Single cell and planar cell for planar cell

Abstract

The utility model relates to a single cell, wherein a cut-out pattern is produced in a first coated metal foil, a second coated metal foil and a pair of separator sheets. The shape of the coated portion of the first electrode is partially cut out from the first foil along the cut-out path. The coated portion remains attached to the foil at a predetermined position of the first electrode tab. The first foil is inserted between the separator sheets, at least one pair of alignment openings in the separator sheets are aligned with each other and with the alignment openings in the first foil. Then, the separator sheets are bonded along the cut-out path to form a first assembly. The second foil is placed on or under the first assembly, aligning the alignment openings in the second foil with the alignment openings in the first assembly. The second foil is attached to the first assembly to obtain a second assembly. The single cell is cut out from the second assembly according to the predefined shape. The utility model also relates to a planar battery having the single cell.

Description

Technical Field

[0001] This utility model relates to batteries, specifically to batteries comprising multiple stacked battery cells. Background Technology

[0002] A battery cell comprises two or more electrodes separated by separators. Battery cells can be manufactured using various production techniques, including winding, folding, and stacking. According to stacking techniques, multiple individual cells are stacked together, each cell including a first electrode, typically a cathode, inserted between two separators. The separators are bonded together along the periphery of the cathode by heating or adhesive, and then cut to form a pouch with the same shape and size as the anode. The pouch containing the cathode is then stacked alternately with the anode in a metal container, and tabs extending from the electrodes are welded together to connect to the battery contacts. The container is filled with liquid electrolyte before final sealing. Alternatively, the stacked cells can be integrated into an aluminum laminated pouch. A general advantage of stacked battery cells is that such batteries can be manufactured in many different shapes, as the shape of the battery cell is not limited to any particular format.

[0003] Each pair of cells containing the cathode and the anode forms a single cell, thus a battery comprises multiple stacked single cells. However, as the cell size decreases, controlling the position of the cathode between the separators becomes more difficult. Therefore, accuracy and efficiency decrease as the cell size decreases. Furthermore, handling and aligning individual single cells becomes more challenging as the size shrinks.

[0004] An improved assembly method has been developed in which single cells are produced by placing cathode sheets, pre-cut to the desired cell shape, between continuous rolls of separator sheets, placing an anode sheet on top or below them, and laminating the sheets together under heat and pressure, then cutting the single cells to the desired shape. This increases the rigidity of the single cells and enables higher processing speeds.

[0005] However, not all types of separator sheets can be easily laminated together. Furthermore, the pressure and heat during lamination can damage the separator and electrodes, leading to adverse consequences such as short circuits or insufficient electrolyte adsorption when assembling a single cell into a battery. Utility Model Content

[0006] This invention relates to a single cell for use in battery production. According to this invention, a cutting pattern / cutting pattern / cut-out pattern is formed in a first coated metal foil, a second coated metal foil, and a pair of separators. The first foil is used to produce the first electrode of the single cell, and the second foil is used to produce the second electrode of the single cell. The first electrode can be a cathode, and the second electrode can be an anode, or vice versa. This invention is hereinafter summarized for the first case (the first electrode is a cathode, and the second electrode is an anode), but the terms cathode and anode can be interchanged.

[0007] The shape of the coated portion of the cathode is partially cut out from the cathode foil along a cutting path. The cut is partial because the coated portion remains attached to the foil at a predetermined position on the cathode tab. The cut pattern in the first foil also includes alignment openings, and the cut patterns in the anode foil and the separator also include respective alignment openings. The cathode foil is inserted between the separators, wherein at least one pair of alignment openings in the separators are aligned with each other and with the alignment openings in the cathode foil. The separators are then bonded along the cutting path to form a first assembly, which includes a pouch containing the coated cathode portion. The anode foil is then placed on or under the first assembly, and the alignment openings in the anode foil are aligned with the alignment openings in the first assembly. The anode foil is attached to the first assembly to obtain a second assembly. A single cell is cut out from the second assembly according to a predetermined shape.

