Square lithium ion battery internal thermophysical parameter identification method

A technology for lithium-ion batteries and thermophysical parameters, which is applied in secondary batteries, circuits, electrical components, etc., can solve the problems of inability to identify the thermal physical properties of batteries, and achieves easy and convenient acquisition and calculation, and ensures the accuracy of experimental measurement. Effect

Active Publication Date: 2019-06-18
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The purpose of the present invention is to solve the problem that the method of directly obtaining the analytical solution of the heat transfer model equation in the existing battery thermophysical parameter identification meth

Method used

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  • Square lithium ion battery internal thermophysical parameter identification method
  • Square lithium ion battery internal thermophysical parameter identification method
  • Square lithium ion battery internal thermophysical parameter identification method

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specific Embodiment approach 1

[0029] Specific implementation mode one: refer to figure 1 and figure 2 This embodiment is specifically described. The method for identifying thermal and physical parameters inside a square lithium-ion battery described in this embodiment includes the following steps:

[0030] Step 1. Place the square heater (2) between two square lithium-ion batteries of the same type, and place a thermocouple at the center of the two battery casings to detect the temperature, and place the square heater (2) ), two square lithium-ion batteries and two thermocouples are placed in an adiabatic environment, thereby simplifying the heat transfer process into a one-dimensional heat conduction process along the thickness direction of the battery;

[0031] Step 2. According to the quality of two square lithium-ion battery shells, the constant pressure specific heat capacity of the battery shell, the internal mass of the battery, the heating power of the battery and the temperature of the battery a...

specific Embodiment approach 2

[0046] Specific embodiment 2: This embodiment is to further explain the identification method of thermal physical property parameters inside the square lithium-ion battery described in specific embodiment 1. In this embodiment, in step 2, the specific heat capacity C at constant pressure inside the battery is obtained P2 The specific process is:

[0047] Place a thermocouple in the center of the two battery cases to detect the temperature change of the battery case. According to the relationship between the case on both sides of a lithium-ion battery and the internal mass m and the temperature with the heating time:

[0048]

[0049] Obtain the constant pressure specific heat capacity C P ,

[0050] In the formula, Q is the heat absorbed or released, and ΔT is the change in temperature;

[0051] Considering that the thermal parameters of the battery casing and the interior are different, there is a formula:

[0052]

[0053] In the formula, m 1 with m 3 are the mass...

specific Embodiment approach 3

[0057] Specific embodiment 3: This embodiment is to further explain the identification method of thermal physical property parameters inside the square lithium-ion battery described in specific embodiment 1. In this embodiment, the size of the square heating plate in step 1 is in contact with the lithium-ion battery Face size is the same.

[0058] In this embodiment, the use of a square heating sheet consistent with the size of the side of the battery can shield the lateral thermal conductivity when identifying the longitudinal thermal conductivity, simplifying the entire heat conduction process to one-dimensional heat conduction.

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Abstract

The invention relates to a square lithium ion battery internal thermophysical parameter identification method and belongs to the field of lithium ion batteries. According to methods for directly obtaining the analytical solutions of heat transfer model equations in existing battery thermophysical parameter identification methods, the overall parameters of batteries are identified, and the internalthermophysical properties of the batteries cannot be identified, while, with the square lithium ion battery internal thermophysical parameter identification method of the invention adopted, the problems in the existing methods can be solved. According to the square lithium ion battery internal thermophysical parameter identification method of the invention, the internal specific heat at constantpressure of a battery is obtained according to battery shell and internal mass, the specific heat at constant pressure of battery shells, heating power and the relation of the temperature of the battery varying with heating time; and the internal longitudinal thermal conductivity coefficient of the battery is obtained according to a heat transfer process, specific heat capacity and boundary conditions; two thermocouples on each battery shell are adopted to obtain two temperatures, and the temperatures of two temperature points at the inner sides of an equal thickness of the lithium ion batteryshells are obtained according to the longitudinal thermal conductivity coefficient and a heat transfer model; and on the basis of the two temperature points and the boundary conditions, the transverse thermal conductivity coefficient of the internal material of the battery is obtained according to the heat transfer model. The method is used to identify the internal thermophysical parameters of the battery.

Description

technical field [0001] The invention relates to a method for identifying thermal and physical property parameters inside a square lithium ion battery. It belongs to the field of lithium-ion batteries. Background technique [0002] As a new type of high-energy chemical power source, lithium-ion batteries have a series of advantages such as large specific energy, high charge and discharge efficiency, and environmental friendliness. They are widely used in consumer electronics, electric vehicles and other fields. They are a new generation of green energy storage devices. Its heat-related issues are related to battery performance, life, and safety, and have received full attention. At present, thermal simulation is an important means to study the thermal problems of lithium-ion batteries, and the correct identification of thermal and physical parameters of the battery is the key to thermal simulation. [0003] However, the thermal safety issue of lithium-ion batteries is very ...

Claims

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Application Information

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IPC IPC(8): G01N25/00G01N25/20H01M10/615H01M10/6555
CPCY02E60/10
Inventor 吕超夏博妍绳亿张爽
Owner HARBIN INST OF TECH
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