systems. This means that a stack of typically 100 layers can be completed in 10 seconds instead of 60 seconds.

[0062] In some embodiments, to maintain the overall production rate of the factory, completed stack assemblies can be quickly removed by a linear shuttle device transverse to the feed direction and replaced with the same stack lifter assembly. This optional shuttle device maximizes the utilization of the stacking process. Downstream processing steps (e.g., packaging, strapping, and other steps) can be performed concurrently with the construction of subsequent stacks.

[0063] Figure 2 A sequence of different lateral material transfer positions 200 is shown in more detail when the central eccentric rotatable multi-faceted gripper 140 rotates counterclockwise while moving eccentrically. Each position in the sequence of different lateral material transfer positions 200 will be explained in detail below.

[0064] First, in Figure 2 the example of, for the sake of brevity, the first eccentric rotatable multi-faceted gripper 136 and the second eccentric rotatable multi-faceted gripper 138 are omitted. Additionally, the movement of the first electrode 126 and the second electrode 134 is simplified such that they are shown as moving vertically downward to meet the arcuate gripper surface of the central eccentric rotatable multi-faceted gripper 140. However, considering the Z-fold stacking machine 100, one skilled in the art should understand that as the first eccentric rotatable multi-faceted gripper 136 rotates counterclockwise and eccentrically, while the second eccentric rotatable multi-faceted gripper 138 rotates clockwise and eccentrically, the electrodes of the Z-fold stacking machine 100 move from a horizontal orientation to a vertical orientation.

[0065] When the first eccentric rotatable multi-faceted gripper 136 ( Figure 1 ) rotates to sequentially present its three arcuate gripper surfaces to the top of the conveyor device 122 ( Figure 1 ), a first position 202 is established, and the conveyor device delivers the first electrode 204 to a position below the opposing arcuate gripper surface among the arcuate gripper surfaces of the first eccentric rotatable multi-faceted gripper 136. Then, when the arcuate gripper surface rotates upward (i.e., counterclockwise), the first electrode 204 is picked up (e.g., using vacuum pressure or electrostatic attraction), and at the same time the arcuate gripper surface moves eccentrically toward the draped section 142 of the diaphragm 116.

[0066] Meanwhile, the central eccentric rotatable multi-faceted gripper 140 has a first arcuate gripper surface 206 that rotates downward and moves eccentrically toward the sagging section 142 as the adjusting idler 208 is adjusted to maintain tension on the diaphragm 116. When the two opposing arcuate gripper surfaces meet at the left-side material transfer position 210, the first electrode 204 is released from the first eccentric rotatable multi-faceted gripper 136 and simultaneously pulled onto the central eccentric rotatable multi-faceted gripper 140 (e.g., by applying a vacuum through the relatively porous sagging section 142 beneath the first electrode 204). Thus, the first arcuate gripper surface 206 holds the first electrode 204 and the fixed portion 212 of the diaphragm 116. Additionally, the second arcuate gripper surface 214 retains the second electrode 216 in an upward intermediate right-side position 218 that is oriented 120° clockwise from the left-side material transfer position 210.

[0067] With the first electrode 204 and the fixed portion 212 retained by the central eccentric rotatable multi-faceted gripper 140, as the central eccentric rotatable multi-faceted gripper 140 continues to rotate downward eccentrically toward the battery stack 118, a second position 220 is established. Thus, the first electrode 204 and the fixed portion 212 pass through the intermediate left-side position 222 and the second electrode 216 reaches the topmost central position 224. An air stream from an air knife, vacuum, or similar force is applied to the slack section 226 of the diaphragm 116 to guide the slack section through the top 228 of the battery stack 118, thereby forming a Z-fold bend in the slack section 226 when preparing to place the first electrode 204 on top of the battery stack 118.

[0068] As the central eccentric rotatable multi-faceted gripper 140 continues to rotate to a third position 230, the first electrode 204 and the fixed portion 212 move further downward and to the right. The second electrode 216 moves further closer to the left-side material transfer position 210.

