Electrode sheet, negative electrode sheet, electrode assembly, and lithium-ion battery

Abstract

An electrode sheet, a negative electrode sheet, an electrode assembly, and a lithium-ion battery, relating to the technical field of batteries. The electrode sheet comprises a current collector and an active material coating layer; the current collector comprises a coating area, and a tab area and a non-tab area which are respectively provided on two opposite sides of the coating area; the active substance coating layer is provided on the coating area; and the surface of the non-tab area is coated with an insulating coating layer. In addition, also provided are an electrode assembly comprising the electrode sheet and a lithium-ion battery using the electrode assembly.

Description

Electrode sheet, negative electrode sheet, electrode assembly and lithium-ion battery

[0001] This application claims priority to three Chinese patent applications filed with the China Patent Office on the same day, September 15, 2023, with application numbers 202322526600.9, 202311200028.5 and 202322529053.X, respectively. The entire contents of the above applications are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to a pole piece, a negative pole piece, an electrode assembly and a lithium-ion battery. Background Art

[0003] During battery operation, the electrode sheets may swell. The negative electrode expands more severely than the positive electrode, causing changes in thickness and width. This expansion can lead to two possibilities: First, due to the change in electrode volume, the expanded edge of the electrode sheet may pierce the separator, causing a short circuit with the positive electrode; second, the negative electrode sheet may bulge out of the separator, directly contacting the positive electrode and causing a short circuit, or even fire and explosion. SUMMARY OF THE INVENTION

[0004] Therefore, how to prevent the negative electrode from expanding and short-circuiting with the positive electrode to improve battery safety is a technical problem that needs to be urgently solved in battery technology.

[0005] In a first aspect, the present application provides a pole piece, comprising:

[0006] A current collector comprising a coating region and a tab region and a non-tab region respectively disposed on opposite sides of the coating region; and

[0007] an active material coating layer, disposed on the coating area;

[0008] Wherein, the surface of the non-tab area is coated with an insulating coating layer.

[0009] In a second aspect, the present application further provides a negative electrode sheet, comprising:

[0010] a negative electrode current collector, the negative electrode current collector comprising a negative electrode coating region and a negative electrode tab disposed on one side of the negative electrode coating region; and

[0011] A negative electrode active material coating layer is provided on the negative electrode coating area;

[0012] Wherein, the surface of the negative electrode active material coating layer facing away from the negative electrode current collector is provided with at least one insulating coating layer;

[0013] Alternatively, a non-tab area is further provided on the side of the negative electrode current collector away from the negative electrode tab; and at least one insulating coating layer is provided on the surface of the non-tab area and the surface of the negative electrode active material coating layer away from the negative electrode current collector.

[0014] In a third aspect, the present application further provides an electrode assembly, comprising a positive electrode sheet, a separator and a negative electrode sheet, wherein the negative electrode sheet is the electrode sheet described in the first aspect, and the positive electrode sheet and the negative electrode sheet are respectively located on opposite sides of the separator.

[0015] In a fourth aspect, the present application further provides an electrode assembly, comprising a positive electrode sheet, a separator, and the negative electrode sheet as described in the second aspect, wherein the positive electrode sheet and the negative electrode sheet are respectively located on opposite sides of the separator.

[0016] In a fifth aspect, the present application also provides a lithium-ion battery comprising the electrode assembly described in the third aspect or the fourth aspect. Beneficial effects

[0017] The present application provides an insulating coating layer in the non-tab area of ​​the negative electrode sheet to prevent the negative electrode sheet from expanding and bulging and causing short circuit with the positive electrode sheet, thereby improving the safety performance of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0019] FIG1 is a cross-sectional view of a first structure of a pole piece in one embodiment of the present application;

[0020] FIG2 is a side view of a first structure of a pole piece in one embodiment of the present application;

[0021] FIG3 is a cross-sectional view of a second structure of a pole piece in one embodiment of the present application;

[0022] FIG4 is a side view of a second structure of a pole piece in one embodiment of the present application;

[0023] FIG5 is a cross-sectional view of a third structure of a pole piece in one embodiment of the present application;

[0024] FIG6 is a side view of a third structure of a pole piece in one embodiment of the present application;

[0025] FIG7 is a schematic structural diagram of an electrode assembly in one embodiment of the present application;

[0026] FIG8 is a cross-sectional view of a first structure of a negative electrode sheet according to an embodiment of the present application;

[0027] FIG9 is a side view of a first structure of a negative electrode sheet according to an embodiment of the present application;

[0028] FIG10 is a cross-sectional view of a second structure of a negative electrode sheet in one embodiment of the present application;

[0029] FIG11 is a side view of a second structure of a negative electrode sheet in one embodiment of the present application;

[0030] FIG12 is a cross-sectional view of a third structure of a negative electrode sheet in one embodiment of the present application;

[0031] FIG13 is a side view of a third structure of a negative electrode sheet in one embodiment of the present application;

[0032] FIG14 is a fourth structural schematic diagram of a negative electrode sheet in one embodiment of the present application;

[0033] FIG15 is a fifth structural diagram of a negative electrode sheet in one embodiment of the present application;

[0034] FIG16 is a sixth structural diagram of a negative electrode sheet in one embodiment of the present application;

[0035] FIG17 is a seventh structural diagram of a negative electrode sheet in one embodiment of the present application;

[0036] FIG18 is an eighth structural schematic diagram of a negative electrode sheet in one embodiment of the present application;

[0037] FIG19 is a schematic structural diagram of an electrode assembly in one embodiment of the present application.

[0038] Description of reference numerals:

[0039] 100, pole piece; 110, current collector; 111, tab region; 112, coating region; 113, non-tab region; 120, active material coating layer; 130, insulating coating layer; 131, first insulating layer; 132, second insulating layer; 200, positive electrode piece; 210, positive electrode tab; 220, positive electrode coating region; 230, positive electrode active material coating layer; 300, separator;

[0040] 1000, negative electrode sheet; 1100, negative electrode current collector; 1110, negative electrode tab; 1120, negative electrode coating area; 1200, negative electrode active material coating layer; 133, third insulating layer; 134, fourth insulating layer; 135, fifth insulating layer; 136, sixth insulating layer; 137, seventh insulating layer; 138, eighth insulating layer; 139, ninth insulating layer; 1310, tenth insulating layer; 1311, eleventh insulating layer. Modes for Carrying Out the Invention

[0041] An embodiment of the present application provides an electrode 100, which can be used as a positive electrode in a battery, and can also be used as a negative electrode in a battery; but considering that the negative electrode expands more severely than the positive electrode during operation, the electrode 100 is used as the negative electrode in the battery to solve the problem of the negative electrode expanding and bulging and short-circuiting with the positive electrode.

[0042] 1-2 , in this embodiment, the electrode 100 includes a current collector 110 and an active material coating layer 120 coated on the surface of the current collector 110 ; wherein the current collector 110 includes a coating area 112 located in the middle thereof and a tab area 111 and a non-tab area 113 respectively arranged on opposite sides of the coating area 112 .

[0043] Specifically, the active material coating layer 120 is uniformly coated on opposite sides of the current collector 110 along the first direction X. The tab region 111 and the non-tab region 113 are respectively located on opposite sides of the current collector 110 along the second direction Y. The portion of the current collector 110 located in the tab region 111 and the portion located in the non-tab region 113 are not covered by the active material coating layer 120; the portion of the current collector 110 located in the tab region 111 forms the tab of the pole piece 100.

