A misalignment-resistant battery cell, a lithium-ion battery, and a method for manufacturing a lithium-ion battery.

Abstract

This invention relates to an anti-misalignment battery cell, a lithium-ion battery, and a method for manufacturing a lithium-ion battery. The battery includes a positive electrode, a separator, and a negative electrode, wherein the positive and negative electrode are respectively attached to opposite sides of the separator. The positive electrode includes a positive active layer, and the negative electrode includes a negative active layer, the width of which is greater than the width of the positive active layer. This invention provides an anti-misalignment battery cell, a lithium-ion battery, and a method for manufacturing a lithium-ion battery, which can prevent misalignment between the positive and negative electrode.

Description

Technical Field

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

[0002] Lithium batteries can be broadly classified into two categories: lithium metal batteries and lithium-ion batteries. Lithium-ion batteries do not contain metallic lithium and are rechargeable. The fifth generation of rechargeable batteries, lithium metal batteries, was developed in 1996. They offer superior safety, specific capacity, self-discharge rate, and price-performance ratio compared to lithium-ion batteries. Due to their high technological requirements, only companies in a few countries produce lithium metal batteries.

[0003] The current method for manufacturing lithium-ion battery cells is winding. For wound cells, the positive electrode, negative electrode, and separator are wound into a core using the rotating needles of a winding machine, and then the finished lithium-ion battery is manufactured. However, during the cell manufacturing process, equipment problems often cause misalignment between the positive and negative electrode sheets during winding; and during the use of lithium-ion batteries, collisions can cause the positive and negative electrode sheets to shift, easily leading to misalignment. This can result in edge lithium plating, powder shedding, and battery swelling, severely affecting the electrochemical and safety performance of the finished battery.

[0004] The aforementioned deficiencies are those that those skilled in the art would like to overcome. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, this invention provides an anti-misalignment battery cell, a lithium-ion battery, and a method for preparing a lithium-ion battery, which can prevent misalignment between the negative electrode and the positive electrode.

[0006] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0007] An anti-misalignment battery cell includes: a positive electrode, a separator, and a negative electrode, wherein the positive electrode and the negative electrode are respectively attached to opposite sides of the separator; the positive electrode includes a positive active layer, the negative electrode includes a negative active layer, and the width of the negative active layer is greater than the width of the positive active layer.

[0008] When the positive and negative electrode plates in the battery cell are misaligned, the width of the negative active layer of the negative electrode plate is greater than the width of the positive active layer of the positive electrode plate. This ensures that the negative active layer of the negative electrode plate always covers the positive active layer of the positive electrode plate, thus preventing misalignment between the positive and negative electrode plates and preventing the active layer of the negative electrode plate from failing to fully cover the active layer of the positive electrode plate. This also prevents phenomena such as edge lithium plating, powder shedding, and battery swelling caused by poor coverage between the positive and negative electrode plates in the battery cell.

[0009] In one embodiment of the present invention, a first insulating layer and a second insulating layer are respectively provided on opposite sides of the positive electrode active layer, and both the first insulating layer and the second insulating layer are used to prevent short circuit between the positive electrode and the negative electrode.

[0010] When the positive and negative electrodes inside the cell shift, they may shift out of the separator's coverage area, allowing the sides of the positive and negative electrodes to make direct contact. By utilizing the first and second insulating layers, a short circuit caused by direct contact between the positive and negative electrodes can be prevented.

[0011] In one embodiment of the present invention, the width of the positive electrode is the same as the width of the negative electrode, the width of the separator is greater than the width of the positive electrode, and / or the width of the separator is greater than the width of the negative electrode.

[0012] In practice, if the width of the positive electrode is smaller than the width of the negative electrode, the energy density of the battery will decrease; if the width of the positive electrode is greater than the width of the negative electrode, the length of the battery will increase; if the width of the positive electrode is equal to the width of the negative electrode, that is, the edges of the positive and negative electrodes are flush, the utilization rate of the electrodes can be maximized. In practice, if the width of the separator is greater than the width of either the positive or negative electrode, it can prevent powder from falling off the edges of the positive and negative electrodes when impacted.

[0013] In one embodiment of the present invention, the first insulating layer is a boehmite layer or an alumina layer, and the second insulating layer is a boehmite layer or an alumina layer.

[0014] To achieve the above objectives, the main technical solution adopted by the present invention also includes:

[0015] A lithium-ion battery comprising: a cell as described above.