[0069] In the fourth position 232, the central eccentric rotatable multi-faceted gripper 140 is located at the bottommost central position 234, at which time the first electrode 204 and the fixed portion 212 are released onto the top 228 of the battery stack 118. The Z-lifter (not shown) of the battery stack 118 decreases downward as the number of layers increases such that placement is always performed at the same height. As described above, the release at the bottommost central position 234 occurs with substantially no lateral movement to avoid abrasion.

[0070] Once released, the central eccentric rotatable multi-faceted gripper 140 continues to rotate and moves toward the second eccentric rotatable multi-faceted gripper 138 ( Figure 1) Movement. The fifth position 236 shows the second electrode 216 and the second arcuate gripper surface 214 at the left material transfer position 210 for abrasion - free loading. Note that the second arcuate gripper surface 214 is not used to hold any part of the separator 116. In some embodiments, an air jet or vacuum pushes the separator 116 away from the second arcuate gripper surface 214, as shown in the sixth position 238. This creates space for the second electrode 216 to move towards the top 228, as shown in the seventh position 240. The seventh position 240 also shows how the third electrode 242 is attached to the first arcuate gripper surface 206 at the right material transfer position 244. The material type of the third electrode 242 is the same as that of the second electrode 216 (e.g., Figure 1 the aluminum cathode 112 in Figure 1 ), and both are provided by the second eccentric rotatable multi - faceted gripper 138 (

[0071] ). Figure 1 ) moves to the left material transfer position 210 such that the process repeats when the third arcuate gripper surface 250 reaches the first position 202.

[0072] Figure 3 The eccentric rotatable multi - faceted gripper assembly 300 is shown. The eccentric rotatable multi - faceted gripper assembly 300 includes an internal gear ring 302, external planetary gears 304, a central eccentric rotatable multi - faceted gripper 140 (e.g., Figure 1 and Figure 2 the central eccentric rotatable multi - faceted gripper 140 in

[0073] ), a balance weight 306, and an input shaft 308 that establishes a pivot axis of rotation 310. In this example, the central eccentric rotatable multi - faceted gripper 140 is a six - sided non - cylindrical body 312 that includes three angularly spaced arcuate gripper surfaces 314 and three angularly spaced frustoconical side surfaces 316.

[0074] Without the truncated sides 316, the arcuate gripper surface 314 would form a three-sided body, similar to a triangle with curved sides. However, in the body 312, the vertices of the triangle are truncated to provide clearance and reduce mass, as these vertices do not perform functions related to stacking. The specific design of the truncated surfaces can be adjusted to accommodate the tension forces on the unconstrained diaphragm (i.e., the tension forces on both the fixed portion 212 and the slack section 226( Figure 2 ))

[0075] The arcuate gripper surface 314 includes pneumatic gripper holes 326 configured to apply vacuum and pressure (obtained from the pneumatic inlet port 322 and the pneumatic outlet port 324) to retain and release layers from the two active arcuate gripper surfaces 314, as previously referenced Figure 2 as explained

[0076] In some embodiments, a continuous negative pressure and a positive pressure are applied to the ports. However, the delivery of these pressures is automatically periodic according to the orbital position through fluid communication channels (not shown) in the body 312, where the fluid communication channels are aligned with fixed internal ports (not shown) as the central eccentric rotatable multi-faceted gripper 140 orbits

[0077] Figure 4 A variant of the Z-fold stacker 400 is shown where the electrodes are provided in separate stacks rather than being conveyed by a transfer device. In other embodiments, the diaphragm can also be monomeric separation (i.e., non-Z-folded).

[0078] To illustrate examples of the holding and transfer forces applied during the transfer of the electrode and diaphragm sections, Figure 5 the Z-fold stacker 400 is shown in more detail during the eighth position 246, the first position 202, and the second position 220, respectively

[0079] In the eighth position 246, the first battery layer 502 (e.g., a copper or aluminum electrode with a graphite coating) is bent to a conforming position on the first arcuate gripper surface 504. The dashed arrow line represents the application of a vacuum force (negative pressure) that pulls the first battery layer 502 onto the first arcuate gripper surface 504. In this example, the drape section 142 is not affected by the vacuum force, but in other embodiments, the drape section 142 may also be pulled towards the first arcuate gripper surface 504 (e.g., see Figure 2 the fourth electrode 248 and the diaphragm 116 therein).

