Laminated battery cell, and preparation method and preparation system for laminated battery cell

Abstract

The present invention provides a laminated battery cell, and a preparation method and preparation system for the laminated battery cell. The laminated battery cell comprises: a composite unit; and at least two single negative electrode sheets, the at least two single negative electrode sheets being spaced apart from each other in the thickness direction of the laminated battery cell, and one composite unit is provided between every two single negative electrode sheets, thereby forming a laminated cell structure. The composite unit comprises a negative electrode sheet, a first positive electrode sheet, a second positive electrode sheet, and a plurality of separator sections; in the thickness direction, the first positive electrode sheet and the second positive electrode sheet are respectively provided on two opposite sides of the negative electrode sheet; the plurality of separator sections are sequentially provided at intervals in the thickness direction; and the first positive electrode sheet or the second positive electrode sheet or the negative electrode sheet is provided between two adjacent separator sections. The technical solution of the present invention solves the problem in the prior art of low preparation efficiency or material utilization rate of a laminated battery cell.

Description

Laminated battery cell, method for preparing laminated battery cell, and system for preparing laminated battery cell

[0001] This application claims priority to a patent application filed with the State Intellectual Property Office of China on January 4, 2024, with application number 2024100161825 and invention name “Laminated battery cells, method for preparing laminated battery cells and preparation system”. Technical Field

[0002] The present invention relates to the technical field of lithium batteries, and in particular to a laminated battery core, a method for preparing the laminated battery core, and a preparation system thereof. Background Art

[0003] With the continuous development of the lithium battery industry, there is a great deal of attention paid to the efficiency and quality of battery production. During the cell production process, especially the efficiency of laminated battery cells, is much lower than that of wound cells.

[0004] In the prior art, the most commonly used preparation methods for laminated batteries are Z-stacking and thermal compounding. Among them, for the Z-stacking preparation method, one positive / negative electrode sheet is carried each time, alternating in sequence, with a diaphragm laid in between to prepare a battery cell. Although the preparation method is mature and stable, the efficiency of single-piece Z-stacking is too low due to the upper limit of the mechanical action speed. The multi-piece stacking has an obvious mechanical speed bottleneck due to the long diaphragm stroke, resulting in low production efficiency and difficult to ensure the stacking accuracy. For the thermal compound preparation method, continuous sheets are stacked and thermally compounded, and the diaphragm of a single battery cell is not cut. The positive / negative electrode sheets are compounded on the diaphragm and then stacked to form a battery cell. This preparation method is more efficient, but it is impossible to remove defective sheets. If defective sheets appear, the entire battery cell can only be scrapped, and the material utilization rate is low. The above method leads to low preparation efficiency or material utilization rate of laminated batteries. Summary of the Invention

[0005] The main purpose of the present invention is to provide a laminated battery core, a method for preparing the laminated battery core, and a preparation system for the laminated battery core, so as to solve the problem of low preparation efficiency or material utilization of the laminated battery core in the prior art.

[0006] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, the present invention provides a laminated battery cell, comprising: a composite unit; at least two single negative electrode sheets, at least two single negative electrode sheets are arranged at intervals along the thickness direction of the laminated battery cell, and a composite unit is provided between two adjacent single negative electrode sheets to form a laminated core structure; wherein the composite unit comprises a negative electrode sheet, a first positive electrode sheet, a second positive electrode sheet and a plurality of diaphragm segments, and along the thickness direction, a first positive electrode sheet and a second positive electrode sheet are respectively provided on opposite sides of the negative electrode sheet, and the plurality of diaphragm segments are sequentially spaced along the thickness direction, and a first positive electrode sheet or a second positive electrode sheet or a negative electrode sheet is provided between two adjacent diaphragm segments.

[0007] Furthermore, there are multiple composite units.

[0008] Furthermore, the laminated battery cell also includes a tail-wound diaphragm, which is coated on the outer periphery of the laminated core structure.

[0009] According to another aspect of the present invention, the present invention provides a method for preparing a laminated battery cell, comprising: a preparation step of preparing a composite unit using a negative electrode sheet, a first positive electrode sheet, a second positive electrode sheet and a plurality of diaphragm segments; and a stacking step of stacking the composite unit between two adjacent single negative electrode sheets to form a stacked core structure.

