Lithium ion battery roll core, manufacturing method thereof and lithium ion battery
By using laser to pre-arrange blank areas and holes on the positive electrode of lithium-ion batteries, combined with the design of the negative electrode, the problems of burrs and stress caused by punching and opening holes are solved, achieving uniform wetting and rapid penetration of electrolyte, thus improving battery performance and production efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- MIANYANG CHUANGMING INTELLIGENT BATTERY CO LTD
- Filing Date
- 2026-02-27
- Publication Date
- 2026-05-29
AI Technical Summary
In the current lithium-ion battery manufacturing process, the punching and opening operation can easily lead to metal burrs and stress problems, resulting in internal short circuits and performance degradation of the battery.
Laser is used to pre-arrange blank areas and form holes on the positive electrode. Combined with the blank areas and hole design of the negative electrode, electrolyte flow channels are formed to ensure uniform wetting and rapid penetration of electrolyte.
It improves the wetting speed and uniformity of the electrolyte, enhances battery performance, avoids metal burrs and stress problems, and improves production efficiency.
Smart Images
Figure CN122118115A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of battery manufacturing technology, and in particular to a lithium-ion battery core, its manufacturing method, and a lithium-ion battery. Background Technology
[0002] In lithium battery manufacturing, the drilling of holes in the electrode sheets is not done to reduce their weight, but to facilitate electrolyte wetting of the core. Current processes typically employ punching, where holes are directly punched into the electrode sheet coated with slurry. Since the electrode sheet substrate is generally aluminum or copper foil, metal burrs are easily created at the drilling site. Furthermore, the punching process can generate stress, which can cause burrs to accidentally penetrate the separator, leading to a short circuit between the positive and negative electrodes inside the battery. This stress can also affect the basic performance of the electrode sheet.
[0003] Therefore, there is an urgent need for a lithium-ion battery core that can solve the above problems, its manufacturing method, and a lithium-ion battery. Summary of the Invention
[0004] The purpose of this invention is to provide a lithium-ion battery core, its manufacturing method, and a lithium-ion battery. The invention uses a method of pre-arranging blank areas and laser melting holes to open holes on the positive electrode sheet, solving the problems of burrs and stress caused by traditional drilling, thus resulting in high battery performance stability.
[0005] To achieve the above objectives, the present invention provides a method for manufacturing a lithium-ion battery core, comprising: providing a sheet-like positive electrode current collector; coating a positive electrode slurry on two opposing surfaces of the positive electrode current collector to form a positive electrode coating area; setting a positive electrode blank area in the middle of the positive electrode coating area; using a laser to melt holes in the positive electrode blank area to form a plurality of positive electrode holes to form a positive electrode sheet, wherein the area of the positive electrode blank area is larger than the area of the positive electrode holes, and there is a gap between the positive electrode holes and the edge of the positive electrode blank area; fabricating a negative electrode sheet and providing a separator, the separator being filled with pores and usable for impregnating and storing electrolyte; stacking the positive electrode sheet, separator, and negative electrode sheet into an electrode stack and then winding them to form a core, wherein the separator is sandwiched between the positive electrode sheet and the negative electrode sheet.
[0006] Specifically, the positive electrode blank area is strip-shaped and extends from one end of the positive electrode current collector to the other end along the length direction of the positive electrode current collector. The positive electrode holes are spaced apart on the positive electrode blank area and arranged in a row along the length direction of the positive electrode sheet to form a positive electrode hole row. The positive electrode blank area forms electrolyte flow channels communicating with all the positive electrode holes. The strip-shaped shape of the positive electrode blank area, extending from one end of the positive electrode current collector to the other end along the length direction of the positive electrode current collector, allows for electrolyte flow after winding into a core. The grooves are set in each layer of the winding, thus forming a spiral electrolyte flow groove extending from the outermost to the innermost side in the core. After the electrolyte is injected, it can quickly spread along the electrolyte flow groove to cover every layer of the entire core and flow evenly into the separator through the positive electrode holes. This allows the separator on both sides of the positive electrode to be quickly wetted along the positive electrode blank area, forming a wetted band in the middle of the separator that covers every layer of the core. This effectively improves the electrolyte wetting speed and uniformity, and also allows the electrolyte flow groove to store electrolyte during subsequent battery operation.
[0007] Preferably, the fabrication of the negative electrode sheet includes: providing a sheet-like negative electrode current collector; coating two opposing surfaces of the negative electrode current collector with a negative electrode slurry to form a negative electrode coating area; setting a negative electrode blank area in the middle of the negative electrode coating area; using a laser to melt holes in the negative electrode blank area to form a plurality of negative electrode holes to form a negative electrode sheet, wherein the area of the negative electrode blank area is larger than the area of the negative electrode holes, and there is a gap between the negative electrode holes and the edges of the negative electrode blank area; after stacking the positive electrode sheet, the separator, and the negative electrode sheet into an electrode stack and winding it to form a core, the position on the positive electrode sheet corresponding to the negative electrode holes and the negative electrode blank area is the positive electrode hole or the positive electrode blank area. This design allows for the creation of corresponding through-holes at the positions of the positive and negative electrode plates and the separator. This ensures that when the wound core is immersed in electrolyte, the separator is partially exposed relative to the electrolyte at or corresponding to the positive and negative electrode holes. This effectively increases the contact area between the separator and the electrolyte on the side of the core, allowing the electrolyte to quickly penetrate through the positive and negative electrode holes into each turn of the separator. This forms a rapid wetting path from the outermost to the innermost layer of the core, significantly improving the electrolyte wetting rate and uniformity, thus enhancing production efficiency and battery performance. Even if electrolyte consumption occurs during subsequent battery use, it can be quickly replenished through this wetting path, further improving battery performance. Furthermore, this invention adds a non-end-face wetting path on the side of the core, shortening the distance the electrolyte travels to penetrate all core areas, increasing the electrolyte wetting rate and improving production efficiency.