[0080] At the first position 202, the upper portion 506 of the first arcuate gripper surface 504 applies a negative pressure, while the bottom portion 508 applies a positive pressure (as indicated by the solid arrow lines). At the same time, the upper portion 510 of the second arcuate gripper surface 512 does not apply pressure, while the bottom portion 514 applies a negative pressure. Thus, the central eccentric rotatable multi-faceted gripper 140 applies a negative force via its second arcuate gripper surface 512 to pull the battery layer out of the left-side material transfer position 210 on the first arcuate gripper surface 504 and bend the battery layer into the conforming position on the second arcuate gripper surface 512.

[0081] In the second position 220, the coordinated action of the pressures transfers the material from one surface to the other. The first arcuate gripper surface 504 applies only a positive pressure 516, while the second arcuate gripper surface 512 applies only a negative pressure 518. The positive pressure 516 generated by the first arcuate gripper surface 504 also helps to form a Z-fold 520 in the slack section 226 ( Figure 2 ).

[0082] Starting from the second position 220, while the negative pressure 518 forces the battery layer to remain bent in the conforming position, the central eccentric rotatable multi-faceted gripper 140 rotates the second arcuate gripper surface 512 together with the battery layer to a second orientation transverse to the left-side material transfer position 210 (i.e., Figure 2 the lowermost central position 234), at which point the negative pressure 518 is released and a reverse force (not shown) is applied to transfer the battery layer from the conforming position on the second arcuate gripper surface 512 and transfer it to a non-bent position on a planar receiving surface (e.g., the top 228 of the battery stack 118). This provides an almost wear-free transfer of the battery layer from the conforming position on the arcuate surface to the non-bent position on the receiving surface for depositing the battery layer into the battery electrode and separator stack.

[0083] Note that in some embodiments, the reverse force (e.g., a positive pressure) is optional. For example, depending on the rotation speed, releasing the force while rotating is sufficient to place the electrode on the top of the battery stack 118 because gravity is sufficient to separate the material from the arcuate surface.

[0084] Figure 6 A Z-fold stacking machine 600 according to another embodiment is shown. In this example, a vacuum transfer device 602 is used instead of the first eccentric rotatable multi-faceted gripper 136 and the second eccentric rotatable multi-faceted gripper 138 to move the electrode into a vertical orientation that facilitates gripping by the central eccentric rotatable multi-faceted gripper 140 and placement on the stack.

[0085] As previously described, the eccentric rotatable multi-faceted gripper 328 includes an arcuate gripper surface 314 for continuous rotational movement. As Figure 7As shown, one of the candidate surface shapes for a continuous rotational motion system is based on the Reuleaux triangle 700. The boundary of the Reuleaux triangle 700 is a constant-width curve based on an equilateral triangle. All points on the side are equidistant from the opposite vertex. The Reuleaux triangle 700 can form a rotor within a square, which can complete a rotation while remaining within the square and always contacting all four sides of the square. In fact, the central part of each surface can be roughly matched to the length of the electrode (measured along the feed direction), so that the gripper surface can adapt to a certain range of lengths (theoretically up to r*π / 3 at most, where r is the side length of the equilateral triangle in the Reuleaux triangle 700, which is also the radius of curvature of the surface). Generally speaking, a shorter electrode length enables a higher production rate, but this depends on the design of the electrode, that is, specifically the placement of the terminal tabs, which are positioned transversely to the feed direction.

[0086] However, it should be noted that there are two problems with a system based on a pure Reuleaux triangle. The first problem is that the orbital motion at the center of the triangle is not a simple circle, but a combined segment of four ellipses. The second problem is that the action of the rotor on the electrodes on the sides of the square is not pure rolling without wear. For pure rolling, the linear distance traveled by the vertex along one side of the square must be equal to the length of the opposing arc rolling along the opposing side. Due to the relative linear motion between the surface and the electrode to be picked up or placed, this difference will cause wear.