[0008] According to one aspect of the present invention, a single cell for a planar battery is provided, characterized in that the single cell includes a first electrode and a second electrode, the first electrode being cut from a first metal foil, the second electrode being cut from a second metal foil, each foil including a coating comprising the chemical composition of the corresponding first and second electrodes, each electrode including a coated metal foil portion and an uncoated metal tab, the coated metal foil portion and the tab having predetermined positions relative to each other and predetermined shapes and surface areas, the coated metal foil portion of the first electrode being cut from the first metal foil according to a predetermined shape along a cutting path extending along the periphery of the predetermined shape, wherein the coated metal foil portion of the first electrode... A first metal foil is attached to a predetermined position on the tab of the first electrode, and a cut first metal foil is inserted between a first diaphragm and a second diaphragm. The first and second diaphragms are aligned with each other and with the first metal foil, and are attached to each other along the cut path that serves as the attachment path, thereby obtaining a first assembly. The first assembly includes a pouch containing a portion of the coated metal foil cut from the portion containing the first electrode. A portion of the tab of the first electrode extends beyond the pouch. A second metal foil is aligned with and attached to the first assembly, thereby obtaining a second assembly. The second assembly is cut along a cut line that conforms to the attachment path and the shape of the tab, thereby obtaining the single cell.

[0009] According to another aspect of the present invention, a planar battery is provided, characterized in that it comprises a plurality of said single cells, said single cells are stacked in a container, said container is closed and sealed, and the tabs of the first electrode and the second electrode of said single cells are connected to corresponding battery contacts.

[0010] Proper positioning of the cathode foil between the diaphragms can be achieved by initially attaching the coated cathode portion to the foil and providing corresponding alignment openings. Attaching the anode foil to the first assembly forms a single cell with sufficient rigidity for easy handling without lamination. Attached Figure Description

[0011] Figure 1 A single cell suitable for battery production via stacking technology is shown.

[0012] Figures 2a to 2d It shows Figure 1 The four components of a single battery are shown.

[0013] Figures 3 to 5 show the cutting patterns of the cathode foil, anode foil, and two diaphragms according to the first embodiment of the present invention.

[0014] Figure 6 and 7 The diagram illustrates how, according to a first embodiment, the cut foil and sheet shown in Figures 3-5 are assembled into a single cell.

[0015] Figure 8 It shows how to get from Figure 7 The assembly steps shown yield a single cell from the component.

[0016] Figure 9 Slight variations of the embodiments shown in Figures 3 to 8 are illustrated.

[0017] Figures 10a to 10c Cutting patterns suitable for continuous foils and diaphragms are shown for application of this invention in continuous production lines.

[0018] Figures 11 and 12 show the cutting patterns of the cathode foil and anode foil according to a second embodiment of the present invention.

[0019] Figure 13a and 13b An assembly of a single cell according to a second embodiment is shown.

[0020] Figures 14a to 14c A set of alternative cutting patterns that can be used in this invention are shown, in which additional alignment openings are provided. Detailed Implementation

[0021] Figure 1A single cell 1 suitable for producing batteries using the stacking method described above is shown. The battery comprises multiple cells respectively stacked in… Figures 2a to 2d The superimposed portion is shown. One of the electrodes is at the bottom of the single cell. In this exemplary case, it is... Figure 2a The anode 2 shown is an example of a cathode. The anode is formed from a coated metal foil comprising a coated electrode portion 3 and an uncoated tab 4. In the case of a rechargeable lithium-ion battery, the anode coating can be a graphite coating. The tab 4 is integral with the anode foil; that is, the tab is the uncoated portion of the foil extending from the coated portion 3. The anode is cut into a "D" shape, which is merely an exemplary single-cell shape. Other shapes are also possible.