[0008] Preferably, the positive electrode blank area is a straight strip parallel to the length direction of the positive electrode sheet and located in the middle of the width direction of the positive electrode coating area. The positive electrode holes are spaced apart on the positive electrode blank area to form a row along the length direction of the positive electrode sheet, thus forming a positive electrode hole row. The negative electrode blank area is a straight strip parallel to the length direction of the negative electrode sheet and located in the middle of the width direction of the negative electrode coating area. The negative electrode holes are spaced apart on the negative electrode blank area to form a row along the length direction of the negative electrode sheet, thus forming a negative electrode hole row.
[0009] Furthermore, the width of the positive electrode blank area is greater than the width of the negative electrode blank area. When the positive electrode sheet, separator, and negative electrode sheet are stacked into an electrode stack, the positions of the positive electrode blank area and the negative electrode blank area correspond, so that after being wound into a core, the positions of the positive electrode blank area and the negative electrode blank area also correspond along the axial direction of the core. This design eliminates the need for precise calculation and control of the winding tightness of the battery cell and the positions of the negative electrode holes and negative electrode blank areas during processing, ensuring that the active ions released from the positive electrode can be completely received by the negative electrode material, thus preventing the precipitation of metal ions.
[0010] Specifically, the width of the negative electrode blank area is 1-3 mm, and the width of the positive electrode blank area is 1-6 mm wider than the width of the negative electrode blank area. These values take into account both the requirements for the fused via and the energy density. If the width of the negative electrode blank area is too small, it will increase the difficulty of manufacturing the fused via and limit the area of the fused via; if the width of the negative electrode blank area is too large, it will waste more active area, thus significantly degrading the energy density of the cell.
[0011] Specifically, the distance between the positive electrode blank area and the negative electrode blank area and the lower edge of the core is between 1 / 3W and 2 / 3W, where W is the core height. The position range of the positive electrode blank area and the negative electrode blank area in the core height ensures that the wetting path on the side of the core is located in the middle of the core.
[0012] Preferably, the positive electrode blank area is coated with an insulating material to form a first insulating layer, and the negative electrode blank area is coated with an insulating material to form a second insulating layer. The first and second insulating layers reinforce the current collector strength around the positive and negative electrode holes, preventing stress problems or structural fragility of the current collector due to the hole opening operation, and reducing the risk of breakage during subsequent winding of the core.
[0013] Specifically, when coating the two opposite surfaces of the positive electrode sheet with positive electrode slurry to form a positive electrode coating area, a positive electrode tab blank area with a preset width is also formed at one end of the positive electrode sheet, and the positive electrode blank area is spaced apart from the positive electrode tab blank area; when coating the two opposite surfaces of the negative electrode current collector with negative electrode slurry to form a negative electrode coating area, a negative electrode tab blank area with a preset width is also formed at one end of the negative electrode sheet, and the negative electrode blank area is spaced apart from the negative electrode tab blank area; when the positive electrode sheet, separator, and negative electrode sheet are stacked into an electrode stack, the positive electrode tab blank area and the negative electrode tab blank area are respectively located on two opposite sides in the width direction of the electrode stack; in addition, the method further includes the step of: flattening the positive electrode tab blank area and the negative electrode tab blank area on the two opposite sides of the winding core to form a positive electrode tab flattening area and a negative electrode tab flattening area.
[0014] Specifically, the maximum length of the positive electrode hole and the negative electrode hole is 0.01 to 1 mm, and the opening ratio in the length direction of the core is 5% to 40%. If the opening ratio is too small, the total hole area decreases, the electrolyte penetration decreases, and the wetting rate decreases; if the opening ratio is too large, the total hole area increases, the effective cross-sectional area of the current collector decreases, the strength decreases, and the current collector is prone to breakage.
[0015] The present invention also discloses a lithium-ion battery core, which is manufactured by the above-described method for manufacturing lithium-ion battery cores.
[0016] In addition, the present invention also discloses a lithium-ion battery, including a battery casing, a core, a battery end cap, and an electrolyte. The core is installed in the battery casing, the electrolyte fills the battery casing and wets the core, and the battery end cap closes the opening of the battery casing. The core is the aforementioned lithium-ion battery core.
[0017] Compared with existing technologies, the present invention forms holes by laser non-contact drilling. On the one hand, it does not cause physical compression to the drilling area, preventing metal burrs from appearing around the hole or causing stress problems that could damage the structural stability. On the other hand, the use of laser drilling makes the hole shape easy to adjust and highly flexible. Attached Figure Description
[0018] Figure 1 This is a flowchart of the manufacturing method of the lithium-ion battery core in Example 1.
[0019] Figure 2 This is a structural diagram of the positive electrode sheet before it is wound in Example 1.
[0020] Figure 3 This is a structural diagram of the positive electrode sheet before it is wound in another embodiment.
[0021] Figure 4This is a structural diagram of the positive electrode sheet before it is wound in another embodiment.
[0022] Figure 5 This is a structural diagram of the positive electrode sheet before it is wound in another embodiment.
[0023] Figure 6 This is a structural diagram of the negative electrode sheet before it is wound in Example 1.
[0024] Figure 7 This is a three-dimensional view of the core in Example 1.
[0025] Figure 8 This is a cross-sectional view of the core cut along the axial direction in Example 1.
[0026] Figure 9 This is a partial top view of the core in Example 1.
[0027] Figure 10 This is a cross-sectional view of the core section cut laterally in Example 1.
[0028] Figure 11 This is a flowchart of the manufacturing method of the lithium-ion battery core in Example 2.
[0029] Figure 12 This is a structural diagram of the positive electrode sheet before it is wound in Example 2.
[0030] Figure 13 This is a structural diagram of the negative electrode sheet before it is wound in Example 2.
[0031] Figure 14 This is a three-dimensional view of the core in Example 2.
[0032] Figure 15 This is a cross-sectional view of the core cut along the axial direction in Example 2.
[0033] Figure 16 This is a partial top view of the core in Example 2.
