CN-121994872-A - Method and device for detecting sodium precipitation threshold of negative electrode material of sodium ion battery

CN121994872ACN 121994872 ACN121994872 ACN 121994872ACN-121994872-A

Abstract

The disclosure provides a method and a device for detecting a sodium precipitation threshold of a negative electrode material of a sodium ion battery, and belongs to the field of lithium ion batteries. The method for detecting the sodium precipitation threshold of the battery cathode material comprises the steps of assembling the cathode material to be detected into a half-battery system, discharging the half-battery system for multiple times by constant current, obtaining voltage change of the half-battery system after each discharge, determining an internal resistance value change curve of the half-battery system in the whole discharge process based on the voltage change of the half-battery system after each discharge, and determining the sodium precipitation threshold of the cathode material of the half-battery system based on the internal resistance value change curve. The method can accurately determine the sodium precipitation threshold of the negative electrode material of the sodium ion battery.

Inventors

CHEN GANG
LU ZEMING
SU HENG
TENG YANMEI

Assignees

广东海四达钠星技术有限公司

Dates

Publication Date: 20260508
Application Date: 20241030

Claims (10)

1. The method for detecting the sodium precipitation threshold of the negative electrode material of the sodium ion battery is characterized by comprising the following steps of: Assembling a negative electrode material to be tested into a half-cell system; Discharging the half-cell system a plurality of times with a constant current; Acquiring the voltage change of the half-cell system after each discharge; Determining an internal resistance value change curve of the half-cell system in the whole discharging process based on the voltage change of the half-cell system after each discharging; And determining a sodium precipitation threshold of the cathode material of the half-cell system based on the internal resistance value change curve.
2. The method for detecting a sodium precipitation threshold of a negative electrode material of a sodium ion battery according to claim 1, wherein the step of obtaining the voltage change of the half-cell system after each discharge comprises the steps of: When the electric quantity released by the half-cell system in each discharging process reaches a preset first electric quantity threshold value, interrupting the discharging process, and enabling the half-cell system to be kept in a static state for a preset first duration; And acquiring the voltage change of the half-cell system after each discharge in the first time period.
3. The method for detecting a sodium precipitation threshold of a negative electrode material of a sodium ion battery according to claim 2, wherein the constant current is 0.1C to 5C, the first electric quantity threshold is 0.1% soc to 5% soc, and the first duration is 1s to 5s.
4. The method for detecting a sodium precipitation threshold of a negative electrode material of a sodium ion battery according to claim 3, wherein the constant current is 0.5C, the first electric quantity threshold is 1% soc, and the first duration is 3s.
5. The method for detecting a sodium precipitation threshold of a negative electrode material of a sodium ion battery according to claim 1, wherein the determining the internal resistance value change curve of the half-cell system in the whole discharging process based on the voltage change of the half-cell system after each discharging comprises: Determining an internal resistance value of the half-cell system after each discharge based on a voltage change of the half-cell system after each discharge; And determining an internal resistance value change curve of the half-cell system in the whole discharging process based on the internal resistance value of the half-cell system after each discharging.
6. The method for detecting a sodium-precipitation threshold of a negative electrode material of a sodium-ion battery according to claim 1, wherein the determining the sodium-precipitation threshold of the negative electrode material of the half-cell system based on the internal resistance value change curve comprises: determining a decay inflection point of the internal resistance value change curve based on the internal resistance value change curve; and determining a sodium precipitation threshold of the cathode material of the half-cell system based on the attenuation inflection point, wherein the sodium precipitation threshold is the accumulated released electric quantity of the half-cell system corresponding to the attenuation inflection point.
7. The method for detecting a sodium precipitation threshold of a negative electrode material of a sodium ion battery according to claim 6, wherein the determining a decay inflection point of the internal resistance value change curve based on the internal resistance value change curve comprises: If the change trend of the internal resistance value change curve is that the internal resistance value change curve is firstly reduced and then gradually reduced, taking the point of the second reduction as a damping inflection point of the internal resistance value change curve; And if the change trend of the internal resistance value change curve is that the internal resistance value change curve is firstly reduced and then continuously reduced, taking the continuously reduced point as a damping inflection point of the internal resistance value change curve.
8. The method for detecting a sodium precipitation threshold of a negative electrode material of a sodium ion battery according to claim 1, further comprising, before the plurality of times of discharging the half-cell system with a constant current: And carrying out formation on the half-cell system by using a formation current, wherein the formation current is 0.01-0.1C.
9. The method for detecting a sodium precipitation threshold of a negative electrode material of a sodium ion battery according to any one of claims 1 to 8, wherein the half-cell system is a button half-cell system, the negative electrode material is assembled into a half-cell system in a negative electrode sheet form, and the half-cell system is assembled according to a negative electrode shell, a sodium sheet, a diaphragm, a negative electrode sheet, a gasket, a spring sheet, and a positive electrode shell.
10. The utility model provides a detection device of sodium ion battery negative pole material sodium precipitation threshold value which characterized in that includes: the assembly unit is used for assembling the negative electrode material to be tested into a half-cell system; the discharge test unit is used for discharging the half-cell system for a plurality of times by using constant current; The voltage acquisition unit is used for acquiring the voltage change of the half-cell system after each discharge; and a determination unit for determining an internal resistance value change curve of the half-cell system in the whole discharging process based on the voltage change of the half-cell system after each discharging, and for determining a sodium precipitation threshold of a negative electrode material of the half-cell system based on the internal resistance value change curve.