[0044] It should be noted that when the electrode 100 is used as a positive electrode, the material of the current collector 110 can be aluminum, and the material of the active material coating layer 120 can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. When the electrode 100 is used as a negative electrode, the material of the current collector 110 can be copper, and the material of the active material coating layer 120 can be carbon or silicon. The specific material can be flexibly selected according to needs and is not specifically limited.

[0045] Meanwhile, the first direction X is the thickness direction of the pole piece 100 , and the second direction Y is perpendicular to the first direction X and is the width direction of the pole piece 100 .

[0046] In this embodiment, to address the issue of the positive and negative electrodes easily contacting and short-circuiting during battery use, the electrode 100 is provided with an insulating coating layer 130 in the non-tab area 113. In actual use, when the electrode 100 expands and bulges, the insulating coating layer 130 can provide insulation protection for the electrode 100, preventing it from directly contacting the corresponding positive or negative electrode and causing a short circuit.

[0047] As shown in Figures 1-2, in one embodiment, the insulating coating layer 130 includes a first insulating layer 131, which is uniformly coated on opposite sides of the non-tab region 113 along the thickness direction of the current collector 110. In this case, a reserved gap can be set between the first insulating layer 131 and the active material coating layer 120, so that a small blank area is formed between the first insulating layer 131 and the active material coating layer 120. The reserved gap can prevent the slurry of the first insulating layer 131 from interacting with the slurry of the active material coating layer 120 and reduce the impact on battery performance. However, in actual applications, the width of the reserved gap should not be too large to avoid the first insulating layer 131 being too narrow and resulting in poor insulation effect. The width of the reserved gap does not exceed 100mm.

[0048] As shown in FIG. 3-4 , in another embodiment, no gap may be provided between the first insulating layer 131 and the active material coating layer 120 , that is, the first insulating layer 131 directly contacts the active material coating layer 120 .

[0049] In addition, in another embodiment, the first insulating layer 131 can also be uniformly coated on one side of the non-tab area 113 along the thickness direction of the current collector 110; at this time, a reserved gap can be set between the first insulating layer 131 and the active material coating layer 120, or no gap can be set directly, so that the first insulating layer 131 and the active material coating layer 120 abut each other.

[0050] As shown in Figures 5-6, in one embodiment, the insulating coating layer 130 further includes a second insulating layer 132, which is disposed on the side of the non-tab region 113 away from the active material coating layer 120. In this case, the second insulating layer 132 can, together with the first insulating layer 131, cover the edge of the non-tab region 113 away from the active material coating layer 120. On the one hand, this can passivate the edge of the non-tab region 113, thereby reducing the risk of the non-tab region deforming due to expansion and puncturing the diaphragm. On the other hand, even if the non-tab region 113 punctures the diaphragm and contacts the positive electrode tab, the first insulating layer 131 and the second insulating layer 132 can cooperate to provide sufficient insulation protection for the edge of the current collector 110 away from the tab region 111, thereby preventing short circuits.

[0051] In various embodiments, the thickness and width of the first insulating layer 131 are set to H3 and W1 respectively (H3 and W1 are the dimensions of the first insulating layer 131 along the thickness and width directions of the current collector 110, respectively), the dimension of the second insulating layer 132 along the thickness direction of the current collector 110 is H4, and its dimension along the width direction of the current collector 110 is W2.

[0052] To ensure the insulation protection effect of the insulating coating layer 130, the dimensions should meet the following conditions: 0.1um≤H3≤H2, 0.1mm≤W1≤100mm; H1≤H4≤2*H3+H1, 0.1um≤W2≤5000um. Among them, H1 is the thickness of the current collector 110, and H2 is the thickness of the active material coating layer 120.

[0053] The specific dimensions of H3, W1, H4, and W2 can be controlled within the following ranges: 5um ≤ H3 ≤ 100um, 1mm ≤ W1 ≤ 100mm, 6um ≤ H4 ≤ 100um, and 1um ≤ W2 ≤ 100um. By properly controlling the thickness H3 of the first insulating layer 131, insufficient insulation due to a too small coating thickness is avoided, while poor processing performance due to an excessive thickness is also prevented. Furthermore, increased electrolyte loss due to swelling of the first insulating layer 131 is avoided, thereby ensuring battery energy density.

[0054] It should be noted that in some embodiments, the insulating coating layer 130 only includes the first insulating layer 131; in this case, only the thickness H3 and width W1 of the first insulating layer 131 need to meet the relevant conditions. To ensure the insulation protection effect, the thickness H3 of the first insulating layer 131 must always be greater than the thickness H2 of the active material coating layer 120 to prevent the electrode from protruding along the thickness direction of the first insulating layer 131 and prevent the electrode from wrinkling when winding, so as to ensure its processability and manufacturing performance. The dimension H4 of the second insulating layer 132 along the thickness direction of the current collector 110 must always be greater than or equal to the thickness H1 of the current collector 110 to ensure that the second insulating layer 132 can always completely cover the end face of the current collector 110 away from the corresponding electrode ear.

[0055] In this embodiment, the first insulating layer 131 and the second insulating layer 132 may use the same coating material or different coating materials; specifically, the coating material may be determined based on different performance requirements for the first insulating layer 131 and the second insulating layer 132 during use.

[0056] For example, in one embodiment, the first insulating layer 131 and the second insulating layer 132 can be made of the same coating material. Specifically, the material of the insulating coating layer 130 includes inorganic materials, organic materials, and solvents.

[0057] The inorganic material may include one or a combination of at least two of boehmite, alumina, silica, hexagonal boron nitride, cubic boron nitride, silicon carbide, and silicon nitride.

[0058] The polymerizable monomer of the organic material includes any one or a combination of at least two of vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, perfluoroethylene, alkyl ether, ethylene, propylene, 1,3-butadiene, vinyl chloride, styrene or vinyl acetate. Alternatively, it may be any one or a combination of at least two of acrylic acid, acrylate, acrylamide, N-vinyl pyrrole, alkane, acrylonitrile, maleic acid, itaconic acid, maleimide or bismaleimide. Alternatively, it may be any one or a combination of at least two of alkyd resin, epoxy resin, polyurethane, silicone resin, polyamide, polyaramid, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, polyphenylene sulfone, polyether sulfone, polyether ether ketone, polyimide, polyamide-imide, polyetherimide or polyester-imide. Alternatively, the organic material may be any one or a combination of at least two of polyimide, polyamide-imide, polyetherimide, polyester-imide, polyvinylidene fluoride, or polytetrafluoroethylene. The organic material may have a weight average molecular weight of 20,000 to 1,000,000.

[0059] The solvent may be an aqueous deionized water solvent or an oily N-methylpyrrolidone (NMP) solvent, and is not particularly limited thereto.

[0060] In the technical solution of the present application, when the electrode 100 is used as a positive electrode or a negative electrode, taking the use as a negative electrode as an example, when the negative electrode has an expansion bulge, the negative electrode can contact the positive electrode through the insulating coating layer 130 to avoid direct contact between the positive and negative electrodes and a short circuit, thereby improving the safety of the battery.

