Novel battery pole piece structure and cylindrical lithium battery

Abstract

The novel battery pole piece structure comprises a positive pole piece and a negative pole piece, a first gap and a second gap are formed in the middles of positive pole active material coatings on the upper side face and the lower side face of the positive pole piece respectively, the left sides of the first gap and the second gap are aligned, the width of the first gap is larger than that of the second gap, and a positive pole lug is arranged on the left side of the first gap. When the positive plate and the negative plate are wound, the negative plate is arranged inside, the positive plate is arranged outside, the first negative tab is arranged at the winding center, the second tab is arranged at the winding center, and the second tab is arranged at the winding center. And the second negative tab is wound to the middle of the second gap and is aligned with the positive tab. According to the utility model, by adding the second negative tab, the internal resistance value of the battery is reduced by about 20%, the high-rate discharge temperature rise of the battery is effectively reduced, the high-energy density performance requirement can be met, and the long endurance requirement is also ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of cylindrical lithium batteries, in particular to a novel battery pole piece structure and a cylindrical lithium battery containing the pole piece structure. Background Art

[0002] Cylindrical lithium-ion batteries have gradually become the battery products of choice for electric vehicles and power tools due to their high energy density, no memory effect, and environmental friendliness. In order to reduce environmental pollution caused by automobile exhaust, electric vehicles will gradually replace fuel vehicles. In order to improve the long-range demand of electric vehicles, downstream customers have put forward higher requirements for battery cell energy density, cycle life, rate performance and safety performance. The negative electrode ear of existing cylindrical lithium-ion batteries is generally located at the right end of the negative electrode sheet, and the positive electrode ear is generally located in the middle of the positive electrode sheet. The battery has a large internal resistance, and the temperature rises quickly during high-rate discharge. There is no time to dissipate heat, which poses a safety risk and cannot meet the requirements of high safety performance, high energy density and high rate at the same time. Utility Model Content

[0003] In order to solve the problem that the electrode structure of the above-mentioned existing cylindrical lithium-ion batteries cannot simultaneously meet the requirements of high safety performance, high energy density and high rate, the utility model provides a new battery electrode structure and a cylindrical lithium battery. By adding a negative electrode ear in the middle of the negative electrode sheet, and aligning the middle negative electrode ear with the positive electrode ear, it can not only meet the requirements of high energy density performance, but also effectively reduce the high-rate discharge temperature rise of the battery, ensure the endurance requirements of electric vehicles, and improve the advantages of rate operation and high safety, providing a new direction for the development of lithium-ion batteries.

[0004] To achieve the above-mentioned purpose, the utility model provides a novel battery electrode sheet structure, including a positive electrode sheet and a negative electrode sheet, the positive electrode sheet includes an aluminum foil, and positive electrode active material coatings are provided on both upper and lower sides of the aluminum foil, a first gap is provided in the middle of the positive electrode active material coating on the upper side, and a second gap is provided in the middle of the positive electrode active material coating on the lower side, the negative electrode sheet includes a copper foil, and negative electrode active material coatings are provided on both upper and lower sides of the copper foil, blank sections are provided at the right ends of the negative electrode active material coatings on the upper and lower sides of the copper foil, and a first negative electrode ear is provided in the blank section on the lower side of the copper foil , characterized in that: the width of the first gap is greater than that of the second gap, and the first gap is aligned with the left end of the second gap, a positive electrode ear is provided on the left side of the first gap, and the positive electrode ear is located in the middle of the second gap, and a third gap aligned with the upper and lower sides of the negative electrode active material coating is provided in the middle of the copper foil, and a second negative electrode ear is provided in the middle of the third gap on the upper side of the copper foil. When the positive electrode sheet and the negative electrode sheet are wound into a cylindrical lithium battery, the negative electrode sheet is inside and the positive electrode sheet is outside, the first negative electrode ear is arranged in the center of the cylindrical lithium battery, and the second negative electrode ear is wound to the middle of the second gap and aligned with the positive electrode ear.

[0005] Furthermore, the thickness of the aluminum foil is set to 12-15 um, the first gap width is set to 67±1 mm, and the second gap width is set to 22±1 mm; the thickness of the copper foil is set to 8-12 um, and the third gap width is set to 20±1 mm.

[0006] Furthermore, the positive electrode ear is made of aluminum strip, the width of the positive electrode ear is set to 13-15 mm, and the thickness is set to 90-100 um; the first negative electrode ear and the second negative electrode ear are both made of copper-nickel composite strip, the width of the first negative electrode ear and the second negative electrode ear are set to 13-15 mm, and the thickness is set to 80-100 um.