[0016] To achieve the above objectives, the main technical solution adopted by the present invention also includes:

[0017] A method for preparing a lithium-ion battery, comprising:

[0018] A positive electrode preparation platform is used to prepare a positive electrode and to extrude and coat a first insulating layer and a second insulating layer on opposite sides of the positive electrode active layer, respectively.

[0019] A negative electrode preparation platform, wherein the negative electrode preparation platform is used to prepare a negative electrode;

[0020] A membrane preparation platform, wherein the membrane preparation platform is used to prepare a membrane;

[0021] A cell winding platform is used to attach the positive electrode sheet and the negative electrode sheet to opposite sides of the separator, and then simultaneously wind the positive electrode sheet, the separator and the negative electrode sheet. The cell winding platform is used to prepare anti-misalignment cells.

[0022] A casing platform, used to load the anti-misalignment battery cell into a packaging bag;

[0023] The electrolyte injection platform is used to inject electrolyte into the packaging bag;

[0024] A packaging platform for sealing packaging bags.

[0025] When manufacturing lithium-ion batteries, the process begins with preparing a positive electrode using a positive electrode preparation platform, a negative electrode using a negative electrode preparation platform, and a separator using a separator preparation platform. The first and second insulating layers of the positive electrode are coated on opposite sides of the positive electrode active layer, ensuring that the positive and negative electrodes have the same width. The positive electrode, separator, and negative electrode are then placed in a cell winding platform, which simultaneously winds them to form an anti-misalignment cell. Next, an insertion platform places the anti-misalignment cell into a packaging bag, an injection platform injects electrolyte into the bag, and finally, an encapsulation platform seals the packaged bag, thus forming the lithium-ion battery.

[0026] In one embodiment of the present invention, the cell winding platform includes a cell winding machine, the cell winding machine is provided with a positive electrode setting slot for placing a positive electrode sheet and a negative electrode setting slot for placing a negative electrode sheet, the positive electrode setting slot and the negative electrode setting slot are arranged opposite to each other and have the same width, and the width of the positive electrode sheet and the width of the negative electrode sheet are the same.

[0027] When winding a cell to prevent misalignment, the positive electrode is placed in the positive electrode slot and the negative electrode is placed in the negative electrode slot. The positive and negative electrode slots are positioned opposite each other, ensuring that the positive and negative electrode pieces are also positioned opposite each other. The equal widths of the positive and negative electrode pieces, as well as the equal widths of the positive and negative electrode slots, ensure that the possible offset distances of the positive and negative electrode pieces during winding are the same, preventing excessive offset between them. Furthermore, the equal width of the positive and negative electrode pieces improves their utilization rate.

[0028] In one embodiment of the present invention, the width of the first insulating layer is smaller than the width of the second insulating layer, and the difference between the width of the negative electrode slot and the width of the negative electrode sheet is less than or equal to the width of the first insulating layer.

[0029] When the positive electrode sheet shifts within the given positive electrode slot and / or the negative electrode sheet shifts within the given negative electrode slot, the difference between the width of the given negative electrode slot and the width of the negative electrode sheet is less than or equal to the width of the first insulating layer. The width of the negative electrode active layer is equal to the width of the negative electrode sheet, ensuring that during the winding process, the negative electrode active layer of the negative electrode sheet always covers the positive electrode active layer of the positive electrode sheet.

[0030] In one embodiment of the present invention, the width of the second insulating layer is smaller than the width of the first insulating layer, and the difference between the width of the negative electrode slot and the width of the negative electrode sheet is less than or equal to the width of the second insulating layer.

[0031] When the positive electrode sheet shifts within the given positive electrode slot and / or the negative electrode sheet shifts within the given negative electrode slot, the difference between the width of the given negative electrode slot and the width of the negative electrode sheet is less than or equal to the width of the first insulating layer. The width of the negative electrode active layer is equal to the width of the negative electrode sheet, ensuring that during the winding process, the negative electrode active layer of the negative electrode sheet always covers the positive electrode active layer of the positive electrode sheet.

[0032] In one embodiment of the present invention, the first insulating layer is equal to the second insulating layer, and the difference between the width of the negative electrode slot and the width of the negative electrode sheet is less than or equal to the width of the first insulating layer; or the difference between the width of the negative electrode slot and the width of the negative electrode sheet is less than or equal to the width of the second insulating layer.

