Lithium ion battery pole piece and pole lug integrated structure with four insulated sides

Abstract

The utility model discloses a lithium ion battery pole piece and tab integrated structure with four insulated sides, and belongs to the field of batteries. Although cutting equipment is provided with a corresponding dust removal device, a certain amount of dust is still adsorbed on the surface of the pole piece and is not easy to remove. N sections of coating layers are symmetrically arranged on the front side and the back side of the metal foil current collector, and the n sections of coating layers are arranged in the length direction of the metal foil current collector; metal foil current collectors are reserved on the left side and the right side of each section of coating layer, and the four edges of each section of coating layer are coated with white glue layers; each section of coating layer comprises 2m active material layers, the 2m active material layers are arranged in an m * 2 array form, a gap is reserved between two adjacent active material layers in the m * 2 array, and a white glue insulating layer is arranged at the gap; the white glue insulating layers are used as cutting lines, metal foil current collectors with preset sizes are cut on the metal foil current collectors on the left side and the right side of each section of coating layer to serve as tabs, and each tab and each active material layer are of an integrated structure. The utility model relates to a lithium ion battery pole piece with four insulated sides.

Description

Technical Field

[0001] The utility model relates to positive and negative electrode sheet rolls for lithium ion batteries and belongs to the field of batteries. Background Art

[0002] Lithium-ion positive electrode plates use PVDF to bond ternary materials with particle sizes of about 3 to 10 um, lithium iron phosphate and other positive electrode active materials to the surface of aluminum foil and compact and compress them to form positive electrode plates. The negative electrode uses SBR adhesive to bond graphite with a particle size of about 7 to 15 um to the surface of copper foil and compact and compress it to form negative electrode plates. During the blade slitting process, high-speed die-cutting process or laser cutting, the bite of the blade and the high temperature of the laser will cause the edge particles of the above-made pole plates to break and the particles to fall off during the bonding process, generating a large amount of particles and dust. Although the slitting, die-cutting or laser cutting equipment will be equipped with corresponding dust removal devices, there is still a certain amount of dust and particles falling and adsorbed on the surface of the pole plates.

[0003] After the above-mentioned active material particles are adsorbed on the surface of the electrode and then formed into a battery cell through a winding or lamination process, the conductive active material particles are sandwiched between the positive electrode, the diaphragm, and the negative electrode. During the insulation short-circuit test, under high voltage conditions, the conductive particles will be broken down by the voltage and release heat, thereby damaging the diaphragm.

[0004] The above-mentioned active material dust and particles are mixed between the diaphragm and the electrode. After the battery is exposed to high temperature, low temperature, and vibration during use, the particulate matter will move and move to the thinner position of the diaphragm, causing tip discharge, affecting the self-discharge of the battery, and even affecting the safety of the battery under harsh conditions.

[0005] When the battery cell experiences thermal runaway under extreme circumstances or when the lithium-ion battery is tested using the needle puncture method, that is, a steel needle is used to pierce the lithium-ion battery to observe whether the battery catches fire or explodes, the residual active substance dust and particles may also cause the battery to experience thermal runaway under extreme circumstances, and strong short-circuit discharge may occur on the four sides of the electrode, aggravating the severity of thermal runaway and reducing the pass rate of the needle puncture.

[0006] Therefore, although the slitting, die-cutting or laser cutting equipment is currently equipped with corresponding dust removal devices, there is still a certain amount of dust and particles that fall and adsorb on the surface of the electrode, which is not easy to remove. Utility Model Content

[0007] The purpose of the utility model is to solve the problem that although the current slitting, die-cutting or laser cutting equipment is equipped with corresponding dust removal devices, there is still a certain amount of dust and particles falling and adsorbed on the surface of the electrode, which is not easy to remove cleanly. A lithium-ion battery electrode and electrode ear integrated structure with four-side insulation is proposed.

[0008] A four-sided insulated lithium-ion battery pole piece and pole ear integrated structure, the structure comprising a metal foil current collector, a white glue insulating layer and n-segment coating layers;

[0009] The front and back sides of the metal foil current collector are symmetrically provided with n coating layers, and the n coating layers are arranged along the length direction of the metal foil current collector; the metal foil current collector is left on the left and right sides of each coating layer, and the four sides of each coating layer are coated with a white glue insulating layer;

[0010] Each coating layer includes 2m active material layers, which are arranged in an m×2 array, and a gap is left between two adjacent active material layers in the m×2 array, and a white glue insulating layer is provided in the gap; m is determined by the width of the metal foil current collector (1) and the size of the active material layer;

[0011] The white glue insulating layer is used as a cutting line, and metal foil current collectors of a preset size are cut out on the metal foil current collectors on the left and right sides of each coating layer as pole ears, and each pole ear is an integrated structure with each active material layer.