[0061] Referring to FIG7 , an embodiment of the present application provides an electrode assembly comprising a positive electrode sheet 200 , a separator 300 , and a negative electrode sheet. In this electrode assembly, the negative electrode sheet is used as the electrode sheet 100 . Therefore, for ease of description and understanding, the term “negative electrode sheet” will be used to refer to the electrode sheet 100 hereinafter.

[0062] The electrode assembly is the component in the battery where chemical reactions occur. It is primarily formed by winding or stacking a positive electrode sheet 200 and a negative electrode sheet, with a separator 300 typically disposed between the positive and negative electrode sheets. A positive electrode coating region 220 is disposed on the positive electrode sheet 200, while a corresponding negative electrode coating region (corresponding to coating region 112 on the electrode sheet 100) is disposed on the negative electrode sheet. The positive electrode coating region 220 and the negative electrode coating region are coated with a positive electrode active material coating layer 230 and a negative electrode active material coating layer (corresponding to active material coating layer 120 on the electrode sheet 100), respectively. The portion of the positive electrode sheet 200 where the positive electrode active material coating layer 230 is disposed and the portion of the negative electrode sheet where the negative electrode active material coating layer is disposed constitute the main body of the electrode assembly. The portions of the positive electrode sheet 200 and the negative electrode sheet where the active material coating layer is disposed are each provided with a tab, namely a positive electrode tab 210 and a negative electrode tab (corresponding to tab region 111 on the electrode sheet 100), respectively. Taking the negative electrode sheet as an example, it adopts the structural design of the electrode sheet 100 in Example 1, so the negative electrode tab on it constitutes the so-called "tab area 111", and the opposite side of the negative electrode tab constitutes the so-called "non-tab area 113".

[0063] As shown in Figure 7, in this embodiment, the electrode assembly includes multiple positive electrode sheets 200 and multiple negative electrode sheets. The positive electrode sheets 200 and the negative electrode sheets are arranged alternately, and a separator 300 is disposed between any adjacent positive electrode sheets 200 and negative electrode sheets. In this case, taking one set of adjacent positive electrode sheets 200 and negative electrode sheets as an example, the positive electrode sheets 200 and the negative electrode sheets are located on opposite sides of the separator 300, and the positive electrode tabs 210 and the negative electrode tabs can also be located on opposite sides of the electrode assembly.

[0064] In this embodiment, to address the short circuit issue between the positive electrode sheet 200 and the negative electrode sheet, the width of the separator 300 is greater than or equal to the width of the negative electrode coating region, and the width of the negative electrode coating region is greater than or equal to the width of the positive electrode coating region 220. "Width" refers to the dimension of the corresponding component along the second direction Y.

[0065] At the same time, the non-tab area 113 on the negative electrode sheet is provided with an insulating coating layer 130, and the insulating coating layer 130 includes a first insulating layer 131 and a second insulating layer 132. The specific configuration of the first insulating layer 131 and the second insulating layer 132 can refer to the relevant description above and will not be repeated here. In this electrode assembly, the edge of the first insulating layer 131 close to the negative electrode coating area should not exceed the adjacent position of the positive electrode coating area 220 and the positive electrode tab 210, that is, in the second direction Y, the edge of the first insulating layer 131 close to the negative electrode coating area should correspond to the position of the positive electrode tab 210 on the positive electrode sheet 200, without covering the section where the positive electrode coating area 220 is located, or not completely covering the section where the positive electrode coating area 220 is located.

[0066] In this way, when the negative electrode sheet expands and punctures the diaphragm 300, it can ensure that the non-tab area 113 contacts the positive electrode tab 210 through the insulating coating layer 130, preventing the positive electrode sheet 200 from making direct contact with the negative electrode sheet, thereby avoiding contact short circuit between the positive electrode sheet 200 and the negative electrode sheet, thereby improving safety.

[0067] Similarly, the edge of the positive electrode coating area 220 away from the positive electrode tab 210 does not exceed the edge of the negative electrode coating area close to the negative electrode tab, that is, in the second direction Y, the edge of the positive electrode coating area 220 away from the positive electrode tab 210 should correspond to the position of the negative electrode coating area on the negative electrode sheet, and prevent it from extending to the section where the tab area 111 is located.

[0068] In this way, when the negative electrode sheet expands and punctures the diaphragm 300, it can ensure that the non-tab area 113 contacts the positive electrode tab 210 through the insulating coating layer 130, preventing the positive electrode sheet 200 from directly contacting the negative electrode sheet, thereby avoiding contact short circuit between the positive electrode sheet 200 and the negative electrode sheet, thereby improving safety.

[0069] An embodiment of the present application provides a lithium-ion battery, which includes an electrode assembly. By applying the electrode assembly in the lithium-ion battery, direct contact between the positive electrode sheet 200 and the negative electrode sheet is avoided during battery use, thereby avoiding contact short circuits and improving battery safety.

[0070] In this embodiment, the lithium-ion battery refers to a single physical module including one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in this embodiment may include a battery module or a battery pack.

[0071] A battery cell includes an electrode assembly and an electrolyte. The electrode assembly is composed of a positive electrode sheet 200, a negative electrode sheet, and a separator 300. The battery cell mainly relies on the movement of metal ions between the positive electrode sheet 200 and the negative electrode sheet to work.

[0072] The positive electrode sheet 200 includes a positive electrode current collector and a positive electrode active material coating layer 230. The positive electrode active material coating layer 230 is coated on the surface of the positive electrode current collector. The positive electrode current collector not coated with the positive electrode active material coating layer 230 protrudes from the positive electrode current collector coated with the positive electrode active material coating layer 230. The positive electrode current collector not coated with the positive electrode active material coating layer 230 serves as the positive electrode tab 210. The positive electrode current collector can be made of aluminum, and the positive electrode active material coating layer 230 can be made of lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide.

[0073] The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material coating layer is coated on the surface of the negative electrode current collector. The negative electrode current collector not coated with the negative electrode active material coating layer protrudes from the negative electrode current collector coated with the negative electrode active material coating layer. The negative electrode current collector not coated with the negative electrode active material coating layer serves as the negative electrode tab. The negative electrode current collector can be made of copper, and the negative electrode active material coating layer can be made of carbon, silicon, or other materials.

[0074] To ensure that high current can pass without melting, the positive electrode tabs 210 can be multiple and stacked together, and the negative electrode tabs can also be multiple and stacked together. The material of the separator 300 can be PP (polypropylene) or PE (polyethylene).

[0075] The battery cell also includes a housing, electrode terminals, and an adapter. The electrode assembly and electrolyte are disposed within the housing, and the electrode terminals are disposed within the housing. An adapter connects the electrode terminals to the tabs of the electrode assembly. An insulating member is disposed between the adapter and the housing to insulate and isolate the adapter from the housing. The specific structural composition of the battery cell is not the focus of this embodiment and is prior art, so it will not be detailed here.

[0076] 8-9 , an embodiment of the present application provides a negative electrode sheet, wherein the negative electrode sheet 1000 includes a negative electrode current collector 1100 and a negative electrode active material coating layer 1200 coated on the surface of the negative electrode current collector 1100; wherein the negative electrode current collector 1100 includes a negative electrode coating area 1120 located in the middle position thereof and negative electrode tabs 1110 and non-tab areas 113 respectively arranged on opposite sides of the negative electrode coating area 1120.