[0010] Furthermore, the preparation steps include: a first forming step of compounding a first diaphragm, a plurality of negative electrode sheets and a second diaphragm to form a continuous first composite sheet; a second forming step of compounding a plurality of first positive electrode sheets and a third diaphragm on one side of the first composite sheet to form a continuous second composite sheet; and a third forming step of compounding a plurality of second positive electrode sheets and a fourth diaphragm on the other side of the first composite sheet to form a continuous third composite sheet.

[0011] Furthermore, the preparation step further includes: cutting the third composite sheet to form a plurality of composite units; wherein the first diaphragm, the second diaphragm, the third diaphragm and the fourth diaphragm are formed into a corresponding plurality of diaphragm segments after cutting.

[0012] Furthermore, the first forming step includes: unwinding the first separator and the second separator; spacing the plurality of negative electrode sheets between the first separator and the second separator along the unwinding direction; and thermally compounding the first separator, the plurality of negative electrode sheets, and the second separator.

[0013] Furthermore, the second forming step includes: making multiple first positive electrode sheets adhere to one side of the first composite sheet in sequence along the unwinding direction; placing the third separator on the side of the first positive electrode sheet away from the first composite sheet and unwinding; and thermally compounding the multiple first positive electrode sheets and the third separator to the first composite sheet.

[0014] Furthermore, the third forming step includes: attaching multiple second positive electrode sheets to the other side of the first composite sheet; placing the fourth separator on the side of the second positive electrode sheet away from the first composite sheet and unwinding it; and thermally compounding the multiple second positive electrode sheets and the fourth separator to the first composite sheet.

[0015] Furthermore, the tail roll diaphragm is wrapped around the outer periphery of the stacked core structure.

[0016] Furthermore, before the stacking step and after the preparation step, the method for preparing the laminated battery cell further includes: testing the composite unit; and testing the single negative electrode sheet.

[0017] According to another aspect of the present invention, the present invention provides a system for preparing a laminated battery cell, which adopts the above-mentioned method for preparing a laminated battery cell to prepare a laminated battery cell. The system for preparing a laminated battery cell includes: a negative electrode unwinding mechanism for outputting a negative electrode sheet; two positive electrode unwinding mechanisms for outputting a first positive electrode sheet and a second positive electrode sheet, respectively. Along the thickness direction of the laminated battery cell, the two positive electrode unwinding mechanisms are arranged at intervals so that the output first positive electrode sheet and the second positive electrode sheet are respectively located on both sides of the negative electrode sheet, and along the unwinding direction, the negative electrode unwinding mechanism and the positive electrode unwinding mechanism are arranged at intervals. The invention relates to a device comprising: a plurality of diaphragm unwinding mechanisms for outputting a plurality of diaphragms spaced apart in the thickness direction, wherein a diaphragm unwinding mechanism is provided between the negative electrode unwinding mechanism and each positive electrode unwinding mechanism along the unwinding direction, and a diaphragm unwinding mechanism is provided on the side of each positive electrode unwinding mechanism away from the negative electrode unwinding mechanism, so that a first positive electrode sheet or a second positive electrode sheet or a negative electrode sheet is provided between two adjacent diaphragms; a compounding mechanism for thermally compounding a plurality of diaphragms, a first positive electrode sheet, a second positive electrode sheet and a negative electrode sheet to form a compound unit; a single negative electrode unwinding mechanism for outputting a plurality of single negative electrode sheets.

[0018] By applying the technical solution of the present invention, a composite unit can be prepared by thermal recombination, and the composite unit and the single negative electrode sheet can be first inspected by a detection device, and then the qualified composite unit and the qualified single negative electrode sheet can be stacked by a Z-stacking method to form a stacked core structure. In this way, on the one hand, compared with Z-stacking, the preparation of the stacked core structure can not only reduce the number of times the electrode sheets are transported, thereby improving the preparation efficiency of the stacked core structure, but also eliminate the stacking diaphragm action and improve the stacking accuracy; on the other hand, compared with continuous thermal recombination, the preparation of the stacked core structure can discharge bad single negative electrode sheets or bad composite units, thereby avoiding the scrapping of the entire stacked core structure, which not only improves the material utilization rate, but also ensures the quality of the stacked battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0020] FIG1 shows a schematic structural diagram of an embodiment of a composite unit of a laminated battery cell of the present invention;

[0021] FIG2 shows a schematic diagram of the preparation process of the composite unit of FIG1 ;

[0022] FIG3 shows a schematic structural diagram of an embodiment of a single negative electrode sheet of a laminated battery cell according to the present invention;

[0023] FIG4 shows a schematic diagram of the preparation process of the stacked core structure of the laminated battery cell of the present invention;

[0024] FIG5 is a schematic structural diagram of an embodiment of a laminated core structure of a laminated battery cell according to the present invention;

[0025] FIG6 shows a schematic structural diagram of an embodiment of a laminated battery cell of the present invention;

[0026] FIG7 is a schematic flow chart showing an embodiment of a method for preparing a laminated battery cell according to the present invention;

[0027] FIG8 shows a schematic structural diagram of an embodiment of a system for preparing a laminated battery cell according to the present invention.