[0012] Preferably, the width of the metal foil current collector left on the left and right sides of each coating layer is 0.5 mm to 200 mm.

[0013] Preferably, when the lithium-ion battery electrode is used as a positive electrode, the active material layer is prepared by mixing the ternary material, PVDF, a conductive agent, and NMP in a mixer to form a slurry having a uniform and stable viscosity;

[0014] The white glue insulation layer is prepared by mixing aluminum oxide, PVDF and NMP in a mixer to form a uniformly mixed white glue slurry.

[0015] Preferably, when the lithium-ion battery electrode is used as a positive electrode, the metal foil current collector is aluminum foil, carbon-coated aluminum foil or mesh aluminum foil.

[0016] Preferably, when the lithium-ion battery pole piece is used as a negative pole piece, the active material layer is prepared by mixing graphite material, SBR, conductive agent and pure water in a mixer to form a slurry having a uniform mixture and stable viscosity.

[0017] The white glue insulation layer is prepared by mixing water-based aluminum oxide, SBR and pure water in a mixer to form a uniformly mixed white glue slurry.

[0018] Preferably, when the lithium-ion battery electrode is used as a negative electrode, the metal foil current collector is copper foil, carbon-coated copper foil or mesh copper foil.

[0019] Preferably, n is 3.

[0020] The beneficial effects of the utility model are:

[0021] The utility model coats white glue insulating layers on all four sides of each active material layer. During the slitting, die-cutting and laser cutting processes of the lithium-ion battery pole pieces manufactured in this way, the active material layer will not be cut, and no active material layer powder particles will be generated. Instead, only the white glue insulating layer will be cut, and only a small amount of white glue dust will be generated. The white glue dust is an insulating and high-temperature resistant material with reliable material. Therefore, the utility model can prevent the problems of active material particle residue and splashing during the slitting, die-cutting and laser cutting processes, and can fundamentally solve the problem of active material particles falling onto the pole piece and the diaphragm at the cutting edge.

[0022] The use of the utility model can improve the pass rate of the Hipot high-voltage insulation impedance test process in the lamination or winding production process, reduce the probability of diaphragm damage, improve the pass rate of the Hipot process, and improve the safety of the battery during use.

[0023] In the acupuncture test of the battery pole piece made by the utility model, the high temperature resistant insulating white glue insulation layer used around the pole piece can effectively avoid the short circuit around the pole piece caused by the shrinkage of the diaphragm, thereby reducing the reaction temperature of the battery cell during acupuncture. The ceramic coating diaphragm can effectively block the high temperature, and the insulating coating can isolate the contact between the positive and negative pole pieces to reduce or avoid the short circuit at the pole piece edge, reduce the generation of short circuit points inside the battery cell, and finally improve the pass rate of acupuncture. During the thermal runaway process of the battery, the short circuit around the pole piece caused by the shrinkage of the diaphragm can effectively avoid the phenomenon of aggravating the thermal runaway, thereby effectively reducing the severity of the thermal runaway. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of a pole piece with empty foil between coating layers;

[0025] Figure 2 It is a schematic diagram of coating with white glue insulation layer on four edges after coating is completed;

[0026] Figure 3 It is a schematic diagram of the structure of each coating layer;

[0027] Figure 4 This is a schematic diagram of the cutting position of the pole piece with white glue insulation layer on the four edges. In the figure, the green line is the cutting line;

[0028] Figure 5 In accordance with Figure 4 Schematic diagram of a single coil pole piece after longitudinal green line slitting;

[0029] Figure 6 For Figure 5 Schematic diagram of a single pole piece with a white glue insulation layer on the four edges formed after transverse cutting. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0031] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0032] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0033] Example:

[0034] Combination Figures 1 to 6 This embodiment is described, a four-side insulated lithium-ion battery pole piece and pole ear integrated structure, the structure includes a metal foil current collector 1, a white glue insulating layer 2 and an n-segment coating layer 3;

[0035] The front and back sides of the metal foil current collector 1 are symmetrically provided with n coating layers 3, and the n coating layers 3 are arranged along the length direction of the metal foil current collector 1; the metal foil current collector 1 is left on the left and right sides of each coating layer 3, and the four sides of each coating layer 3 are coated with a white glue insulating layer 2;