[0077] Specifically, the negative electrode active material coating layer 1200 is uniformly disposed on opposite sides of the negative electrode current collector 1100 along the first direction X. The negative electrode tab 1110 and the non-tab region 113 are respectively disposed on opposite sides of the negative electrode current collector 1100 along the second direction Y. Neither the negative electrode tab 1110 nor the non-tab region 113 is covered by the negative electrode active material coating layer 1200.

[0078] It should be noted that the negative electrode current collector 1100 may be made of copper, while the negative electrode active material coating layer 1200 may be made of carbon or silicon, etc. The two materials may be flexibly selected according to actual needs and are not specifically limited thereto.

[0079] Meanwhile, the first direction X is the thickness direction of the negative electrode sheet 1000 , and the second direction Y is perpendicular to the first direction X and is the width direction of the negative electrode sheet 1000 .

[0080] To address the issue of positive and negative electrode sheets easily contacting and short-circuiting during battery use, the negative electrode sheet 1000 is provided with an insulating coating layer 130 on the non-tab area 113 and / or the negative electrode active material coating layer 1200. In actual use, when the negative electrode sheet 1000 expands and bulges, the insulating coating layer 130 can provide insulation protection for the negative electrode sheet 1000, preventing it from directly contacting the corresponding positive or negative electrode sheet and causing a short circuit.

[0081] Since the insulating coating layer 130 can be disposed on the non-tab region 113 and / or the negative electrode active material coating layer 1200, in practical applications, the structure of the negative electrode sheet 1000 includes at least three types: first, the insulating coating layer 130 is disposed only in the non-tab region 113; second, the insulating coating layer 130 is disposed only on the negative electrode active material coating layer 1200; and third, the insulating coating layer 130 is disposed on both the non-tab region 113 and the negative electrode active material coating layer 1200. The specific structure of the negative electrode sheet 1000 will be described below in combination with these three types.

[0082] Regarding the first type of negative electrode sheet 1000 (i.e., the insulating coating layer 130 is only provided in the non-tab area 113 ), the details are as follows:

[0083] As shown in Figures 8-9, in one embodiment, the insulating coating layer 130 includes a first insulating layer 131, which is uniformly coated on opposite sides of the non-tab region 113 along the thickness direction of the negative electrode current collector 1100. In this case, a reserved gap can be provided between the first insulating layer 131 and the negative electrode active material coating layer 1200, so that a small blank area is formed between the first insulating layer 131 and the negative electrode active material coating layer 1200. The reserved gap can prevent the slurry in the first insulating layer 131 from interacting with the slurry in the negative electrode active material coating layer 1200 and reduce the impact on battery performance. However, in actual applications, the width of the reserved gap should not be too large to avoid the first insulating layer 131 being too narrow, resulting in poor insulation effect. The width of the reserved gap does not exceed 100 mm.

[0084] As shown in FIG. 10-11 , in another embodiment, different from the embodiment, no gap may be provided between the first insulating layer 131 and the negative electrode active material coating layer 1200 , that is, the first insulating layer 131 and the negative electrode active material coating layer 1200 are in direct contact with each other.

[0085] In addition, in another embodiment, the first insulating layer 131 can also be uniformly coated on one side of the non-tab area 113 along the thickness direction of the negative electrode current collector 1100; at this time, a reserved gap can be set between the first insulating layer 131 and the negative electrode active material coating layer 1200, or no gap can be set directly, so that the first insulating layer 131 and the negative electrode active material coating layer 1200 are in contact with each other.

[0086] As shown in Figures 12-13, in one embodiment, the insulating coating layer 130 further includes a second insulating layer 132, which is disposed on the side of the non-tab region 113 away from the negative electrode active material coating layer 1200. In this case, the second insulating layer 132 can, together with the first insulating layer 131, cover the edge of the non-tab region 113 away from the negative electrode active material coating layer 1200. On the one hand, this has a passivating effect on the edge of the non-tab region 113, reducing the risk of the non-tab region puncturing the separator due to expansion and deformation. On the other hand, even if the non-tab region 113 punctures the separator and contacts the positive electrode tab, the first insulating layer 131 and the second insulating layer 132 can cooperate to provide sufficient insulation protection for the edge of the negative electrode current collector 1100 away from the negative electrode tab 1110, preventing the occurrence of a short circuit.

[0087] In various embodiments of the first type of negative electrode sheet 1000, the thickness and width of the first insulating layer 131 are set to H3 and W1 respectively (H3 and W1 are the dimensions of the first insulating layer 131 along the thickness and width directions of the negative electrode current collector 1100, respectively), the dimension of the second insulating layer 132 along the thickness direction of the negative electrode current collector 1100 is H4, and its dimension along the width direction of the negative electrode current collector 1100 is W2.

[0088] To ensure the insulation protection effect of the insulating coating layer 130, the dimensions should meet the following conditions: 0.1um≤H3≤H2, 0.1mm≤W1≤100mm; H1≤H4≤2*H3+H1, 0.1um≤W2≤5000um. Among them, H1 is the thickness of the negative electrode current collector 1100, and H2 is the thickness of the negative electrode active material coating layer 1200.

[0089] The specific dimensions of H3, W1, H4, and W2 can be controlled within the following ranges: 5um ≤ H3 ≤ 100um, 1mm ≤ W1 ≤ 100mm, 6um ≤ H4 ≤ 100um, and 1um ≤ W2 ≤ 100um. By properly controlling the thickness H3 of the first insulating layer 131, insufficient insulation due to a too small coating thickness is avoided, while poor processing performance due to an excessive thickness is also prevented. Furthermore, increased electrolyte loss due to swelling of the first insulating layer 131 is avoided, thereby ensuring battery energy density.

[0090] It should be noted that in some embodiments, the insulating coating layer 130 includes only the first insulating layer 131; in this case, only the thickness H3 and width W1 of the first insulating layer 131 need to meet the relevant requirements. To ensure effective insulation protection, the thickness H3 of the first insulating layer 131 must always be greater than the thickness H2 of the negative active material coating layer 1200. This prevents the negative electrode sheet 1000 from protruding along the thickness direction of the first insulating layer 131 and wrinkling during winding, thereby ensuring its processability and manufacturing performance. The dimension H4 of the second insulating layer 132 along the thickness direction of the negative electrode current collector 1100 must always be greater than or equal to the thickness H1 of the negative electrode current collector 1100 to ensure that the second insulating layer 132 can always completely cover the end surface of the negative electrode current collector 1100 away from the corresponding tab.

[0091] At the same time, each embodiment is merely an example of the first type of negative electrode sheet 1000 provided in this application, and other combination forms are not excluded, which will not be listed here in full.

[0092] Regarding the second type of negative electrode sheet 1000 (i.e., the case where the insulating coating layer 130 is only provided on the negative electrode active material coating layer 1200), the details are as follows:

[0093] Considering that the insulating coating layer 130 is only provided on the negative electrode active material coating layer 1200, it is difficult for the insulating coating layer 130 to provide protection for the non-tab area 113. Therefore, the non-tab area 113 can be eliminated. That is, the side of the negative electrode current collector 1100 away from the negative electrode tab 1110 is entirely covered by the negative electrode active material coating layer 1200. The following description of the second type of negative electrode sheet 1000 will be based on the case where the non-tab area 113 is eliminated. However, it should be understood that whether the non-tab area 113 is eliminated may not affect the effectiveness of the protective effect of the insulating coating layer 130, but may only affect the degree of actual protection that can be achieved.