Description

Method and device for detecting sodium precipitation threshold of negative electrode material of sodium ion battery Technical Field The disclosure relates to the technical field of sodium ion batteries, in particular to a method and a device for detecting a sodium precipitation threshold of a negative electrode material of a sodium ion battery. Background Sodium ion batteries are a type of rechargeable battery that primarily use sodium ions as charge carriers to move between the positive and negative electrodes of the battery to effect the charge-discharge process. In the charging process of the sodium ion battery, the negative electrode material is easy to generate sodium precipitation phenomenon. However, the existing sodium-precipitation detection method of the sodium ion battery has difficulty in accurately determining the sodium-precipitation threshold of the anode material. Disclosure of Invention The embodiment of the disclosure aims to provide a method, a device, equipment and a storage medium, which aim to accurately measure the sodium precipitation threshold of a negative electrode material of a sodium ion battery. In order to achieve the above objective, in a first aspect, an embodiment of the present disclosure provides a method for detecting a sodium precipitation threshold of a negative electrode material of a sodium ion battery, which includes assembling the negative electrode material to be detected into a half-cell system, discharging the half-cell system for a plurality of times by using a constant current, obtaining a voltage change of the half-cell system after each discharge, determining an internal resistance change curve of the half-cell system in the whole discharging process based on the voltage change of the half-cell system after each discharge, and determining the sodium precipitation threshold of the negative electrode material of the half-cell system based on the internal resistance change curve. In some embodiments, acquiring the voltage change of the half-cell system after each discharge includes interrupting the discharge process when the electric quantity released by the half-cell system in each discharge process reaches a preset first electric quantity threshold value, and keeping the half-cell system in a static state for a preset first duration, wherein the voltage change of the half-cell system after each discharge is acquired in the first duration. In some embodiments, the constant current is 0.1C to 5C, the first charge threshold is 0.1% soc to 5% soc, and the first duration is 1s to 5s. In some embodiments, the constant current is 0.5C, the first charge threshold is 1% soc, and the first duration is 3s. In some embodiments, determining the internal resistance value change curve of the half-cell system in the whole discharging process based on the voltage change of the half-cell system after each discharging comprises determining the internal resistance value of the half-cell system after each discharging based on the voltage change of the half-cell system after each discharging, and determining the internal resistance value change curve of the half-cell system in the whole discharging process based on the internal resistance value of the half-cell system after each discharging. In some embodiments, determining a sodium precipitation threshold of the negative electrode material of the half-cell system based on the internal resistance value change curve comprises determining a decay inflection point of the internal resistance value change curve based on the internal resistance value change curve, and determining a sodium precipitation threshold of the negative electrode material of the half-cell system based on the decay inflection point, wherein the sodium precipitation threshold is an accumulated released electric quantity of the half-cell system corresponding to the decay inflection point. In some embodiments, determining the decay inflection point of the internal resistance value change curve based on the internal resistance value change curve includes taking a point of the second decrease as the decay inflection point of the internal resistance value change curve if the change trend of the internal resistance value change curve is decreasing first and then gradually decreasing, and taking a point of the continuous decrease as the decay inflection point of the internal resistance value change curve if the change trend of the internal resistance value change curve is decreasing first and then continuously decreasing. In some embodiments, prior to discharging the half-cell system multiple times with the constant current, further comprising forming the half-cell system with a formation current, wherein the formation current is 0.01C to 0.1C. In some embodiments, the half cell system is a button half cell system, the negative electrode material is assembled into the half cell system in the form of a negative electrode sheet, and the half cell system is assembled accord