Methods and units for manufacturing battery cells

Abstract

The present invention relates to a method (12) for manufacturing a cell for a secondary battery, the method comprising: - a first operation (O1) of moving a stacking platform, wherein the movement is performed along a first direction of movement; - a second operation (O2) of unwinding a separator onto the stacking platform, wherein the separator includes a first electrode pre-positioned thereon; - a third operation (O3) of moving the stacking platform along a second direction of movement opposite to the first direction of movement; - a fourth operation (O4) of placing a second electrode onto the separator, wherein the polarity of the second electrode is opposite to that of the first electrode; - a fifth operation (O5) of moving the stacking platform along the first direction of movement.

Description

Technical Field

[0001] This invention relates to the field of rechargeable batteries for electric vehicles. In particular, it relates to the manufacture of battery cells. More specifically, it relates to a method and apparatus for manufacturing "pouch" type lithium-ion electrochemical cells. The invention may also relate to a method and apparatus for manufacturing prism-shaped lithium-ion electrochemical cells. Background Technology

[0002] Cells used in rechargeable batteries (such as those called pouch cells) can be manufactured in a variety of ways.

[0003] One way to manufacture these cells is to cut electrodes of opposite polarity, then stack these electrodes on top of each other and separate them with an insulating membrane.

[0004] The separator is unwound as the electrode is placed on it. Therefore, the separator is first unwound. The first electrode is placed. The separator is then unwound again to cover the first electrode. A second electrode with the opposite polarity to the first electrode is then placed on the separator. The separator is then unwound again to cover the second electrode. These operations are repeated several times depending on capacity and power requirements.

[0005] Under the generally accepted business model, battery cell manufacturing plants operate at high production rates, both to achieve economies of scale and to meet the growing demands of the automotive industry. Therefore, the core operation involves stacking electrodes one on top of another to form an electrode stack, where precision and speed work in tandem to ensure plant productivity, cell reliability, and end-user safety. During the stacking operations within the manufacturing cell, tools move at high speeds. Thus, typically, a manufacturing cell forms an electrode stack containing more than 50 electrodes in less than a minute. To continuously improve production rates, the various movements of the tools must be optimized.

[0006] Therefore, the present invention aims to improve existing battery cell manufacturing methods and manufacturing units to increase productivity. Summary of the Invention

[0007] Therefore, a method for manufacturing a cell for a secondary battery is first proposed, the method comprising: - A first operation to move the stacking platform, the movement being performed along a first direction of movement. - A second operation of unwinding a separator film on the stacking table, the separator film including a first electrode pre-positioned thereon. - A third operation: moving the stacking platform in a second direction opposite to the first direction of movement. - A fourth operation is to place the second electrode on the insulating membrane, wherein the polarity of the second electrode is opposite to that of the first electrode. - The fifth operation of moving the stacking platform along the first direction of movement. - A sixth operation involves unwinding the insulating membrane to cover the second electrode, the insulating membrane also including a first electrode pre-assembled thereon and placed on the insulating membrane above the second electrode. - The seventh operation is to move the stacking platform along the second direction. In the method, the fourth, fifth, sixth and seventh operations are repeated until an electrode stack is formed, in which electrodes of opposite polarity are separated by an insulating membrane.

[0008] This method allows for industrial production rates to be achieved while reducing the number of operations. This optimizes the movement of various tools.

