A method for manufacturing folded battery cells

Abstract

This invention discloses a method for manufacturing a folded battery cell, relating to the field of lithium battery technology. Multiple first composite electrodes and multiple second composite electrodes are alternately and equally spaced between a first electrolyte membrane and a second electrolyte membrane, wherein the first and second composite electrodes are arranged in reverse order. Multiple third composite electrodes are placed below the second electrolyte membrane, and multiple fourth composite electrodes are placed on the first electrolyte membrane. The third composite electrodes, first electrolyte membrane, first composite electrodes, second composite electrodes, second electrolyte membrane, and fourth composite electrodes are rolled together to form a composite strip. The composite strip is then folded in a Z-shape to form a battery cell. The folded battery cell manufacturing method provided by this invention can produce battery cells with higher output voltages, shortening the electron flow path within the cell and reducing the overall resistance of the cell.

Description

Technical Field

[0001] This invention relates to the field of lithium battery technology, and more specifically, to a method for manufacturing folded battery cells. Background Technology

[0002] With the development of science and technology, lithium batteries are used as power sources in many fields such as digital products, military industry, and new energy vehicles. As a result, the lithium battery industry has developed rapidly in recent years, and cell manufacturing is an important part of lithium battery production. Currently, conventional cell manufacturing methods produce cells with relatively low output voltages. In daily use, multiple cells are usually connected in series to ensure that the overall output voltage meets the requirements. However, this results in a complex series structure that is difficult to implement and has high material costs.

[0003] In view of this, designing a cell folding manufacturing method that can improve the cell output voltage is particularly important in cell production. Summary of the Invention

[0004] The purpose of this invention is to provide a method for manufacturing folded battery cells, which can produce battery cells with higher output voltage, thereby shortening the electron flow path within the battery cell and reducing the overall resistance of the battery cell.

[0005] The present invention is achieved by the following technical solution.

[0006] A method for manufacturing a folded battery cell includes: placing a plurality of first composite electrodes and a plurality of second composite electrodes alternately and at equal intervals between a first electrolyte membrane and a second electrolyte membrane, wherein the first and second composite electrodes are arranged in reverse order; placing a plurality of third composite electrodes below the second electrolyte membrane and placing a plurality of fourth composite electrodes on the first electrolyte membrane, wherein each third composite electrode is stacked with one first composite electrode and each fourth composite electrode is stacked with one second composite electrode; rolling the third composite electrodes, the first electrolyte membrane, the first composite electrodes, the second composite electrodes, the second electrolyte membrane, and the fourth composite electrodes together to form a composite strip; and folding the composite strip in a Z-shape to form a battery cell.

[0007] Optionally, a plurality of first composite electrodes and a plurality of second composite electrodes are sequentially and alternately placed between a first electrolyte membrane and a second electrolyte membrane at equal intervals. The step of reversing the arrangement of the first composite electrodes and the second composite electrodes includes: unwinding and cutting the first composite electrode roll and feeding the resulting first composite electrode onto the second electrolyte membrane; unwinding and cutting the second composite electrode roll and feeding the resulting second composite electrode onto the second electrolyte membrane; and controlling the second electrolyte membrane to move so as to move the first composite electrode and the second composite electrode to below the first electrolyte membrane.

[0008] Optionally, the first composite electrode includes a first active material layer, a first composite current collector layer and a second active material layer stacked sequentially from top to bottom, and the second composite electrode includes a second active material layer, a first composite current collector layer and a first active material layer stacked sequentially from top to bottom.

[0009] Optionally, the first active material layer is made of lithium metal or graphite, the second active material layer is made of lithium iron phosphate or ternary material, and the first composite current collector layer is made of aluminum metal or aluminum-copper alloy.

[0010] Optionally, the area of ​​the first active material layer is greater than the area of ​​the first composite current collector layer, and the area of ​​the first composite current collector layer is equal to the area of ​​the second active material layer.

