Process and unit for manufacturing a cell for an electric battery

Abstract

A method (12) for manufacturing a secondary battery cell comprising: - a first operation (O1) of moving a stacking table, said movement being carried out along a first direction of movement, - a second operation (O2) of unwinding a separator film onto the stacking table, said separator film comprising a first electrode previously positioned thereon, - a third operation (O3) of moving the stacking table along a second direction of movement opposite to the first direction of movement, - a fourth operation (O4) of depositing a second electrode onto the separator film, said second electrode having the opposite polarity to the first electrode, - a fifth operation (O5) of moving the stacking table along the first direction of movement. Figure for the abbreviation: Figure 4

Description

Title of the invention: Method and unit for manufacturing a cell for an electric battery Technical field of the invention

[0001] The invention relates to the field of rechargeable electric batteries for electric vehicles. In particular, the invention relates to the manufacture of electrical cells intended for use in electric batteries. More precisely, the invention relates to a method and a manufacturing unit for pouch-type lithium-ion electrochemical cells, that is, cells in sachets. The invention may also relate to a method and a manufacturing unit for prismatic-type lithium-ion electrochemical cells. Technical background

[0002] Electric cells, such as pouch cells, i.e. cells in sachets, intended to equip rechargeable electric batteries, can be manufactured in different ways.

[0003] One way of manufacturing these cells consists of cutting and then depositing electrodes of opposite polarity on top of each other, separating them with an insulating separator film.

[0004] The separator film is unrolled as the electrodes are deposited onto it. Thus, the separator film is first unrolled. A first electrode is deposited. The separator film is unrolled again to cover the first electrode. A second electrode of opposite polarity to the first electrode is deposited onto the separator film. The separator film is then unrolled again to cover the second electrode. These operations are repeated several times depending on the required capacity and power.

[0005] Production rates are high in electrical cell manufacturing plants, in accordance with the commonly accepted economic model, both to achieve economies of scale and to meet the growing needs of the automotive industry. The operations of stacking electrodes on top of each other to form an electrode stack are therefore a critical step where precision and speed work together to guarantee plant productivity, cell reliability, and end-user safety. During stacking operations in a manufacturing unit, the tools move at high speeds. Thus, typically, a manufacturing unit forms an electrode stack of more than fifty electrodes in less than a minute. In a constant effort to increase production rates, the various movements performed by the tools are optimized. are expected to be optimized.

[0006] The invention therefore aims to improve existing electrical cell manufacturing processes and units in order to increase their productivity. Summary of the invention

[0007] To this end, a method for manufacturing a secondary battery cell is proposed firstly, comprising: - a first operation of moving a stacking table, said movement being carried out along a first direction of movement, - a second operation of unwinding a separator film onto the stacking table, said separator film comprising a first electrode previously positioned on it, - a third operation to move the stacking table along a second direction of movement opposite to the first direction of movement, - a fourth operation involving the placement of a second electrode onto the separating film, said second electrode being of opposite polarity to the first electrode, - a fifth operation to move the stacking table, along the first direction of movement, - a sixth operation of unwinding the separator film so as to cover the second electrode, said separator film further comprising a first electrode pre-assembled on it and placed on the separator film above the second electrode, - a seventh operation of moving the stacking table along the second direction, process in which the fourth, fifth, sixth, seventh operations are repeated until a stack of electrodes is formed in which the electrodes of opposite polarity are separated by the separator film.

[0008] This process makes it possible to achieve industrial production rates by reducing the number of operations. The movements of the various tools are thus optimized.