[0036] Each coating layer 3 includes 2m active material layers 3-1, which are arranged in an m×2 array, and a gap is left between two adjacent active material layers 3-1 in the m×2 array, and a white glue insulating layer 2 is arranged in the gap; m is determined by the width of the metal foil current collector 1 and the size of the active material layer 3-1;

[0037] The white glue insulating layer 2 is used as a cutting line, and the metal foil current collector 1 of a preset size is cut out on the metal foil current collector 1 on the left and right sides of each coating layer 3 as a tab, and each tab is an integral structure with each active material layer 3-1.

[0038] The remaining width of the metal foil current collector 1 is further defined below:

[0039] The width of the metal foil current collector 1 left on the left and right sides of each coating layer 3 is 0.5 mm to 200 mm.

[0040] The materials for preparing the positive electrode sheet are further defined below:

[0041] When the lithium-ion battery electrode is used as a positive electrode, the active material layer 3-1 is made of ternary material, PVDF, conductive agent, and NMP, which are stirred by a mixer to form a slurry with a uniform and stable viscosity;

[0042] The white glue insulating layer 2 is made of aluminum oxide, PVDF, and NMP, which are stirred by a mixer to form a uniformly mixed white glue slurry.

[0043] Specifically, the present embodiment can be used to manufacture a positive electrode sheet of a lithium-ion battery or a negative electrode sheet of a lithium-ion battery.

[0044] When making a positive electrode for a lithium-ion battery, a ternary material, PVDF, a conductive agent, and NMP are used and stirred in a mixer to form a slurry with a uniform and stable viscosity as an active material layer 3-1, which is coated on the front and back sides of a metal foil current collector 1. When making a positive electrode for a lithium-ion battery, a white glue insulating layer 2 is used which is mixed with aluminum oxide, PVDF, and NMP.

[0045] Ternary materials include 5 series single crystal ternary materials, 5 series polycrystalline ternary materials, 6 series single crystal ternary materials, 6 series polycrystalline ternary materials, 7 series single crystal ternary materials, 7 series polycrystalline ternary materials, 8 series single crystal ternary materials, 8 series polycrystalline ternary materials, cobalt-free single crystal ternary materials, cobalt-free polycrystalline ternary materials, lithium iron phosphate materials, polyanion sodium ion positive electrode materials, and layered oxide sodium ion-free positive electrode materials.

[0046] The following further defines the metal foil current collector 1 used in making the positive electrode sheet of a lithium-ion battery:

[0047] When the lithium-ion battery electrode is used as a positive electrode, the metal foil current collector 1 is aluminum foil, carbon-coated aluminum foil or mesh aluminum foil.

[0048] Specifically, when manufacturing the positive electrode sheet of a lithium-ion battery, the metal foil current collector 1 is made of aluminum foil.

[0049] The materials for preparing the negative electrode sheet are further defined below:

[0050] When the lithium-ion battery electrode is used as a negative electrode, the active material layer 3 - 1 is prepared by mixing graphite material, SBR, conductive agent, and pure water in a mixer to form a slurry having a uniform and stable viscosity.

[0051] When the white glue insulating layer 2 is used to make a negative electrode sheet of a lithium-ion battery, the white glue insulating layer 2 is prepared by mixing aqueous aluminum oxide, SBR, and pure water in a mixer to form a uniformly mixed white glue slurry.

[0052] Specifically, when making a negative electrode sheet for a lithium-ion battery, a graphite material, SBR, a conductive agent, and pure water are used and stirred in a mixer to form a mixed slurry with a uniform and stable viscosity as the active material layer 3-1, which is coated on the front and back sides of the metal foil current collector 1. When making a negative electrode sheet for a lithium-ion battery, a white glue insulating layer 2 is used, which is made of a mixture of aqueous aluminum oxide, SBR, and pure water.

[0053] Graphite materials include natural graphite, artificial graphite materials, and hard carbon materials.

[0054] The following further defines the metal foil current collector 1 used in making the negative electrode sheet of a lithium-ion battery:

[0055] When the lithium-ion battery electrode is used as a negative electrode, the metal foil current collector 1 is copper foil, carbon-coated copper foil or mesh copper foil.

[0056] Specifically, when manufacturing a negative electrode sheet for a lithium-ion battery, the metal foil current collector 1 is made of copper foil; however, when preparing a negative electrode sheet for a sodium-lithium ion battery according to the latest technology, aluminum foil can also be used.