[0028] The above drawings include the following reference numerals:

[0029] 1. Negative electrode unwinding mechanism; 2. Diaphragm unwinding mechanism; 3. Positive electrode unwinding mechanism; 4. Composite mechanism; 5. Composite unit cutting structure; 6. Composite unit detection structure; 7. Single negative electrode cutting unit; 8. Single negative electrode detection unit; 10. Tail roll winding mechanism; 12. Single negative electrode unwinding mechanism; 20. Composite unit; 21. Single negative electrode sheet; 22. Negative electrode sheet; 23. First positive electrode sheet; 24. Second positive electrode sheet; 25. Diaphragm segment; 26. Tail roll diaphragm. DETAILED DESCRIPTION

[0030] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0031] As shown in Figures 1 to 6, an embodiment of the present invention provides a laminated battery cell. The laminated battery cell includes a composite unit 20 and at least two single negative electrode sheets 21. The at least two single negative electrode sheets 21 are spaced apart along the thickness direction of the laminated battery cell, and a composite unit 20 is provided between two adjacent single negative electrode sheets 21 to form a laminated core structure. The composite unit 20 includes a negative electrode sheet 22, a first positive electrode sheet 23, a second positive electrode sheet 24, and a plurality of diaphragm segments 25. Along the thickness direction, the first positive electrode sheet 23 and the second positive electrode sheet 24 are provided on opposite sides of the negative electrode sheet 22, respectively. The plurality of diaphragm segments 25 are spaced apart in sequence along the thickness direction, and the first positive electrode sheet 23, the second positive electrode sheet 24, or the negative electrode sheet 22 is provided between two adjacent diaphragm segments 25.

[0032] In the above technical solution, the composite unit 20 can be prepared by thermal compounding, and the composite unit 20 and the single negative electrode sheet 21 can be first inspected by a detection device, and then the qualified composite unit 20 and the qualified single negative electrode sheet 21 can be stacked by the Z-stacking method to form a stacked core structure. In this way, on the one hand, compared with Z-stacking, the preparation of the stacked core structure can not only reduce the number of times the electrode sheets are transported, thereby improving the preparation efficiency of the stacked core structure, but also eliminate the stacking diaphragm action and improve the stacking accuracy; on the other hand, compared with continuous thermal compounding, the preparation of the stacked core structure can discharge defective single negative electrode sheets 21 or defective composite units 20, thereby avoiding the scrapping of the entire stacked core structure, which not only improves the material utilization rate, but also ensures the quality of the stacked battery cell.

[0033] Specifically, the laminated battery cell of the embodiment of the present invention combines Z-stacking with thermal compounding, which improves the stacking efficiency and the utilization rate of the laminated materials while ensuring the quality of the laminated battery cell.

[0034] Specifically, as shown in Figure 2, in an embodiment of the present invention, since the size of the first positive electrode sheet 23 and the second positive electrode sheet 24 are smaller than the size of the negative electrode sheet, in the composite unit 20, the first positive electrode sheet 23 and the second positive electrode sheet 24 are arranged on both sides of the negative electrode sheet 22. This helps CCD photography and detection, ensuring that the coating size of the composite unit is excellent.

[0035] It should be noted that the Z-stacking method for preparing stacked battery cells requires dedicated Z-stacking equipment, while the thermal composite method for preparing battery cells requires the use of thermal composite equipment to directly form stacked battery cells. The fusion of the two stacking methods requires not only considering the sequence of the stacking steps to ensure stacking efficiency, stacking accuracy and material utilization, but also re-producing special equipment to prepare stacked battery cells.

[0036] Preferably, in an embodiment of the present invention, the number of diaphragm segments is four.

[0037] It should be noted that, in the embodiment of the present invention, the single negative electrode sheet 21 refers to the negative electrode sheet 22 outside the composite unit 20 , so as to distinguish it from the negative electrode sheet 22 in the composite unit 20 .

[0038] As shown in Figures 4 and 5, in the embodiment of the present invention, there are multiple composite units 20. In this way, different laminated battery cells can be prepared according to battery parameters.