[0009] Various additional features may be provided alone or in combination: - the first direction of movement is oriented vertically downwards, and the second direction of movement is oriented vertically upwards, a process in which the stacking table moves only along a substantially straight trajectory during the stacking of the electrodes; - the electrodes are arranged one on top of the other to form a stack of electrodes, the electrodes being separated from each other by a separator film; - the second operation and the sixth operation are initiated respectively at the end of the first operation and the fifth operation; - the fourth operation is initiated at the end of the third operation or at the end of the seventh operation; - the separator film is unrolled continuously; - during the first operation, the stacking table performs a vertical rectilinear translational movement in the first direction from a first high position located at a first height to a first low position and during the third operation, the stacking table performs a vertical rectilinear translational movement in the second direction from the first low position to a second high position located at a second height lower than the first height, said heights being measured from a fixed reference point in a vertical direction; - during the fifth operation, the stacking table performs a vertical rectilinear translational movement in the first direction from the second high position to a second low position and during the seventh operation, the stacking table performs a vertical rectilinear translational movement in the second direction from the second low position to a third high position located at a third height lower than the second height, said heights being measured from the fixed reference point in a vertical direction; - the fourth, fifth, sixth and seventh operations form a sequence, the said process comprising at least two sequences so as to form a stack of electrodes in which the electrodes of opposite polarity are separated by a separating film; - the sequences differ from each other such that the third pitch of a given sequence is higher than the first pitch of another sequence that immediately follows the given sequence; - the stroke of the stacking table during the first operation is approximately equal to the stroke of the stacking table during the fifth operation; - the stroke of the stacking table during the third operation is approximately equal to the stroke of the stacking table during the seventh operation; - the first electrodes are pre-positioned on an underside of the separator film, said underside being located on the side of the stacking table.

[0010] Secondly, a manufacturing unit comprising: - a mobile stacking table that translates along a straight trajectory, - means of moving the stacking table, - means for unwinding a separator film onto the stacking table, - means for depositing a second electrode onto the separator film, - a control unit comprising a computer program capable of putting into implements a process such as previously described.

[0011] Various additional features may be provided alone or in combination: - the means for unwinding the separator film are also capable of maintaining a first electrode, of opposite polarity to the second electrode, in contact with the separator film so as to convey said first electrode onto the stacking table or onto a second electrode. Brief description of the figures

[0012] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, for an understanding of which reference should be made to the accompanying drawings in which:

[0013] [Fig-1] [Fig.1] is a side view of a schematic representation of a unit of fa cell brication according to the invention.

[0014] [Fig.2] [Fig.2] is a graph representing the operations of a process according to the invention, the x-axis being time and the y-axis being height.

[0015] [Fig.3] [Fig.3] is a front view of the manufacturing unit of [Fig.1].

[0016] [Fig.4] [Fig.4] is a representation of a method according to the invention. Detailed description of the invention

[0017] Figure 1 shows a unit 1 for manufacturing electrical cells intended to be integrated into electric batteries.

[0018] The manufacturing unit 1 comprises a stacking table 2. The stacking table 2 is movable in translation along a substantially rectilinear trajectory.

[0019] The manufacturing unit 1 advantageously includes means 3 for moving the stacking table 2.

[0020] Advantageously, the manufacturing unit 1 includes unwinding means 4 suitable for unwinding the separator film 7 by placing it on the stacking table 2.

[0021] Advantageously, the manufacturing unit 1 includes means 5 for depositing a second electrode 9 on the separator film 7.

[0022] Advantageously, the manufacturing unit 1 comprises a control unit 1 including a computer program for controlling: - the stacking table 2, - the means 3 for moving the stacking table 2, - the 4 means of unwinding, - the 5 means of deposit.

[0023] A conveyor (not shown in the drawings) transports the first electrodes 6 so as to bring them into contact with the separator film 7. The first electrodes 6 are positioned on the separator film 7 before being placed on the table 2 stacking. In other words, the first rectangular electrodes are positioned on the separator film, spaced apart from each other, before being placed on the stacking table.

[0024] Advantageously, the unwinding means 4 comprise two clips arranged on either side of the separator film 7. The separator film 7 comes from a reel 8.

[0025] Advantageously, the grippers are capable of simultaneously grasping the separator film 7 and a first electrode 6 so as to hold the latter against the separator film 7. The grippers can thus simultaneously unwind the separator film 7 and convey a first electrode 6 so as to deposit it on the stacking table 2 or on a second electrode 9.

[0026] In what follows a method 12 for manufacturing a cell for a secondary battery will be described.