[0094] As shown in FIG14 , in one embodiment, the insulating coating layer 130 is entirely disposed on the edge of the negative electrode active material coating layer 1200 away from the negative electrode tab 1110. The insulating coating layer 130 includes two third insulating layers 133 coated on opposite sides of the negative electrode active material coating layer 1200, and the two third insulating layers 133 are made of the same insulating material.

[0095] At this point, assuming the length of the third insulating layer 133 is S1 and the width is L1, and the thicknesses of the two third insulating layers 133 are d1 and d2, respectively, then S1, L1, d1, and d2 satisfy the following conditions: S1 ≤ S; 0.1 mm ≤ L1 ≤ 50 mm; 10 mm ≤ d1 ≤ 500 mm, 10 mm ≤ d2 ≤ 500 mm, and 0 < d1: d2 ≤ 1. Where S is the length of the negative electrode sheet 1000 (i.e., the dimension of the negative electrode sheet 1000 along its winding direction).

[0096] The length, width, and thickness of the third insulating layer 133 can be flexibly optimized as needed. For example, in practical applications, the width of the third insulating layer 133 can be 1 mm, 5 mm, 10 mm, 20 mm, or 40 mm, or other values; the thickness of the third insulating layer 133 can be 10 mm, 30 mm, 50 mm, 100 mm, 200 mm, or 300 mm, or other values, and are not specifically limited thereto. The third insulating layers 133 on both sides can have the same dimensional parameters or different dimensional parameters, but considering the ease of processing, the third insulating layers 133 on both sides use the same dimensional parameters.

[0097] Similarly, in this embodiment, by properly controlling the dimensional parameters of the third insulating layer 133, not only is the insulation performance of the third insulating layer 133 ensured, but it also prevents the third insulating layer 133 from affecting the processing performance of the electrode sheet. Furthermore, the swelling of the third insulating layer 133 can be prevented, which would increase electrolyte loss, thereby ensuring battery energy density. The purpose of controlling the dimensional parameters of each insulating layer is the same and will not be further elaborated.

[0098] As shown in FIG15 , in another embodiment, the insulating coating layer 130 includes a fourth insulating layer 134 and a fifth insulating layer 135 , which are respectively arranged on opposite sides of the negative electrode active material coating layer 1200 , and the fourth insulating layer 134 and the fifth insulating layer 135 are made of different insulating materials.

[0099] At this time, the fourth insulating layer 134 and the fifth insulating layer 135 can both have a length of S1 and a width of L1. The thicknesses of the fourth insulating layer 134 and the fifth insulating layer 135 are d1 and d2, respectively. Then, S1, L1, d1, and d2 satisfy the following conditions: S1 ≤ S; 0.1 mm ≤ L1 ≤ 50 mm; 10 mm ≤ d1 ≤ 500 mm, 10 mm ≤ d2 ≤ 500 mm, and 0 < d1: d2 ≤ 1. Where S is the length of the negative electrode sheet 1000 (i.e., the dimension of the negative electrode sheet 1000 along its winding direction).

[0100] Among them, the length, width and thickness of the fourth insulating layer 134 and the fifth insulating layer 135 can be flexibly optimized and designed as needed. For example, taking the fourth insulating layer 134 as an example, the width of the fourth insulating layer 133 can be 1mm or 5mm or 10mm or 20mm or 40mm, or other values; the thickness of the fourth insulating layer 133 can be 10mm or 30mm or 50mm or 100mm or 200mm or 300mm, or other values, which are not specifically limited. At the same time, the fourth insulating layer 134 and the fifth insulating layer 135 can use the same dimensional parameters or different dimensional parameters, but considering the convenience of processing, the two use the same dimensional parameters.

[0101] As shown in FIG16 , in another embodiment, the insulating coating layer 130 includes a sixth insulating layer 136 and a seventh insulating layer 137 respectively disposed on opposite sides of the negative active material coating layer 1200 ; the sixth insulating layer 136 and the seventh insulating layer 137 each include at least two layers of different insulating materials.

[0102] At this point, assume that the length of the sixth insulating layer 136 and the width of the seventh insulating layer 137 are both S1 and L1, and the thicknesses of the sixth insulating layer 136 and the seventh insulating layer 137 are d1 and d2, respectively. Then, S1, L1, d1, and d2 satisfy the following conditions: S1 ≤ S; 0.1 mm ≤ L1 ≤ 50 mm; 10 mm ≤ d1 ≤ 500 mm, 10 mm ≤ d2 ≤ 500 mm, and 0 < d1: d2 ≤ 1. Where S is the length of the negative electrode sheet 1000 (i.e., the dimension of the negative electrode sheet 1000 along its winding direction).

[0103] It should be noted that, at this time, the sixth insulating layer 136 and the seventh insulating layer 137 are both formed by stacking multiple layers of insulating materials, so their thickness should be the sum of the thicknesses of the stacked layers of insulating materials.

[0104] At this time, the length, width and thickness of the sixth insulating layer 136 and the seventh insulating layer 137 can be flexibly optimized and designed as needed. For example, taking the sixth insulating layer 134 as an example, the width of the fourth insulating layer 133 can be 1mm, 5mm, 10mm, 20mm, or 40mm, or other values; the thickness of the sixth insulating layer 136 can be 10mm, 30mm, 50mm, 100mm, 200mm, or 300mm, or other values, and there is no specific limitation on this. At the same time, the sixth insulating layer 136 and the seventh insulating layer 137 can use the same dimensional parameters or different dimensional parameters, but considering the convenience of processing, the two use the same dimensional parameters.

[0105] In another embodiment, the insulating coating layer 130 includes an eighth insulating layer 138, which is disposed on a side of the negative electrode sheet 1000 away from the negative electrode tab 1110. It should be understood that the eighth insulating layer 138 can be disposed based on various embodiments of the second type of negative electrode sheet 1000.

[0106] For example, as shown in FIG17 , in one embodiment, the insulating coating layer 130 includes an eighth insulating layer 138 and two third insulating layers 133. In this embodiment, the two third insulating layers 133 are disposed on opposite sides of the negative electrode active material coating layer 1200, while the eighth insulating layer 138 is located on the end face of the negative electrode sheet 1000 away from the negative electrode tab 1110. Thus, the eighth insulating layer 138 and the two third insulating layers 133 can completely cover the side of the negative electrode sheet 1000 away from the negative electrode tab 1110, thereby ensuring insulation protection.

[0107] At this time, assume that the length of the third insulating layer 133 and the eighth insulating layer 138 are both S1, the width of the third insulating layer 133 is L1, and the thickness is d, and the width of the eighth insulating layer 138 is L2 (i.e., the dimension of the eighth insulating layer 138 along the thickness direction of the negative electrode sheet 1000) and the thickness is n. Then, S1, L1, d, L2, and n satisfy the following conditions: S1 ≤ S; 0.1 mm ≤ L1 ≤ 50 mm; 10 mm ≤ d ≤ 500 mm; D ≤ L2 ≤ 700 mm, and 10 mm ≤ n ≤ 500 mm. Where S is the length of the negative electrode sheet 1000 (i.e., the dimension of the negative electrode sheet 1000 along its winding direction), and D is the thickness of the negative electrode sheet 1000.