[0011] Optionally, a plurality of third composite electrodes are placed below the second electrolyte membrane, and a plurality of fourth composite electrodes are placed on the first electrolyte membrane. The steps of stacking each third composite electrode with a first composite electrode and stacking each fourth composite electrode with a second composite electrode include: unwinding and cutting the third composite electrode roll and sending the resulting third composite electrode below the second electrolyte membrane; unwinding and cutting the fourth composite electrode roll and sending the resulting fourth composite electrode on the first electrolyte membrane.

[0012] Optionally, the third composite electrode includes a first active material layer, a first composite current collector layer and a second active material layer stacked sequentially from top to bottom, and the fourth composite electrode includes a second active material layer, a first composite current collector layer and a first active material layer stacked sequentially from top to bottom.

[0013] Optionally, in the step of rolling the fourth composite electrode, the first electrolyte membrane, the second composite electrode, the second electrolyte membrane and the third composite electrode to form a composite strip, the rolling temperature range is 40 degrees Celsius to 80 degrees Celsius and the rolling pressure range is 0.1 MPa to 0.2 MPa.

[0014] Optionally, after the step of folding the composite strip in a Z-shape to form a battery cell, the battery cell folding manufacturing method further includes: sequentially attaching a third electrolyte membrane, a third active material layer, and a second composite current collector layer to one side of the battery cell, and sequentially attaching a fourth active material layer and a third composite current collector layer to the other side of the battery cell.

[0015] Optionally, the second composite current collector layer is provided with a first electrode tab, and the third composite current collector layer is provided with a second electrode tab, wherein the first electrode tab and the second electrode tab have opposite polarities.

[0016] The battery cell folding manufacturing method provided by this invention has the following beneficial effects:

[0017] The present invention provides a battery cell folding manufacturing method, which involves sequentially and alternately placing multiple first composite electrodes and multiple second composite electrodes at equal intervals between a first electrolyte membrane and a second electrolyte membrane, wherein the first and second composite electrodes are arranged in reverse order; multiple third composite electrodes are placed below the second electrolyte membrane, and multiple fourth composite electrodes are placed on the first electrolyte membrane, wherein each third composite electrode is stacked with one first composite electrode, and each fourth composite electrode is stacked with one second composite electrode; the third composite electrodes, the first electrolyte membrane, the first composite electrodes, the second composite electrodes, the second electrolyte membrane, and the fourth composite electrodes are rolled together to form a composite strip; the composite strip is then folded in a Z-shape to form a battery cell. Compared with the prior art, the battery cell folding manufacturing method provided by the present invention, due to the step of rolling together the third composite electrodes, the first electrolyte membrane, the first composite electrodes, the second composite electrodes, the second electrolyte membrane, and the fourth composite electrodes to form a composite strip, can manufacture a battery cell with a higher output voltage, shortening the electron flow path within the battery cell and reducing the overall resistance of the battery cell. Attached Figure Description

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 This is a flowchart illustrating the steps of a battery cell folding manufacturing method provided in the first embodiment of the present invention.

[0020] Figure 2 A schematic diagram of the structure of a battery cell production line used in the battery cell folding manufacturing method provided in the first embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of the structure of a battery cell manufactured by the battery cell folding manufacturing method provided in the first embodiment of the present invention;

[0022] Figure 4 A schematic diagram of a battery cell with tabs manufactured by the battery cell folding manufacturing method provided in the first embodiment of the present invention;

[0023] Figure 5 A schematic diagram of a battery cell with tabs manufactured by the battery cell folding manufacturing method provided in the second embodiment of the present invention;

[0024] Figure 6 This is a flowchart of the first production process of the composite electrode in the battery cell folding manufacturing method provided in the second embodiment of the present invention;

[0025] Figure 7 This is a flowchart of the second production process of the composite electrode in the battery cell folding manufacturing method provided in the second embodiment of the present invention.