[0007] Furthermore, the positive electrode active material coating includes nickel cobalt lithium manganese oxide, and the thickness of the positive electrode active material coating is set to 60-80 um; the negative electrode active material coating includes graphite or silicon-based material, and the thickness of the negative electrode active material coating is set to 60-70 um.

[0008] The utility model also provides a cylindrical lithium battery, which comprises the novel battery pole piece structure.

[0009] Furthermore, the cylindrical lithium battery also includes a diaphragm arranged between the positive electrode sheet and the negative electrode sheet, and the diaphragm is made of PP or PE material and coated with a ceramic layer on the surface.

[0010] Compared with the prior art, the beneficial effects of the utility model are as follows: 1. By adding a second negative electrode ear in the middle of the negative electrode sheet, the internal structure of the battery is a parallel structure, which reduces the internal resistance of the battery by about 20%, effectively reducing the temperature rise of the battery during high-rate discharge, so that the cylindrical lithium battery can meet the requirements of high energy density performance, ensure the endurance requirements of electric vehicles, and improve the safety performance of high-rate operation; 2. When winding, the second negative electrode ear added in the middle is aligned with the positive electrode ear, so that the second negative electrode ear is arranged in the second gap, so as to use the second gap to reduce the thickness of the negative electrode ear exceeding the thickness of the corresponding negative electrode active material coating, maintain the roundness of the winding core, reduce the force on the aluminum foil at the second negative electrode ear during the battery charging and discharging process, prevent the positive electrode aluminum foil from light transmission and breakage, and achieve high safety and long life of the cylindrical lithium-ion battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a schematic diagram of the structure of the positive electrode ear and the second negative electrode ear when the positive and negative electrode sheets are wound in an embodiment of the utility model;

[0012] Figure 2 This is a schematic diagram of the unfolded structure of the positive electrode sheet of the embodiment of the utility model;

[0013] Figure 3 This is a schematic diagram of the unfolded structure of the negative electrode sheet of an embodiment of the utility model.

[0014] In the figure: 1, positive electrode sheet, 101, aluminum foil, 102, positive electrode active material coating, 103, first gap, 104, positive electrode ear, 105, second gap, 2, negative electrode sheet, 201, copper foil, 202, negative electrode active material coating, 203, blank section, 204, first negative electrode ear, 205, third gap, 206, second negative electrode ear. DETAILED DESCRIPTION

[0015] 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.

[0016] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0017] like Figures 1 to 3 As shown, the embodiment of the utility model includes a positive electrode sheet 1 and a negative electrode sheet 2. The positive electrode sheet 1 includes an aluminum foil 101. A positive electrode active material coating 102 is provided on both the upper and lower sides of the aluminum foil 101. A first gap 103 is provided in the middle of the positive electrode active material coating 102 on the upper side. A second gap 105 is provided in the middle of the positive electrode active material coating 102 on the lower side. The width of the first gap 103 is greater than the second gap 105, and the first gap 103 is aligned with the left end of the second gap 105. The positive electrode ear 104 is provided on the left side of the first gap 103 on the upper side of the aluminum foil 101 and is located in the middle of the second gap 105. The negative electrode sheet 2 includes a copper foil 201. A negative electrode active material coating 102 is provided on both the upper and lower sides of the copper foil 201. The negative electrode active material coating 202 is provided with a blank section 203 at the right end of the negative electrode active material coating 202 on the upper and lower sides of the copper foil 201, and the blank section 203 on the lower side of the copper foil 201 is provided with a first negative electrode ear 204. The negative electrode active material coatings 202 on the upper and lower sides of the copper foil 201 are provided with a third gap 205 aligned up and down in the middle, and a second negative electrode ear 206 is provided in the middle of the third gap 205 on the upper side of the copper foil 201. When the positive electrode sheet 1 and the negative electrode sheet 2 are wound into a cylindrical lithium battery, the negative electrode sheet 2 is inside and the positive electrode sheet 1 is outside. The first negative electrode ear 204 is arranged in the center of the cylindrical lithium battery, and the second negative electrode ear 206 is wound to the middle of the second gap 105 and aligned with the positive electrode ear 104.

[0018] Furthermore, the thickness of the aluminum foil 101 is set to 12 um, the width L1 of the first gap 103 is set to 66 mm, and the width L2 of the second gap 105 is set to 22 mm; the thickness of the copper foil 201 is set to 8 um, and the width L3 of the third gap 205 is set to 20 mm.

[0019] Furthermore, the positive electrode ear 104 is made of aluminum tape, the width of the positive electrode ear 104 is set to 13 mm, and the thickness is set to 90 um; the first negative electrode ear 204 and the second negative electrode ear 206 are both made of copper-nickel composite tape, the width of the first negative electrode ear 204 and the second negative electrode ear 206 are set to 14 mm, and the thickness is set to 80 um.