[0027] The manufacturing process 12 comprises a first operation 01 of moving the stacking table 2 of the manufacturing unit. This movement is carried out along a first direction 10. In practice, the stacking table 2 moves vertically downwards, that is, towards the ground, on which said stacking table 2 rests. The stacking table includes a depositing face 14 which extends in a plane substantially perpendicular to the first direction.

[0028] The process 12 includes a second operation 02 of unwinding the separator film 7 onto the depositing face 14 of the stacking table 2. The separator film 7 includes a first electrode 6 previously positioned on it. The first electrode 6 is pre-positioned on the separator film 7 by means of the conveyor. During the second operation 02, the grippers each grasp the separator film 7 and the first electrode 6 and move them towards the stacking table 2 to deposit the first electrode 6 onto the stacking table 2.

[0029] Advantageously, the method 12 includes a third operation 03 of moving the stacking table 2. This movement is carried out along a second direction 11 of movement opposite to the first direction 10 of movement. In practice, the stacking table 2 moves vertically upwards, that is, away from the ground.

[0030] Advantageously, the method 12 includes a fourth operation 04 of depositing a second electrode 9 onto the separator film 7. The second electrode 9 has the opposite polarity to the first electrode 6. During this fourth operation 04, the depositing means 5 grasp a second electrode 9 from a dedicated area and then deposit it onto the separator film 7, substantially opposite the first electrode 6.

[0031] Advantageously, the method 12 comprises a fifth operation 05 of moving the stacking table 2 along the first direction 10. The table 2 The stack then moves upwards away from the ground.

[0032] Advantageously, the method 12 includes a sixth operation 06 of unwinding the separator film 7. The sixth unwinding operation 06 is substantially identical to the second unwinding operation 02. Thus, during the sixth unwinding operation 06, the grippers each grasp the separator film 7 and the first electrode 6 (pre-assembled on the separator film) and move it towards the stacking table 2 to deposit the first electrode 6 onto a second electrode 9 deposited during the fourth operation 04. During the sixth operation 06, the second electrode 9 is covered by the separator film 7 by a translational movement of the grippers towards the stacking table 2, and a first electrode 6 is deposited on the separator film 7 and substantially opposite the second electrode 9. It should be noted that the electrodes are, of course, not in direct contact, the separator film 7 being arranged between them.

[0033] Advantageously, the method 12 includes a seventh operation 07 of moving the stacking table 2 along the second direction 11.

[0034] Advantageously, the fourth operation 04, the fifth operation 05, the sixth operation 06 and the seventh operation 07 are repeated in order to form a stack of electrodes. In this stack, the electrodes are separated by the separator film 7.

[0035] As previously mentioned, when the separator film 7 is unwound, i.e., during the second operation 02 and the sixth operation 06, the first electrode 6 that is grasped by the grippers is enveloped by the separator film 7 during the movement of said grippers towards the stacking table. This is made possible by pre-positioning the first electrode 6 on the separator film 7 and in particular on a lower face 13 of said separator. The lower face 13 of the separator film 7 is defined as the one located on the side of the stacking table 2, with reference to [Fig. 1].

[0036] This process 12 makes it possible to achieve industrial production rates by reducing the number of operations. The movements of the various tools are thus optimized.

[0037] Advantageously, the stacking table 2 moves only along a substantially straight trajectory during the stacking of the electrodes.

[0038] This ensures the secure stacking of the electrodes. Indeed, other movements could cause misalignment of the electrodes, which could lead to short circuits. Furthermore, more complex movements, i.e., non-linear movements, would increase manufacturing time.

[0039] The electrodes are arranged one on top of the other while being separated from each other by separator film 7.

[0040] Advantageously, the second operation 02 is initiated after the first operation 01, and the sixth operation 06 is initiated after the fifth operation 05. In other words, the second operation 02 is performed after the first operation 01, and the sixth operation 06 is performed after the fifth operation 05.

[0041] The movement of the grippers is thus optimized. Indeed, they can move along the shortest path, or one of the shortest possible paths, towards the stacking table 2. That is to say, essentially in a straight line towards the stacking table 2, since the latter is moved downwards to allow the grippers to pass. When the stacking table 2 is moved downwards, the grippers can move above the stacking table 2 to unwind the separator film 7 and deposit the first electrode 6.