[0039] As shown in FIG5 , in an embodiment of the present invention, the laminated battery cell further includes a tail-wound separator 26 , which is wrapped around the outer periphery of the laminated core structure, thereby increasing the safety of the laminated battery cell.

[0040] As shown in Figure 7, an embodiment of the present invention provides a method for preparing a laminated battery cell, including: a preparation step of preparing a composite unit 20 using a negative electrode sheet 22, a first positive electrode sheet 23, a second positive electrode sheet 24 and a plurality of diaphragm segments 25; and a stacking step of stacking the composite unit 20 between two adjacent single negative electrode sheets 21 to form a stacked core structure.

[0041] In the above technical solution, the composite unit 20 can be prepared by thermal compounding, and the composite unit 20 and the single negative electrode sheet 21 can be additionally tested by a detection device, and then the qualified composite unit 20 and the qualified single negative electrode sheet 21 are stacked by the Z-stacking method to form a stacked core structure. In this way, on the one hand, compared with Z-stacking, the preparation of the stacked core structure can not only reduce the number of times the electrode sheets are transported, thereby improving the preparation efficiency of the stacked core structure, but also eliminate the stacking diaphragm action and improve the stacking accuracy; on the other hand, compared with continuous thermal compounding, the preparation of the stacked core structure can discharge defective single negative electrode sheets 21 or defective composite units 20, thereby avoiding the scrapping of the entire stacked core structure, which not only improves the material utilization rate, but also ensures the quality of the stacked battery cell.

[0042] Specifically, in an embodiment of the present invention, composite units 20 are prepared individually by thermal lamination on one side, while single negative electrode sheets 21 are simultaneously prepared on the other side. Composite units 20 and single negative electrode sheets 21 are each inspected by a CCD. Those that pass the inspection enter the lamination unit for lamination. Unqualified composite units 20 and single negative electrode sheets 21 are discarded. The lamination sequence is: negative electrode sheet + composite unit 20 + negative electrode sheet + ... + composite unit 20 + negative electrode sheet. Once the required number of layers is reached, a core stacking structure is formed.

[0043] Specifically, in an embodiment of the present invention, after the preparation step and before the stacking step, the preparation method further includes the steps of unwinding the single negative electrode sheet and cutting the single negative electrode sheet to form a plurality of single negative electrode sheets 21 .

[0044] As shown in Figure 2, in an embodiment of the present invention, the preparation steps include: a first forming step of combining a first separator, multiple negative electrode sheets 22, and a second separator to form a continuous first composite sheet; a second forming step of combining multiple first positive electrode sheets 23 and a third separator on one side of the first composite sheet to form a continuous second composite sheet; and a third forming step of combining multiple second positive electrode sheets 24 and a fourth separator on the other side of the first composite sheet to form a continuous third composite sheet. In this way, multiple connected composite units 20 can be quickly prepared, facilitating the rapid preparation of a single composite unit 20.

[0045] As shown in Figure 8 , in an embodiment of the present invention, the preparation step further includes cutting the third composite sheet to form a plurality of composite units 20. The first, second, third, and fourth separators are cut to form a corresponding plurality of separator segments 25. This facilitates rapid preparation of multiple composite units 20, improving the efficiency of laminated cell production.

[0046] It should be noted that in the embodiment of the present invention, the first diaphragm, the second diaphragm, the third diaphragm and the fourth diaphragm are arranged at intervals along the thickness direction of the laminated battery cell, and are arranged corresponding to the multiple diaphragm segments 25. The first positive electrode sheet 23 or the second positive electrode sheet 24 or the negative electrode sheet 22 is provided between adjacent two of the first diaphragm, the second diaphragm, the third diaphragm and the fourth diaphragm. The first diaphragm, the second diaphragm, the third diaphragm and the fourth diaphragm can form corresponding multiple diaphragm segments 25 after being cut.

[0047] As shown in Figure 8, in an embodiment of the present invention, the first forming step includes: unwinding the first and second separators; spacing the plurality of negative electrode sheets 22 between the first and second separators along the unwinding direction; and thermally laminating the first separator, the plurality of negative electrode sheets 22, and the second separator. This allows the plurality of negative electrode sheets 22 to be placed between the first and second separators, isolating the positive and negative electrode sheets and improving the safety of the laminated battery cell.