[0087] Figure 7 and Figure 8 shows a way to quantify the wear. Consider a Reuleaux triangle 700 with side length r, continuously orbiting within a square perimeter 702 with side length also r. Pick up the electrode from the left and right sides of the square perimeter 702 and place the electrode on a stack (not shown) at the bottom of the square perimeter 702. For a general half-angle Θ, where Θ varies between 0° (vertical contact in the middle of the stack) and 30° (π / 6), then as Θ increases from 0°, the rotational (arc) distance traveled is r*Θ. The distance X is given by X = rsin(π / 6 + Θ) = r / 2*(cosΘ + √3sinΘ). Subtracting r / 2 from X, the linear distance traveled is r / 2*(cosΘ + √3sinΘ - 1). The wear is the difference between the two: r / 2*(2Θ + 1 - cosΘ - √3sinΘ).

[0088] Figure 8 Shown as a percentage of r, the wear effect is significant. Since the wear can be characterized mathematically, it can be compensated for, but this requires additional reciprocating motion for both the input positioning and the output stack. Similarly, the complex elliptical orbit of the rotor can be achieved through fine motion control or cam design, but pure rotational motion is more favored due to its simplicity and reliability. These effects will all be addressed in the modified Reuleaux triangle, as explained below.

[0089] The first step in designing the modified Reuleaux triangle is to create an anti-slip profile path for the centroid of the shape. This anti-slip path will ensure pure rolling motion at the curved surface. This is achieved by assuming that the rolling traversal distance is equal to the lateral movement of the vertices of the Reuleaux triangle. This is similar to an anti-slip wheel traversing a distance, where the specification is that the arc length in contact with the ground during the motion is equal to the lateral distance of the axle traveled.

[0090] Figure 9 The non-circular centroid orbital paths 900 in the X and Y directions are shown as a function of theta: X = (r * Θ) - (r centroid * sin(Θ)); Y = r centroid * cos(Θ). Each of the four arc paths 902 is the result of plotting the non-circular centroid orbital path 900 for appropriate r and r centroid values. Note that for any one of the four (square perimeter) sides defined by the Reuleaux triangle, the range of definition of Θ is ±15° from its central position, which is the path range before the adjacent curve of the triangle contacts the next orthogonal side of the larger square. Figure 9 The non-circular centroid orbital path 900 is shown to have sharp corners. This is neither suitable nor practical for the motion using standard gear drive components.

[0091] Accordingly, Figures 10 to 17 An example of an empirical method is shown that smooths the non-circular centroid orbital path 900 by inscribing a circular centroid orbital path 1000 ( Figure 10 ) as the orbit driven by an eccentric gear or planetary gear system (as described above).

[0092] To achieve zero wear, constant angular velocity gear motion, and proportional centroid Θ reverse rotation during orbital motion, Figure 10 the arc length of the arc path 1002 is shown to be proportional to the rotation Θ angle of the Reuleaux triangle. For simplicity of illustration, both path 902 and path 1002 are shown divided into 1° increments of Θ. The total Θ span is 30° (±15°), which corresponds to the total rolling contact range on one side of the outer square before contacting the adjacent side of the square.

[0093] Figure 11 An overview diagram 1100 of the non-circular centroid orbital path 900 and the circular centroid orbital path 1000 is shown to compare the complete orbits between the original path and the modified path. The new circular centroid orbital path 1000 should also adopt a new contact rolling surface design, because if the new circular centroid orbital path follows the arc path 1002, the original Reuleaux triangle surface will not achieve consistent non-wear contact. Figures 12 to 17Shows the way to create a new arc contact surface profile by initially setting the Reuleaux triangle to Θ = -15°.

[0094] Figure 13 Shown in more detail, to map the non-wearing rolling surface onto the locus of the circular centroid path 1000, a set of lines 1302 project downward from each Θ position on the circular centroid path 1000 to the surface 1304 being rolled. To ensure non-wearing, starting from the tangent intersection point 1308 of the vertical projection 1310, the projection lines are equidistant 1306 for each common increment of Θ.

[0095] Figure 14 Shows how to create the line intersection points 1402 corresponding to the Θ positions of the circular centroid path 1000. These corresponding line intersection points 1402 are at 15° to 0° with respect to the vertical direction and they correspond to the new Θ orientations.