[0009] Various additional features can be provided individually or in combination: - The first direction of movement is vertically downward and the second direction of movement is vertically upward. In this method, during electrode stacking, the stacking platform moves only along a generally straight path. - The electrodes are stacked one on top of the other, and the electrodes are separated from each other by the insulating membrane; - The second and sixth operations are initiated at the end of the first and fifth operations, respectively; - The fourth operation is initiated at the end of the third operation or at the end of the seventh operation; - The separator film is continuously unwound; - During the first operation, the stacking platform is vertically translated in a first direction from a first high position to a first low position at a first height. During the third operation, the stacking platform is vertically translated in a second direction from a first low position to a second high position, where the second high position is located at a second height lower than the first height, and the height is measured in a vertical direction from a fixed reference point. - During the fifth operation, the stacking platform is vertically translated from the second high position to the second low position along the first direction. During the seventh operation, the stacking platform is vertically moved from the second low position to the third high position along the second direction. The third high position is located at a third height lower than the second height, which is measured vertically from the fixed reference point. - The fourth, fifth, sixth and seventh operations form a sequence, the method comprising at least two sequences to form an electrode stack in which electrodes of opposite polarity are separated by an insulating membrane; - The sequences are different from each other, such that the third height of a given sequence is greater than the first height of another sequence immediately following the given sequence; - The travel of the stacking platform during the first operation is approximately equal to the travel of the stacking platform during the fifth operation; - The travel of the stacking platform during the third operation is approximately equal to the travel of the stacking platform during the seventh operation; - The first electrode is pre-positioned on the lower surface of the isolation membrane, the lower surface being located on the stacking platform side.

[0010] Secondly, a manufacturing unit is proposed, the manufacturing unit comprising: - A stacking platform that can be translated along a straight path. - A device for moving the stacking platform. - A device for unwinding the release film on the stacking table. - A device for placing the second electrode on the insulating membrane. - A control unit, the control unit comprising a computer program capable of performing the methods disclosed above.

[0011] Various additional features can be provided individually or in combination: - The device for unwinding the separator film can also keep the first electrode, which has a polarity opposite to that of the second electrode, in contact with the separator film so as to transfer the first electrode to the stacking platform or to the second electrode. Attached Figure Description

[0012] Further features and advantages of the present invention will become apparent from the following detailed description. For a better understanding of this detailed description, please refer to the accompanying drawings, in which: Figure 1 This is a schematic side view of a cell manufacturing unit according to the present invention.

[0013] Figure 2 It is a graph representing the operation according to the method of the present invention, with the x-axis representing time and the y-axis representing height.

[0014] Figure 3 yes Figure 1 The front view of the manufacturing unit shown.

[0015] Figure 4 This is a schematic representation of the method according to the present invention. Detailed Implementation

[0016] Figure 1 Unit 1 is shown for manufacturing a cell to be integrated into a battery.

[0017] Manufacturing unit 1 includes a stacking platform 2. The stacking platform 2 can be translated along a generally straight path.

[0018] Advantageously, the manufacturing unit 1 includes a device 3 for moving the stacking platform 2.

[0019] Advantageously, the manufacturing unit 1 includes an unwinding device 4, which is capable of unwinding the release film 7 by placing the release film 7 on the stacking table 2.

[0020] Advantageously, the manufacturing unit 1 includes a device 5 for placing the second electrode 9 on the insulating membrane 7.

[0021] Advantageously, the manufacturing unit 1 includes a control unit 1, which includes a computer program for controlling the following: - Stacking platform 2, - Device 3 for moving the stacking platform 2 - Unwinding device 4, - Placement device 5.

[0022] A conveyor belt (not shown) transports the first electrodes 6 so that they come into contact with the insulating membrane 7. The first electrodes 6 are positioned on the insulating membrane 7 before being placed on the stacking platform 2. In other words, the first rectangular electrodes are positioned on the insulating membrane at a certain distance from each other before being placed on the stacking platform.

[0023] Advantageously, the unwinding device 4 includes two clamps arranged on both sides of the release film 7. The release film 7 comes from the reel 8.

[0024] Advantageously, the clamp can simultaneously hold the separator 7 and the first electrode 6 so as to keep the first electrode 6 in close contact with the separator 7. Therefore, the clamp can simultaneously unwind the separator 7 and convey the first electrode 6 so as to place the first electrode 6 on the stacking platform 2 or on the second electrode 9.

[0025] The following describes method 12 for manufacturing cells for secondary batteries.

[0026] Manufacturing method 12 includes a first operation O1 of moving the stacking platform 2 of the manufacturing unit. This movement is performed along a first direction 10. In practice, the stacking platform 2 moves vertically downward, i.e., toward the floor on which it is placed. The stacking platform includes a placement surface 14 extending in a plane substantially perpendicular to the first direction.