[0042] Advantageously, the fourth operation 04 is initiated at the end of the third operation 03 or at the end of the seventh operation 07.

[0043] The movement of the depositing means 5 is thus optimized. Indeed, they can move along the shortest path or one of the shortest possible paths towards the stacking table.

[0044] Advantageously, the separator film 7 is unwound continuously. In other words, the separator film 7 is not cut during the stacking operations. The separator film 7 comes from a reel 8, which is unwound by means of the grippers without being cut, except at the very end of the stacking process when the stack is ready to be removed from the stacking table 2.

[0045] This makes it possible to reduce the number of operations and thus improve production rates.

[0046] In what follows, the heights are measured from a fixed reference point, along a vertical direction (for example the first direction 10 and the second direction H).

[0047] Advantageously, and with reference to [Fig. 2], during the first operation 01, the stacking table 2 undergoes a vertical rectilinear translational movement along the first direction 10. This translational movement is initiated from a first high position Plh located at a first height H1 to a first low position Pib. During the third operation 03, the stacking table 2 undergoes a vertical rectilinear translational movement along the second direction 11. This translational movement is initiated from the first low position Pib to a second high position P2h located at a second height H2. Advantageously, the second height H2 is lower than the first height HL

[0048] This difference between the first height H1 and the second height H2 advantageously accommodates the increase in the thickness of the electrode stack. In other words, the stacking table 2 does not return to its initial position (first high position Plh) to allow the passage of the clamps. Indeed, if it were to return to its initial position (first high position Plh), the clamps would be likely to strike the stack of electrodes and in order to avoid this it would then be necessary to modify the movement of the grippers which would slow down the production rate.

[0049] Advantageously, and with reference to [Fig. 2], during the fifth operation 05, the stacking table 2 undergoes a vertical rectilinear translational movement along the first direction. This translational movement is initiated from the second upper position P2h, located at the second height H2, to a second lower position P2b. During the seventh operation 07, the stacking table 2 undergoes a vertical rectilinear translational movement along the second direction 11. This translational movement is initiated from the second lower position P2b to a third upper position P3h, located at a third height H3. Advantageously, the third height H3 is lower than the second height H2.

[0050] This difference between the second height H2 and the third height H3 advantageously accommodates the increase in the thickness of the electrode stack, as previously explained.

[0051] Advantageously: - the fourth operation 04, - the fifth operation 05, - the sixth operation 06, - the seventh operation 07, form a sequence.

[0052] The method advantageously comprises at least two sequences to form a stack of electrodes separated by separator film 7.

[0053] However, the sequences are different from each other.

[0054] Advantageously, the third height H3 of a given sequence is greater than the first height H1 of another sequence which immediately follows the given sequence.

[0055] This advantageously accommodates the increase in the thickness of the electrode stack.

[0056] Advantageously, the stroke of the stacking table 2 during the first operation 01 is substantially equal to the stroke of the stacking table 2 during the fifth operation 05.

[0057] This allows for a stepped motion profile as shown in [Fig. 2]. In this way, it becomes possible to reduce unnecessary movements by limiting the stroke of the stacking table 2 to the bare minimum. This increases the production rate.

[0058] Advantageously, the stroke of the stacking table 2 during the third operation 03 is substantially equal to the stroke of the stacking table 2 during the seventh operation 07.

[0059] This allows for a stepped motion profile as shown in [Fig. 2]. In this way, it becomes possible to reduce unnecessary movements by limiting the stacking table's travel to the bare minimum. This, in turn, increases the production rate.