[0026] Icons: 100 - Cell; 110 - First composite electrode; 120 - Second composite electrode; 130 - Third composite electrode; 140 - Fourth composite electrode; 150 - First electrolyte membrane; 160 - Second electrolyte membrane; 170 - First active material layer; 180 - First composite current collector layer; 190 - Second active material layer; 200 - Third electrolyte membrane; 210 - Third active material layer; 220 - Second composite current collector layer; 221 - First tab; 230 - Fourth active material layer; 240 - Third composite current collector layer; 241 - Second tab. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0029] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0030] In the description of this invention, it should be noted that the terms "inner," "outer," "upper," "lower," "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0031] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "connected," "installed," and "connected" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0032] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, features in the following embodiments can be combined with each other.

[0033] First Embodiment

[0034] Please refer to Figures 1 to 4 , ( Figure 2 (The hollow arrow in the diagram indicates the direction of the conveyor belt). This invention provides a cell folding manufacturing method for folding and manufacturing cell 100, applicable to the production of liquid batteries, semi-solid batteries, and solid batteries. It can produce cell 100 with a higher output voltage, shortening the electron flow path within the cell 100 and reducing the overall resistance of the cell 100.

[0035] It should be noted that the cell folding manufacturing method is applied to the cell production line. The cell production line can use the cell folding manufacturing method to process the raw materials of each layer to produce cell 100. Cell 100 has a high output voltage, a short internal electron flow path, and a low overall resistance.

[0036] The battery cell folding manufacturing method includes the following steps:

[0037] Step S110: A plurality of first composite electrodes 110 and a plurality of second composite electrodes 120 are placed alternately and at equal intervals between the first electrolyte membrane 150 and the second electrolyte membrane 160, wherein the first composite electrodes 110 and the second composite electrodes 120 are arranged in reverse order.

[0038] Specifically, step S110 includes three steps, namely:

[0039] Step S111: Unwind and cut the first composite electrode roll, and send the resulting first composite electrode 110 onto the second electrolyte membrane 160.

[0040] It should be noted that in step S111, the first composite electrode roll is first unwound using the feeding mechanism and sent to the corresponding position of the cutting mechanism; then the cutting mechanism is used to cut it into multiple sheets of equal area, thus forming the first composite electrode 110; then the feeding mechanism is used to send the first composite electrode 110 onto the second electrolyte membrane 160.

[0041] Step S112: Unwind and cut the second composite electrode roll, and send the resulting second composite electrode 120 onto the second electrolyte membrane 160.

[0042] It should be noted that in step S112, the feeding mechanism is first used to drive the second composite electrode roll to unwind and send it to the corresponding position of the cutting mechanism; then the cutting mechanism is used to cut it into multiple sheets of equal area, thus forming the second composite electrode 120; then the feeding mechanism is used to send the second composite electrode 120 onto the second electrolyte membrane 160.

[0043] Step S113: Control the second electrolyte membrane 160 to move along the belt, so as to move the first composite electrode 110 and the second composite electrode 120 to below the first electrolyte membrane 150.

[0044] It should be noted that steps S111 and S112 are performed alternately at equal intervals to feed multiple first composite electrodes 110 and multiple second composite electrodes 120 onto the second electrolyte membrane 160 alternately and at equal intervals. During this process, the roller conveyor mechanism continuously drives the second electrolyte membrane 160 to move forward, thereby driving the multiple first composite electrodes 110 and multiple second composite electrodes 120 to move below the first electrolyte membrane 150. At this time, the multiple first composite electrodes 110 and multiple second composite electrodes 120 are all located between the first electrolyte membrane 150 and the second electrolyte membrane 160 to facilitate subsequent composite processing.

[0045] It is worth noting that the first composite electrode 110 and the second composite electrode 120 are arranged in reverse order, that is, the stacking order of the first composite electrode 110 and the second composite electrode 120 is reversed. Specifically, the first composite electrode 110 includes a first active material layer 170, a first composite current collector layer 180, and a second active material layer 190 stacked sequentially from top to bottom. The second composite electrode 120 includes a second active material layer 190, a first composite current collector layer 180, and a first active material layer 170 stacked sequentially from top to bottom.

