Lithium ion battery positive plate structure and battery

Abstract

The utility model relates to the technical field of battery manufacturing, in particular to a lithium ion battery positive plate structure and a battery. According to the utility model, the internal resistance and the discharge efficiency of the battery cell can be improved, the discharge rate capacity of the battery can be effectively improved by 10-30%, and the capacity fading rate of the battery can be effectively improved by 5-10%. The solar cell comprises a current collector, an active material layer, an empty foil area and the like, active material layers with specific sizes are coated on two surfaces of a current collector in an extrusion coating mode, a fixed empty foil area is reserved in the relative middle position of the whole pole piece by changing the existing coating mode, meanwhile, the welding position of a tab is adjusted to the position of the empty foil area, and the original process that the tab is welded on the head of a negative pole piece is adopted. And the upper positive and negative plates and the diaphragm are sequentially stacked and wound to form the battery. Therefore, the internal resistance and the discharge efficiency of the battery cell can be improved, the discharge rate capacity of the battery can be effectively improved by 10-30%, and the capacity fading rate of the battery can be effectively improved by 5-10%.

Description

Technical Field

[0001] The utility model relates to the technical field of battery manufacturing, in particular to a structure of a positive electrode sheet of a lithium-ion battery and a battery. Background Art

[0002] A lithium-ion battery is an energy storage device. Since its birth in the 1990s, its applications have extended to all corners of our lives. With the progress of technology and the rapid development and application of smart phones, tablet computers, notebooks, two-wheel vehicles, and portable energy storage, new requirements have been put forward for the performance of lithium-ion batteries, requiring higher capacity and better cycle performance under the same volume conditions, and meeting fast charging and discharging (charging performance 1-5C, discharging performance 1-10C). In the existing design structure of the electrode sheet, usually the tab is welded on the empty foil area at both ends of the current collector aluminum foil or copper foil. This design makes it necessary for electrons to travel a long distance during charge and discharge when the electrode sheet exceeds 1m to reach the tab end from the electrode sheet end or reach the electrode sheet end from the tab end, resulting in a reduction in the battery discharge efficiency and the battery capacity not being fully utilized, and the discharge capacity at currents above 0.5C being affected. Therefore, it is indeed necessary to develop a new design solution to solve the deficiencies in the existing technology. Summary of the Utility Model

[0003] In view of this, the utility model provides a structure of a positive electrode sheet of a lithium-ion battery and a battery, which can improve the internal resistance and discharge efficiency of the battery cell, effectively increase the battery discharge rate capacity by 10%-30% and improve the battery capacity attenuation rate by 5%-10%.

[0004] The technical solution is: a structure of a positive electrode sheet of a lithium-ion battery and a battery, which consists of a positive electrode sheet and a tab. The electrode sheet includes a current collector and an active material layer coated on the surface of the current collector. And a certain size range of empty foil areas are left vacant on two surfaces of the relative middle part of the current collector by means of extrusion coating, and strict size range control is carried out. The positive electrode tab is welded to the empty foil area. The alloy at the lower root of the CPP is connected to the current collector by spot welding, laser welding, or ultrasonic welding. The alloy at the upper root of the CPP is connected to an external protection circuit (protection board, wire, etc.). The negative electrode sheet adopts a traditional process.

[0005] Further, the current collector of the positive electrode sheet is aluminum alloy or coated aluminum alloy.

[0006] Further, the current collector of the negative electrode sheet is copper alloy, coated copper alloy, or composite current collector.

[0007] Further, the active material layer is a positive electrode active material layer or a negative electrode active material layer.

[0008] Furthermore, the tab metal alloy positive electrode is made of aluminum alloy, and the negative electrode is a combination of nickel or nickel-plated copper alloy and CPP insulating glue, which are collectively referred to as tabs.

[0009] The beneficial effects are as follows: In the present utility model, by means of extrusion coating, active material layers of specific sizes are coated on two surfaces of the current collector, and by changing the existing coating method, a fixed empty foil area is left at a relatively middle position of the entire electrode sheet. At the same time, the welding position of the tab is adjusted to this empty foil area. The negative electrode sheet adopts the original process of welding the tab at the head. The positive and negative electrode sheets and the separator are stacked and wound in sequence to form a battery, which can effectively increase the battery discharge rate capacity by 10%-30% and reduce the battery capacity attenuation rate by 5-10%. Description of the Drawings

[0010] Figure 1 It is a top view structural schematic diagram of the positive electrode sheet of the present utility model.

[0011] Figure 2 It is a cross-sectional structural schematic diagram of the positive electrode sheet of the present utility model.

[0012] Figure 3 It is a top view structural schematic diagram of the negative electrode sheet of the present utility model.

[0013] Figure 4 It is a cross-sectional structural schematic diagram of the negative electrode sheet of the present utility model.