[0027] Method 12 includes a second operation O2 for unwinding a release liner 7 onto a placement surface 14 of a stacking platform 2. The release liner 7 includes a first electrode 6 pre-positioned thereon. The first electrode 6 is pre-positioned on the release liner 7 via a conveyor belt. During the second operation O2, a clamp holds the release liner 7 and the first electrode 6 respectively and moves along the direction of the stacking platform 2 to place the first electrode 6 on the stacking platform 2.

[0028] Advantageously, method 12 includes a third operation O3 for moving the stacking platform 2. This movement is carried out in a second movement direction 11 opposite to the first movement direction 10. In practice, the stacking platform 2 moves vertically upward, i.e., away from the floor.

[0029] Advantageously, method 12 includes a fourth operation O4 for placing the second electrode 9 on the insulating membrane 7. The polarity of the second electrode 9 is opposite to that of the first electrode 6. During this fourth operation O4, the placement device 5 picks up the second electrode 9 from a dedicated area and places it on the insulating membrane 7, substantially opposite to the first electrode 6.

[0030] Advantageously, method 12 includes a fifth operation O5 of moving the stacking platform 2 along the first direction of movement 10. The stacking platform 2 then moves upward, away from the ground.

[0031] Advantageously, method 12 includes a sixth operation O6 of unwinding the separator 7. The sixth unwinding operation O6 is substantially the same as the second unwinding operation O2. Thus, during the sixth unwinding operation O6, the clamps hold the separator 7 and the first electrode 6 (pre-assembled on the separator 7) respectively and move toward the stacking platform 2 to place the first electrode 6 on the second electrode 9 placed during the fourth operation O4. During the sixth operation O6, due to the translation of the clamps along the direction of the stacking platform 2, the second electrode 9 is covered by the separator 7, and the first electrode 6 is placed on the separator 7, substantially opposite to the second electrode 9. Of course, the electrodes do not directly contact each other because the separator 7 is arranged between them.

[0032] Advantageously, method 12 includes a seventh operation O7 of moving the stacking platform 2 along the second direction 11.

[0033] Advantageously, operations O4, O5, O6, and O7 are repeated to form an electrode stack. In this electrode stack, the electrodes are separated by an insulating membrane 7.

[0034] As previously described, when the separator 7 is unwound, i.e., during the second operation O2 and the sixth operation O6, as the jig moves toward the stacking table, the first electrode 6 held by the jig is covered by the separator 7. This can be achieved by pre-positioning the first electrode 6 on the separator 7, particularly on the lower surface 13 of the separator. (See reference...) Figure 1 The lower surface 13 of the isolation membrane 7 is defined as the lower surface of one side of the stacking platform 2.

[0035] Method 12 allows for increased industrial production rates by reducing the number of operations. This optimizes the movement of various tools.

[0036] Advantageously, the stacking stage 2 moves only along a roughly straight path during electrode stacking.

[0037] This keeps the electrode stack in place. Other movements can cause electrode misalignment, leading to short circuits. Moreover, more complex movements, i.e., non-linear movements, can increase manufacturing time.

[0038] The electrodes are arranged one on top of the other and separated from each other by the insulating membrane 7.

[0039] Advantageously, the second operation O2 is initiated at the end of the first operation O1, and the sixth operation O6 is initiated at the end of the fifth operation O5. In other words, the second operation O2 is performed after the first operation O1, and the sixth operation O6 is performed after the fifth operation O5.

[0040] This optimizes the movement of the clamp. In fact, the clamp can move toward the stacking platform 2 along one of the shortest paths or the shortest possible paths. In other words, the clamp can move toward the stacking platform 2 in a roughly straight line as the stacking platform 2 moves downward to allow the clamp to pass. As the stacking platform 2 moves downward, the clamp can move above the stacking platform 2 to unwind the separator 7 and place the first electrode 6.