[0048] Specifically, in an embodiment of the present invention, before the first forming step, the preparation step further includes unwinding the negative electrode sheet and cutting the negative electrode sheet into a plurality of negative electrode sheets 22. In this way, there is a gap between two adjacent negative electrode sheets 22, which facilitates the subsequent cutting of the third composite sheet to form a plurality of composite units 20.

[0049] It should be noted that, in the embodiment of the present invention, the plurality of negative electrode sheets 22 are spaced between the first separator and the second separator along the unwinding direction, and the first separator and the second separator are unwound simultaneously without any order.

[0050] As shown in Figure 8, in an embodiment of the present invention, the second forming step includes: sequentially attaching multiple first positive electrode sheets 23 to one side of the first composite sheet along the unwinding direction; placing the third separator on the side of the first positive electrode sheet 23 facing away from the first composite sheet and unwinding the sheet; and thermally laminating the multiple first positive electrode sheets 23 and the third separator to the first composite sheet. This allows the first positive electrode sheet 23 to be positioned between the first composite sheet and the third separator, protecting it from external dust contamination and isolating it from the single negative electrode sheet 21, thereby improving the safety of the laminated battery cell.

[0051] Specifically, in an embodiment of the present invention, after the first forming step and before the second forming step, the preparation step further includes unwinding the first positive electrode sheet strip and cutting the first positive electrode sheet strip into a plurality of first positive electrode sheets 23. In this way, there is a gap between two adjacent first positive electrode sheets 23, which facilitates the subsequent cutting of the third composite sheet to form a plurality of composite units 20.

[0052] It should be noted that, in the embodiment of the present invention, the lamination of the plurality of first positive electrode sheets 23 to the first composite sheet and the unwinding of the third separator are performed simultaneously, without any particular order.

[0053] As shown in Figure 8, in an embodiment of the present invention, the third forming step includes: attaching multiple second positive electrode sheets 24 to the other side of the first composite sheet; placing the fourth separator on the side of the second positive electrode sheet 24 facing away from the first composite sheet and unwinding the sheet; and thermally laminating the multiple second positive electrode sheets 24 and the fourth separator to the first composite sheet. This allows the second positive electrode sheet 24 to be placed between the first composite sheet and the fourth separator, protecting the second positive electrode sheet 24 from external dust contamination and isolating it from the single negative electrode sheet 21, thereby improving the safety of the laminated battery cell.

[0054] Specifically, in an embodiment of the present invention, after the second forming step and before the third forming step, the preparation step further includes unwinding the second positive electrode sheet strip and cutting the second positive electrode sheet strip into a plurality of second positive electrode sheets 24. In this way, there is a gap between two adjacent second positive electrode sheets 24, which facilitates the subsequent cutting of the third composite sheet to form a plurality of composite units 20.

[0055] It should be noted that, in the embodiment of the present invention, the lamination of the plurality of second positive electrode sheets 24 to the first composite sheet and the unwinding of the fourth separator are performed simultaneously, without any particular order.

[0056] As shown in Figure 6, in an embodiment of the present invention, a tail-wound separator 26 is wrapped around the outer periphery of the stacked core structure. Thus, the tail-wound separator 26 can wrap the first and last negative electrode sheets 22 to enclose the stacked core structure, forming a finished battery cell and improving the safety of the stacked core.

[0057] Specifically, in the embodiment of the present invention, the tail-wound diaphragm 26 is wound around the outer circumference of the stacked core structure for one and a half circles, so that the stacked core structure can be better covered.

[0058] It should be noted that, in the embodiment of the present invention, the tail-wound diaphragm 26 is wound around the outer periphery of the stacked core structure, which means that the tail-wound diaphragm 26 is wrapped around the outer periphery of the stacked core structure.

[0059] As shown in Figure 8 , in an embodiment of the present invention, before the stacking step and after the preparation step, the method for preparing a laminated battery cell further includes: testing the composite unit 20; and testing the single negative electrode sheet 21. This allows defective single negative electrode sheets 21 or composite units 20 to be discarded, thereby avoiding the entire laminated cell structure from being scrapped. This not only improves material utilization but also ensures the quality of the laminated battery cell.

[0060] Furthermore, the laminated battery cell prepared after multiple tests and coating with the tail-wound diaphragm 26 has higher safety and reliability.

[0061] Specifically, in the embodiment of the present invention, the composite unit 20 and the single negative electrode sheet 21 can be subjected to CCD detection and determination.