[0108] Among them, the width of the eighth insulating layer 138 should ensure that it can completely cover the end face of the electrode away from the negative electrode tab 1110, and its thickness can be flexibly optimized and designed as needed while ensuring the insulation performance. For example, the thickness of the eighth insulating layer 138 can be 10mm or 15mm or 20mm or 30mm or 40mm or 50mm, and there is no specific limitation on this.

[0109] It should be understood that the eighth insulating layer 138 can also be provided in conjunction with the fourth insulating layer 134 , the fifth insulating layer 135 , the sixth insulating layer 136 and the seventh insulating layer 137 to form a negative electrode sheet 1000 of different structures. However, the combination principle remains unchanged and will not be enumerated here.

[0110] Regarding the third type of negative electrode sheet 1000 (i.e., the insulating coating layer 130 is provided with the non-tab area 113 and on the negative electrode active material coating layer 1200 at the same time), it is equivalent to combining the first type of negative electrode sheet 1000 and the second type of negative electrode sheet 1000; since the first type of negative electrode sheet 1000 and the second type of negative electrode sheet 1000 themselves include multiple situations, after the third type of negative electrode sheet 1000 is combined with the first type and the second type of negative electrode sheet 1000, negative electrode sheets 1000 of multiple different structures will be formed.

[0111] For example, as shown in FIG18 , in one embodiment, the insulating coating layer 130 includes a ninth insulating layer 139 and a tenth insulating layer 1310 . The ninth insulating layer 139 is disposed on the negative electrode active material coating layer 1200 , and the tenth insulating layer 1310 is disposed in the non-tab region 113 .

[0112] At this time, the ninth insulating layer 139 may include a single insulating layer or may be formed by stacking multiple insulating layers; moreover, when the ninth insulating layer 139 is formed by stacking multiple insulating layers, the multiple insulating layers constituting the ninth insulating layer 139 may use the same or different insulating materials.

[0113] Similarly, the tenth insulating layer 1310 may include a single insulating layer or may be formed by stacking multiple insulating layers; moreover, when the tenth insulating layer 1310 is formed by stacking multiple insulating layers, the multiple insulating layers constituting the tenth insulating layer 1310 may use the same or different insulating materials.

[0114] In one embodiment, the insulating coating layer 130 may further include an eleventh insulating layer 1311 disposed on the side of the negative electrode sheet 1000 away from the negative electrode tab 1110. In this case, the eleventh insulating layer 1311 can cooperate with the ninth insulating layer 139 and the tenth insulating layer 1310 to entirely cover the side of the negative electrode sheet 1000 away from the negative electrode tab 1110 to ensure insulation protection.

[0115] The specific structure and size parameters of the ninth insulating layer 139 can refer to the setting form of the insulating coating layer 130 on the first type of negative electrode sheet 1000 above, the specific structure and size parameters of the tenth insulating layer 1310 can refer to the setting form of the insulating coating layer 130 on the second type of negative electrode sheet 1000 above, and the specific structure and size parameters of the eleventh insulating layer 1311 can refer to the setting form of the eighth insulating layer 138 above, and will not be repeated here.

[0116] It should be understood that, regarding the third type of negative electrode sheet 1000, since it can be composed of the first type of negative electrode sheet 1000 and the second type of negative electrode sheet 1000, the combination principle can refer to the relevant description of the ninth insulating layer 139, the tenth insulating layer 1310 and the eleventh insulating layer 1311 in the previous text, so more combination forms are not listed here.

[0117] In this embodiment, regardless of the configuration of the insulating coating layer 130, the material of the insulating coating layer 130 can be selected as an insulating material that meets the requirements. Specifically, the material of the insulating coating layer 130 can include inorganic materials, organic materials, and solvents.

[0118] The inorganic material may include one or a combination of at least two of boehmite, alumina, silica, hexagonal boron nitride, cubic boron nitride, silicon carbide, and silicon nitride.

[0119] The polymerizable monomer of the organic material includes any one or a combination of at least two of vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, perfluoroethylene, alkyl ether, ethylene, propylene, 1,3-butadiene, vinyl chloride, styrene or vinyl acetate. Alternatively, it may be any one or a combination of at least two of acrylic acid, acrylate, acrylamide, N-vinyl pyrrole, alkane, acrylonitrile, maleic acid, itaconic acid, maleimide or bismaleimide. Alternatively, it may be any one or a combination of at least two of alkyd resin, epoxy resin, polyurethane, silicone resin, polyamide, polyaramid, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, polyphenylene sulfone, polyether sulfone, polyether ether ketone, polyimide, polyamide-imide, polyetherimide or polyester-imide. Alternatively, the organic material may be any one or a combination of at least two of polyimide, polyamide-imide, polyetherimide, polyester-imide, polyvinylidene fluoride, or polytetrafluoroethylene. The organic material may have a weight average molecular weight of 20,000 to 1,000,000.

[0120] The solvent may be an aqueous deionized water solvent or an oily N-methylpyrrolidone (NMP) solvent, and is not particularly limited thereto.

[0121] It should be noted that for different types of negative electrode sheets 1000, the materials of the different insulating layers on the negative electrode sheet 1000 can be the same or different, as long as they meet the insulation protection requirements. When the different insulating layers use the same insulating material, the specific material can be selected from the combination of multiple materials described above; when the different insulating layers use different insulating materials, the specific materials can be selected from two or more of the combination of multiple materials described above, without specific limitation.

[0122] By adopting the technical solution, when the negative electrode sheet 1000 is used as a positive electrode sheet or a negative electrode sheet, taking the use as a negative electrode sheet as an example, when the negative electrode sheet has an expansion bulge, the negative electrode sheet can contact the positive electrode sheet through the insulating coating layer 130, avoiding direct contact between the positive and negative electrode sheets and short circuit, thereby improving the safety of the battery.

[0123] 19 , an embodiment of the present application provides an electrode assembly, including a positive electrode sheet 200 , a separator 300 , and a negative electrode sheet 1000 .

[0124] The electrode assembly is the component in the battery where chemical reactions occur. It is mainly formed by winding or stacking a positive electrode sheet 200 and a negative electrode sheet 1000, and a separator 300 is usually provided between the positive electrode sheet 200 and the negative electrode sheet 1000. A positive electrode coating area 220 is provided on the positive electrode sheet 200, and a negative electrode coating area 1120 is correspondingly provided on the negative electrode sheet 1000. The positive electrode coating area 220 and the negative electrode coating area 1120 are coated with a positive electrode active material coating layer 230 and a negative electrode active material coating layer 1200, respectively. The portion of the positive electrode sheet 200 provided with the positive electrode active material coating layer 230 and the portion of the negative electrode sheet 1000 provided with the negative electrode active material coating layer 1200 constitute the main body of the electrode assembly. The portions of the positive electrode sheet 200 and the negative electrode sheet 1000 without the active material coating layer are each provided with a tab, namely a positive electrode tab 210 and a negative electrode tab 1110, respectively.