[0020] Furthermore, the positive electrode active material coating 102 includes lithium nickel cobalt manganese oxide, and the thickness of the positive electrode active material coating 102 is set to 70 um; the negative electrode active material coating 202 includes graphite or silicon-based materials, and the thickness of the negative electrode active material coating 202 is set to 70 um.

[0021] In this embodiment, by adding a second negative electrode ear 206 in the middle of the negative electrode sheet 2, the inside of the cylindrical battery is made into a parallel structure, which reduces the internal resistance of the cylindrical battery by about 20%, effectively reducing the high-rate discharge temperature rise of the battery, so that the cylindrical lithium battery can meet the requirements of high energy density performance, ensure the endurance requirements of electric vehicles, and improve the safety performance of high-rate operation.

[0022] like Figure 1 As shown, during winding, the second negative electrode ear 206 added in the middle is aligned with the positive electrode ear 104, so that the second negative electrode ear 206 is arranged in the second gap 105, so that the second gap 105 is used to reduce the thickness of the second negative electrode ear 206 that is higher than the thickness of the corresponding negative electrode active material coating 202, maintain the roundness of the winding core, reduce the stress on the aluminum foil 101 at the second negative electrode ear 206 during the battery charging and discharging process, prevent the positive electrode aluminum foil from light transmission and breakage, and achieve high safety and long life of the cylindrical lithium-ion battery.

[0023] The embodiment of the utility model further provides a cylindrical lithium battery, comprising the above-mentioned positive electrode sheet 1 and negative electrode sheet 2.

[0024] Furthermore, the cylindrical lithium battery also includes a diaphragm disposed between the positive electrode sheet 1 and the negative electrode sheet 2. The diaphragm is made of PP or PE material and coated with a ceramic layer.

[0025] The above are only preferred implementations of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. A novel battery electrode structure, comprising a positive electrode and a negative electrode, wherein the positive electrode comprises an aluminum foil, wherein positive electrode active material coatings are disposed on both upper and lower sides of the aluminum foil, wherein a first gap is disposed in the middle of the positive electrode active material coating on the upper side, and a second gap is disposed in the middle of the positive electrode active material coating on the lower side, wherein the negative electrode comprises a copper foil, wherein negative electrode active material coatings are disposed on both upper and lower sides of the copper foil, wherein blank sections are disposed at the right ends of the negative electrode active material coatings on the upper and lower sides of the copper foil, and wherein a first negative electrode ear is disposed in the blank section on the lower side of the copper foil, Features: The width of the first gap is greater than that of the second gap, and the left ends of the first gap and the second gap are aligned. A positive electrode ear is provided on the left side of the first gap, and the positive electrode ear is located in the middle of the second gap. A third gap aligned upward and downward is provided in the middle of the negative electrode active material coatings on the upper and lower sides of the copper foil, and a second negative electrode ear is provided in the middle of the third gap on the upper side of the copper foil. When the positive electrode sheet and the negative electrode sheet are wound into a cylindrical lithium battery, the negative electrode sheet is inside and the positive electrode sheet is outside. The first negative electrode ear is arranged in the center of the cylindrical lithium battery, and the second negative electrode ear is wound to the middle of the second gap and aligned with the positive electrode ear.

2. A new battery electrode structure according to claim 1, Features: The thickness of the aluminum foil is set to 12-15um, the first gap width is set to 67±1mm, and the second gap width is set to 22±1mm; the thickness of the copper foil is set to 8-12um, and the third gap width is set to 20±1mm.

3. A new battery pole piece structure according to claim 1, Features: The positive electrode ear is made of aluminum strip, the width of the positive electrode ear is set to 13-15mm, and the thickness is set to 90-100um; the first negative electrode ear and the second negative electrode ear are both made of copper-nickel composite strip, the width of the first negative electrode ear and the second negative electrode ear are set to 13-15mm, and the thickness is set to 80-100um.

4. A new battery pole piece structure according to claim 1, Features: The positive electrode active material coating comprises lithium nickel cobalt manganese oxide, and the thickness of the positive electrode active material coating is set to 60-80 um; the negative electrode active material coating comprises graphite or silicon-based material, and the thickness of the negative electrode active material coating is set to 60-70 um.

5. A cylindrical lithium battery, Features: The cylindrical lithium battery comprises the novel battery pole piece structure as described in any one of claims 1 to 4.

6. A cylindrical lithium battery according to claim 5, Features: The cylindrical lithium battery also includes a diaphragm arranged between the positive electrode sheet and the negative electrode sheet. The diaphragm is made of PP or PE material and has a ceramic layer coated on the surface.

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