[0033] When the positive electrode sheet shifts within the given positive electrode slot and / or the negative electrode sheet shifts within the given negative electrode slot, the difference between the width of the given negative electrode slot and the width of the negative electrode sheet is less than or equal to the width of the first insulating layer. The width of the negative electrode active layer is equal to the width of the negative electrode sheet, ensuring that during the winding process, the negative electrode active layer of the negative electrode sheet always covers the positive electrode active layer of the positive electrode sheet.

[0034] Compared with the prior art, the beneficial effects of the present invention are:

[0035] 1. By utilizing the fact that the width of the negative active layer of the negative electrode sheet is greater than the width of the positive active layer of the positive electrode sheet, the negative active layer of the negative electrode sheet always covers the positive active layer of the positive electrode sheet, thereby preventing misalignment between the positive and negative electrode sheets and preventing the active layer of the negative electrode sheet from failing to fully cover the active layer of the positive electrode sheet. This also prevents phenomena such as edge lithium plating, powder shedding, and battery swelling caused by poor coverage between the positive and negative electrode sheets within the battery cell.

[0036] 2. By utilizing the first and second insulating layers, short circuits caused by direct contact between the positive and negative electrode plates are prevented.

[0037] 3. The positive electrode is placed in the positive electrode slot and the negative electrode is placed in the negative electrode slot. The positive and negative electrode slots are positioned opposite each other, which also ensures that the positive and negative electrode are positioned opposite each other. The widths of the positive and negative electrode are equal, and the widths of the positive and negative electrode slots are also equal. This ensures that the positive electrode can be offset by the same distance as the negative electrode during winding, preventing excessive offset between the positive and negative electrode during the winding process. Attached Figure Description

[0038] Figure 1 This is a partial structural schematic diagram of the positive electrode sheet in Embodiment 1 of the present invention;

[0039] Figure 2 This is a partial structural schematic diagram of the negative electrode sheet in Embodiment 1 of the present invention;

[0040] Figure 3 This is a partial structural cross-sectional view of the battery cell in Embodiment 1 of the present invention;

[0041] Figure 4 This is a partial structural diagram of the first insulating layer pressing against the side wall of the positive electrode given slot in Embodiment 3 of the present invention;

[0042] Figure 5 This is a partial structural diagram of the second insulating layer pressing against the side wall of the positive electrode given slot in Embodiment 3 of the present invention;

[0043] Figure 6This is a partial structural diagram of the second insulating layer pressing against the side wall of the positive electrode given slot in Embodiment 4 of the present invention;

[0044] Figure 7 This is a partial structural diagram of the first insulating layer pressing against the side wall of the positive electrode given slot in Embodiment 4 of the present invention;

[0045] Figure 8 This is a partial structural schematic diagram of the positive electrode reference slot and the negative electrode reference slot in Embodiment 5 of the present invention.

[0046] [Explanation of Labels in the Attached Image]

[0047] 1. Positive electrode sheet; 11. Positive active layer; 12. Positive current collector layer; 13. First insulating layer; 14. Second insulating layer; 15. Positive electrode tab; 16. Positive electrode tab adhesive; 2. Negative electrode sheet; 21. Negative active layer; 22. Negative current collector layer; 23. Negative electrode tab; 24. Negative electrode tab adhesive; 3. Separator; 4. Cell winding machine; 41. Positive electrode setting slot; 42. Negative electrode setting slot. Detailed Implementation

[0048] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] Example 1

[0050] For an embodiment of the anti-misalignment battery cell provided by the present invention, please refer to [link / reference]. Figure 1 , Figure 2 and Figure 3 As shown, an anti-misalignment battery cell includes: a positive electrode 1, a separator 3, and a negative electrode 2, wherein the positive electrode 1 and the negative electrode 2 are respectively attached to opposite sides of the separator 3 in the thickness direction.

[0051] Please continue reading. Figure 1 and Figure 3 The positive electrode sheet 1 includes a positive current collector layer 12 and a positive active layer 11. Preferably, in one embodiment of this application, there are two positive active layers 11, which are respectively coated on opposite sides of the positive current collector layer 12 in the thickness direction. The sum of the width of the positive active layer 11, the width of the first insulating layer 13, and the width of the second insulating layer 14 is the same as the width of the positive current collector layer 12. The positive electrode sheet 1 also includes a positive electrode tab 15 and a positive electrode tab adhesive 16. One end of the positive electrode tab 15 is fixedly connected to one end of the positive current collector layer 12 in the length direction, and the positive electrode tab adhesive 16 is fixedly connected to the positive electrode tab 15.