[0022] The top of the anode 2 is a bag portion 11, which includes first and second diaphragm sheets, with the cathode inserted between the diaphragm sheets. The cathode 5 is... Figure 2c As shown, it is also formed of a metal foil having a coated portion 6 and an uncoated tab 7. In the case of a rechargeable lithium-ion battery, the cathode coating may include lithium cobalt oxide or another lithium-based active component. (The last two sentences appear to be incomplete and require further context.) Figure 2b and 2d Diaphragms 8 and 9, as shown, are attached to each other along the periphery of the coated cathode portion 6 in attachment path 10. Figure 1 The cathode tab 7 is indicated by dashed lines. It includes a portion 7a located between the diaphragm sheets 8 and 9 and a portion 7b extending from the pouch portion 11 and located near the anode tab 4 in the assembled single cell. The outer perimeter of the coated portion 3 of the anode 2 corresponds to the outer perimeter of the pouch portion 11 containing the cathode.

[0023] According to this utility model, such as Figure 1 The single cell 1 shown is assembled from individual material sheets pre-cut according to a specific pattern, which are then aligned and assembled. This invention will be described with reference to a D-shaped single cell, but it is applicable to any single cell shape.

[0024] Figures 3 to 5 illustrate the first embodiment. Figure 3a A rectangular cathode foil 14 is shown. It is a metal foil, and its entire surface is coated with a cathode coating except for a strip 16 along one side of the foil, i.e., the strip 16 is formed from bare metal foil. Therefore, the cathode foil 14 includes a coated portion 15 and an uncoated portion 16. From this foil, as... Figure 3bAs shown, the coated portion 6 of the cathode is partially cut out by removing the coated foil material through a cutout path 17 that surrounds the shape of the coated portion 6. Additionally, an alignment opening 18 is cut out from the uncoated foil strip 16, resulting in a cut that includes the cutout path 17 and the alignment opening 18. The alignment opening completely covers a predetermined surface area of ​​the anode tab 4 at its predetermined location and extends to the left side of the anode tab location. The coated cathode portion 6 remains attached to the foil at a predetermined location 19, which is the designated location of the cathode tab.

[0025] Figure 4a A rectangular anode foil 20 is shown, which also includes a coated portion 21 and an uncoated strip 22. Alignment openings 23a are cut from the foil in the uncoated strip 22, as shown... Figure 4b As shown.

[0026] The left edges of the two alignment openings 18 and 23a are positioned at the same distance from the predefined anode tab position, which will achieve the final alignment, as explained further in this paper.

[0027] In addition to aligning the opening 23a, a tab opening 23b is cut from the anode foil 20 on the opposite side of the intended anode tab location. The width of the tab opening 23b is equal to the total width of the spacing between the cathode tab 7 and the single cell tabs 4 and 7. More generally, the tab opening 23b is sized to at least cover a predetermined surface area of ​​the portion 7b extending from the pouch portion 11 of the cathode tab 7 at a predetermined location.

[0028] Figure 5a A rectangular diaphragm 25 is shown. (See figure) Figure 5b As shown, alignment openings 26 are cut out, with the height of opening 26 equal to the height of anode tab 4, and the width of opening 26 equal to the sum of the total width of adjacent tabs 4 and 7 (including the spacing between the tabs) and the width of alignment opening 23a in the anode foil. Two diaphragm sheets 25 are cut out in this manner, each with alignment openings 26 of the same size. Sheets 25 are formed of materials that can be attached to each other under the influence of heat and / or light. For example, polyethylene sheets and polypropylene sheets can be bonded together in this way by heating. All cutting steps used to create the cut paths and openings can be performed, for example, by laser cutting.

[0029] After these cutting steps, the diaphragm 25 and the cathode foil 14 are... Figure 6The diaphragms are stacked as shown. In the stacked image, the diaphragm sheets 25 are shown in a transparent view. Cathode foils 14 are placed between the diaphragm sheets 25, and the openings 26 of the same size on the diaphragm sheets 25 are aligned with each other. The left edge of the alignment opening 18 is aligned with the left edge of the alignment opening 26. When the cathode foils 14 and the diaphragm sheets 25 are aligned in this manner, the diaphragm sheets come into contact with each other along the cut path 17. When pressed together and heated, for example, by a physical heater or laser, the diaphragm sheets adhere to the area corresponding to the cut path 17, thereby forming assembly 27. The cut path 17 now becomes Figure 1 The attachment path 10 is shown. Component 27 includes a pouch 11 containing a coated cathode portion 6. The coated cathode portion 6 is secured and sandwiched between diaphragm sheets 25 by adhesive bonding within the attachment path 10, while still remaining attached to the cathode foil 14 at a predetermined position 19 of the cathode tab.