[0046] In this embodiment, the first active material layer 170 is made of lithium metal or graphite, the second active material layer 190 is made of lithium iron phosphate or ternary material, and the first composite current collector layer 180 is made of aluminum metal or aluminum-copper alloy.

[0047] In this embodiment, both the first composite electrode 110 and the second composite electrode 120 are rectangular, and the areas of the first active material layer 170, the first composite current collector layer 180, and the second active material layer 190 are equal.

[0048] Step S120: Place a plurality of third composite electrodes 130 below the second electrolyte membrane 160 and place a plurality of fourth composite electrodes 140 on the first electrolyte membrane 150, wherein each third composite electrode 130 is stacked with a first composite electrode 110 and each fourth composite electrode 140 is stacked with a second composite electrode 120.

[0049] Specifically, step S120 includes two steps, namely:

[0050] Step S121: Unwind and cut the third composite electrode roll, and send the resulting third composite electrode 130 below the second electrolyte membrane 160.

[0051] It should be noted that in step S121, the feeding mechanism first drives the third composite electrode roll to unwind and send it to the corresponding position of the cutting mechanism; then the cutting mechanism cuts it into multiple sheets of equal area, thus forming the third composite electrode 130; then the feeding mechanism clamps the third composite electrode 130 and sends it below the second electrolyte membrane 160, so that the third composite electrode 130 is attached to the second electrolyte membrane 160, and the position of the third composite electrode 130 corresponds to the position of the first composite electrode 110. This process is repeated to place multiple third composite electrodes 130 one by one below multiple first composite electrodes 110.

[0052] Step S122: Unwind and cut the fourth composite electrode roll, and send the resulting fourth composite electrode 140 onto the first electrolyte membrane 150.

[0053] It should be noted that in step S122, the feeding mechanism first drives the fourth composite electrode roll to unwind and send it to the corresponding position of the cutting mechanism; then the cutting mechanism cuts it into multiple sheets of equal area, thus forming the fourth composite electrode 140; then the feeding mechanism clamps the fourth composite electrode 140 and sends it above the first electrolyte membrane 150, so that the fourth composite electrode 140 is attached above the first electrolyte membrane 150, and the position of the fourth composite electrode 140 corresponds to the position of the second composite electrode 120. This process is repeated to place multiple fourth composite electrodes 140 one by one above multiple second composite electrodes 120.

[0054] It is worth noting that steps S121 and S122 are performed alternately at equal intervals to deliver multiple third composite electrodes 130 and multiple fourth composite electrodes 140 alternately and at equal intervals to the outer sides of the first electrolyte membrane 150 and the second electrolyte membrane 160. During this process, the roller conveyor mechanism continuously drives the first electrolyte membrane 150 and the second electrolyte membrane 160 to move synchronously, thereby synchronously driving multiple first composite electrodes 110, multiple second composite electrodes 120, multiple third composite electrodes 130 and multiple fourth composite electrodes 140 to move forward.

[0055] It is worth noting that the third composite electrode 130 and the fourth composite electrode 140 are arranged in reverse order, that is, the stacking order of the third composite electrode 130 and the fourth composite electrode 140 is opposite, and the stacking order of the third composite electrode 130 is the same as that of the first composite electrode 110, while the stacking order of the fourth composite electrode 140 is the same as that of the second composite electrode 120. Specifically, the third composite electrode 130 includes a first active material layer 170, a first composite current collector layer 180, and a second active material layer 190 stacked sequentially from top to bottom. The fourth composite electrode 140 includes a second active material layer 190, a first composite current collector layer 180, and a first active material layer 170 stacked sequentially from top to bottom.

[0056] Step S130: Roller-press the fourth composite electrode 140, the first electrolyte membrane 150, the first composite electrode 110, the second composite electrode 120, the second electrolyte membrane 160 and the third composite electrode 130 to form a composite strip.

