A laminated battery pole piece, a laminated battery cell, a preparation method thereof and a lithium ion battery

Abstract

This invention discloses a stacked battery electrode, a stacked battery cell, a method for preparing the same, and a lithium-ion battery. The stacked battery electrode includes a current collector and an active material layer disposed on the surface of the current collector. The active material layer includes two or more active units, which are spaced apart along the length of the current collector. The gaps between adjacent active units on the current collector form a predetermined bending section of the stack. The stacked battery electrode of this invention is a continuous electrode, wherein the predetermined bending section of the stack is a hollow foil structure, which can serve as the bending corner of the stack core. During the stacking and core preparation process, there will be no corner powder shedding or subsequent corner lithium deposition, thus improving battery performance and reliability. Furthermore, the stacked battery electrode has a simple structure, is easy to process, and its structural design can improve the manufacturing efficiency of the stacked battery.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a stacked battery electrode, a stacked battery cell, a method for preparing the same, and a lithium-ion battery. Background Technology

[0002] Lithium-ion batteries are widely used in various digital products and mobile devices due to their advantages such as high energy density, low self-discharge, wide operating temperature range, and no environmental pollution. Stacked lithium-ion batteries are a common structure, but issues such as manufacturing efficiency, reliability, and efficiency improvement are particularly prominent.

[0003] Conventional commercially available stacked lithium-ion batteries typically use die-cut cathode and anode wafers, which are then stacked one by one through Z-shaped stacking or other roll-and-roll combinations, separated by a separator. This process is slow and requires managing multiple die-cut wafers, increasing the difficulty of process management. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a stacked battery electrode, a stacked battery cell, a method for preparing the same, and a lithium-ion battery.

[0005] A first aspect of the present invention provides a stacked battery electrode, comprising:

[0006] current collector;

[0007] An active material layer is disposed on the surface of the current collector; the active material layer includes two or more active units, and each active unit is arranged at intervals along the length direction of the current collector; the gap between adjacent active units on the current collector forms a pre-defined bending section of the stack.

[0008] According to embodiments of the present invention, the stacked battery electrode has at least the following beneficial effects: The stacked battery electrode is designed by comprising two or more active units spaced apart along the length of the current collector, with the gap between adjacent active units along the length of the current collector forming a predetermined bending section. Therefore, the stacked battery electrode serves as a continuous electrode, and the predetermined bending section can serve as a core corner during stacking. Specifically, during the stacking process for cell fabrication, after the stacked battery electrode has separators on both sides and covers each active unit to form a composite structure layer, it can be bent and folded along the predetermined bending section, and then the two adjacent composite layers after bending... Small electrode sheets are inserted between the composite structural layers to form a stacked battery cell. Therefore, based on the above-mentioned stacked battery electrode arrangement, the manufacturing efficiency of stacked batteries can be improved. Furthermore, since the active units on the current collector of the stacked battery electrode are arranged at intervals along the length direction, i.e., an empty foil structure is used between adjacent active units, when the battery cell is subsequently fabricated, bending and folding along the predetermined bending section formed by the gap between adjacent active units (i.e., the empty foil) will not result in corner powder shedding or subsequent corner lithium plating, thus improving battery performance and reliability. Moreover, the above-mentioned stacked battery electrode structure is simple and reliable, easy to process and industrialize.

[0009] In some embodiments of the present invention, the gap width between adjacent active units on the current collector is 0.5 to 10 mm.

[0010] In some embodiments of the present invention, one or more tabs are provided on one side of the current collector; preferably, two or more tabs are provided on one side of the current collector so that each tab is connected in parallel during the stacking of battery cells.

[0011] In some embodiments of the present invention, the stacked battery electrode is a cathode sheet, the current collector is a cathode current collector, and the active material layer is a cathode active material layer.

[0012] In some embodiments of the present invention, the stacked battery electrode is an anode sheet, the current collector is an anode current collector, and the active material layer is an anode active material layer.

[0013] In a first aspect, the present invention provides a method for preparing any of the stacked battery electrodes proposed in the first aspect of the present invention, comprising the following steps:

[0014] S11. Two or more active slurry layer units are coated at intervals along a predetermined straight direction on the current collector foil to form an active slurry layer;

[0015] S12. After drying the active slurry layer, roll pressing and die cutting are performed.

[0016] In some embodiments of the present invention, in step S11, two or more active slurry layer units are coated at intervals along a predetermined straight direction on the current collector foil, and an empty foil area is left on at least one side of the active slurry layer unit along the predetermined straight direction on the current collector foil; in step S12, the electrode tab is die-cut in the empty foil area.