[0030] refer to Figure 7 Then, the cut anode foil 20 is placed under the assembly 27 of the diaphragm and cathode foil, so that the left edge of the aligned opening 23a is aligned with the left edges of the aligned openings 18 and 26 in the assembly 27. Figure 7 The overlay image shows the cathode foil, anode foil, and diaphragm sheet in a transparent view to visually demonstrate the alignment of openings 18, 23a, and 26. The anode foil 20 is then attached to the pouch containing the cut-out coated portion 6 of the cathode using a suitable adhesive, thereby forming another assembly 28. Subsequently, for example, by laser cutting along... Figure 8 The cutting line 29 shown cuts out the single cell 1 from the component 28.

[0031] By partially cutting out the cathode, i.e., attaching it to the foil 14 at the tab position 19 before bonding the separator layer 25, and by providing alignment openings 18, 26 to ensure proper alignment of the cathode foil 14 and the separator sheet 25, the correct positioning of the cathode between the separator sheets is ensured regardless of the cathode size. Furthermore, the alignment opening 23a in the anode foil also allows for proper alignment of the electrodes with each other. Additionally, arranging the openings 18, 23a, 26 at predetermined positions relative to the tabs allows the single cell to be cut along a single cut line 29 after assembling the various foils and sheets. All components of the single cell are attached together to form a rigid, easy-to-handle single cell without the need for laminated constituent layers.

[0032] refer to Figure 9A slight variation of the above embodiment is shown. This figure illustrates an alternative cutout pattern for the cathode foil 14. The cathode foil now includes an alignment opening 18a and a tab opening 18b. The tab opening 18b is integrally formed with the cutout path 17 and covers a predetermined surface area of ​​the anode tab 4 at a predetermined location. The cutout patterns in the anode foil 20 and the diaphragm sheet 25 are the same as in the previous embodiment. The only difference from the previous embodiment is that the alignment opening 18a and the tab opening 18b of the cathode foil 14 are physically separated, illustrating a more general principle of this embodiment: both foils 14, 20 and both diaphragm sheets 25 are provided with matching alignment openings, allowing the foils and sheets to be overlapped and aligned by aligning the corresponding alignment openings along at least one edge of the opening (the left edge in the illustrated embodiment).

[0033] Setting the tab openings 18b and 23b is not for alignment purposes, but rather to enable the final component to be cut in a single cutting step, thereby obtaining... Figure 1 The required single cell is shown. For this purpose, the tab opening 18b in the cathode foil 14 needs to at least cover the predetermined surface area of ​​the anode tab 4 at its predetermined position, and the tab opening 23b in the anode foil 20 needs to at least cover the predetermined surface area of ​​the cathode tab portion 7b extending from the bag portion 11 at its predetermined position.

[0034] Therefore, the embodiment of Figures 3-7 is a special case in which the alignment opening 18a and the tab opening 18b in the cathode foil 14 form a single continuous opening 18, which can be referred to as an "alignment opening" even though it performs a dual function: alignment and the ability to cut out a single cell in a single cutting step.

[0035] According to one embodiment, alignment openings 18a, 23a, and 26 may also be provided in the cathode foil, anode foil, and separator, but no tab openings may be provided. In this case, after cutting the assembly 28 along the cutting line 29, the tabular portions of the cathode foil and anode foil need to be cut off to obtain the desired single cell.

[0036] Similarly, the alignment opening 26 in the separator 25 can have the same shape and size as the alignment openings 18a, 23a in the foil, regardless of the shape and position of the tabs. In this case, after cutting the assembly 28 along the cutting line 29, the remaining separator portion between the tabs needs to be cut off to obtain the desired single cell.