[0125] As shown in FIG19 , in this embodiment, the electrode assembly includes a plurality of positive electrode sheets 200 and a plurality of negative electrode sheets 1000. The positive electrode sheets 200 and the negative electrode sheets 1000 may be arranged alternately, and a separator 300 is disposed between any adjacent positive electrode sheets 200 and negative electrode sheets 1000. In this case, taking one set of adjacent positive electrode sheets 200 and negative electrode sheets 1000 as an example, the positive electrode sheets 200 and the negative electrode sheets 1000 are located on opposite sides of the separator 300, respectively, and the positive electrode tabs 210 and the negative electrode tabs 1110 may also be located on opposite sides of the electrode assembly.

[0126] In this embodiment, to address the short circuit issue between the positive electrode sheet 200 and the negative electrode sheet 1000, the width of the separator 300 is greater than or equal to the width of the negative electrode coating region 1120, and the width of the negative electrode coating region 1120 is greater than or equal to the width of the positive electrode coating region 220. The "width" refers to the dimension of the corresponding component along the second direction Y.

[0127] At the same time, an insulating coating layer 130 is provided in the non-tab area 113 on the negative electrode sheet 1000. The insulating coating layer 130 includes a first insulating layer 131 and a second insulating layer 132. The specific setting form of the first insulating layer 131 and the second insulating layer 132 can refer to the relevant description above and will not be repeated here.

[0128] In this electrode assembly, the edge of the first insulating layer 131 close to the negative electrode coating area 1120 should not exceed the edge of the positive electrode coating area 220 close to the positive electrode tab 210, that is, in the second direction Y, the edge of the first insulating layer 131 close to the negative electrode coating area 1120 should correspond to the position of the positive electrode tab 210 on the positive electrode sheet 200, without covering the section where the positive electrode coating area 220 is located, or not completely covering the section where the positive electrode coating area 220 is located.

[0129] Similarly, the edge of the positive electrode coating area 220 away from the positive electrode tab 210 does not exceed the edge of the negative electrode coating area 122 close to the negative electrode tab 1110, that is, in the second direction Y, the edge of the positive electrode coating area 220 away from the positive electrode tab 210 should correspond to the position of the negative electrode coating area 1120 on the negative electrode sheet 1000, and does not cover the section where the negative electrode tab 1110 is located, or does not completely cover the section where the negative electrode tab 1110 is located.

[0130] In this way, when the negative electrode sheet 1000 expands and punctures the diaphragm 300, it can ensure that the non-tab area 113 contacts the positive electrode tab 210 through the insulating coating layer 130, preventing the positive electrode sheet 200 from making direct contact with the negative electrode sheet, thereby avoiding contact short circuit between the positive electrode sheet 200 and the negative electrode sheet 1000, thereby improving safety.

[0131] It should be noted that, in this embodiment, the negative electrode sheet 1000 has a variety of different types of structural forms. For the negative electrode sheets 1000 of different structural forms, what should actually be ensured is that: the width of the diaphragm 300 is greater than or equal to the width of the negative electrode coating area 1120, and the width of the negative electrode coating area 1120 is greater than or equal to the width of the positive electrode coating area 220. It can be understood that: the projection of the negative electrode coating area 1120 on the diaphragm 300 coincides with the diaphragm 300 or is located within the range of the diaphragm 300, and the projection of the positive electrode coating area 220 on the negative electrode coating area 1120 coincides with the negative electrode coating area 1120 or is located within the range of the negative electrode coating area 1120; at the same time, the edge of the insulating coating layer 130 close to the negative electrode tab 1110 does not exceed the edge of the positive electrode coating area 220 close to the positive electrode tab 210, and the edge of the positive electrode coating area 220 away from the positive electrode tab 210 does not exceed the edge of the negative electrode coating area 1120 close to the negative electrode tab 1110.

[0132] An embodiment of the present application provides a lithium-ion battery, which includes an electrode assembly. By applying the electrode assembly in the lithium-ion battery, direct contact between the positive electrode sheet 200 and the negative electrode sheet 1000 is avoided during battery use, thereby avoiding contact short circuits and improving battery safety.

[0133] In this embodiment, the lithium-ion battery refers to a single physical module including one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in this embodiment may include a battery module or a battery pack.

[0134] A battery cell includes an electrode assembly and an electrolyte. The electrode assembly is composed of a positive electrode sheet 200, a negative electrode sheet 1000, and a separator 300. The battery cell mainly relies on the movement of metal ions between the positive electrode sheet 200 and the negative electrode sheet 1000 to operate.

[0135] The positive electrode sheet 200 includes a positive electrode current collector and a positive electrode active material coating layer 230. The positive electrode active material coating layer 230 is coated on the surface of the positive electrode current collector. The positive electrode current collector not coated with the positive electrode active material coating layer 230 protrudes from the positive electrode current collector coated with the positive electrode active material coating layer 230. The positive electrode current collector not coated with the positive electrode active material coating layer 230 serves as the positive electrode tab 210. The positive electrode current collector can be made of aluminum, and the positive electrode active material coating layer 230 can be made of lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide.

[0136] The negative electrode sheet 1000 includes a negative electrode current collector 1100 and a negative electrode active material layer 120. The negative electrode active material coating layer 1200 is coated on the surface of the negative electrode current collector 1100. The negative electrode current collector 1100 not coated with the negative electrode active material coating layer 1200 protrudes from the negative electrode current collector 1100 coated with the negative electrode active material coating layer 1200. The negative electrode current collector 1100 not coated with the negative electrode active material coating layer 1200 serves as the negative electrode tab 1110. The negative electrode current collector 1100 can be made of copper, and the negative electrode active material coating layer 1200 can be made of carbon, silicon, or the like.

[0137] To ensure that high current can pass without melting, the positive electrode tabs 210 can be multiple and stacked together, and the negative electrode tabs 1110 can also be multiple and stacked together. The material of the separator 300 can be PP (polypropylene) or PE (polyethylene).

[0138] The battery cell also includes a housing, electrode terminals, and an adapter. The electrode assembly and electrolyte are disposed within the housing, and the electrode terminals are disposed within the housing. An adapter connects the electrode terminals to the tabs of the electrode assembly. An insulating member is disposed between the adapter and the housing to insulate and isolate the adapter from the housing. The specific structural composition of the battery cell is not the focus of this embodiment and is prior art, so it will not be detailed here.

Claims

1. A pole piece, comprising: A current collector, the current collector comprising a coating area and a tab area and a non-tab area respectively disposed on opposite sides of the coating area; as well as an active material coating layer, disposed on the coating area; Wherein, the surface of the non-tab area is coated with an insulating coating layer.

2. The pole piece according to claim 1, wherein: A reserved gap is provided between the insulating coating layer and the active material coating layer; or the insulating coating layer and the active material coating layer are in contact with each other.

3. The pole piece according to claim 1, wherein: The insulating coating layer includes a first insulating layer, and the first insulating layer is disposed on one side or two opposite sides of the current collector in a thickness direction.

4. The pole piece according to claim 3, wherein: The insulating coating layer also includes a second insulating layer, which is arranged on a side of the non-tab area away from the active material coating layer and together with the first insulating layer covers an edge of the non-tab area away from the active material coating layer.

5. The pole piece according to claim 3 or 4, wherein: The dimension of the first insulating layer along the thickness direction of the current collector is H3, and H3 satisfies the following condition: 0.1 um≤H3≤H2; wherein H2 is the thickness of the active material coating layer.