[0017] In some embodiments of the present invention, in step S11, the length L1 of the active slurry layer unit along the direction perpendicular to the predetermined straight line is greater than or equal to twice the length L2 of the active unit on the target stacked battery electrode along the direction perpendicular to the current collector length. Preferably, L1 = 2 × L2 + (0 ~ 25 mm); and empty foil areas are left on both sides of the active slurry layer unit along the predetermined straight line on the current collector foil.

[0018] In some embodiments of the present invention, step S11 specifically includes: coating two or more active slurry layer units at intervals along a predetermined straight line direction and perpendicular to the predetermined straight line direction on the current collector foil to form an active slurry layer.

[0019] In some embodiments of the present invention, the width W1 of the active slurry layer unit on the current collector foil corresponding to the outermost active unit on the target stacked battery electrode is greater than or equal to the width W2 of each active slurry layer unit corresponding to each active unit in the middle region on the target stacked battery electrode; preferably, W1 = W2 + (0 ~ 20 mm).

[0020] A third aspect of the present invention provides a laminated battery cell, comprising:

[0021] The first electrode is formed by bending and folding any of the stacked battery electrode proposed in the first aspect of the present invention along a predetermined bending section of the stack.

[0022] The second electrode is inserted between two adjacent layers of laminated battery electrodes;

[0023] A diaphragm is disposed between the first electrode and the second electrode.

[0024] A fourth aspect of the present invention provides a method for preparing any of the laminated battery cells proposed in the three aspects of the present invention, comprising the following steps:

[0025] S21. A separator is provided on both surfaces of the stacked battery electrode, and the separator covers each active unit on the stacked battery electrode to form a composite structure layer.

[0026] S22. The composite structure layer is bent and folded along the predetermined bending section of the stacked battery electrode; then, a second electrode is inserted between adjacent composite structure layers.

[0027] In a fifth aspect, the present invention provides a lithium-ion battery comprising any of the stacked cells proposed in the third aspect of the present invention. Attached Figure Description

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0029] Figure 1 This is a schematic diagram of the structure of an embodiment of the stacked battery electrode of the present invention;

[0030] Figure 2 This is a schematic diagram of the process structure of an embodiment of the method for preparing stacked battery electrodes of the present invention;

[0031] Figure 3 This is a schematic diagram of the structure of an embodiment of the laminated battery cell of the present invention;

[0032] Figure 4 This is a schematic diagram of the process structure of an embodiment of the method for preparing a laminated battery cell according to the present invention. Detailed Implementation

[0033] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0034] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0035] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0036] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0037] Please see Figure 1 , Figure 1 A schematic diagram of the structure of an embodiment of the stacked battery electrode of the present invention is shown. Figure 1 As shown, the stacked battery electrode includes a current collector 11 and an active material layer 12, wherein the active material layer 12 is disposed on the surface of the current collector 11; the active material layer 12 includes two or more active units 121, and each active unit 121 is arranged at intervals along the length direction M of the current collector 11; the gap between adjacent active units 121 on the current collector 11 forms a predetermined bending section 111 of the stack. The stacked battery electrode is a continuous electrode, wherein the predetermined bending section 111 between adjacent active units 121 along the length direction M of the current collector 11 is not covered with active material and is a hollow foil structure, which is used to be bent and folded to form a stacked core corner during subsequent stacking and cell fabrication.

[0038] The gap width between adjacent active units 121 on the current collector 11 (this width is the width along the length direction M of the current collector 11) is 0.5-10 mm, for example, it can be designed to be 0.5-5 mm, 2-4 mm, or 5-10 mm, specifically 0.5 mm, 1 mm, 1.5 mm, 2 mm, 3 mm, 5 mm, 6 mm, 8 mm, 9 mm, or 10 mm; the gap width can be the same or different, but generally the same design is used. The active units 121 along the length direction M of the current collector 11 can be the same or different, but generally the same design is used. In this embodiment, the gap width between adjacent active units 121 on the current collector 11 is the same, and the active units 121 along the length direction M of the current collector 11 are the same, to facilitate manufacturing.