[0057] It should be noted that in step S130, when the first electrolyte membrane 150 and the second electrolyte membrane 160 drive the first composite electrode 110, the second composite electrode 120, the third composite electrode 130 and the fourth composite electrode 140 to the position corresponding to the rolling mechanism, the conveyor belt of the first electrolyte membrane 150 and the second electrolyte membrane 160 is paused. The rolling mechanism is used to roll and composite the fourth composite electrode 140, the first electrolyte membrane 150, the first composite electrode 110, the second composite electrode 120, the second electrolyte membrane 160 and the third composite electrode 130 to fix the relative position of each layer structure and prevent relative displacement of each layer structure, thereby ensuring the accuracy and stability of the subsequent stacking process.

[0058] Furthermore, during the rolling process of the composite strip, the rolling temperature range is 40 degrees Celsius to 80 degrees Celsius, and the rolling pressure range is 0.1 MPa to 0.2 MPa to ensure the rolling effect.

[0059] Step S140: Fold the composite strip in a Z-shape to form cell 100.

[0060] It should be noted that in step S140, the composite strip is folded in a Z-shape using a stacking mechanism to fold the composite strip back and forth to form the battery cell 100. Specifically, the length of the composite strip is determined according to the required output voltage of the battery cell 100, that is, the length of the composite strip is different in battery cells 100 with different output voltages, and the number of each layer structure is also different.

[0061] Step S150: On one side of the battery cell 100, a third electrolyte membrane 200, a third active material layer 210, and a second composite current collector layer 220 are sequentially attached, and on the other side of the battery cell 100, a fourth active material layer 230 and a third composite current collector layer 240 are sequentially attached.

[0062] It should be noted that in step S150, the two outermost layers of the battery cell 100 are the second active material layer 190 and the first electrolyte membrane 150, respectively. A third electrolyte membrane 200, a third active material layer 210, and a second composite current collector layer 220 are sequentially attached outside the outermost second active material layer 190. A fourth active material layer 230 and a third composite current collector layer 240 are sequentially attached outside the outermost first electrolyte membrane 150. The third active material layer 210 is identical to the first active material layer 170, and the fourth active material layer 230 is identical to the second active material layer 190.

[0063] Specifically, in the process of attaching the third electrolyte membrane 200, the third active material layer 210, and the second composite current collector layer 220, or attaching the fourth active material layer 230 and the third composite current collector layer 240, the same three steps of unwinding, cutting, and lamination are required. Taking the attachment of the third electrolyte membrane 200 as an example, firstly, the feeding mechanism drives the third electrolyte membrane roll to unwind and sends it to the corresponding position of the cutting mechanism; then, the cutting mechanism cuts it into multiple pieces of equal area to form the third electrolyte membrane 200; finally, the third electrolyte membrane 200 is laminated to the outermost second active material layer 190 of the battery cell 100.

[0064] In this embodiment, the second composite current collector layer 220 is provided with a first tab 221, and the third composite current collector layer 240 is provided with a second tab 241. The first tab 221 and the second tab 241 have opposite polarities. The first tab 221 and the second tab 241 work together to serve as the external tabs of the entire cell 100. In this way, there are no tabs occupying space inside the cell 100, which can effectively improve the energy density of the cell 100. Furthermore, since there are no tabs inside the cell 100 to collect current and generate heat, the contact between the layers is uniform, so the cell 100 has high reliability and good consistency.

[0065] It is worth noting that, because the electrolyte membrane can conduct protons and ions while isolating electrons, and because there are no tabs inside the cell 100 and the internal structure of the cell 100 is a series structure, the cell 100 manufactured by the cell 100 cutting and stacking manufacturing method has a higher output voltage, a shorter electron flow path, a lower overall resistance, and a higher energy density.