[0014] Figure 5 It is a comparison diagram of the 1C rate between the solution of the present utility model and the conventional structure solution.

[0015] Figure 6 It is a comparison diagram of the capacity retention rate between the solution of the present utility model and the conventional structure solution

[0016] Reference numerals in the drawings: 1 - current collector, 2 - active material layer, 3 - CPP, 4 - tab metal alloy, W1 - composed of the empty foil area for welding the positive electrode tab. Detailed Embodiments

[0017] The present utility model will be further described below with reference to the drawings and embodiments.

[0018] Embodiment 1: A lithium-ion battery positive electrode sheet structure and battery, as Figures 1-4As shown, it includes a current collector, an active material layer, a CPP, a tab metal alloy, and a positive tab welding empty foil area. In the positive electrode sheet of the present utility model, an active material layer with a certain size and surface density is coated on two surfaces of the current collector along the thickness direction. A positive tab welding empty foil area is arranged at a relatively middle position of the current collector. The size range of the positive electrode sheet is 10 - 40 mm. The empty foil area is welded with a tab CPP (the thickness size range is 0.15 - 0.25 mm, the length size range is 10 - 20 mm, and the width size range is 4 - 7 mm) and a tab metal alloy (the width size range is 4 - 20 mm). The negative electrode sheet is made according to the existing process, and the above size ranges are preferably selected according to the actual situation.

[0019] The positive and negative electrode sheets are combined with a separator, an aluminum-plastic film, and an electrolyte to form a battery. This technical solution can effectively improve the rate discharge efficiency of the battery and improve the low-temperature discharge performance of the battery core.

[0020] In the present utility model, the current collector is a positive current collector or a negative current collector; the active material layer is a positive active material layer or a negative active material layer; the tab is a general term for CPP and tab metal alloy. Among them, the positive current collector is aluminum alloy, coated aluminum alloy, with a thickness of 12 - 16 μm, and the negative current collector is copper alloy, coated copper alloy, composite current collector, with a thickness of 4.5 - 8 μm; the positive tab is aluminum alloy and CPP, and the negative tab is copper, nickel-plated copper, and CPP; the single-sided surface density of the positive active material layer is 16 - 22 mg / cm3, and the active material is a metal compound containing lithium and sodium, such as lithium cobaltate, lithium nickel cobalt manganate, lithium iron phosphate, lithium manganate, lithium iron manganese phosphate, sodium oxide, etc., as well as supporting PVDF, PAA, SP, CNTs, etc. The single-sided surface density of the negative active material layer is 6.5 - 11.5 mg / cm3, and the active material is mainly carbon-based materials or silicon-based materials, such as graphite, hard carbon, silicon-carbon alloy, etc., as well as supporting CMC, SP, SBR, modified PAA.

[0021] In the present utility model, the tab includes CPP and tab metal alloy. The tab metal alloy below the CPP is connected to the current collector by spot welding, laser welding, or ultrasonic welding, and the tab metal alloy above the CPP is connected to an external protection circuit (protection board, wire, etc.).

[0022] The battery composed of the positive and negative electrode sheets of the present utility model combined with a separator, an aluminum-plastic film, and an electrolyte can reduce the internal resistance of the battery.

[0023] In the present utility model, pouch lithium 1260110-10000 is also produced in the same production environment. Among them, in Solution 1, the tab of the present utility model is located in the middle of the electrode plate of the pouch lithium-ion battery, and in Solution 2, it is a pouch lithium-ion battery with a conventional structure (the positive and negative tabs are located at the head of the electrode plate). The areal density of the two groups of electrode plates is the same and other designs are the same. The results show that the effect of the solution of the present utility model is better, as Figures 5-6 shown.

[0024] The above are only the preferred embodiments of the present utility model. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present utility model, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present utility model.

Claims

1. A lithium-ion battery positive electrode sheet structure, characterized in that: It consists of a positive electrode sheet and a pole ear. The pole sheet includes a current collector and an active material layer coated on the surface of the current collector, and an empty foil area of ​​a certain size range is left on the two surfaces of the relatively middle part of the current collector by extrusion coating, and strict size range control is performed. The positive electrode pole ear is welded in the empty foil area. The metal alloy of the pole ear is an aluminum alloy for the positive electrode, and a combination of nickel or copper-plated nickel alloy and CPP insulating glue for the negative electrode, collectively referred to as the pole ear. The CPP lower root alloy is connected to the current collector by spot welding, laser welding, and ultrasonic welding. The positive electrode sheet current collector is an aluminum alloy or a coated aluminum alloy. The negative electrode sheet current collector is a copper alloy, a coated copper alloy, or a composite current collector. The CPP upper root alloy is connected to the external protection circuit, protection plate, and wire. The active material layer is a positive electrode active material layer or a negative electrode active material layer. The negative electrode sheet adopts traditional processes.

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