[0039] Conventional stacked lithium-ion batteries typically employ a stacked structure with multiple small electrodes stacked sequentially. The number of tabs corresponds to the number of small electrodes, and if any one tab breaks, the battery will suffer capacity loss because it cannot charge or discharge the electrode with the broken tab. The stacked battery electrode design of this application is based on a continuous electrode structure. One or more tabs 13 can be provided on one side of the current collector 11. The number of tabs 13 can be less than or equal to the number of active cells 121 (i.e., the number of layers formed by the stacking), offering high flexibility. If the number of tabs 13 is designed to be less than the number of active cells 121, the electrode structure can be simplified.

[0040] Preferably, two or more tabs 13 can be provided on one side of the current collector 11, so that each tab 13 can be connected in parallel during the stacking of battery cells. More preferably, the tabs 13 are provided corresponding to at least a portion of the active cells 121. For example, the tabs 13 can be provided on the current collector 11 corresponding to each active cell 121, so that the number of tabs 13 is equal to the number of active cells 121; or, the tabs 13 can be provided on the current collector 11 at positions corresponding to some active cells 121, so that the number of tabs 13 is less than the number of active cells 121. During the subsequent stacking of battery cells, the tabs 13 corresponding to each active cell 121 (or each layer of stacked battery electrodes) can be connected in parallel, so that if the tab 13 of a certain layer of stacked battery electrodes breaks during subsequent use, it will not affect the cell capacity and normal charging and discharging, thereby improving battery performance. In this embodiment, tabs 13 are provided on one side of the current collector 11 corresponding to each active unit 121, that is, the number of tabs 13 is equal to the number of active units 121.

[0041] In this embodiment, the tab 13 and the current collector 11 adopt an integrated structure. Specifically, during the electrode preparation process, an empty foil area can be reserved when coating the current collector foil to prepare the active material layer. Then, the tab 13 is subsequently die-cut into the empty foil area, thereby forming an integrated structure of the tab 13 and the current collector 11. Of course, in other embodiments, the tab 13 can also be separately connected and set on the current collector 11.

[0042] The above-mentioned stacked battery electrode can be a cathode or an anode. If the stacked battery electrode is a cathode, the current collector 11 is a cathode current collector and the active material layer 12 is a cathode active material layer. If the stacked battery electrode is an anode, the current collector 11 is an anode current collector and the active material layer 12 is an anode active material layer.

[0043] The above-mentioned stacked battery electrode is designed by making the active material layer 12 on the current collector 11 include two or more active units 121 arranged at intervals along the length direction M of the current collector 11. The gap between adjacent active units 121 on the current collector 11 along the length direction M forms a predetermined bending section 111 for stacking. Thus, the stacked battery electrode is a continuous electrode, and the predetermined bending section 111 on it can serve as the core corner during stacking. Specifically, when stacking to prepare the battery cell, after the separator is set on both sides of the stacked battery electrode and covers each active unit 121 to form a composite structure layer, it can be bent and folded along the predetermined bending section 111. After bending, the two adjacent composite layers are then connected. Small electrode sheets are inserted between the layers to form a stacked battery cell. Based on the above stacked battery electrode sheets, the manufacturing efficiency of stacked batteries can be improved. Since the active units 121 are arranged at intervals along the length direction M on the current collector 11 of the stacked battery electrode sheets, that is, the adjacent active units 121 are designed with an empty foil structure, when the cells are subsequently stacked, the stacked cells are bent and folded along the predetermined bending section 111 formed by the gap between adjacent active units 121 (i.e., the empty foil), which will not cause corner powder shedding or subsequent corner lithium plating, thus improving battery performance. Furthermore, the above stacked battery electrode sheet structure is simple and reliable, and easy to process and industrialize.

[0044] This invention also proposes a method for preparing electrode sheets of a multi-layered battery, specifically as follows: Figure 2 As shown, Figure 2 A schematic flowchart of an embodiment of the method for preparing the laminated battery electrode of the present invention is shown. The preparation method includes the following steps:

[0045] S11. Two or more active slurry layer units 221 are coated at intervals along a predetermined straight line direction Y on the current collector foil 21 to form an active slurry layer 22.

[0046] S12. After drying the active slurry layer 22, roll it and die-cut it.

[0047] In step S11, an active slurry of a certain length can be applied to the current collector foil 21 at intervals along a predetermined straight direction Y using a spacer design to achieve the intermittent coating of the active slurry layer units 221. Specifically, the spacer design can be used to ensure that the active slurry layer units 221 are not coated with active slurry, thus leaving a section of empty foil. In some embodiments, during the process of coating two or more active slurry layer units 221 at intervals along a predetermined straight direction Y on the current collector foil 21, an empty foil area 211 can be left on at least one side of the current collector foil 21 along the predetermined straight direction Y, without being coated with active slurry. Then, in step S12, the electrode tab can be die-cut from the empty foil area 211 during the die-cutting process. By reserving an empty foil area 211 for die-cutting the electrode tab during the coating process of the active slurry layer 22, the electrode tab can be directly die-cut from the empty foil area 211, thereby improving the preparation efficiency and structural stability.