[0041] Advantageously, the fourth operation O4 is initiated at the end of the third operation O3 or at the end of the seventh operation O7.

[0042] This optimizes the movement of the placement devices 5. In fact, they can move toward the stacking platform along the shortest path or one of the shortest possible paths.

[0043] Advantageously, the separator 7 is continuously unwound. In other words, the separator 7 is not cut during the stacking operation. The separator 7 comes from the reel 8 and is unwound by a jig without being cut except at the very end of the stacking process when the electrode stack is ready to be removed from the stacking table 2.

[0044] This reduces the number of operations and increases production rate.

[0045] In the following text, the height is measured from a fixed reference point along a vertical direction (e.g., first direction 10 and second direction 11).

[0046] Advantageously, refer to Figure 2 During the first operation O1, the stacking platform 2 performs a linear vertical translation along the first direction 10. This translation begins at a first high position P1h at a first height H1 and ends at a first low position P1b. During the third operation O3, the stacking platform 2 performs a linear vertical translation along the second direction 11. This translation begins at the first low position P1b and ends at a second high position P2h at a second height H2. Advantageously, the second height H2 is less than the first height H1.

[0047] This difference between the first height H1 and the second height H2 advantageously accommodates the increase in electrode stack thickness. In other words, the stacking stage 2 will not return to its initial position (first high position P1h) to allow the fixtures to pass through. In fact, if the fixtures were to return to their initial position (first high position p1h), they would easily collide with the electrode stack, and to avoid this, the movement of the fixtures would need to be modified, which would reduce the production rate.

[0048] Advantageously, refer to Figure 2 During the fifth operation O5, the stacking platform 2 undergoes a linear vertical translation along the first direction. This translation begins at the second highest position P2h at the second height H2 and ends at the second lowest position P2b. During the seventh operation O7, the stacking platform 2 undergoes a linear vertical translation along the second direction 11. This translation begins at the second lowest position P2b and ends at the third highest position P3h at the third height H3. Advantageously, the third height H3 is less than the second height H2.

[0049] As previously mentioned, this difference between the second height H2 and the third height H3 advantageously accommodates the increase in electrode stack thickness.

[0050] Advantageous: - Fourth operation O4, - Fifth operation O5, - Sixth operation O6, - Seventh operation O7, Form a sequence.

[0051] The method advantageously includes at least two sequences to form an electrode stack separated by the isolation membrane 7.

[0052] However, the sequences are different from each other.

[0053] Advantageously, the third height H3 of a given sequence is greater than the first height H1 of another sequence immediately following the given sequence.

[0054] This is advantageously suited to the increase in electrode stack thickness.

[0055] Advantageously, the travel of stacking platform 2 during the first operation O1 is approximately equal to the travel of stacking platform 2 during the fifth operation O5.

[0056] This results in a stepped moving profile, such as Figure 2 As shown in the diagram. In this way, by reducing the stroke of stacking table 2 to a strictly necessary level, unnecessary movement can be reduced. This increases production speed.

[0057] Advantageously, the travel of stack 2 during the third operation O3 is approximately equal to the travel of stack 2 during the seventh operation O7.

[0058] This results in a stepped moving profile, such as Figure 2 As shown in the diagram. This reduces unnecessary movement by minimizing the travel of the stacking platform to a strictly necessary level. This increases production speed.

Claims

1. A method (12) for manufacturing a cell for a secondary battery, the method comprising: - The first operation (O1) of the moving stacking platform (2), the movement being performed along a first movement direction (10), - A second operation (O2) involves unwinding a separator (7) on the stacking platform (2), the separator (7) comprising a first electrode (6) pre-positioned thereon. - A third operation (O3) involves moving the stacking platform (2) along a second movement direction (11) opposite to the first movement direction (10). The method is characterized by comprising: - A fourth operation (O4) involves placing the second electrode (9) on the insulating membrane (7), wherein the polarity of the second electrode (9) is opposite to that of the first electrode (6). - The fifth operation (O5) of moving the stacking platform (2) along the first moving direction (10), - A sixth operation (O6) is performed to unwind the insulating membrane (7) to cover the second electrode (9), the insulating membrane (6) further comprising a first electrode (6) pre-assembled thereon and placed on the insulating membrane (7) above the second electrode (9). - The seventh operation (O7) of moving the stacking platform (2) along the second direction (11), In the method, the fourth, fifth, sixth and seventh operations (O4-O7) are repeated until an electrode stack is formed, in which electrodes of opposite polarity are separated by the insulating membrane (7).