[0096] Figure 15 Shows how to define the angle α. For each Θ position, this angle corresponds to the included angle between a set of lines 1302 and the corresponding line intersection points 1402. Now a table can be constructed to map the angle Θ to the projection line length D, and then to the included angle of the projection line with the new centroid α. Using each D and α in the table, Figure 16 Shows how to now construct the new non-wearing surface 1602 around the new centroid.

[0097] Θ D α 15 139.56 35.07 14 137.11 32.88 13 134.81 30.66 12 132.67 28.42 11 130.69 26.16 10 128.88 23.87 9 127.23 21.56 8 125.74 19.22 7 124.43 16.87 6 123.29 14.51 5 122.32 12.13 4 121.52 9.74 3 120.9 7.34 2 120.46 4.95 1 120.19 2.62 0 120.1 0

[0098] Figure 17 Shows how to pattern the surface 1602 on three sides spaced at 120° angular intervals around the centroid, thereby forming a three-lobed shape 1702 suitable for a specified orbital and centroid rotational motion. In some embodiments, the three-lobed shape 1702 can be part of a hollow or solid body (e.g., see the body 312 in Figure 3 ), to form a prism-shaped (i.e., suitable for gearing) that runs around an annular path and has non-wearing rolling surfaces on three outer surfaces. In other embodiments, the sides of the three-lobed shape 1702 can be connected by spokes on a hub (not shown).

[0099] In other embodiments, a greater number of sides can also be used. Those skilled in the art will also understand that, in addition to the empirical methods described previously, closed-form analysis techniques can also be employed to develop the arc gripper surface shape.

[0100] Figures 18 to 20 Shows another embodiment of the Z-fold stacking machine 1800. In this embodiment, instead of using the prism design described above, a reciprocating carriage 1802 reciprocates from side to side to pick up electrode layers and fold diaphragms (such as Figure 19and Figure 20 as shown), while placing the electrode layer and the separator in stack 1804.

[0101] Figure 19 Illustrates the reciprocating motion sequence 1900 of the reciprocating carriage 1802. The reciprocating carriage 1802 includes: a first gripper 1902 for the first electrode 1904, a second gripper 1906 for the second electrode 1908, and a gap for z-folding the separator 1910 as the reciprocating carriage 1802 moves from one side to the other.

[0102] Figure 20 Illustrates the manner in which the z-folding stacker 1800 implements the rolling transfer of the battery layers in order to reduce wear. For clarity, Figure 20 the reciprocating carriage 1802 is omitted.

[0103] In the first position 2002, the first electrode 1904 is horizontally oriented on top of the first vacuum roll 2004, where the first electrode can be lifted by the negative pressure applied by the first gripper 1902 ( Figure 19 ). At the same time, the second electrode 1908 is introduced into the second vacuum roll 2006.

[0104] In the second position 2008, the first electrode 1904 is released by the first vacuum roll 2004 and shuttles on top of the stack 1804. At the same time, the second vacuum roll 2006 applies a vacuum force via its arcuate surface to the second electrode 1908 to move the second electrode from its initial position and bend the second electrode to a conforming position on the arcuate surface.

[0105] Then, it reaches the third position 2010 as follows. While the vacuum force keeps the second electrode 1908 bent in the conforming position, the second vacuum roll 2006 rotates such that the arcuate surface holding the second electrode 1908 moves to a second orientation (e.g., horizontal), which is transverse to the first orientation when the second electrode 1908 is introduced.

[0106] To transition to the fourth position 2012, the second vacuum roll 2006 releases its vacuum force, while the second gripper 1906 ( Figure 19 ) applies a vacuum force to transfer the second electrode 1908 from the conforming position on the arcuate surface to a non-bent position on the receiving surface of the second gripper 1906 in a substantially wear-free manner for depositing the second electrode 1908 into the battery electrode and separator stack 1804.