[0048] In step S11 of this embodiment, the length L1 of the active slurry layer unit 221 covered on the current collector foil 21 along the direction X is greater than or equal to twice the length L2 of the active unit on the target stacked battery electrode along the direction perpendicular to the length of the current collector. Furthermore, empty foil areas 211 can be reserved on both sides of the active slurry layer unit 221 along the predetermined straight direction Y on the current collector foil 21 for die-cutting out the electrode tabs. Herein, the direction X is perpendicular to the predetermined straight direction Y, and the length direction of the current collector on the target stacked battery electrode generally corresponds to the predetermined straight direction Y. Preferably, L1 = 2 × L2 + (0 ~ 25 mm). Based on the above structural setup, in step S12, the die-cutting process cuts each of the spaced-apart active slurry layer units 221 along a predetermined straight line direction Y (preferably centered cutting), so that the predetermined straight line direction Y corresponds to the current collector length direction of the target stacked battery electrode. The die-cutting position in direction X is generally within the active slurry layer unit 221 corresponding to the outermost active unit at both ends of the current collector length direction on the target stacked battery electrode. Furthermore, electrode tabs are die-cut in the empty foil area 211. Through the combination of the above active slurry layer 22 coating process and die-cutting method, at least two stacked battery electrodes can be quickly prepared, improving the manufacturing efficiency of the stacked battery electrodes. Specifically, die-cutting can be performed using a die-cutting knife or laser die-cutting, and based on the above design of the active slurry layer unit 221 length and the reserved empty foil area 211 on both sides, see [reference needed]. Figure 2 In section (b), two die-cutting dies 23 with a mirror-symmetrical structure can be used for die-cutting. After the stacked battery electrode sheet is cut by one die-cutting die and flipped 180°, it can be consistent with the stacked battery electrode sheet cut by the other die-cutting die, thereby improving production efficiency.

[0049] Furthermore, the length of the current collector foil 21 along the predetermined straight line direction Y and the number of active slurry layer units 221 can be designed to correspond to the length of one or more target stacked battery electrodes and the number of active units. Accordingly, the width W1 of the active slurry layer unit 221 on the current collector foil 21 corresponding to the outermost active unit on the target stacked battery electrode is generally controlled to be greater than or equal to the width W2 of each active slurry layer unit 221 corresponding to each active unit in the middle region of the target stacked battery electrode. Preferably, W1 = W2 + (0~20mm) to ensure that the two outermost active slurry layer units 221 can be completely cut into the active slurry area during die cutting. The outermost active unit on the target stacked battery electrode refers to the outermost active units at both ends along the length direction of the current collector on the target stacked battery electrode; the active units in the middle region of the target stacked battery electrode refer to the active units in the middle region along the length direction of the current collector on the target stacked battery electrode. The die-cutting process generally controls the current collector length direction of the target stacked battery electrode to correspond to a predetermined straight line direction Y on the current collector foil 21. Therefore, the width specifically refers to the width of the active slurry layer unit 221 along the predetermined straight line direction Y. In this embodiment, the length of the current collector foil 21 along the predetermined straight line direction Y and the number of active slurry layer units 221 correspond to the length of one target stacked battery electrode and the number of active units arranged. Furthermore, the width of the outermost active slurry layer units 221 at both ends along the predetermined straight line direction Y on the current collector foil 21 is greater than or equal to the width of each active slurry layer unit 221 in the middle region.