[0037] This invention is suitable for the continuous production of single cells and battery packs. Figures 10a to 10c The cathode foil 14 is shown. Figure 10a ), anode foil 20 ( Figure 10b ) and two diaphragms 25 ( Figure 10cRepeated cut-out patterns in a continuous roll of material. The aforementioned cut-out patterns are repeated at regular intervals, thereby enabling continuous alignment and assembly of various components in the manner described above.

[0038] Figures 11 and 12 illustrate yet another embodiment, showing the cut patterns in the cathode foil 14 and anode foil 20. The cut pattern in the diaphragm 25 is the same as in the previous embodiment, namely, cut openings 26. Figure 11a and 12a The rectangular cathode foil 14 and anode foil 20 shown are now fully coated, meaning there are no uncoated metal strips on the sides of the foils. Therefore, in the area corresponding to the tabs, the coating will be locally removed. This is in Figure 11b and 12b The figures show cathode tab region 40 and anode tab region 41, respectively. Localized removal of the coating can be accomplished by laser ablation. The cutting patterns of the cathode foil 14 and anode foil 20 are the same as in the first embodiment, i.e., for the cathode foil 14, a cutting line 17 and an alignment opening 18 (combining alignment and tab opening), and for the anode foil 20, an alignment opening 23a and a tab opening 23b. Removal of the coating in the tab regions can be performed before or after the cutting operation. Figure 13a It shows how to insert a cathode foil between two diaphragms and align them to obtain the first component 27. Figure 13b It shows that along Figure 8 The same cutting line 29 shown illustrates how the first component is aligned with the anode foil to obtain the second component 28 before cutting the single cell.

[0039] Figures 14a to 14b One embodiment is shown in which additional openings are provided on opposite sides of the electrodes. In the case shown, this is a mirror copy 18' of the first alignment opening 18, and mirror copies 23a', 26' of the alignment openings 23a and 26. These additional openings are included purely for alignment purposes and do not form part of the final cut-out single cell. The presence of these openings improves alignment before the diaphragm is bonded and before the anode foil is adhered to the first assembly.

[0040] This invention is applicable to rechargeable and non-rechargeable planar batteries of any practically achievable shape and size. A planar battery according to this invention is obtained by stacking single cells produced according to any embodiment of this invention into a container, connecting the tabs of the first and second electrodes of the single cells to corresponding battery contacts, and then closing and sealing the container.

Claims

1. A single cell (1) for a planar battery, characterized in that The single cell includes a first electrode (5) and a second electrode (2). The first electrode is cut from a first metal foil, and the second electrode is cut from a second metal foil. Each foil includes a coating that contains the chemical composition of the corresponding first and second electrodes. Each electrode includes a metal foil-coated portion (6, 3) and an uncoated metal tab (7, 4), the metal foil-coated portion and the tab having predetermined positions relative to each other, as well as predetermined shapes and surface areas. The coated metal foil portion (6) of the first electrode is cut out of the first metal foil according to a predetermined shape along a cutting path (17), the cutting path extending along the periphery of the predetermined shape, wherein the coated metal foil portion (6) of the first electrode is attached to the first metal foil (14) at a predetermined position (19) of the tab (7) of the first electrode (5). A first metal foil (14) is cut and inserted between a first diaphragm and a second diaphragm, the first and second diaphragms being aligned with each other and with the first metal foil, and attached to each other along the cut path (17) serving as the attachment path (10), thereby obtaining a first assembly (27) comprising a pouch (11) containing a portion (6) of coated metal foil cut from the portion holding the first electrode (5), and a portion (7b) of the tab (7) of the first electrode extending beyond the pouch (11). The second metal foil (20) is aligned with and attached to the first component (27) to obtain the second component (28), which is cut along a cutting line (29) that conforms to the shape of the attachment path (10) and the tabs (7, 4) to obtain the single cell.

2. A planar battery, characterized by The device includes multiple single cells (1) according to claim 1, the single cells are stacked in a container, the container is closed and sealed, and the tabs (7) of the first electrode (5) and the tabs (4) of the second electrode (2) of the single cells are connected to corresponding battery contacts.

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