[0107] Figure 21Another Z-fold stacker 2100 is shown that includes a pair of reciprocating rollers 2102 in a stacking sequence. The function of the pair of reciprocating rollers 2102 is similar to that of the reciprocating carriage 1802, but instead of lifting and placing electrodes, each of the reciprocating rollers 2102 rotates as the curved electrode conforms to the roller surface (e.g., a vacuum force is applied through a pneumatic gripper hole, not shown), while gradually releasing the negative pressure and applying a positive pressure as the roller moves over the top of stack 2104. For example, the right roller 2106 collects the electrodes provided on the right side, shuttles the right roller to the left while applying a vacuum force and rotating the right roller above the stack 2104, and then gradually releases the vacuum force while applying a positive pressure according to the lateral position above the stack 2104.

[0108] Figure 22 A method 2200 for forming a battery electrode and separator stack is shown (the method can be implemented by any one and / or a multi-faceted gripper of stackers 100, 400, 600, 1800, or 2100). In block 2202, method 2200 applies a force to the battery layer via an arcuate surface to move the battery layer from a first position and bend the battery layer to a conforming position on the arcuate surface. In block 2204, while the force keeps the battery layer bent in the conforming position, method 2200 rotates the arcuate surface with the battery layer to a second position transverse to the first position. In block 2206, method 2200 releases the force and optionally applies a reverse force to transfer the battery layer from the conforming position on the arcuate surface to a non-bent position on the receiving surface with substantially no abrasion, thereby depositing the battery layer into the battery electrode and separator stack. The method can also include eccentric rotation of the arcuate surface, lateral and vertical displacement of the arcuate surface relative to the receiving surface.

[0109] Figure 23 A method 2300 is shown (in some embodiments, the method can be performed by stackers 100, 400, 600, 1800, or 2100 and / or a multi-faceted gripper) for transporting a battery layer from a first position to a second position using an arcuate surface, which can be part of forming an electrode and separator stack.

[0110] Method 2300 includes applying a force 2302 to the battery layer via an arcuate surface to move the battery layer from a first position and bend the battery layer into a conforming position on the arcuate surface. In some embodiments, the applied force can be applied via vacuum, and in some embodiments, it can be applied electrostatically. In some embodiments, the arcuate surface can be located in a multi-faceted gripper and / or a stacker.

[0111] In step 2304, when a force holds the battery layer in a bent position in the fitting position, the method includes transporting the arcuate surface with the battery layer to a receiving surface. The transporting may include rotating the arcuate surface, where the rotation may include eccentric rotation. The receiving surface is located at a second position different from the first position. In some embodiments, the receiving surface is angularly offset from the first position. In some embodiments, the second position is transverse to the first position.

[0112] In step 2306, method 2300 includes transferring the battery layer from the fitting position on the arcuate surface to the receiving surface, where the transfer includes releasing the force applied via the arcuate surface and optionally applying a reverse force to provide the transfer. In some embodiments, the transfer may be wear-free or substantially wear-free.

[0113] In some embodiments, the receiving surface is another arcuate surface. In some embodiments, the receiving surface is located on an electrode and separator stack, and the transfer includes depositing the battery layer into the battery electrode and separator stack.

[0114] Methods 2200, 2300 may further include eccentrically rotating the arcuate surface and laterally and vertically displacing the arcuate surface relative to the receiving surface.

[0115] In another embodiment, methods 2200, 2300 may further include applying a force by evacuating through holes in the arcuate surface.

[0116] In another embodiment, methods 2200, 2300 may further include a battery layer having discrete electrodes located on top of a continuous separator sheet.

[0117] In another embodiment, methods 2200, 2300 may further include a battery layer having discrete electrodes located on top of discrete separator sheets.

[0118] In another embodiment, methods 2200, 2300 may further include applying a force by evacuating through pores in a continuous separator sheet to bend the battery layer.

[0119] In another embodiment, methods 2200, 2300 may further include applying a force by evacuating through holes in a laterally reciprocating gripper.

[0120] In another embodiment, methods 2200, 2300 may further include applying an optional force by gradually applying a positive pressure through holes in a laterally reciprocating roller according to a lateral position.

[0121] In another embodiment, methods 2200, 2300 may further include a first position, where the first position is a vertically oriented material transfer position defined by the arcuate surface facing another arcuate surface used as a pick-and-place device.