[0062] As shown in FIG8 , an embodiment of the present invention provides a system for preparing a laminated battery cell, wherein the laminated battery cell is prepared by the above-mentioned method for preparing a laminated battery cell. The system for preparing a laminated battery cell comprises: a negative electrode unwinding mechanism 1 for outputting a negative electrode sheet 22; two positive electrode unwinding mechanisms 3 for outputting a first positive electrode sheet 23 and a second positive electrode sheet 24, respectively. Along the thickness direction of the laminated battery cell, the two positive electrode unwinding mechanisms 3 are arranged at intervals so that the output first positive electrode sheet 23 and the second positive electrode sheet 24 are respectively located on both sides of the negative electrode sheet 22, and along the unwinding direction, the negative electrode unwinding mechanism 1 and the positive electrode unwinding mechanism 3 are arranged at intervals; a plurality of intervals are provided. A membrane unwinding mechanism 2 is used to output multiple membranes spaced apart along the thickness direction. Along the unwinding direction, a membrane unwinding mechanism 2 is provided between the negative electrode unwinding mechanism 1 and each positive electrode unwinding mechanism 3. A membrane unwinding mechanism 2 is provided on the side of each positive electrode unwinding mechanism 3 facing away from the negative electrode unwinding mechanism 1, so that a first positive electrode sheet 23 or a second positive electrode sheet 24 or a negative electrode sheet 22 is provided between two adjacent membranes; a compounding mechanism 4 is used to thermally compound multiple membranes, a first positive electrode sheet 23, a second positive electrode sheet 24 and a negative electrode sheet 22 to form a compound unit 20; a single negative electrode unwinding mechanism 12 is used to output multiple single negative electrode sheets 21.

[0063] In the above technical solution, the negative electrode unwinding mechanism 1, two positive electrode unwinding mechanisms 3 and multiple diaphragm unwinding mechanisms 2 can be used to unwind, and then the multiple diaphragms, the first positive electrode sheet 23, the second positive electrode sheet 24 and the negative electrode sheet 22 can be thermally composited to form a composite unit 20 by using a composite mechanism 4 to prepare the composite unit 20; the single negative electrode unwinding mechanism 12 can be used to output multiple single negative electrode sheets 21, and then the composite unit 20 and the single negative electrode sheet 21 can be tested by an additional detection device, and then the qualified composite unit 20 and the qualified single negative electrode sheet can be tested. 21 utilizes the Z-stacking method to stack the sheets to form a stacked core structure. Thus, on the one hand, compared with the Z-stacking mechanism, the preparation system can not only reduce the number of times the electrode sheets are transported, thereby improving the preparation efficiency of the stacked core structure, but also eliminate the stacking diaphragm action and improve the stacking accuracy; on the other hand, compared with the continuous hot composite mechanism, the preparation system can discharge the defective single negative electrode sheet 21 or the defective composite unit 20, thereby avoiding the scrapping of the entire stacked core structure, which not only improves the material utilization rate, but also ensures the quality of the stacked battery cell.

[0064] It should be noted that, in the embodiment of the present invention, the plurality of diaphragms are respectively arranged corresponding to the first diaphragm, the second diaphragm, the third diaphragm and the fourth diaphragm.

[0065] As shown in FIG8 , in an embodiment of the present invention, the laminated cell preparation system further includes a single negative electrode unwinding mechanism 12 for unwinding a single negative electrode strip and a single negative electrode cutting unit 7 for cutting the single negative electrode strip into a plurality of single negative electrode sheets 21. In this way, a plurality of single negative electrode sheets 21 can be formed.

[0066] As shown in FIG8 , in an embodiment of the present invention, the laminated cell preparation system further includes a single negative electrode detection unit 8 located on one side of the single negative electrode cutting unit 7 to detect multiple single negative electrode sheets 21. The single negative electrode detection unit 8 is preferably a CDD camera.

[0067] As shown in Figure 8, in an embodiment of the present invention, the laminating mechanism 4 includes a first laminating roller structure, a second laminating roller structure, and a third laminating roller structure, spaced apart along the unwinding direction. Each of the first, second, and third laminating roller structures includes two laminating rollers spaced apart along the thickness direction of the laminated cell. Preferably, the first, second, and third laminating roller structures are disposed corresponding to the first, second, and third laminating sheets, respectively.

[0068] As shown in Figure 8, in an embodiment of the present invention, the laminated cell manufacturing system further includes a composite unit cutting structure 5 for cutting the third composite sheet into a plurality of composite units 20, and a composite unit detection structure 6 for detecting the coating dimensions of the plurality of composite units 20. Preferably, the composite unit detection structure 6 includes two detection components spaced apart along the thickness direction of the laminated cell, and each composite unit 20 can be detected by the detection component while passing between the two detection components.