Claims

Demands

1. A method (12) for manufacturing a secondary battery cell comprising: - a first operation (01) of moving a stacking table (2), said movement being carried out along a first direction (10) of movement, - a second operation (02) of unwinding a separator film (7) onto the stacking table (2), said separator film (7) comprising a first electrode (6) previously positioned thereon, - a third operation (03) of moving the stacking table (2) along a second direction (11) of movement opposite to the first direction (10) of movement, - a fourth operation (04) of depositing a second electrode (9) onto the separator film (7), said second electrode (9) being of opposite polarity to the first electrode (6), - a fifth operation (05) of moving the stacking table (2), along the first direction (10) of movement,- a sixth operation (06) of unwinding the separator film (7) so as to cover the second electrode (9), said separator film (7) further comprising a first electrode (6) pre-assembled thereon and placed on the separator film (7) above the second electrode (9), - a seventh operation (07) of moving the stacking table (2) along the second direction (11), a process in which the fourth, fifth, sixth, and seventh operations (04-07) are repeated until a stack of electrodes is formed in which the electrodes of opposite polarity are separated by the separator film (7).

2. Method (12) according to claim 1 wherein, the first direction (10) of movement is oriented vertically downwards, and the second direction (11) of movement is oriented vertically upwards, method (12) wherein the stacking table (2) moves only along a substantially straight path during the stacking of the electrodes.

3. A method (12) according to any one of the preceding claims, wherein the electrodes are arranged one on top of the other to form an electrode stack, the electrodes being separated from each other from the others by film (7) separator.

4. Method (12) according to any one of the preceding claims wherein the second operation (02) and the sixth operation (06) are respectively initiated at the end of the first operation (01) and the fifth operation (05).

5. Method (12) according to any one of the preceding claims wherein the fourth operation (04) is initiated at the end of the third operation (03) or at the end of the seventh operation (07).

6. Method (12) according to any one of the preceding claims wherein the separator film (7) is unwound continuously.

7. A method (12) according to any one of the preceding claims wherein, during the first operation (01), the stacking table (2) performs a vertical rectilinear translational movement along the first direction (10) from a first high position (Plh) located at a first height (Hl) to a first low position (Pib) and during the third operation (03), the stacking table (2) performs a vertical rectilinear translational movement along the second direction (l1) from the first low position (Pib) to a second high position (P2h) located at a second height (H2) lower than the first height (Hl), said heights being measured from a fixed reference point along a vertical direction.

8. Method (12) according to claim 7 wherein, during the fifth operation (05), the stacking table (2) performs a vertical rectilinear translational movement along the first direction (10) from the second high position (P2h) to a second low position (P2b) and during the seventh operation (07), the stacking table (2) performs a vertical rectilinear translational movement along the second direction (11) from the second low position (P2b) to a third high position (P3h) located at a third height (H3) lower than the second height (H2), said heights being measured from the fixed reference point along a vertical direction.

9. A method (12) according to any one of the preceding claims in which the fourth, fifth, sixth and seventh operations (04 - 07) form a sequence, said method (12) comprising at least two sequences so as to form a stack of electrodes in which the electrodes of opposite polarity are separated by a separator film (7).

10. Method (12) according to claim 9 in combination with claim 8 wherein the sequences differ from each other such that the third height (H3) of a given sequence is greater than the first height (H1) of another sequence which immediately follows the given sequence.

11. Method (12) according to any one of the preceding claims wherein the stroke of the stacking table (2) during the first operation (01) is substantially equal to the stroke of the stacking table (2) during the fifth operation (05).

12. Method (12) according to any one of the preceding claims wherein the stroke of the stacking table (2) during the third operation (03) is substantially equal to the stroke of the stacking table (2) during the seventh operation (07).

13. Method (12) according to any one of the preceding claims wherein the first electrodes (6) are pre-positioned on a lower face (13) of the separator film, said lower face (13) being located on the side of the stacking table (2).

14. Manufacturing unit (1) comprising: - a stacking table (2) movable in translation along a rectilinear trajectory, - means (3) for moving the stacking table (2), - means (4) for unwinding a separator film (7) onto the stacking table (2), - means (5) for depositing a second electrode (9) onto the separator film (7), - a control unit comprising a computer program capable of implementing a method according to any one of claims 1 to 13.

15. Unit (1) according to the preceding claim in which, the means for (4) unwinding the separator film (7) are further able to keep a first electrode (6), of opposite polarity to the second electrode (9), in contact with the separator film (7) so as to convey said first electrode (6) onto the stacking table (2) or onto a second electrode (9).

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