[0066] The battery cell folding manufacturing method provided in this embodiment of the invention involves placing a plurality of first composite electrode sheets 110 and a plurality of second composite electrode sheets 120 alternately and at equal intervals between a first electrolyte membrane 150 and a second electrolyte membrane 160, wherein the first composite electrode sheets 110 and the second composite electrode sheets 120 are arranged in reverse order; placing a plurality of third composite electrode sheets 130 below the second electrolyte membrane 160 and placing a plurality of fourth composite electrode sheets 140 on the first electrolyte membrane 150, wherein each third composite electrode sheet 130 is stacked with one first composite electrode sheet 110 and each fourth composite electrode sheet 140 is stacked with one second composite electrode sheet 120; the third composite electrode sheets 130, the first electrolyte membrane 150, the first composite electrode sheets 110, the second composite electrode sheets 120, the second electrolyte membrane 160 and the fourth composite electrode sheets 140 are rolled together to form a composite strip; the composite strip is then folded in a Z-shape to form a battery cell 100. Compared with the prior art, the battery cell folding manufacturing method provided by the present invention adopts the step of rolling and bonding the third composite electrode 130, the first electrolyte membrane 150, the first composite electrode 110, the second composite electrode 120, the second electrolyte membrane 160 and the fourth composite electrode 140 to form a composite strip. Therefore, it can manufacture a battery cell 100 with a higher output voltage, which shortens the electron flow path in the battery cell 100 and reduces the overall resistance of the battery cell 100.

[0067] Second Embodiment

[0068] Please refer to Figures 5 to 7 This invention provides a method for manufacturing folded battery cells. Compared with the first embodiment, the difference in this embodiment lies in the different structure of the composite electrode.

[0069] In this embodiment, in the composite electrode (including the first composite electrode 110, the second composite electrode 120, the third composite electrode 130, and the fourth composite electrode 140), the area of ​​the first active material layer 170 is larger than the area of ​​the first composite current collector layer 180, and the area of ​​the first composite current collector layer 180 is equal to the area of ​​the second active material layer 190. The projection of the second active material layer 190 onto the first active material layer 170 is entirely within the first active material layer 170, thus satisfying the structural requirement of excess negative electrode in the battery cell 100. However, this is not the only option. In other embodiments, the area of ​​the first active material layer 170 can also be equal to the area of ​​the first composite current collector layer 180, in which case the area of ​​the first composite current collector layer 180 is larger than the area of ​​the second active material layer 190, which also satisfies the structural requirement of excess negative electrode in the battery cell 100.

[0070] It should be noted that there are two production processes for composite electrodes. The first production process involves unwinding and cutting the first active material layer roll, the first composite current collector layer roll, and the second active material layer roll to form multiple first active material layers 170, multiple first composite current collector layers 180, and multiple second active material layers 190. Subsequently, the multiple first active material layers 170, multiple first composite current collector layers 180, and multiple second active material layers 190 are rolled together one by one to obtain multiple composite electrodes. At this time, the area of ​​the first active material layer 170 in the composite electrode is larger than the area of ​​the first composite current collector layer 180, and the area of ​​the first composite current collector layer 180 is equal to the area of ​​the second active material layer 190.

[0071] The second production process involves first continuously unwinding the first composite current collector layer roll; then continuously coating one side of the unwound first composite current collector layer 180 with a first active material layer 170, and coating multiple second active material layers 190 at equal intervals on the other side of the first composite current collector layer 180; then using a cutter to cut the first composite current collector layer 180 and the first active material layer 170 between two adjacent second active material layers 190 to obtain multiple composite electrodes. At this time, the area of ​​the first active material layer 170 in the composite electrode is equal to the area of ​​the first composite current collector layer 180, and the area of ​​the first composite current collector layer 180 is greater than the area of ​​the second active material layer 190.

[0072] The beneficial effects of the cell folding manufacturing method provided in this embodiment of the invention are the same as those in the first embodiment, and will not be repeated here.