[0052] Please continue reading. Figure 2 and Figure 3The negative electrode sheet 2 includes a negative current collector layer 22 and a negative active layer 21. Preferably, in one embodiment of this application, the negative active layer 21 consists of two layers, which are respectively coated on opposite sides of the negative current collector layer 22. The width of the negative current collector layer 22 is equal to the width of the negative active layer 21. The width of the negative active layer 21 is greater than the width of the positive active layer 11. The negative electrode sheet 2 also includes a negative electrode tab 23 and a negative electrode tab adhesive 24. One end of the negative electrode tab 23 is fixedly connected to one end of the negative current collector layer 22 along its length, and the negative electrode tab adhesive 24 is fixedly connected to the negative electrode tab 23.

[0053] When it is necessary to wind the anti-misalignment battery cell, the workers place the positive electrode 1, separator 3 and negative electrode 2 in sequence, and use a winding machine to wind the positive electrode 1, separator 3 and negative electrode 2. Even if the positive electrode 1 and negative electrode 2 are prone to misalignment during the winding process, the width of the negative active layer 21 is greater than the width of the positive active layer 11, so that the positive active layer 11 of the positive electrode 1 is still within the coverage of the negative active layer 21, thereby preventing misalignment between the positive electrode 1 and negative electrode 2 (i.e. the active layer of the negative electrode 2 cannot completely cover the active layer of the positive electrode 1), and thus preventing edge lithium plating, powder shedding, battery swelling and other phenomena in the battery cell due to poor coverage between the positive electrode 1 and negative electrode 2.

[0054] Please see Figure 1 , Figure 2 and Figure 3 Specifically, a first insulating layer 13 and a second insulating layer 14 are respectively disposed on opposite sides of the positive electrode active layer 11. Both the first insulating layer 13 and the second insulating layer 14 are used to prevent short circuits between the positive electrode plate 1 and the negative electrode plate 2. The thickness of the first insulating layer 13 is the same as the thickness of the second insulating layer 14. The minimum thickness of the first insulating layer 13 is 0.01 mm, and the maximum thickness of the first insulating layer 13 is 0.1 mm.

[0055] Preferably, in one embodiment of this application, the thickness of the first insulating layer 13 can be 0.03 mm.

[0056] Preferably, in one embodiment of this application, the first insulating layer 13 may be a boehmite layer or an alumina layer.

[0057] Preferably, in one embodiment of this application, the second insulating layer 14 can be a boehmite layer or an alumina layer.

[0058] When the winding machine winds the anti-misalignment battery cell, the positive electrode 1 and the negative electrode 2 are prone to misalignment, which can easily cause both the positive electrode 1 and the negative electrode 2 to fall out of the coverage of the separator 3. This makes it easy for the side of the positive electrode 1 and the side of the negative electrode 2 to come into direct contact. The first insulating layer 13 and the second insulating layer 14 are used to prevent short circuits caused by direct contact between the positive electrode 1 and the negative electrode 2.

[0059] When a lithium-ion battery is used, if the lithium-ion battery is bumped or dropped, the positive electrode 1 and the negative electrode 2 inside the lithium-ion battery may easily become misaligned. The first insulating layer 13 and the second insulating layer 14 are used to prevent direct contact between the positive electrode 1 and the negative electrode 2, thereby preventing a short circuit between the positive electrode 1 and the negative electrode 2.

[0060] Please see Figure 1 , Figure 2 and Figure 3 Specifically, the width of the positive electrode 1 is equal to the sum of the widths of the positive active layer 11, the first insulating layer 13, and the second insulating layer 14. The width of the negative electrode 2 is equal to the width of the negative active layer 21, and also equal to the width of the positive electrode 1, thereby improving the utilization rate of both the positive and negative electrodes. Meanwhile, the width of the separator 3 is greater than the width of the positive electrode 1, and / or the width of the separator 3 is greater than the width of the negative electrode 2. This separator width design enhances the protection of both the positive and negative electrodes, preventing powder from falling off the edges of the positive and negative electrodes when impacted.

[0061] Example 2

[0062] One embodiment of the present invention provides a lithium-ion battery, which includes the anti-misalignment cell as described above.

