Long life lithium polymer battery for energy storage systems

Abstract

The utility model discloses a long -lived lithium polymer battery for energy storage system relates to battery technical field, include: modified nickel cobalt manganese ternary material as positive material, the surface of positive material is coated with aluminium oxide, negative material with graphite as main component and doped silicon particle, the gel polymer electrolyte based on PVDF HFP and the diaphragm with ceramic coating, positive material, negative material, polymer electrolyte and diaphragm constitute the electric core, the outside of electric core is provided with the packaging shell. The utility model's positive material has adopted the gradient structure design of high conductivity bottom layer and intermediate layer, and has added carbon nanotube or graphene etc. high -efficient conductive additive in high conductivity bottom layer inside, and this design not only reduces the battery internal resistance, also effectively alleviates the stress caused by volume change in the process of charge and discharge, thereby greatly improves the cycle stability and service life of battery.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to a long-life lithium polymer battery for energy storage systems. Background Technology

[0002] As the world's reliance on renewable energy continues to deepen, the demand for efficient energy storage systems has become increasingly urgent. Lithium-ion batteries, as a widely used energy storage device, play a crucial role in portable electronic devices, electric vehicles, and large-scale energy storage. However, traditional lithium-ion batteries still have certain limitations in terms of lifespan, safety, and environmental adaptability. Especially in large-scale energy storage applications requiring long-term stable operation, batteries must be able to withstand thousands or even more charge-discharge cycles while maintaining relatively stable performance.

[0003] To address the aforementioned challenges, existing lithium-ion batteries often fall short of meeting the comprehensive requirements of energy storage systems for high energy density, long cycle life, and good safety. For example, the selection and design of the cathode material directly affects the battery's energy density and cycle stability, and existing cathode materials still need improvement in terms of enhancing conductivity and reducing stress caused by volume changes during charging and discharging. Furthermore, the significant volume expansion of the anode material, especially when using silicon-based materials, during charging and discharging urgently needs to be addressed to prevent rapid performance degradation. Therefore, this invention proposes a long-life lithium polymer battery for energy storage systems. Summary of the Invention

[0004] Technical problems to be solved The purpose of this invention is to overcome the shortcomings of the existing technology and provide a long-life lithium polymer battery for energy storage systems.

[0005] Technical solution To achieve the above objectives, this utility model provides the following technical solution: a long-life lithium polymer battery for energy storage systems, comprising: a modified nickel-cobalt-manganese ternary material as the positive electrode material, an alumina coating on the surface of the positive electrode material, a negative electrode material with graphite as the main component and doped with silicon particles, a PVDF-HFP-based gel polymer electrolyte, and a separator with a ceramic coating, wherein the positive electrode material, the negative electrode material, the polymer electrolyte, and the separator constitute a battery cell, and the battery cell is provided with an encapsulation shell.

[0006] Preferably, the positive electrode material comprises a highly conductive bottom layer and an intermediate layer. The highly conductive bottom layer is disposed on the side close to the current collector. The highly conductive bottom layer is made of a highly conductive nickel-cobalt-manganese ternary material, and the intermediate layer is made of a nickel-cobalt-manganese ternary material with relatively lower conductivity. The positive electrode material adopts a gradient structure design between the highly conductive bottom layer and the intermediate layer, and highly efficient conductive additives such as carbon nanotubes or graphene are added inside the highly conductive bottom layer. This design not only reduces the internal resistance of the battery, but also effectively alleviates the stress caused by volume changes during charging and discharging, thereby greatly improving the cycle stability and service life of the battery. The surface of the positive electrode material is coated with an aluminum oxide film with a thickness of 0.1 to 1 micrometer. This protective film enhances the thermal stability of the battery, reduces the side reactions between the positive electrode material and the electrolyte under high temperature conditions, and further ensures the safe operation and long-term stability of the battery.

[0007] Preferably, an appropriate amount of carbon nanotubes and / or graphene additives are added to the interior of the highly conductive bottom layer.

[0008] Preferably, the thickness of the alumina coating layer on the surface of the positive electrode material is from 0.5 to 0.5 micrometers.