[0057] The preferred number of n is given below: n is 3.

[0058] Specifically, the number of coating layers coated by the coating machine at one time can be determined by the maximum width of the coating machine and the designed electrode height. The coating machine can coat 1 section, 2 sections, 3 sections, 4 sections or 5 sections at one time. Figure 1 Three sections of coating layer 3 are provided, which are commonly used in the industry. Each section of coating layer 3 is composed of six active material layers 3-1.

[0059] The production process of this embodiment:

[0060] When manufacturing the positive electrode sheet of a lithium-ion battery, for example, a coating machine is set to coat three sections of coating layers 3 at a time, and the configured positive electrode active material layer is set on the coating machine. When the coating machine performs the first coating, the positive electrode active material layer is squeezed out from the slit, and the positive electrode active material layer is coated on the metal foil current collector 1 to form three sections of coating layers 3, each section has two active material layers 3-1, and an empty foil is left between the two active material layers 3-1. When the coating machine performs the second coating, the extruded positive electrode active material layer is separated from the positive electrode active material layer coated for the first time by a section of empty foil. After the second coating, three sections of coating layers 3 are formed, each section has two active material layers 3-1, and an empty foil is left between the two active material layers 3-1. When the coating machine performs the third coating, the extruded positive electrode active material layer is separated from the positive electrode active material layer coated for the second time by a section of empty foil. After the third coating, three sections of coating layers 3 are formed, each section has two active material layers 3-1, and an empty foil is left between the two active material layers 3-1. After three coatings, a coating sheet is formed. Figure 1 As shown in the figure, the positive electrode white glue insulation layer is coated on the empty foil and on the four sides of each coating layer 3; after the positive electrode white glue insulation layer is coated, each active material layer 3-1 is cut along the white glue insulation layer by slitting, die cutting or laser cutting, and a connecting pole ear is cut for each active material layer 3-1. The cutting process will not produce active material layer particles, avoiding the occurrence of lithium battery explosion and other phenomena in the later lithium ion battery experiment. Therefore, the lithium ion battery positive electrode sheet produced in this embodiment is safe.

[0061] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments, and other arrangements may be designed without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the features described in the various dependent claims and herein may be combined in a manner different from that described in the original claims. It may also be understood that the features described in conjunction with the individual embodiments may be used in other described embodiments.

Claims

1. A lithium-ion battery pole piece and pole ear integrated structure with four-side insulation, characterized in that: The structure comprises a metal foil current collector (1), a white glue insulating layer (2) and n-segment coating layers (3); N sections of coating layers (3) are symmetrically arranged on both the front and back sides of the metal foil current collector (1), and the n sections of coating layers (3) are arranged along the length direction of the metal foil current collector (1); the metal foil current collector (1) is left on both sides of each section of coating layer (3), and the four sides of each section of coating layer (3) are coated with a white glue insulating layer (2); Each coating layer (3) includes 2m active material layers (3-1), the 2m active material layers (3-1) are arranged in an m×2 array, and a gap is left between two adjacent active material layers (3-1) in the m×2 array, and a white glue insulating layer (2) is arranged in the gap; m is determined by the width of the metal foil current collector (1) and the size of the active material layer (3-1); The white glue insulating layer (2) is used as a cutting line, and a metal foil current collector (1) of a preset size is cut out on the metal foil current collector (1) on the left and right sides of each coating layer (3) to serve as a pole ear, and each pole ear is an integral structure with each active material layer (3-1).

2. The four-side insulated lithium-ion battery pole piece and pole ear integrated structure according to claim 1, characterized in that: The width of the metal foil current collector (1) left on the left and right sides of each coating layer (3) is 0.5 mm to 200 mm.

3. The four-side insulated lithium-ion battery pole piece and pole tab integrated structure according to claim 1, characterized in that: When the lithium ion battery electrode is used as a positive electrode, the metal foil current collector (1) is aluminum foil, carbon-coated aluminum foil or mesh aluminum foil.

4. The four-side insulated lithium-ion battery pole piece and pole tab integrated structure according to claim 1, characterized in that: When the lithium ion battery electrode is used as a negative electrode, the metal foil current collector (1) is copper foil, carbon-coated copper foil or mesh copper foil.

5. The four-side insulated lithium-ion battery pole piece and pole tab integrated structure according to claim 1, characterized in that: n is 3.

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