[0122] In another embodiment, methods 2200, 2300 may further include applying, rotating, and transferring and / or releasing a force in combination with a first laterally reciprocating roller on a first side of the battery stacker, and the method further includes repeating the applying, rotating, and transferring and / or releasing of the force in combination with a second laterally reciprocating roller on a second side of the battery stacker.

[0123] Those skilled in the art should understand that various modifications can be made to the details of the above-described embodiments without departing from the basic principles of the present invention. For example, these embodiments can be used in other applications, including unstacking, singulation separation, and pick-and-place uses. Therefore, the scope of the present invention should be determined only by the claims and their equivalents.

Claims

1. A method of forming a battery electrode and separator stack implemented by a battery stacking machine, the method comprising: Applying a force to a battery layer via an arcuate surface to move the battery layer from a first position and cause the battery layer to bend to a conforming position on the arcuate surface; While the force holds the battery layer bent in the conforming position, rotating the arcuate surface together with the battery layer to a second position; And Transferring the battery layer from the conforming position on the arcuate surface to a receiving surface, wherein the transfer includes releasing the force applied via the arcuate surface.

2. The method according to claim 1, characterized in that, The receiving surface is another arcuate surface, and wherein the transfer includes applying a force using the arcuate receiving surface to bend the battery layer to a conforming position on the receiving surface.

3. The method according to claim 1, wherein The receiving surface is a battery electrode and separator stack including a substantially flat surface, and wherein the transfer includes transferring the battery layer to an unbent position.

4. The method according to claim 1, characterized in that, The rotation includes eccentrically rotating the arcuate surface such that the arcuate surface is laterally and vertically displaced relative to the receiving surface.

5. The method according to claim 1, wherein The application of the force includes evacuating through holes in the arcuate surface.

6. The method according to claim 1, characterized in that, The method further includes gradually applying a positive pressure through holes in a laterally reciprocating roller according to a lateral position.

7. The method according to claim 1, wherein The first position is a vertically oriented material transfer position defined by the arcuate surface opposed to another arcuate surface serving as a pick-and-place device.

8. The method according to claim 1, characterized in that The method further includes performing the application of the force, the rotation, and the transfer in combination with a first laterally reciprocating roller on a first side of the battery stacking machine; the method further includes repeating the application of the force, the rotation, and the transfer in combination with a second laterally reciprocating roller on a second side of the battery stacking machine.

9. A battery stacking machine, the battery stacking machine comprising: An arcuate surface configured to apply a force to pull a battery layer from a first position and cause the battery layer to bend to a conforming position on the arcuate surface; An axis about which the arcuate surface is rotatable while the force holds the battery layer bent in the conforming position to rotate the battery layer to a second position; And A receiving surface for receiving the battery layer in response to the release of the force to transfer the battery layer from the conforming position on the arcuate surface to the receiving surface.

10. The battery stacking machine according to claim 9, characterized in that, The receiving surface is another arcuate surface.

11. The battery stacking machine according to claim 9, characterized in that, The receiving surface is a battery electrode and separator stack including a substantially flat surface.

12. The battery stacking machine according to claim 9, characterized in that, The battery stacking machine further includes a rotatable multi-faceted gripper including the arcuate surface.

13. The battery stacking machine according to claim 9, characterized in that, The force is a vacuum force applied through holes in the arcuate surface.

14. The battery stacking machine according to claim 9, wherein, The force is a first force, and wherein the arcuate surface is configured to apply a second force as a positive pressure applied through holes in the arcuate surface.

15. A rotatable multi-faceted gripper for conveying a battery layer, the rotatable multi-faceted gripper comprising: A body, the body comprising: Three arcuate gripper surfaces angularly spaced apart from each other; and Three frustoconical side surfaces angularly spaced apart from each other, Each arcuate gripper surface includes means for applying a force to a battery layer positioned on the arcuate gripper surface to hold the battery layer in a conforming position on the arcuate gripper surface.

16. The rotatable multi-faceted gripper according to claim 15, characterized in that, Each arcuate gripper surface further includes means for applying a second force as a positive pressure to the battery layer to release the battery layer and / or transfer the battery layer to a receiving surface.

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