[0034] Figure 17 This is a cross-sectional view of the core cut horizontally in Example 2 (with corresponding positive and negative electrode holes).
[0035] Figure 18 This is a cross-sectional view of the core in Example 2, cut horizontally (with the positive and negative holes staggered).
[0036] Figure 19 This is a structural diagram of the positive electrode sheet before it is wound in Example 3.
[0037] Figure 20 This is a structural diagram of the negative electrode sheet before it is wound in Example 3.
[0038] Figure 21This is a cross-sectional view of the core cut along the axial direction in Example 3.
[0039] Figure 22 This is a cross-sectional view of the core section cut horizontally in Example 3.
[0040] Icons: 1-Positive electrode sheet, 11-Positive current collector, 12-Positive electrode coating area, 13-Positive electrode blank area, 14-Positive electrode hole, 15-Positive electrode tab flattening area, 15a-Positive electrode tab blank area, 2-Negative electrode sheet, 21-Negative electrode current collector, 22-Negative electrode coating area, 23-Negative electrode blank area, 24-Negative electrode hole, 25-Negative electrode tab flattening area, 25a-Negative electrode tab blank area, 41-First insulating layer, 42-Second insulating layer. Detailed Implementation
[0041] To illustrate the technical content, structural features, objectives, and effects of the present invention in detail, the following description is provided in conjunction with the embodiments and accompanying drawings.
[0042] Example 1: refer to Figure 1 The present invention discloses a method for manufacturing a lithium-ion battery core, including steps S1-S4, the specific steps of which are shown below.
[0043] Step S1, refer to Figure 2 A sheet-shaped positive electrode current collector 11 is provided. A positive electrode slurry is coated on the two opposite surfaces of the positive electrode current collector 11 to form a positive electrode coating area 12. A positive electrode blank area 13 is provided in the middle of the positive electrode coating area 12. The positive electrode current collector 11 coated with the positive electrode slurry is rolled to achieve a suitable compaction density.
[0044] Step S2, as follows Figure 2 As shown, a laser is used to melt holes in the positive electrode blank area 13 to form a number of positive electrode holes 14. The material after melting holes is cut to a suitable width to make a positive electrode sheet 1. The area of the positive electrode blank area 13 is larger than the area of the positive electrode holes 14, and there is a gap between the positive electrode holes 14 and the edge of the positive electrode blank area 13.
[0045] In this embodiment, the positive electrode sheet 1 includes the positive electrode current collector 11 and the positive electrode coating area 12. The positive electrode blank area 13 is strip-shaped and disposed in the middle of the positive electrode coating area 12 (not disposed along the edge of the positive electrode coating area 12). It extends from one end of the positive electrode current collector to the other end of the positive electrode current collector in the length direction of the positive electrode current collector 11. The positive electrode holes 14 are spaced apart on the positive electrode blank area 13 and arranged in a row along the length direction of the positive electrode sheet 1 to form a row of positive electrode holes. The positive electrode blank area 13 forms an electrolyte flow groove that communicates with all the positive electrode holes 14.
[0046] Specifically, in this embodiment, the positive electrode blank area 13 is a straight strip parallel to the length direction of the positive electrode sheet 1 and located in the middle of the width direction of the positive electrode coating area 12. The positive electrode holes 14 are spaced apart on the positive electrode blank area 13 to form a row along the length direction of the positive electrode sheet 1, thus forming a row of positive electrode holes.
[0047] In other embodiments, the shape of the positive electrode blank area 13 can be other forms, and the positive electrode holes 14 can also be arranged in other forms, such as... Figure 3 As shown, the positive electrode blank area 13a is V-shaped. This positive electrode blank area 13a extends upwards for a certain distance along the length of the positive electrode sheet 1, and then extends downwards for a certain distance. The positive electrode holes 14 are spaced apart on the positive electrode blank area 13a, arranged upwards at intervals, and then downwards at intervals, following the shape of the positive electrode blank area 13a. (Reference) Figure 4 The positive electrode blank area 13b is wavy. More preferably, in another embodiment, reference... Figure 5 The positive electrode blank area 13c extends from one end to the other along the length of the positive electrode coating area 12, and also extends along the width of the positive electrode coating area 12, especially extending from one end to the other along the width of the positive electrode coating area 12, so that the positive electrode blank area 13c is inclined. This design allows the electrolyte flow grooves to extend along each layer of the core after it is wound into a core, and also extend along the height of the core, so that when the electrolyte wets the core, it can quickly wet the entire core.
[0048] In this embodiment, when the positive electrode slurry is coated on the two opposite surfaces of the positive electrode sheet 1 to form the positive electrode coating area 12, a positive electrode tab blank area 15a with a preset width is also formed at one end of the positive electrode sheet 1.
[0049] In this embodiment, the positive electrode current collector 11 is aluminum foil; the positive electrode slurry is composed of active material, conductive agent, binder and solvent. The active material includes lithium iron phosphate (LFP), lithium cobalt oxide, lithium manganese oxide or ternary high nickel, etc. The conductive agent includes one or more of conductive carbon black (SP), carbon nanotubes (CNT), graphene or conductive graphite. The binder includes polyvinylidene fluoride (PVDF), LA133 (aqueous dispersion of acrylonitrile copolymer), etc. The solvent is N-methylpyrrolidone (NMP).
[0050] Step S3: Fabricate negative electrode 2 and provide separator 3, wherein the separator 3 is covered with pores and can be used to wet and store electrolyte.
[0051] Specifically, such as Figure 6As shown, the fabrication of the negative electrode sheet 2 includes: providing a sheet-shaped negative electrode current collector 21; coating the two opposing surfaces of the negative electrode current collector 21 with a negative electrode slurry to form a negative electrode coating area 22; and rolling the negative electrode current collector 21 after coating with the negative electrode slurry to achieve a suitable compaction density.
[0052] refer to Figure 6 In this embodiment, the negative electrode 2 includes the negative electrode current collector 21 and the negative electrode coating area 22.