[0050] Furthermore, in this embodiment, step S11 specifically includes: coating two or more active slurry layer units 221 at intervals along a predetermined straight line direction Y and a direction X perpendicular to the predetermined straight line direction Y on the current collector foil 21 to form an active slurry layer 22, specifically as follows: Figure 2As shown in (a). The spaced coating arrangement of the active slurry layer units 221 along the predetermined straight direction Y can be achieved through a gasket design; the spaced coating arrangement along the direction X perpendicular to the predetermined straight direction Y can be achieved through a roller skipping mechanism. Based on the above, in the formed active slurry layer 22, each active slurry layer unit 221 spaced along the predetermined straight direction Y on the current collector foil 21 can be considered as a unit component. Correspondingly, multiple unit components spaced along the direction X perpendicular to the predetermined straight direction Y can be die-cut to produce multiple stacked battery electrodes, which is more conducive to the mass production of stacked battery electrodes. Along the direction X perpendicular to the predetermined straight direction Y, the gaps between the active slurry layer units 221 serve as empty foil areas 211 for die-cutting to produce electrode tabs. Therefore, the spacing width of the active slurry layer units 221 along the direction X is generally greater than the spacing width of the active slurry layer units 221 along the predetermined straight direction Y. The spacing width of the active slurry layer unit 221 along direction X can be set according to the structure of the corresponding target stacked battery electrode. For example, if the width of the active slurry layer unit 221 along direction X on the current collector foil 21 is greater than or equal to the length L2 of the active unit on the target stacked battery electrode, but less than twice L2, then the spacing width of the active slurry layer unit 221 along direction X is generally slightly greater than the length of the electrode tab on the target stacked battery electrode along the direction perpendicular to the current collector length, and an empty foil area 211 is left at at least one end of the current collector foil 21 along direction X for die-cutting the electrode tab; if the width of the active slurry layer unit 221 along direction X on the current collector foil 21 is greater than or equal to twice the length L2 of the active unit on the target stacked battery electrode, then the spacing width of the active slurry layer unit 221 along direction X is generally greater than or equal to twice the length of the electrode tab on the target stacked battery electrode along the direction perpendicular to the current collector length, and empty foil areas 211 are left at both ends of the current collector foil 21 along direction X for die-cutting the electrode tab. Through these methods, rapid fabrication of stacked battery electrodes can be achieved, improving manufacturing efficiency.

[0051] The above-mentioned stacked battery electrodes can be further used in stacked battery cells, and therefore, this invention also proposes a stacked battery cell. For example... Figure 3 As shown, Figure 3 This diagram illustrates a structural schematic of an embodiment of the laminated battery cell of the present invention. The laminated battery cell includes a first electrode 31, a second electrode 32, and a separator 33. In this embodiment, the first electrode 31 adopts a similar... Figure 1The stacked battery electrode shown is formed by bending and folding along a predetermined bending section of the stacked battery electrode. The bending directions of adjacent predetermined bending sections of the stacked battery electrode are opposite, forming a multi-layer structure. A second electrode 32 is inserted between two adjacent layers of stacked battery electrodes. A separator 33 is disposed between the first electrode 31 and the second electrode 32, separating the two electrodes. Specifically, the first electrode 31 includes a straight active section 311 and a bent connecting section 312. The straight active section 311 corresponds to the active cell coverage area on the stacked battery electrode, and the bent connecting section 312 corresponds to the predetermined bending section of the stacked battery electrode. The straight active section 311 and the bent connecting section 312 are arranged alternately, with the straight active sections 311 stacked in layers. The bent connecting sections 312 connect adjacent straight active sections 311, and the bending directions of adjacent bent connecting sections 312 are opposite. The second electrode 32 is specifically inserted between two adjacent straight active sections 311 of the first electrode 31; the diaphragm 33 is sandwiched between the straight active sections 311 and the second electrode 32, and specifically covers both sides of the first electrode 31. In this embodiment, the first electrode 31 is an anode sheet, and both sides of the first electrode 31 with active units are covered by the diaphragm 33; the second electrode 32 is a cathode sheet, including a first cathode sheet 321 with a cathode active material layer coated on both sides and a second cathode sheet 322 with a cathode active material layer coated on one side. The second cathode sheet 322 is disposed at the outermost layers of both ends of the stacked cell, and the first cathode sheet 321 is inserted between adjacent straight active sections 311 of the first electrode 31 covered by the diaphragm 33. In this embodiment, the outermost layer of the stacked battery cell uses a second cathode sheet 322 with a single-sided coating of cathode active material, which improves space utilization and energy density. Compared to the first cathode sheet 321 with a double-sided coating of cathode active material, the volumetric energy density is increased by approximately 1% to 1.5%. Of course, in other embodiments, the first electrode 31 can also be a cathode sheet, and the second electrode 31 can be designed as an anode sheet accordingly. The specific structure of the stacked battery cell can be adjusted as needed.

[0052] This invention also proposes a method for preparing stacked battery cells using the above-mentioned stacked battery electrodes; please refer to the details below. Figure 4 , Figure 4 The diagram illustrates a flow chart of an embodiment of the method for preparing a laminated battery cell according to the present invention. The method for preparing the laminated battery cell includes the following steps:

[0053] S21. Take the stacked battery electrode 41, and set the separator 43 on both surfaces of the stacked battery electrode 41. The separator 43 covers each active unit 411 on the stacked battery electrode 41 to form a composite structure layer.