[0009] Preferably, the negative electrode material comprises a high-stability substrate and a lithium storage capacity enhancement layer. The high-stability substrate is disposed on the side closest to the current collector and is made of high-purity graphite. The negative electrode material adopts a design of a high-stability substrate composed of high-purity graphite and a lithium storage capacity enhancement layer with a gradually increasing proportion of silicon particles. This design fully utilizes the high specific capacity advantage of silicon, and at the same time, by setting polyacrylonitrile as a buffer layer to absorb the volume expansion of silicon material during charging and discharging, it achieves an effective improvement in battery energy density without sacrificing its cycle life.

[0010] Preferably, the proportion of silicon particles in the lithium storage capacity enhancement layer is increased compared to the high stability underlying layer.

[0011] Preferably, the lithium storage capacity enhancement layer further includes a buffer layer, which is made of polyacrylonitrile.

[0012] Preferably, the negative electrode material is coated with a metal oxide thin film.

[0013] Beneficial effects: Compared with existing technologies, this long-life lithium polymer battery for energy storage systems has the following advantages: I. The positive electrode material of this utility model adopts a gradient structure design of a highly conductive bottom layer and an intermediate layer, and adds highly efficient conductive additives such as carbon nanotubes or graphene inside the highly conductive bottom layer. This design not only reduces the internal resistance of the battery, but also effectively alleviates the stress caused by volume changes during charging and discharging, thereby greatly improving the cycle stability and service life of the battery. The surface of the positive electrode material is coated with an aluminum oxide film with a thickness of 0.1 to 1 micrometer. This protective film enhances the thermal stability of the battery, reduces the side reactions between the positive electrode material and the electrolyte under high temperature conditions, and further ensures the safe operation and long-term stability of the battery.

[0014] II. The negative electrode material of this invention adopts a high-stability bottom layer composed of high-purity graphite and a lithium storage capacity enhancement layer with a gradually increasing proportion of silicon particles. This design fully utilizes the high specific capacity advantage of silicon, and at the same time, by setting polyacrylonitrile as a buffer layer to absorb the volume expansion of silicon material during charging and discharging, it achieves an effective improvement in battery energy density without sacrificing its cycle life. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the diaphragm structure of this utility model; Figure 3 This is a cross-sectional structural diagram of the present invention; Figure 4 This is a cross-sectional structural diagram of the present invention.

[0017] In the picture: 1. Battery cell; 101. Positive electrode material; 102. Negative electrode material; 103. Polymer electrolyte; 104. Separator; 1011. High conductivity bottom layer; 1012. Intermediate layer; 1021. High stability bottom layer; 1022. Lithium storage capacity enhancement layer; 1023. Buffer layer; 2. Packaging shell; 3. Current collector. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0019] Please see Figures 1-4 As shown, this utility model provides a technical solution: a long-life lithium polymer battery for energy storage systems, comprising: a modified nickel-cobalt-manganese ternary material as a positive electrode material 101, an alumina coating on the surface of the positive electrode material 101, a negative electrode material 102 with graphite as the main component and doped with silicon particles, a PVDF-HFP-based gel polymer electrolyte 103, and a separator 104 with a ceramic coating. The positive electrode material 101, the negative electrode material 102, the polymer electrolyte 103, and the separator 104 constitute a cell 1, and the cell 1 is provided with an encapsulation shell 2.

[0020] Please refer to the following carefully. Figure 3 and Figure 4 The positive electrode material 101 includes a highly conductive bottom layer 1011 and an intermediate layer 1012. The highly conductive bottom layer 1011 is located on the side close to the current collector 3. The highly conductive bottom layer 1011 uses a highly conductive nickel-cobalt-manganese ternary material, while the intermediate layer 1012 uses a nickel-cobalt-manganese ternary material with relatively lower conductivity. An appropriate amount of carbon nanotubes and / or graphene additives are added inside the highly conductive bottom layer 1011. The thickness of the alumina coating layer on the surface of the positive electrode material is 0.1 to 1 micrometer. The positive electrode material adopts a gradient structure design between the highly conductive bottom layer and the intermediate layer, and highly efficient conductive additives such as carbon nanotubes or graphene are added inside the highly conductive bottom layer. This design not only reduces the internal resistance of the battery, but also effectively alleviates the stress caused by volume changes during charging and discharging, thereby greatly improving the cycle stability and service life of the battery. A 0.1 to 1 micrometer thick alumina film is coated on the surface of the positive electrode material. This protective film enhances the thermal stability of the battery, reduces the side reactions between the positive electrode material and the electrolyte under high temperature conditions, and further ensures the safe operation and long-term stability of the battery.