[0053] In this embodiment, the positive electrode hole 14 can be of any geometric shape. Preferably, the positive electrode hole 14 is a circular hole, but in other embodiments, the positive electrode hole 14 can also be square, rhomboid, etc.
[0054] Specifically, the maximum length of the positive electrode hole 14 is 0.01 to 1 mm. In this embodiment, the hole diameter within the above-mentioned range is adopted, which takes into account both the electrolyte permeability and the current collector strength and stress distribution. This allows the electrolyte to flow smoothly through the hole, accelerating the electrolyte wetting rate, while reducing the risk of breakage due to a decrease in the current collector strength.
[0055] Specifically, the positive electrode hole 14 has an opening ratio of 5% to 40% along the length of the winding core. In this embodiment, the opening ratio is set within the above range because, on the one hand, if the opening ratio is too small, the total area of the holes decreases, the amount of electrolyte permeation decreases, and the wetting rate decreases; on the other hand, if the opening ratio is too large, the total area of the holes increases, the effective cross-sectional area of the current collector decreases, the strength decreases, and the current collector is prone to breakage.
[0056] Step S4, refer to Figures 7 to 9 The positive electrode 1, the separator 3, and the negative electrode 2 are stacked into an electrode stack and then wound to form a core 5, with the separator 3 sandwiched between the positive electrode 1 and the negative electrode 2.
[0057] It should be noted that when the positive electrode 1, the separator 3, and the negative electrode 2 are stacked into an electrode stack, the positive electrode tab blank area 15a and the negative electrode tab blank area 25a are located on two opposite sides in the width direction of the electrode stack.
[0058] In this embodiment, after the positive electrode 1, the separator 3, and the negative electrode 2 are wound to form the core 5, the step further includes: flattening the blank areas 15a and 25a of the positive electrode tabs on both opposite sides of the core 5 to form the flattened positive electrode tab area 15 and the flattened negative electrode tab area 25.
[0059] refer to Figure 9 and Figure 10Since the positive electrode blank area 13 is strip-shaped and extends from one end of the positive electrode current collector 11 to the other end of the positive electrode current collector 11 along the length direction of the positive electrode current collector 11, the positive electrode holes 14 are spaced apart on the positive electrode blank area 13 and arranged in a row along the length direction of the positive electrode sheet 1 to form a positive electrode hole row. The positive electrode blank area 13 forms an electrolyte flow channel 130 that communicates with all the positive electrode holes 14.
[0060] The order of steps S1-S2 and step S3 can be interchanged or performed simultaneously.
[0061] The lithium-ion battery core manufactured according to the present invention includes a positive electrode 1, a negative electrode 2, and a separator 3. The separator 3 is covered with pores. The positive electrode 1, separator 3, and negative electrode 2 are stacked and wound into a core. The separator 3 is spaced between the positive electrode 1 and the negative electrode 2. The positive electrode 1 includes a positive electrode coating area 12 and a positive electrode current collector 11. The positive electrode coating area 12 has a positive electrode blank area 13, and positive electrode holes 14 are formed on the positive electrode blank area 13. The positive electrode 1, negative electrode 2, and separator 3 are wound into a core.
[0062] Specifically, the positive electrode blank area 13 is strip-shaped and extends from one end of the positive electrode current collector 11 to the other end of the positive electrode current collector 11 along the length direction of the positive electrode current collector 11. The positive electrode holes 14 are spaced apart on the positive electrode blank area 13 and arranged in a row along the length direction of the positive electrode sheet 1 to form a row of positive electrode holes. The positive electrode blank area 13 forms an electrolyte flow channel 130 that communicates with all the positive electrode holes 14.
[0063] refer to Figure 9 and Figure 10This invention also discloses a method for manufacturing a lithium-ion battery, providing a core 5 manufactured by the above-described method for manufacturing a lithium-ion battery core, providing a battery casing and a battery end cap, installing the core 5 in the battery casing, installing the battery end cap on the battery casing, injecting electrolyte into the battery casing through the injection hole, the electrolyte is located in the outer periphery and center hole of the core 5, if the positive electrode 1 is placed outside the negative electrode 2 for winding, the electrolyte enters the electrolyte flow groove 130 formed in the positive electrode blank area 13 from the outside of the core 5, and then enters each positive electrode hole 14 along the electrolyte flow groove 130, wetting the positions of the separator 3 on both sides of the positive electrode 1 and the positive electrode blank area 13 along the positive electrode hole 14, and then wetting the entire separator 3 upward and downward from this position respectively, realizing the full wetting of the core 5. In addition, the electrolyte also enters the core 5 from the ends through the tabs at the upper and lower ends of the core 5. If the positive electrode 1 is placed inside the negative electrode 2 and wound, the electrolyte enters the electrolyte flow groove 130 formed in the positive electrode blank area 13 from the center hole of the core 5. Other wetting paths are the same and will not be described in detail.
[0064] in, Figure 10 The arrows in the diagram indicate the path of electrolyte penetration. Figure 9 The distribution of electrolyte flow channels 130 in the core 5 is shown.
[0065] This embodiment also includes a lithium-ion battery, comprising a battery casing, a core 5, a battery end cap, and an electrolyte. The core 5 is installed in the battery casing, the electrolyte fills the battery casing and wets the core 5, and the battery end cap closes the opening of the battery casing. The core 5 is manufactured by the above-described lithium-ion battery core manufacturing method.
[0066] Example 2: refer to Figure 11 The present invention discloses a method for manufacturing a lithium-ion battery core, including steps S1-S4, the specific steps of which are shown below.
[0067] Step S1, refer to Figure 12 A sheet-shaped positive electrode current collector 11 is provided. A positive electrode slurry is coated on the two opposite surfaces of the positive electrode current collector 11 to form a positive electrode coating area 12. A positive electrode blank area 13 is provided in the middle of the positive electrode coating area 12. The positive electrode current collector 11 coated with the positive electrode slurry is rolled to achieve a suitable compaction density.