[0054] In this embodiment, the stacked battery electrode 41 specifically adopts a similar method. Figure 1The stacked battery electrode shown is specifically provided with a separator 43 on both surfaces of the active unit 411 on the stacked battery electrode 41, and then thermal bonding is performed so that the active unit 411 on the stacked battery electrode 41 is wrapped by the separator 43, and the tab 412 is left exposed for welding, thus obtaining a composite structure layer.

[0055] S22. The composite structure layer is bent and folded along the predetermined bending section 413 of the stacked battery electrode 41, and then a second electrode 42 that matches it is inserted between two adjacent composite structure layers.

[0056] In this process, the composite structure layer is bent and folded in a Z-shape along the predetermined bending section 413 of the stacked battery electrode 41. Each bending area corresponds to the predetermined bending section 413 of the stacked battery electrode 41 (i.e., the empty foil position between active units 411 along the current collector length direction). Since there is no coating in the corner area, there is no problem of corner powder shedding or subsequent corner lithium plating. Then, a second electrode 42 is set between two adjacent composite structure layers after bending to cooperate with it. After the stacking is completed, hot pressing is performed, and the tabs 412 are welded together and led out in parallel to obtain the stacked core. In this embodiment, the single stacked core obtained by the above steps S21 and S22 is used as the stacked battery cell. In other embodiments, multiple stacked cores can also be obtained according to the above steps S21 and S22, and then the stacked cores can be arranged side by side or stacked, and the tabs can be welded together in parallel to form a stacked battery cell. The capacity of the cells after parallel connection is the sum of the capacities of each stack of cells. Therefore, by connecting multiple stacks of cells in parallel, the capacity of the cells can be increased, and the thickness of the subsequent packaging shell can be reduced, thereby increasing the volumetric energy density.

[0057] The stacked cells obtained above can be further used to prepare lithium-ion batteries. Specifically, the stacked cells can be packaged and then subjected to processes such as liquid injection and formation to obtain lithium-ion batteries. Furthermore, this invention also proposes a lithium-ion battery, which includes any of the stacked cells proposed above. In the stacked cells of this lithium-ion battery, no auxiliary materials are placed in the corner areas of the continuously stacked battery electrodes, so that powder shedding and lithium deposition at the corners will not occur, thereby improving the performance and reliability of the lithium-ion battery.

[0058] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for preparing stacked battery electrodes, characterized in that, Includes the following steps: S11. Two or more active slurry layer units are coated at intervals along a predetermined straight line on the current collector foil to form an active slurry layer; wherein, the length of the active slurry layer unit along the direction perpendicular to the predetermined straight line is greater than or equal to twice the length of the active unit on the target stacked battery electrode along the direction perpendicular to the current collector length; during the process of coating two or more active slurry layer units at intervals along the predetermined straight line on the current collector foil, empty foil areas are left on both sides of the active slurry layer unit along the predetermined straight line on the current collector foil; and the width of the active slurry layer unit on the current collector foil corresponding to the outermost active unit at both ends along the current collector length direction on the target stacked battery electrode is greater than or equal to the width of the outermost active unit at both ends along the current collector length direction on the target stacked battery electrode. S12. After drying the active slurry layer, roll pressing and die cutting are performed. During the die cutting process, each active slurry layer unit arranged at intervals is cut along a predetermined straight line direction, so that the predetermined straight line direction corresponds to the current collector length direction of the target stacked battery electrode. The die cutting position in the direction perpendicular to the predetermined straight line direction is within the active slurry layer unit corresponding to the outermost active unit at both ends of the current collector length direction on the target stacked battery electrode. Furthermore, tabs are die-cut in the empty foil area.

2. The method for preparing the stacked battery electrode according to claim 1, characterized in that, Step S11 specifically includes: coating two or more active slurry layer units at intervals along a predetermined straight line direction and perpendicular to the predetermined straight line direction on the current collector foil to form an active slurry layer.

3. The method for preparing stacked battery electrodes according to claim 1 or 2, characterized in that, The width of the active slurry layer unit on the current collector foil corresponding to the outermost active unit on the target stacked battery electrode is greater than or equal to the width of each active slurry layer unit corresponding to each active unit in the middle region on the target stacked battery electrode.

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