[0063] Example 3

[0064] Reference Figure 1 , Figure 2 and Figure 3 The present invention provides a method for preparing a lithium-ion battery, which includes: a positive electrode preparation platform, a negative electrode preparation platform, a separator preparation platform, a cell winding platform, a casing platform, a liquid injection platform, and a packaging platform.

[0065] The positive electrode preparation platform is used to prepare the positive electrode 1. Workers first use the platform to prepare the positive electrode current collector 12, positive electrode active slurry, and insulating slurry. The platform includes a first extrusion coating machine. The die of the first extrusion coating machine extrudes the positive electrode active slurry onto the sidewall of the positive electrode current collector 12, forming the positive electrode active layer 11. Simultaneously, the die of the first extrusion coating machine extrudes the insulating slurry onto opposite sides of the width of the positive electrode active layer 11, forming the first insulating layer 13 and the second insulating layer 14, respectively. Workers then fix the positive electrode tab 15 to one end of the positive electrode current collector 12 and then apply adhesive to the tab 15, thus completing the preparation of the positive electrode 1.

[0066] The negative electrode preparation platform is used to prepare negative electrode 2. Workers use the platform to prepare the negative electrode current collector layer 22 and the negative electrode active slurry. The platform includes a second extrusion coating machine, which uses its die to extrude the negative electrode active slurry onto the sidewall of the negative electrode current collector layer 22, thus forming the negative electrode active layer 21. Workers then fix the negative electrode tab 23 to one end of the negative electrode current collector layer 22 and apply adhesive to the tab 23, thus completing the preparation of the negative electrode 2.

[0067] Among them, the diaphragm preparation platform is used to prepare diaphragm 3.

[0068] The cell winding platform is used to attach the positive electrode 1 and the negative electrode 2 to the opposite sides of the separator 3, and then simultaneously wind the positive electrode 1, the separator 3 and the negative electrode 2. The cell winding platform is used to prepare anti-misalignment cells.

[0069] The casing platform is used to pack the anti-misalignment battery cells into the packaging bag.

[0070] The electrolyte injection platform is used to inject electrolyte into the packaging bag.

[0071] The packaging platform is used to seal the packaging bags.

[0072] When preparing a lithium-ion battery, the process involves first preparing a positive electrode 1 using a positive electrode preparation platform, preparing a negative electrode 2 using a negative electrode preparation platform, and preparing a separator 3 using a separator preparation platform. The first insulating layer 13 and the second insulating layer 14 of the positive electrode 1 are coated on opposite sides of the positive electrode active layer 11, ensuring that the positive electrode 1 and negative electrode 2 have the same width. The positive electrode 1, separator 3, and negative electrode 2 are then placed in a cell winding platform, which simultaneously winds them to form an anti-misalignment cell. The anti-misalignment cell is then placed into a packaging bag using a casing platform, and liquid is injected into the packaging bag using a liquid injection platform. Finally, the packaged bag is sealed using a sealing platform, thus forming a lithium-ion battery.

[0073] During the anti-misalignment winding process of the battery cell, even if the positive electrode 1 is offset along its width direction, since the width of the negative electrode active layer 21 is greater than the width of the positive electrode active layer 11, the positive electrode active layer 11 is always within the coverage area of ​​the negative electrode active layer 21, so as to prevent misalignment between the positive electrode 1 and the negative electrode 2. The first insulating layer 13 and the second insulating layer 14 in the positive electrode 1 prevent direct contact between the positive electrode active layer 11 and the negative electrode active layer 21 after the positive electrode 1 and the negative electrode 2 are wound later, thereby preventing short circuit between the positive electrode 1 and the negative electrode 2.

[0074] Reference Figure 4 As shown, specifically, the battery cell winding platform includes a battery cell winding machine 4. The battery cell winding machine 4 is provided with a positive electrode setting slot 41 for placing the positive electrode sheet 1 and a negative electrode setting slot 42 for placing the negative electrode sheet 2. The positive electrode setting slot 41 and the negative electrode setting slot 42 are arranged opposite to each other and have the same width. The width of the positive electrode sheet 1 and the width of the negative electrode sheet 2 are the same.