[0068] Step S2, as follows Figure 12As shown, a laser is used to melt holes in the positive electrode blank area 13 to form a number of positive electrode holes 14. The material after melting holes is cut to a suitable width to make a positive electrode sheet 1. The area of the positive electrode blank area 13 is larger than the area of the positive electrode holes 14, and there is a gap between the positive electrode holes 14 and the edge of the positive electrode blank area 13.
[0069] In this embodiment, the positive electrode sheet 1 includes the positive electrode current collector 11 and the positive electrode coating area 12. The positive electrode blank area 13 is strip-shaped and disposed in the middle of the positive electrode coating area 12 (not disposed along the edge of the positive electrode coating area 12). The positive electrode current collector 11 extends from one end of the positive electrode current collector 11 to the other end of the positive electrode current collector 11 in the length direction. The positive electrode holes 14 are spaced apart on the positive electrode blank area 13 and arranged in a row along the length direction of the positive electrode sheet 1 to form a row of positive electrode holes. The positive electrode blank area 13 forms an electrolyte flow groove that communicates with all the positive electrode holes 14.
[0070] Specifically, in this embodiment, the positive electrode blank area 13 is a straight strip parallel to the length direction of the positive electrode sheet 1 and located in the middle of the positive electrode coating area 12, and is disposed on the positive electrode sheet 1 along the length direction of the positive electrode current collector 11. The positive electrode holes 14 are spaced apart on the positive electrode blank area 13 to form a row along the length direction of the positive electrode sheet 1, thus forming a positive electrode hole row. In some other embodiments, the shape of the positive electrode blank area 13 can be other forms, and the positive electrode holes 14 can also be arranged in other forms.
[0071] In this embodiment, when the positive electrode slurry is coated on the two opposite surfaces of the positive electrode sheet 1 to form the positive electrode coating area 12, a positive electrode tab blank area 15a with a preset width is also formed at one end of the positive electrode sheet 1, and the positive electrode blank area 13 and the positive electrode tab blank area 15a are spaced apart.
[0072] In this embodiment, the positive electrode current collector 11 is aluminum foil; the positive electrode slurry is composed of active material, conductive agent, binder and solvent. The active material includes lithium iron phosphate (LFP), lithium cobalt oxide, lithium manganese oxide or ternary high nickel, etc. The conductive agent includes one or more of conductive carbon black (SP), carbon nanotubes (CNT), graphene or conductive graphite. The binder includes polyvinylidene fluoride (PVDF), LA133 (aqueous dispersion of acrylonitrile copolymer), etc. The solvent is N-methylpyrrolidone (NMP).
[0073] Step S3: Fabricate negative electrode 2 and provide separator 3, wherein the separator 3 is covered with pores and can be used to wet and store electrolyte.
[0074] Step S3 includes steps S31 and S32.
[0075] refer to Figure 13 In step S31, a sheet-like negative electrode current collector 21 is provided. A negative electrode slurry is coated on the two opposite surfaces of the negative electrode current collector 21 to form a negative electrode coating area 22. A negative electrode blank area 23 is provided in the middle of the negative electrode coating area 22. The negative electrode current collector 21 coated with negative electrode slurry is rolled to achieve a suitable compaction density.
[0076] refer to Figure 13 In step S32, a laser is used to melt holes in the negative electrode blank area 23 to form a plurality of negative electrode holes 24 to make a negative electrode sheet 2, wherein the area of the negative electrode blank area 23 is larger than the area of the negative electrode holes 24, and there is a gap between the negative electrode holes 24 and the edge of the negative electrode blank area 23.
[0077] In this embodiment, the negative electrode sheet 2 includes the negative electrode current collector 21 and the negative electrode coating area 22. The negative electrode blank area 23 is a straight strip parallel to the length direction of the negative electrode sheet 2 and located in the middle of the width direction of the negative electrode coating area 22. The negative electrode blank area 23 is disposed on the negative electrode sheet 2 along the length direction of the negative electrode current collector 21. The negative electrode holes 24 are spaced apart on the negative electrode blank area 23 to form a row along the length direction of the negative electrode sheet 2, thus forming a row of negative electrode holes.
[0078] In this embodiment, the positive electrode hole 14 and the negative electrode hole 24 can be of any geometric shape. Preferably, both the positive electrode hole 14 and the negative electrode hole 24 are circular holes. In other embodiments, the positive electrode hole 14 and the negative electrode hole 24 can also be square, rhomboid, etc.
[0079] Specifically, the maximum length of the positive electrode hole 14 and the negative electrode hole 24 is 0.01 to 1 mm. In this embodiment, the hole diameter within the above-mentioned range is adopted, which takes into account both the electrolyte permeability and the current collector strength and stress distribution. This allows the electrolyte to flow smoothly through the hole, accelerating the electrolyte wetting rate, while reducing the risk of breakage due to a decrease in the current collector strength.
[0080] Specifically, the opening ratio of the positive electrode hole 14 and the negative electrode hole 24 in the length direction of the winding core is 5% to 40%. In this embodiment, the opening ratio is adopted within the above-mentioned range because, on the one hand, if the opening ratio is too small, the total area of the holes decreases, the amount of electrolyte penetration decreases, and the wetting rate will decrease; on the other hand, if the opening ratio is too large, the total area of the holes increases, the effective cross-sectional area of the current collector decreases, the strength decreases, and the current collector is prone to breakage.
[0081] In this embodiment, when negative electrode slurry is coated on the two opposite surfaces of the negative electrode current collector 21 to form negative electrode coating area 22, a negative electrode tab blank area 25a with a preset width is also formed at one end of the negative electrode sheet 2, and the negative electrode blank area 23 and the negative electrode tab blank area 25a are spaced apart.
