Unlock instant, AI-driven research and patent intelligence for your innovation.

Method for measuring equivalent coulombic efficiency and method for predicting cycle life of power battery

A technology of power battery and coulomb efficiency, applied in the field of power battery, can solve the problem of inability to accurately measure the battery coulomb efficiency

Pending Publication Date: 2021-05-18
CHINA AUTOMOTIVE BATTERY RES INST CO LTD
View PDF0 Cites 1 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, the accuracy of the charge and discharge test equipment commonly used in the market is about 0.05%-0.1%, so it is impossible to accurately measure the Coulombic efficiency of the battery and then accurately predict the life of the battery

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Method for measuring equivalent coulombic efficiency and method for predicting cycle life of power battery
  • Method for measuring equivalent coulombic efficiency and method for predicting cycle life of power battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] This embodiment provides a method for determining equivalent coulombic efficiency, comprising the following steps:

[0029] Step 1, select 25°C±2°C as the temperature to be tested, and the following steps are all carried out under this temperature condition;

[0030] Step 2: Charge the lithium-ion battery to be tested at a constant current of 1.0C to a voltage of 4.2V, then charge it at a constant voltage of 4.2V to a current of 1 / 20C, and after standing for 30 minutes, discharge the battery at a constant current of 1C to a voltage of 2.8V, to carry out 1100 cycles of charging and discharging tests, and record the corresponding charging power in the nth (n=1,2,3,...,1100) cycles as Q cn , and the corresponding discharge power in the nth cycle is denoted as Q dn ;

[0031] Step 3, calculate the coulombic efficiency of the nth cycle as η n =Q dn / Q cn ;

[0032] Step four, for η n (n>1) for correction, the correction coefficient is β n =Q cn / Q dn-1 , where Q d...

Embodiment 2

[0038] This embodiment provides a method for determining equivalent coulombic efficiency, comprising the following steps:

[0039] Step 1, select 45°C±2°C as the temperature to be tested, and the following steps are all carried out under this temperature condition;

[0040] Step 2: Charge the lithium-ion battery to be tested at a constant current of 0.5C to a voltage of 4.2V, then charge at a constant voltage of 4.2V to a current of 1 / 20C, and after standing for 30 minutes, discharge the battery at a constant current of 0.2C to a voltage of It is 2.8V, and 1100 cycles of charging and discharging tests are carried out, and the corresponding charging quantity in the nth (n=1, 2, 3, ..., 1100) cycle is recorded as Q cn , and the corresponding discharge power in the nth cycle is denoted as Q dn ;

[0041] Step 3, calculate the coulombic efficiency of the nth cycle as η n =Q dn / Q cn ;

[0042] Step four, for η n Correction, the correction coefficient is β n =Q cn / Q dn-1 ,...

Embodiment 3

[0045] This embodiment provides a method for determining equivalent coulombic efficiency, comprising the following steps:

[0046] Step 1, select -20°C±2°C as the temperature to be tested, and the following steps are all carried out under this temperature condition;

[0047] Step 2: Charge the lithium-ion battery to be tested at a constant current of 0.5C to a voltage of 4.2V, then charge at a constant voltage of 4.2V to a current of 1 / 20C, and after standing for 30 minutes, discharge the battery at a constant current of 0.2C to a voltage of It is 2.8V, and 1100 cycles of charging and discharging tests are carried out, and the corresponding charging quantity in the nth (n=1, 2, 3, ..., 1100) cycle is recorded as Q cn , and the corresponding discharge power in the nth cycle is denoted as Q dn ;

[0048] Step 3, calculate the coulombic efficiency of the nth cycle as η n =Q dn / Q cn ;

[0049] Step four, for η n Correction, the correction coefficient is β n =Q cn / Q dn-...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention provides a method for measuring the equivalent coulombic efficiency and a method for the predicting cycle life of a power battery, and the measurement method comprises the following steps: selecting a certain temperature in a working temperature range of a to-be-measured power battery as a to-be-measured temperature, and carrying out the following steps under the temperature condition; carrying out charging and discharging cycles on the to-be-tested battery under a certain condition, recording the charging electric quantity corresponding to the nth cycle as Qcn, and recording the discharging electric quantity corresponding to the nth cycle as Qdn; calculating the coulombic efficiency eta n of the nth cycle; and correcting the eta n, wherein the correction coefficient is beta n = Qcn / Qdn-1; and obtaining the equivalent coulombic efficiency corresponding to the nth cycle. The measuring method is suitable for charging and discharging detection equipment with common precision, the coulombic efficiency is corrected according to the correction coefficient beta n, the obtained equivalent coulombic efficiency is more accurate, accurate calculation of the capacity retention ratio is facilitated, and therefore rapid prediction of the cycle life of the power battery is achieved.

Description

technical field [0001] The invention relates to the technical field of power batteries, in particular to a method for measuring equivalent coulombic efficiency and a method for predicting cycle life of power batteries. Background technique [0002] As a new type of high-energy green battery, lithium-ion batteries are widely used in new energy electric vehicles and other fields. This puts forward higher requirements for the energy density of lithium-ion batteries, but at the same time, high-energy-density power batteries face serious capacity fading problems. The main reasons for capacity fading include the following three aspects: (1) consumption of active lithium; (2) consumption of active materials; (3) increase of impedance. Among them, side reactions are considered to be the main reason for the consumption of active lithium and the most important cause of capacity fading. The side reactions that occur at the interface of positive and negative electrode materials mainly ...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
IPC IPC(8): G06Q10/04G06F30/20G06F119/04
CPCG06Q10/04G06F30/20G06F2119/04
Inventor 高敏云凤玲方彦彦刘施阳唐玲王琳卢世刚
Owner CHINA AUTOMOTIVE BATTERY RES INST CO LTD