[0075] When it is necessary to wind the anti-misalignment battery cell, the positive electrode 1 is placed in the positive electrode slot 41 and the negative electrode 2 is placed in the negative electrode slot 42. The positive electrode slot 41 and the negative electrode slot 42 are arranged opposite to each other, so that the positive electrode 1 and the negative electrode 2 are also arranged opposite to each other. By using the fact that the width of the positive electrode 1 and the width of the negative electrode 2 are equal, and the width of the positive electrode slot 41 and the negative electrode slot 42 are equal, the range of displacement that the positive electrode 1 can make during the winding process is the same as the range of displacement that the negative electrode 2 can make during the winding process, so as to prevent the positive electrode 1 and the negative electrode 2 from having an excessive displacement distance during the winding process.

[0076] Reference Figure 4 As shown, the width of the first insulating layer 13 is less than the width of the second insulating layer 14, and the difference between the width of the negative electrode slot 42 and the width of the negative electrode sheet 2 is less than or equal to the width of the first insulating layer 13.

[0077] Please continue to refer to Figure 4As shown, during the process of winding the anti-misalignment battery cell by the battery cell winding machine 4, the negative electrode 2 shifts to one side of the width direction of the negative electrode slot 42, and the positive electrode 1 shifts away from the negative electrode 2 along the width direction of the positive electrode slot 41. At the same time, the positive electrode 1 drives the first insulating layer 13 to press against the side wall of the positive electrode slot 41. At this time, it is the maximum offset distance between the positive electrode 1 and the negative electrode 2. By utilizing the fact that the difference between the width of the negative electrode slot 42 and the width of the negative electrode 2 is less than or equal to the width of the first insulating layer 13, and the width of the first insulating layer 13 is less than the width of the second insulating layer 14, the negative electrode active layer 21 still completely covers the positive electrode active layer 11, thereby preventing misalignment between the positive electrode 1 and the negative electrode 2 after the battery cell is wound out in the later stage.

[0078] Reference Figure 5 As shown, when the second insulating layer 14 is pressed against the side wall of the positive electrode slot 41, and the negative electrode 2 is pressed against the side of the negative electrode slot 42 away from the positive electrode 1, the difference between the width of the negative electrode slot 42 and the width of the negative electrode 2 is less than or equal to the width of the first insulating layer 13, so that the negative electrode active layer 21 always completely covers the positive electrode active layer 11, thereby preventing misalignment between the positive electrode 1 and the negative electrode 2 after the cell is wound out later.

[0079] Example 4

[0080] The difference between Example 4 and Example 3 is that, referring to Figure 6 As shown, the width of the second insulating layer 14 is smaller than the width of the first insulating layer 13, and the difference between the width of the negative electrode slot 42 and the width of the negative electrode sheet 2 is less than or equal to the width of the second insulating layer 14.

[0081] Please continue to refer to Figure 6 As shown, during the winding process of the anti-misalignment battery cell by the battery cell winding machine 4, the negative electrode 2 shifts to one side of the width direction of the negative electrode slot 42, and the positive electrode 1 shifts away from the negative electrode 2 along the width direction of the positive electrode slot 41. At the same time, the positive electrode 1 drives the second insulating layer 14 to press against the side wall of the positive electrode slot 41. At this time, it is the maximum offset distance between the positive electrode 1 and the negative electrode 2. By utilizing the fact that the difference between the width of the negative electrode slot 42 and the width of the negative electrode 2 is less than or equal to the width of the second insulating layer 14, and the width of the second insulating layer 14 is less than the width of the first insulating layer 13, the negative electrode active layer 21 still completely covers the positive electrode active layer 11, thereby preventing misalignment between the positive electrode 1 and the negative electrode 2 after the battery cell is wound out in the later stage.

[0082] Please continue to refer to Figure 7As shown, when the first insulating layer 13 is pressed against the side wall of the positive electrode slot 41, and the negative electrode 2 is pressed against the side of the negative electrode slot 42 away from the positive electrode 1, the difference between the width of the negative electrode slot 42 and the width of the negative electrode 2 is less than or equal to the width of the first insulating layer 13, so that the negative electrode active layer 21 always completely covers the positive electrode active layer 11, thereby preventing misalignment between the positive electrode 1 and the negative electrode 2 after the cell is wound out later.

[0083] Example 5

[0084] The difference between Example 5 and Example 3 is that, referring to Figure 8 As shown, the first insulating layer 13 is equal to the second insulating layer 14. The difference between the width of the negative electrode slot 42 and the width of the negative electrode sheet 2 is less than or equal to the width of the first insulating layer 13, and the difference between the width of the negative electrode slot 42 and the width of the negative electrode sheet 2 is less than or equal to the width of the second insulating layer 14.