[0069] Preferably, in an embodiment of the present invention, the detection component is a CDD camera.

[0070] Specifically, in an embodiment of the present invention, the system for preparing the laminated battery cell further includes a lamination mechanism for laminating the plurality of composite units 20 and the plurality of single negative electrode sheets 21 .

[0071] As shown in FIG8 , in an embodiment of the present invention, the system for preparing the laminated battery cell further includes a tail winding mechanism 10 for winding the tail diaphragm 26 around the outer periphery of the laminated core structure.

[0072] Specifically, the specific preparation process of the embodiment of the present invention is:

[0073] First, composite unit preparation can be performed on one side: After the negative electrode sheet 22 and two separators are unwound, they are thermally composited on a first composite roller structure to form a first composite sheet consisting of [first separator + negative electrode sheet 22 + second separator]. The first positive electrode sheet 23 is then unwound and attached to the top of the first composite sheet. A third separator is then unwound over the first positive electrode sheet 23, covering the third separator. Thermal composite is then performed on a second composite roller to form a second composite sheet consisting of [third separator + first positive electrode sheet + first separator + first negative electrode sheet + second separator]. The second positive electrode sheet 24 is then unwound and attached to the bottom of the second composite sheet. A fourth separator is then unwound under the second positive electrode sheet 24. Thermal composite is then performed on a third composite roller to form a third composite sheet consisting of [third separator + first positive electrode sheet + first separator + first negative electrode sheet + second separator + second positive electrode sheet + fourth separator]. This third composite sheet, consisting of a continuous separator, is then cut by the composite unit cutting structure 5 to form individual composite units 20 (as shown in FIG. 2 ).

[0074] Second, the single negative electrode sheet 21 is prepared on the other side: the single negative electrode sheet 21 is unrolled and passes through the single negative electrode cutting unit 7 to form individual single negative electrode sheets 21 .

[0075] Third, after the composite unit 20 and the single negative electrode sheet 21 pass the composite unit detection structure 6 and the single negative electrode detection unit 8 respectively, the composite unit 20 and the single negative electrode sheet 21 are stacked to form a stacked core structure lacking the first and last layer separators (i.e., the stacked core semi-finished product in Figure 8).

[0076] Fourth, the stacked core structure can wrap the first and last single negative electrode sheets 21 after one and a half turns of the tail winding to form a finished stacked core product.

[0077] The above-mentioned system for preparing the laminated battery core has all the advantages of the above-mentioned method for preparing the laminated battery core, which will not be described in detail here.

[0078] From the above description, it can be seen that the above-mentioned embodiments of the present invention achieve the following technical effects: the composite unit can be prepared by thermal compounding, the composite unit and the single negative electrode sheet can be first detected by a detection device, and then the qualified composite unit and the qualified single negative electrode sheet are stacked by the Z-stacking method to form a stacked core structure. In this way, on the one hand, compared with Z-stacking, the preparation of the stacked core structure can not only reduce the number of times the electrode sheets are transported, thereby improving the preparation efficiency of the stacked core structure, but also eliminate the stacking diaphragm action and improve the stacking accuracy; on the other hand, compared with continuous thermal compounding, the preparation of the stacked core structure can discharge bad single negative electrode sheets or bad composite units, thereby avoiding the scrapping of the entire stacked core structure, which not only improves the material utilization rate, but also ensures the quality of the stacked battery cell.

[0079] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A laminated battery cell, characterized in that, include: Composite unit (20); At least two single negative electrode sheets (21), at least two of the single negative electrode sheets (21) are arranged at intervals along the thickness direction of the laminated battery core, and one of the composite units (20) is provided between two adjacent single negative electrode sheets (21) to form a laminated core structure; The composite unit (20) comprises a negative electrode sheet (22), a first positive electrode sheet (23), a second positive electrode sheet (24) and a plurality of diaphragm segments (25); along the thickness direction, the first positive electrode sheet (23) and the second positive electrode sheet (24) are respectively arranged on opposite sides of the negative electrode sheet (22); the plurality of diaphragm segments (25) are arranged in sequence and spaced apart along the thickness direction; the first positive electrode sheet (23) or the second positive electrode sheet (24) or the negative electrode sheet (22) is arranged between two adjacent diaphragm segments (25).

2. The laminated cell according to claim 1, characterized in that, The composite unit (20) is multiple.

3. The laminated cell according to claim 1, characterized in that, The laminated battery core further comprises a tail-wound diaphragm (26), wherein the tail-wound diaphragm (26) is coated on the outer periphery of the laminated core structure.