[0082] In this embodiment, the negative electrode current collector 21 is copper foil; the negative electrode slurry is composed of active material, conductive agent, binder and solvent. The active material includes graphite or modified graphite (such as silicon-carbon composite graphite), the conductive agent includes one or more of conductive carbon black (SP), carbon nanotubes (CNT), graphene or conductive graphite, the binder includes water-based styrene-butadiene rubber latex (SBR), sodium carboxymethyl cellulose (CMC) or oil-based polyvinylidene fluoride (PVDF), the solvent is deionized water, and the conductivity, particle size and dissolved oxygen of the deionized water must be strictly controlled.
[0083] Step S4, refer to Figures 14 to 16 The positive electrode 1, the separator 3, and the negative electrode 2 are stacked into an electrode stack and then wound to form a core 5, with the separator 3 sandwiched between the positive electrode 1 and the negative electrode 2.
[0084] It should be noted that when the positive electrode 1, the separator 3, and the negative electrode 2 are stacked into an electrode stack, the positive electrode tab blank area 15a and the negative electrode tab blank area 25a are located on two opposite sides in the width direction of the electrode stack.
[0085] In this embodiment, after the positive electrode 1, the separator 3, and the negative electrode 2 are wound to form the core 5, the step further includes: flattening the blank areas 15a and 25a of the positive electrode tabs on both opposite sides of the core 5 to form the flattened positive electrode tab area 15 and the flattened negative electrode tab area 25.
[0086] refer to Figure 16 The negative electrode blank area 23 is strip-shaped and extends from one end of the negative electrode current collector 21 to the other end of the negative electrode current collector 21 along the length direction of the negative electrode current collector 21. The negative electrode holes 24 are spaced apart on the negative electrode blank area 23 and arranged in a row along the length direction of the negative electrode sheet 2 to form a row of negative electrode holes. The negative electrode blank area 23 forms an electrolyte flow channel 230 that communicates with all the negative electrode holes 24.
[0087] The order of steps S1-S2 and step S3 can be interchanged or performed simultaneously.
[0088] The lithium-ion battery core manufactured according to the present invention includes a positive electrode 1, a negative electrode 2, and a separator 3. The separator 3 is covered with pores. The positive electrode 1, separator 3, and negative electrode 2 are stacked and wound into a core. The separator 3 is spaced between the positive electrode 1 and the negative electrode 2. In the region corresponding to the separator 3, a plurality of positive electrode holes 14 penetrating the positive electrode 1 are provided on the positive electrode 1. In the region corresponding to the separator 3, a plurality of negative electrode holes 24 penetrating the negative electrode 2 are provided on the negative electrode 2. The positive electrode 1, negative electrode 2, and separator 3 are wound into a core, and an electrolyte wetting path is formed on the core, extending to the center of the core through the electrode holes and separator pores.
[0089] The positive electrode 1 includes a positive electrode coating area 12 and a positive electrode current collector 11. The positive electrode coating area 12 has a positive electrode blank area 13 along the length direction of the positive electrode 1. A row of positive electrode holes is formed on the positive electrode blank area 13. The positive electrode blank area 13 is a strip-shaped area along the length direction of the positive electrode 1 and is located in the middle of the positive electrode coating area 12 in the core axis, forming a groove concave to the positive electrode 1. The negative electrode 2 includes a negative electrode coating area 22 and a negative electrode current collector 21. The negative electrode coating area 22 has a negative electrode blank area 23 along the length direction of the negative electrode 2. A row of negative electrode holes is formed on the negative electrode blank area 23. The negative electrode blank area 23 is a strip-shaped area along the length direction of the negative electrode 2 and is located in the middle of the negative electrode coating area 22 in the core axis, forming a groove concave to the negative electrode 2. Reference Figure 14 The positive electrode blank area 13 and the negative electrode blank area 23 are positioned in the axial direction of the core, and the width of the positive electrode blank area 13 in the axial direction of the core is greater than the width of the negative electrode blank area 23 in the axial direction of the core.
[0090] refer to Figure 14 and Figure 15 The positive electrode sheet 1 has a positive electrode tab blank area 15a at one long edge, and the negative electrode sheet 2 has a negative electrode tab blank area 25a at one long edge. After the core is wound, the positive electrode tab blank area 15a is flattened to form the positive electrode tab flattening area 15, and the negative electrode tab blank area 25a is flattened to form the negative electrode tab flattening area 25. The lithium-ion battery core of the present invention also includes a positive electrode tab flattening area 15 formed at one end of the core and a negative electrode tab flattening area 25 formed at the other end of the core.
[0091] Specifically, the width of the negative electrode blank area 23 is 1-3mm, and the width of the positive electrode blank area 13 is 1-6mm wider than the width of the negative electrode blank area 23.
[0092] In this embodiment, the width of the negative electrode blank area 23 is smaller than the width of the positive electrode blank area 13, so that the area of the negative electrode coating area 22 is larger than the area of the positive electrode coating area 12, to ensure that the active ions released from the positive electrode can be completely received by the negative electrode material and to avoid the precipitation of metal ions.
[0093] Furthermore, the width of the negative electrode blank area 23 is set at 1–3 mm, taking into account both the requirements for the fused via and the energy density. If the width of the negative electrode blank area 23 is too small, it will increase the difficulty of manufacturing the fused via and limit the area of the fused via. If the width of the negative electrode blank area 23 is too large, it will waste more active area, thus significantly degrading the energy density of the cell.
[0094] The positive electrode hole array includes a plurality of positive electrode holes 14, and the negative electrode hole array includes a plurality of negative electrode holes 24, wherein all the positive electrode holes 14 and negative electrode holes 24 can be arranged in corresponding positions (e.g., Figure 17 As shown), the positions can also be staggered (e.g. Figure 18 (As shown). In this embodiment, some of the positive electrode holes 14 and negative electrode holes 24 can be positioned correspondingly, while some of the positive electrode holes 14 and negative electrode holes 24 can be positioned offset (e.g., Figure 17 and Figure 18 (As shown). In this embodiment, the positive electrode hole array and the negative electrode hole array are arranged in a straight line, and the positive electrode blank area 13 and the negative electrode blank area 23 are corresponding straight strips.