[0085] Please continue to refer to Figure 8 As shown, when the first insulating layer 13 or the second insulating layer 14 is pressed against the side wall of the positive electrode slot 41, and the negative electrode 2 is pressed against the side of the negative electrode slot 42 away from the positive electrode 1, the difference between the width of the negative electrode slot 42 and the width of the negative electrode 2 is less than or equal to the width of the first insulating layer 13, and the width of the first insulating layer 13 is equal to the width of the second insulating layer 14, so that the negative electrode active layer 21 always completely covers the positive electrode active layer 11, thereby preventing misalignment between the positive electrode 1 and the negative electrode 2 after the cell is wound out later.

[0086] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a lithium-ion battery, comprising: A positive electrode preparation platform is used to prepare a positive electrode (1) and to extrude and coat a first insulating layer (13) and a second insulating layer (14) on opposite sides of the positive electrode active layer (11); A negative electrode preparation platform, wherein the negative electrode preparation platform is used to prepare a negative electrode (2); A membrane preparation platform, wherein the membrane preparation platform is used to prepare a membrane (3); The cell winding platform is used to attach the positive electrode (1) and the negative electrode (2) to the opposite sides of the separator (3) respectively, and then simultaneously wind the positive electrode (1), the separator (3) and the negative electrode (2). The cell winding platform is used to prepare anti-misalignment cells. A casing platform, used to load the anti-misalignment battery cell into a packaging bag; The electrolyte injection platform is used to inject electrolyte into the packaging bag; A packaging platform for sealing packaging bags; The battery cell winding platform includes a battery cell winding machine (4), which is provided with a positive electrode setting slot (41) for placing a positive electrode sheet (1) and a negative electrode setting slot (42) for placing a negative electrode sheet (2). The positive electrode setting slot (41) and the negative electrode setting slot (42) are arranged opposite to each other and have the same width. The width of the positive electrode sheet (1) and the width of the negative electrode sheet (2) are the same. Wherein: the width of the first insulating layer (13) is smaller than the width of the second insulating layer (14), and the difference between the width of the negative electrode slot (42) and the width of the negative electrode sheet (2) is less than or equal to the width of the first insulating layer (13); Alternatively, the width of the second insulating layer (14) is smaller than the width of the first insulating layer (13), and the difference between the width of the negative electrode slot (42) and the width of the negative electrode sheet (2) is less than or equal to the width of the second insulating layer (14). Alternatively, the width of the first insulating layer (13) is equal to the width of the second insulating layer (14), and the difference between the width of the negative electrode slot (42) and the width of the negative electrode sheet (2) is less than or equal to the width of the first insulating layer (13); or the difference between the width of the negative electrode slot (42) and the width of the negative electrode sheet (2) is less than or equal to the width of the second insulating layer (14).

2. A misalignment-preventing battery cell, characterized in that, The lithium-ion battery prepared by the method of claim 1 includes: a positive electrode (1), a separator (3), and a negative electrode (2), wherein the positive electrode (1) and the negative electrode (2) are respectively attached to opposite sides of the separator (3); the positive electrode (1) includes a positive active layer (11), the negative electrode (2) includes a negative active layer (21), the width of the negative active layer (21) is greater than the width of the positive active layer (11), and a first insulating layer (13) and a second insulating layer (14) are respectively disposed on opposite sides of the positive active layer (11), wherein the width of the first insulating layer (13) is less than the width of the second insulating layer (14), or the width of the second insulating layer (14) is less than the width of the first insulating layer (13), or the width of the first insulating layer (13) is equal to the width of the second insulating layer (14).

3. The anti-misalignment battery cell as described in claim 2, characterized in that: The width of the positive electrode (1) is the same as the width of the negative electrode (2), the width of the separator (3) is greater than the width of the positive electrode (1), and / or the width of the separator (3) is greater than the width of the negative electrode (2).

4. The anti-misalignment battery cell as described in claim 2, characterized in that: The first insulating layer (13) is a boehmite layer or an alumina layer, and the second insulating layer (14) is a boehmite layer or an alumina layer.

5. A lithium-ion battery, characterized in that: It includes: The anti-misalignment battery cell according to any one of claims 2 to 4.

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