4. A preparation method of a laminated battery cell, characterized in that, include: The preparation step of preparing a composite unit (20) using a negative electrode sheet (22), a first positive electrode sheet (23), a second positive electrode sheet (24) and a plurality of separator segments (25); The composite unit (20) is stacked between two adjacent single negative electrode sheets (21) to form a stacking step of a core stacking structure.

5. The preparation method of the laminated battery cell according to claim 4, wherein, The preparation steps include: A first forming step of compounding a first separator, a plurality of the negative electrode sheets (22) and a second separator to form a continuous first compound sheet; A second forming step of compounding a plurality of the first positive electrode sheets (23) and a third separator on one side of the first composite sheet to form a continuous second composite sheet; The third forming step is to composite a plurality of the second positive electrode sheets (24) and the fourth separator onto the other side of the first composite sheet to form a continuous third composite sheet.

6. The manufacturing method of the stacked battery cell according to claim 5, characterized in that, The preparation step further comprises: cutting the third composite sheet to form a plurality of composite units (20); Wherein, the first diaphragm, the second diaphragm, the third diaphragm and the fourth diaphragm are cut to form the corresponding plurality of diaphragm segments (25).

7. The method for preparing a laminated battery cell according to claim 5, characterized in that, The first forming step comprises: Unwinding the first diaphragm and the second diaphragm; The plurality of negative electrode sheets (22) are spaced apart and located between the first separator and the second separator along the unwinding direction; The first separator, the plurality of negative electrode sheets (22) and the second separator are thermally composited.

8. The manufacturing method of the laminated battery cell according to claim 5, characterized in that, The second forming step comprises: A plurality of the first positive electrode sheets (23) are sequentially attached to one side of the first composite sheet along an unwinding direction; Placing the third separator on a side of the first positive electrode sheet (23) away from the first composite sheet and unwinding the film; A plurality of the first positive electrode sheets (23) and the third separator tape are thermally composited to the first composite sheet.

9. The manufacturing method of the laminated battery cell according to claim 5, characterized in that, The third forming step comprises: Pasting a plurality of the second positive electrode sheets (24) on the other side of the first composite sheet; Placing the fourth separator on a side of the second positive electrode sheet (24) away from the first composite sheet and unwinding the film; A plurality of the second positive electrode sheets (24) and the fourth separator are thermally composited to the first composite sheet.

10. The method for preparing a laminated battery cell according to claim 4, wherein The tail roll diaphragm (26) is wrapped around the outer periphery of the stacked core structure.

11. The preparation method of the laminated battery cell according to claim 4, characterized in that, Before the stacking step and after the preparation step, the method for preparing the laminated battery core further includes: Detecting the composite unit (20); The single negative electrode sheet (21) is tested.

12. A preparation system for a stacked battery cell, characterized in that, The laminated battery cell is prepared by the method for preparing the laminated battery cell according to claim 4, and the laminated battery cell preparation system comprises: A negative electrode unwinding mechanism (1) for outputting the negative electrode sheet (22); Two positive electrode unwinding mechanisms (3) are respectively used to output the first positive electrode sheet (23) and the second positive electrode sheet (24); along the thickness direction of the laminated battery core, the two positive electrode unwinding mechanisms (3) are arranged at intervals so that the output first positive electrode sheet (23) and the second positive electrode sheet (24) are respectively located on both sides of the negative electrode sheet (22); along the unwinding direction, the negative electrode unwinding mechanism (1) and the positive electrode unwinding mechanism (3) are arranged at intervals; A plurality of separator unwinding mechanisms (2) for outputting a plurality of separators spaced apart along the thickness direction, wherein along the unwinding direction, one separator unwinding mechanism (2) is provided between the negative electrode unwinding mechanism (1) and each of the positive electrode unwinding mechanisms (3), and one separator unwinding mechanism (2) is provided on a side of each of the positive electrode unwinding mechanisms (3) away from the negative electrode unwinding mechanism (1), so that the first positive electrode sheet (23) or the second positive electrode sheet (24) or the negative electrode sheet (22) is provided between two adjacent separators; A composite mechanism (4) for thermally composite the plurality of the separators, the first positive electrode sheet (23), the second positive electrode sheet (24) and the negative electrode sheet (22) to form the composite unit (20); The single negative electrode unwinding mechanism (12) is used to output a plurality of the single negative electrode sheets (21).

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