2. The method (12) according to claim 1, wherein the first moving direction (10) is oriented vertically downward and the second moving direction (11) is oriented vertically upward, wherein in the method (12), the stacking platform (2) moves only along a generally straight path during electrode stacking.

3. The method (12) according to any of the preceding claims, wherein the electrodes are stacked on top of each other to form an electrode stack, and the electrodes are separated from each other by the insulating membrane (7).

4. The method (12) according to any of the preceding claims, wherein the second operation (O2) and the sixth operation (O6) are initiated at the end of the first operation (O1) and the end of the fifth operation (O5), respectively.

5. The method (12) according to any of the preceding claims, wherein the fourth operation (O4) is initiated at the end of the third operation (O3) or at the end of the seventh operation (O7).

6. The method (12) according to any one of the preceding claims, wherein the separator (7) is continuously unwound.

7. The method (12) according to any of the preceding claims, wherein during a first operation (O1), the stacking platform (2) is vertically translated in a straight line along a first direction (10) from a first high position (P1h) at a first height (H1) to a first low position (P1b), and during a third operation (O3), the stacking platform (2) is vertically translated in a straight line along a second direction (11) from the first low position (P1b) to a second high position (P2h), the second high position (P2h) being located at a second height (H2) lower than the first height (H1), the height being measured in a vertical direction from a fixed reference point.

8. The method (12) according to claim 7, wherein during the fifth operation (O5), the stacking platform (2) is vertically translated in a straight line along a first direction (10) from the second high position (P2h) to the second low position (P2b), and during the seventh operation (O7), the stacking platform (2) is vertically translated in a straight line along a second direction (11) from the second low position (P2b) to the third high position (P3h), the third high position (P3h) being located at a third height (H3) lower than the second height (H2), the height being measured in a vertical direction from the fixed reference point.

9. The method (12) according to any one of the preceding claims, wherein the fourth, fifth, sixth and seventh operations (O4-O7) form a sequence, the method (12) comprising at least two sequences for forming an electrode stack in which electrodes of opposite polarity are separated by an isolation membrane (7).

10. The method (12) according to claim 9 in conjunction with claim 8, wherein the sequences are different from each other such that the third height (H3) of a given sequence is greater than the first height (H1) of another sequence immediately following the given sequence.

11. The method (12) according to any of the preceding claims, wherein the travel of the stacking platform (2) during the first operation (O1) is substantially equal to the travel of the stacking platform (2) during the fifth operation (O5).

12. The method (12) according to any of the preceding claims, wherein the travel of the stacking platform (2) during the third operation (O3) is substantially equal to the travel of the stacking platform (2) during the seventh operation (O7).

13. The method (12) according to any of the preceding claims, wherein the first electrode (6) is pre-positioned on the lower surface (13) of the isolation membrane, the lower surface (13) being located on the side of the stacking platform (2).

14. A manufacturing unit (1), the manufacturing unit (1) comprising: - A stacking platform that can be translated along a straight path (2), - A device (3) for moving the stacking platform (2), - A device for unwinding the release film (7) on the stacking table (2), - A device (5) for placing the second electrode (9) on the insulating membrane (7), - A control unit comprising a computer program capable of executing the method according to any one of claims 1-13.

15. The unit (1) according to claim 14, wherein the means (4) for unwinding the separator (7) is also capable of keeping the first electrode (6) with a polarity opposite to that of the second electrode (9) in contact with the separator (7) so as to transfer the first electrode (6) to the stack (2) or to the second electrode (9).

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