[0073] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for manufacturing folded battery cells, characterized in that, include: Multiple first composite electrodes (110) and multiple second composite electrodes (120) are alternately and equally spaced between a first electrolyte membrane (150) and a second electrolyte membrane (160), wherein the first composite electrodes (110) and the second composite electrodes (120) are arranged in reverse order. The first composite electrode (110) includes a first active material layer (170), a first composite current collector layer (180) and a second active material layer (190) stacked from top to bottom. The second composite electrode (120) includes a second active material layer (190), a first composite current collector layer (180) and a first active material layer (170) stacked from top to bottom. The area of ​​the first active material layer (170) is larger than the area of ​​the first composite current collector layer (180), and the area of ​​the first composite current collector layer (180) is equal to the area of ​​the second active material layer (190). Multiple third composite electrodes (130) are placed below the second electrolyte membrane (160), and multiple fourth composite electrodes (140) are placed on the first electrolyte membrane (150), wherein each third composite electrode (130) is stacked with one first composite electrode (110), and each fourth composite electrode (140) is stacked with one second composite electrode (120); The fourth composite electrode (140), the first electrolyte membrane (150), the first composite electrode (110), the second composite electrode (120), the second electrolyte membrane (160) and the third composite electrode (130) are rolled together to form a composite strip; The composite strip is folded in a Z-shape to form a battery cell (100).

2. The cell folding manufacturing method according to claim 1, characterized in that, The step of placing a plurality of first composite electrodes (110) and a plurality of second composite electrodes (120) alternately and at equal intervals between a first electrolyte membrane (150) and a second electrolyte membrane (160), wherein the first composite electrodes (110) and the second composite electrodes (120) are arranged in reverse order, includes: The first composite electrode (110) roll is unwound and cut, and the resulting first composite electrode (110) is sent onto the second electrolyte membrane (160); The second composite electrode (120) roll is unwound and cut, and the resulting second composite electrode (120) is sent onto the second electrolyte membrane (160); The second electrolyte membrane (160) is controlled to move along the belt, thereby moving the first composite electrode (110) and the second composite electrode (120) to below the first electrolyte membrane (150).

3. The cell folding manufacturing method according to claim 1, characterized in that, The first active material layer (170) is made of lithium metal or graphite material, the second active material layer (190) is made of lithium iron phosphate or ternary material, and the first composite current collector layer (180) is made of aluminum metal or aluminum-copper alloy material.

4. The cell folding manufacturing method according to claim 1, characterized in that, The step of placing a plurality of third composite electrodes (130) below the second electrolyte membrane (160) and placing a plurality of fourth composite electrodes (140) on the first electrolyte membrane (150), wherein each of the third composite electrodes (130) is stacked with one of the first composite electrodes (110) and each of the fourth composite electrodes (140) is stacked with one of the second composite electrodes (120) includes: The third composite electrode (130) roll is unwound and cut, and the resulting third composite electrode (130) is sent below the second electrolyte membrane (160); The fourth composite electrode (140) roll is unwound and cut, and the resulting fourth composite electrode (140) is sent onto the first electrolyte membrane (150).

5. The cell folding manufacturing method according to claim 1, characterized in that, The third composite electrode (130) includes a first active material layer (170), a first composite current collector layer (180) and a second active material layer (190) stacked from top to bottom, and the fourth composite electrode (140) includes the second active material layer (190), the first composite current collector layer (180) and the first active material layer (170) stacked from top to bottom.

6. The cell folding manufacturing method according to claim 1, characterized in that, In the step of rolling composite material strips formed by rolling the fourth composite electrode (140), the first electrolyte membrane (150), the first composite electrode (110), the second composite electrode (120), the second electrolyte membrane (160), and the third composite electrode (130), the rolling temperature range is 40 degrees Celsius to 80 degrees Celsius, and the rolling pressure range is 0.1 MPa to 0.2 MPa.

7. The cell folding manufacturing method according to claim 1, characterized in that, After the step of zig-folding the composite strip to form a battery cell (100), the battery cell folding manufacturing method further includes: A third electrolyte membrane (200), a third active material layer (210), and a second composite current collector layer (220) are sequentially attached to one side of the battery cell (100), and a fourth active material layer (230) and a third composite current collector layer (240) are sequentially attached to the other side of the battery cell (100).

8. The cell folding manufacturing method according to claim 7, characterized in that, The second composite current collector layer (220) is provided with a first tab (221), and the third composite current collector layer (240) is provided with a second tab (241). The first tab (221) and the second tab (241) have opposite polarities.

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