[0095] Of course, the positive electrode blank area 13 and the negative electrode blank area 23 are not limited to straight strips. When the positive electrode hole array and the negative electrode hole array are curved, such as wavy, the positive electrode blank area 13 and the negative electrode blank area 23 are correspondingly curved, such as wavy.
[0096] Preferably, the distance between the positive electrode hole 14 and the lower edge of the core in the width direction (core axial direction) of the positive electrode sheet 1 is between 1 / 3W and 2 / 3W, and the distance between the negative electrode hole 24 and the lower edge of the core in the width direction (core axial direction) of the negative electrode sheet 2 is between 1 / 3W and 2 / 3W, where W is the height of the core. This design ensures that the positive electrode hole 14 and the negative electrode hole 24 are at a certain distance from the end face of the core, allowing the electrolyte to wet from the middle region of the core. In addition to the existing wettability paths at the top and bottom of the core, a non-end face wettability path with a significantly shortened distance is added. Specifically, in this embodiment, both the positive electrode hole array and the negative electrode hole array are located at the very center of the core in the axial direction.
[0097] In this embodiment, the positive electrode holes 14 and the negative electrode holes 24 are uniformly distributed along the length of the core, and the maximum length of the positive electrode holes 14 and the negative electrode holes 24 is 0.01 to 1 mm. This balances electrolyte permeability and current collector strength and stress distribution, achieving the technical objective of the invention while reducing the risk of breakage due to decreased current collector strength. The opening ratio of the positive electrode holes 14 and the negative electrode holes 24 along the length of the core is 5% to 40%. If the opening ratio is too small, the total hole area decreases, the electrolyte permeation decreases, and the wetting rate decreases; if the opening ratio is too large, the total hole area increases, the effective cross-sectional area of the current collector decreases, the strength decreases, and the current collector is prone to breakage.
[0098] refer to Figures 16 to 18 In the core of this embodiment, the positive electrode blank area 13 and the negative electrode blank area 23 form an electrolyte flow channel that connects all the positive electrode holes 14 and negative electrode holes 24 respectively. This acts as a confluence channel, allowing the electrolyte to pass through the diaphragm 3 and enter the electrolyte flow channel of each layer during electrolyte wetting. The electrolyte flows freely in the electrolyte flow channel and enters the positive electrode holes 14 and negative electrode holes 24 that are connected to it. This not only accelerates the wetting speed of the electrolyte but also forms a rapid electrolyte wetting band at the positions corresponding to the positive electrode blank area 13 and the negative electrode blank area 23 on the diaphragm 3. After rapidly wetting the rapid electrolyte wetting band, the electrolyte flows rapidly towards the end of the core through the rapid electrolyte wetting band, thereby completely wetting all areas of the entire core.
[0099] This invention also discloses a lithium-ion battery, providing a core 5 manufactured by the above-described method for manufacturing lithium-ion battery cores, a battery housing and a battery end cap, the core 5 being installed in the battery housing, the battery end cap being installed on the battery housing, and electrolyte being injected into the battery housing through the injection hole, the electrolyte being located in the outer periphery and center hole of the core 5, and the electrolyte entering the electrolyte flow groove 130 formed in the positive electrode blank area 13 and the electrolyte flow groove 2 formed in the negative electrode blank area 23 from the outer side and center hole of the core 5. In step 30, the electrolyte then flows into each positive electrode hole 14 and negative electrode hole 24 along the aforementioned electrolyte flow channels. It wets the positions corresponding to the positive electrode blank areas 13 on both sides of the positive electrode plate 1 along the positive electrode hole 14, and the positions corresponding to the negative electrode blank areas 23 on both sides of the negative electrode plate 2 along the negative electrode hole 24. Then, it wets the entire separator 3 upwards and downwards from these positions, while simultaneously rapidly wetting the core inside through adjacent positive electrode holes 14 and negative electrode holes 24, thus achieving full wetting of the core 5. Furthermore, the electrolyte also enters the core 5 from the ends through the tabs at the top and bottom ends.
[0100] in, Figure 15 , Figure 17 , Figure 18 The arrows in the diagram indicate the path of electrolyte penetration. Figure 16 The distribution of electrolyte flow channels (including 130 and 230) in core 5 is shown.
[0101] Example 3: Unlike Example 2, in Example 3, reference is made to... Figure 19 In step S1, an insulating material is also filled or coated on the positive electrode blank area 13 to form a first insulating layer 41, which covers the entire positive electrode blank area 13. For example, the first insulating layer 41 is at least one of an alumina layer or a boehmite layer.
[0102] refer to Figure 20 In step S31, an insulating material is also filled or coated in the negative electrode blank area 23 to form a second insulating layer 42, which covers the entire negative electrode blank area 23. For example, the second insulating layer 42 is at least one of an alumina layer or a boehmite layer.
[0103] In this embodiment, the first insulating layer 41 and the second insulating layer 42 reinforce the current collector strength around the positive electrode hole 14 and the negative electrode hole 24, preventing stress problems or structural fragility of the current collector due to the hole opening operation, and reducing the risk of breakage during the subsequent winding of the core.
[0104] This invention also discloses a lithium-ion battery, providing a core 5 manufactured by the above-described method for manufacturing lithium-ion battery cores, a battery casing, and a battery end cap. The core 5 is installed in the battery casing, and the battery end cap is installed on the battery casing. Because the positive electrode blank area 13 and the negative electrode blank area 23 are respectively coated with a first insulating layer 41 and a second insulating layer 42, there are no electrolyte flow grooves formed in the positive electrode blank area 13 and the negative electrode blank area 23 in this embodiment. After the electrolyte is injected into the battery casing through the injection hole, the electrolyte is located in the outer periphery and the center hole of the core 5. The electrolyte enters the positive electrode hole 14 and the negative electrode hole 24 from the outer side and the center hole of the core 5, and passes through the pores on the separator 3 to enter the adjacent negative electrode hole 24 and positive electrode hole 14, thereby circulating and wetting the inside of the core. At the same time, it wets the entire separator 3 from these positions upward and downward, thereby achieving full wetting of the core 5. Based on this, the electrolyte also enters the winding core 5 from the ends through the tabs at the upper and lower ends of the winding core 5. Among these, Figure 22 The arrows in the diagram indicate the path of electrolyte penetration.