6. The pole piece according to claim 3 or 4, wherein: The dimension of the first insulating layer along the width direction of the current collector is W1, and W1 satisfies the following condition: 0.1 mm≤W1≤100 mm.

7. The pole piece according to claim 4, wherein: The dimension of the second insulating layer along the thickness direction of the current collector is H4, and H4 satisfies the following condition: H1≤H4≤2*H3+H1; wherein H1 is the thickness of the current collector, and H3 is the thickness of the first insulating layer.

8. The pole piece according to claim 4, wherein: The dimension of the second insulating layer along the width direction of the current collector is W2, and W2 satisfies the following condition: 0.1um≤W2≤5000um.

9. A negative electrode sheet, comprising: A negative electrode current collector, the negative electrode current collector comprising a negative electrode coating region and a negative electrode tab disposed on one side of the negative electrode coating region; as well as A negative electrode active material coating layer is disposed on the negative electrode coating area; Wherein, at least one insulating coating layer is provided on the surface of the negative electrode active material coating layer away from the negative electrode current collector; Alternatively, a non-tab region is further provided on the side of the negative electrode current collector away from the negative electrode tab; and at least one insulating coating layer is provided on the surface of the non-tab region and the surface of the negative electrode active material coating layer away from the negative electrode current collector.

10. The negative electrode sheet according to claim 9, wherein: In the non-tab area, a reserved gap is provided between the insulating coating layer and the negative electrode active material coating layer; or the insulating coating layer and the negative electrode active material coating layer abut against each other at a side away from the negative electrode tab.

11. The negative electrode sheet according to claim 10, wherein: In the non-tab area, the insulating coating layer includes a first insulating layer, and the first insulating layer is disposed on one side or two opposite sides of the negative electrode current collector in a thickness direction.

12. The negative electrode sheet according to claim 11, wherein: In the non-tab region, the insulating coating layer further includes a second insulating layer, and the second insulating layer is disposed on an end surface of the non-tab region away from the negative electrode active material coating layer.

13. The negative electrode sheet according to claim 11 or 12, wherein: The dimensions of the first insulating layer along the thickness direction and the width direction of the negative electrode current collector are H3 and W1 respectively, and H3 and W1 satisfy the following conditions: 0.1um≤H3≤H2, 0.1mm≤W1≤100mm; wherein H2 is the thickness of the negative electrode active material coating layer.

14. The negative electrode sheet according to claim 12, wherein: The dimension of the second insulating layer along the thickness direction of the negative electrode current collector is H4, and the dimension of the second insulating layer along the width direction of the negative electrode current collector is W2, and H4 and W2 satisfy the following conditions: H1≤H4≤2*H3+H1,0.1um≤W2≤5000um; wherein H1 is the thickness of the negative electrode current collector, and H3 is the thickness of the first insulating layer.

15. The negative electrode sheet according to claim 9, wherein: On the surface of the negative electrode active material coating layer, the insulating coating layer is located at an edge of the negative electrode active material coating layer away from the negative electrode tab.

16. The negative electrode sheet according to claim 15, wherein: On the surface of the negative electrode active material coating layer, the insulating coating layer includes two third insulating layers respectively coated on opposite sides of the negative electrode active material coating layer, and the two third insulating layers are made of the same insulating material.

17. The negative electrode sheet according to claim 15, wherein: On the surface of the negative electrode active material coating layer, the insulating coating layer comprises: a fourth insulating layer, disposed on one side of the negative electrode active material coating layer; and a fifth insulating layer, disposed on opposite sides of the negative electrode active material coating layer with the fourth insulating layer; Wherein, the fourth insulating layer and the fifth insulating layer are made of different insulating materials.

18. The negative electrode sheet according to claim 15, wherein: On the surface of the negative electrode active material coating layer, the insulating coating layer includes a sixth insulating layer and a seventh insulating layer respectively arranged on opposite sides of the negative electrode active material coating layer; the sixth insulating layer and the seventh insulating layer each include at least two layers of different insulating materials.

19. The negative electrode sheet according to any one of claims 15 to 18, wherein: On the surface of the negative electrode active material coating layer, the insulating coating layer further includes an eighth insulating layer, and the eighth insulating layer is arranged on the end surface of the negative electrode sheet away from the negative electrode tab.

20. The negative electrode sheet according to claim 17, wherein: The insulating coating layer comprises: a ninth insulating layer, disposed on the negative electrode active material coating layer; and a tenth insulating layer, disposed on the surface of the non-ear area; The ninth insulating layer and / or the tenth insulating layer include a single layer or multiple layers of insulating layers, and when the ninth insulating layer and / or the tenth insulating layer adopts multiple layers of insulating layers, each insulating layer adopts the same or different insulating materials.

21. The negative electrode sheet according to claim 20, wherein: The insulating coating layer further includes an eleventh insulating layer disposed on an end surface of the negative electrode sheet away from the negative electrode tab, and the eleventh insulating layer and the tenth insulating layer jointly cover the side of the negative electrode sheet away from the negative electrode tab.

22. An electrode assembly, comprising a positive electrode sheet, a separator and a negative electrode sheet, wherein the negative electrode sheet is the electrode sheet according to any one of claims 1 to 8, and the positive electrode sheet and the negative electrode sheet are respectively located on opposite sides of the separator.

23. The electrode assembly according to claim 22, wherein: The positive electrode sheet is provided with a positive electrode coating area and a positive electrode tab, and the negative electrode sheet is provided with a negative electrode coating area and a negative electrode tab, the negative electrode coating area and the negative electrode tab constitute the coating area and the tab area respectively; the projection of the negative electrode coating area on the diaphragm coincides with the diaphragm or is located within the range of the diaphragm, and the projection of the positive electrode coating area on the negative electrode coating area coincides with the negative electrode coating area or is located within the range of the negative electrode coating area.

24. The electrode assembly according to claim 23, wherein: The positive electrode tab and the negative electrode tab are respectively located on opposite sides of the electrode assembly, and the edge of the first insulating layer close to the negative electrode coating area does not exceed the edge of the positive electrode coating area close to the positive electrode tab, and the edge of the positive electrode coating area away from the positive electrode tab does not exceed the edge of the negative electrode coating area close to the tab area.

25. An electrode assembly, comprising a positive electrode sheet, a separator, and a negative electrode sheet according to any one of claims 9 to 21, wherein the positive electrode sheet and the negative electrode sheet are respectively located on opposite sides of the separator.

26. The electrode assembly according to claim 25, wherein: The positive electrode sheet is provided with a positive electrode coating area and a positive electrode ear; the projection of the negative electrode coating area on the diaphragm coincides with the diaphragm or is located within the range of the diaphragm, and the projection of the positive electrode coating area on the negative electrode coating area coincides with the negative electrode coating area or is located within the range of the negative electrode coating area.

27. The electrode assembly according to claim 26, wherein: The positive electrode tab and the negative electrode tab are respectively located on opposite sides of the electrode assembly, and the edge of the insulating coating layer close to the negative electrode tab does not exceed the edge of the positive electrode coating area close to the positive electrode tab, and the edge of the positive electrode coating area away from the positive electrode tab does not exceed the edge of the negative electrode coating area close to the negative electrode tab.

28. A lithium ion battery comprising the electrode assembly according to any one of claims 22 to 27.

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