[0021] Please refer to the following carefully. Figure 3 and Figure 4The negative electrode material 102 includes a high-stability substrate 1021 and a lithium storage capacity enhancement layer 1022. The high-stability substrate 1021 is located near the current collector 3 and uses high-purity graphite. The lithium storage capacity enhancement layer 1022 has an increased proportion of silicon particles compared to the high-stability substrate 1021. A buffer layer 1023, made of polyacrylonitrile, is also provided in the lithium storage capacity enhancement layer 1022. A metal oxide film is coated on the outside of the negative electrode material 102. This design, employing a high-stability substrate composed of high-purity graphite and a lithium storage capacity enhancement layer with a gradually increasing proportion of silicon particles, fully utilizes the high specific capacity advantage of silicon. Simultaneously, by using polyacrylonitrile as a buffer layer to absorb the volume expansion of silicon material during charging and discharging, it effectively improves the battery's energy density without sacrificing its cycle life.

[0022] Working Principle: The positive electrode material employs a gradient structure design with a highly conductive bottom layer and an intermediate layer. Highly conductive additives such as carbon nanotubes or graphene are added within the highly conductive bottom layer. This design not only reduces the battery's internal resistance but also effectively alleviates stress caused by volume changes during charging and discharging, thereby significantly improving the battery's cycle stability and lifespan. A 0.1 to 1 micrometer-thick alumina film is coated on the surface of the positive electrode material. This protective film enhances the battery's thermal stability and reduces side reactions between the positive electrode material and the electrolyte under high-temperature conditions, further ensuring the battery's safe operation and long-term stability. The negative electrode material uses a highly stable bottom layer composed of high-purity graphite and a lithium storage capacity enhancement layer with a gradually increasing proportion of silicon particles. This design fully utilizes the high specific capacity advantage of silicon and uses polyacrylonitrile as a buffer layer to absorb the volume expansion of silicon material during charging and discharging, achieving an effective increase in battery energy density without sacrificing cycle life.

[0023] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0024] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A long-life lithium polymer battery for energy storage systems, characterized in that: include: A modified nickel-cobalt-manganese ternary material is used as the positive electrode material (101). The surface of the positive electrode material (101) is coated with alumina, a negative electrode material (102) with graphite as the main component and doped with silicon particles, a PVDF-HFP based gel polymer electrolyte (103), and a separator (104) with a ceramic coating. The positive electrode material (101), negative electrode material (102), polymer electrolyte (103), and separator (104) constitute a battery cell (1). The battery cell (1) is provided with an encapsulation shell (2).

2. The long-life lithium polymer battery for energy storage systems according to claim 1, characterized in that: The positive electrode material (101) includes a highly conductive bottom layer (1011) and an intermediate layer (1012). The highly conductive bottom layer (1011) is disposed on the side close to the current collector (3). The highly conductive bottom layer (1011) is made of a highly conductive nickel-cobalt-manganese ternary material, and the intermediate layer (1012) is made of a nickel-cobalt-manganese ternary material with relatively poor conductivity.

3. The long-life lithium polymer battery for energy storage systems according to claim 2, characterized in that: An appropriate amount of carbon nanotubes and / or graphene additives are added inside the highly conductive bottom layer (1011).

4. The long-life lithium polymer battery for energy storage systems according to claim 1, characterized in that: The thickness of the alumina coating on the surface of the cathode material is 0.1 to 1 micrometer.

5. The long-life lithium polymer battery for energy storage systems according to claim 1, characterized in that: The negative electrode material (102) includes a high-stability bottom layer (1021) and a lithium storage capacity enhancement layer (1022). The high-stability bottom layer (1021) is disposed on the side close to the current collector (3), and the high-stability bottom layer (1021) uses high-purity graphite material.

6. The long-life lithium polymer battery for energy storage systems according to claim 5, characterized in that: The lithium storage capacity enhancement layer (1022) has an increased proportion of silicon particles compared to the high stability bottom layer (1021).

7. The long-life lithium polymer battery for energy storage systems according to claim 5, characterized in that: The lithium storage capacity enhancement layer (1022) is further provided with a buffer layer (1023), which is made of polyacrylonitrile.

8. The long-life lithium polymer battery for energy storage systems according to claim 1, characterized in that: The negative electrode material (102) is coated with a metal oxide thin film.

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