[0105] Compared with existing technologies, the present invention forms holes by laser non-contact drilling. On the one hand, it does not cause physical compression to the drilling area, preventing metal burrs from appearing around the hole or causing stress problems that could damage the structural stability. On the other hand, the use of laser drilling makes the hole shape easy to adjust and highly flexible.
[0106] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent variations made in accordance with the scope of the present invention are still within the scope of the present invention.
Claims
1. A method for manufacturing a lithium-ion battery core, characterized in that, include: A sheet-shaped positive electrode current collector is provided, and a positive electrode slurry is coated on the two opposite surfaces of the positive electrode current collector to form a positive electrode coating area, and a positive electrode blank area is set in the middle of the positive electrode coating area; A laser is used to melt holes in the positive electrode blank area to form a number of positive electrode holes in order to manufacture a positive electrode sheet, wherein the area of the positive electrode blank area is larger than the area of the positive electrode holes, and there is a gap between the positive electrode holes and the edge of the positive electrode blank area; A negative electrode sheet is fabricated and a separator is provided, the separator being porous and usable for impregnating and storing electrolyte; The positive electrode, separator, and negative electrode are stacked into an electrode stack and then wound to form a core, with the separator sandwiched between the positive and negative electrode.
2. The method for manufacturing a lithium-ion battery core as described in claim 1, characterized in that, The positive electrode blank area is strip-shaped and extends from one end of the positive electrode current collector to the other end of the positive electrode current collector along the length direction of the positive electrode sheet. The positive electrode holes are spaced apart on the positive electrode blank area and arranged in a row along the length direction of the positive electrode sheet to form a positive electrode hole row. The positive electrode blank area forms an electrolyte flow channel that communicates with all the positive electrode holes.
3. The method for manufacturing a lithium-ion battery core as described in claim 1, characterized in that, The production of negative electrode plates includes: A sheet-like negative electrode current collector is provided, and a negative electrode slurry is coated on the two opposite surfaces of the negative electrode current collector to form a negative electrode coating area, and a negative electrode blank area is set in the middle of the negative electrode coating area; A laser is used to melt holes in the negative electrode blank area to form a number of negative electrode holes in order to manufacture a negative electrode sheet. The area of the negative electrode blank area is larger than the area of the negative electrode holes, and there is a gap between the negative electrode holes and the edge of the negative electrode blank area. After stacking the positive electrode sheet, separator, and negative electrode sheet into an electrode stack and winding it to form a core, the position on the positive electrode sheet corresponding to the negative electrode hole and the negative electrode blank area is the positive electrode hole or the positive electrode blank area.
4. The method for manufacturing a lithium-ion battery core as described in claim 3, characterized in that, The positive electrode blank area is a straight strip parallel to the length direction of the positive electrode sheet and located in the middle of the width direction of the positive electrode coating area. The positive electrode holes are spaced apart on the positive electrode blank area to form a row along the length direction of the positive electrode sheet, thus forming a positive electrode hole row. The negative electrode blank area is a straight strip parallel to the length direction of the negative electrode sheet and located in the middle of the width direction of the negative electrode coating area. The negative electrode holes are spaced apart on the negative electrode blank area to form a row along the length direction of the negative electrode sheet, thus forming a row of negative electrode holes. The width of the positive electrode blank area is greater than the width of the negative electrode blank area, and their positions correspond.
5. The method for manufacturing a lithium-ion battery core as described in claim 4, characterized in that, The width of the negative electrode blank area is 1-3mm, the width of the positive electrode blank area is 1-6mm wider than the width of the negative electrode blank area, and the distance between the positive electrode blank area and the negative electrode blank area and the lower edge of the core is between 1 / 3W and 2 / 3W, where W is the core height.
6. The method for manufacturing a lithium-ion battery core as described in claim 4, characterized in that, The positive electrode blank area is coated with insulating material to form a first insulating layer, and the negative electrode blank area is coated with insulating material to form a second insulating layer.
7. The method for manufacturing a lithium-ion battery core as described in claim 3, characterized in that, When the positive electrode slurry is coated on the two opposite surfaces of the positive electrode sheet to form the positive electrode coating area, a positive electrode tab blank area with a preset width is also formed at one end of the positive electrode sheet, and the positive electrode blank area and the positive electrode tab blank area are spaced apart. When negative electrode slurry is coated on the two opposite surfaces of the negative electrode current collector to form a negative electrode coating area, a negative electrode tab blank area with a preset width is also formed at one end of the negative electrode sheet, and the negative electrode blank area and the negative electrode tab blank area are spaced apart. When the positive electrode, the separator, and the negative electrode are stacked into an electrode stack, the blank areas of the positive electrode tab and the blank areas of the negative electrode tab are located on two opposite sides of the width direction of the electrode stack. The method also includes the step of flattening the blank areas of the positive electrode tabs and the blank areas of the negative electrode tabs on both opposite sides of the core, so as to form the flattened positive electrode tab area and the flattened negative electrode tab area.
8. The method for manufacturing a lithium-ion battery core as described in claim 4, characterized in that, The maximum length of the positive electrode hole and the negative electrode hole is 0.01 to 1 mm, and the opening rate in the length direction of the core is 5% to 40%.
9. A lithium-ion battery core, characterized in that: It is manufactured by the method of manufacturing lithium-ion battery core according to any one of claims 1-8.
10. A lithium-ion battery, characterized in that, The battery includes a battery housing, a winding core, a battery end cap, and an electrolyte. The winding core is installed in the battery housing, the electrolyte fills the battery housing and wets the winding core, and the battery end cap closes the opening of the battery housing. The winding core is a lithium-ion battery winding core as described in claim 9.