WO2023169087A1

WO2023169087A1 - Thermal management and thermal spread suppression method for power battery based on lumped model

Info

Publication number: WO2023169087A1
Application number: PCT/CN2023/072481
Authority: WO
Inventors: 崔纳新; 周剑文; 李长龙; 陆东; 张承慧
Original assignee: 山东大学
Priority date: 2022-03-10
Filing date: 2023-01-17
Publication date: 2023-09-14
Also published as: CN114707184A

Abstract

A thermal management and thermal spread suppression method for a power battery based on a lumped model, which method relates to the technical field of battery management. The method comprises the following steps: constructing a thermal management geometric structure of a power battery on the basis of a liquid-cooling small/ micro-channel and a phase change material; acquiring physical property parameters of the thermal management geometric structure, and establishing battery cell thermal production models; according to a plurality of battery cell thermal production models and the physical property parameters combined with an equivalent circuit, constructing a lumped model of the power battery; and adding, into the lumped model, a management module for suppressing thermal runaway spread, predicting a temperature change of the power battery on the basis of the lumped model, determining that the power battery triggers a thermal runaway condition, and before a thermal runaway trigger condition of the power battery is met, starting the liquid-cooling small/micro-channel, so as to suppress thermal runaway spread. Therefore, thermal management of the power battery is realized.

Description

Power battery thermal management and thermal spread suppression method based on lumped model

This invention claims the priority of the Chinese patent application submitted to the China Patent Office on March 10, 2022, with the application number 202210238421.2 and the invention name "Power battery thermal management and thermal spread suppression method based on lumped model", and its entire content incorporated herein by reference.

Technical field

The present disclosure belongs to the field of battery management technology, and specifically relates to a power battery thermal management and thermal spread suppression method based on a lumped model.

Background technique

The statements in this section merely provide background technical information related to the present disclosure and do not necessarily constitute prior art.

Lithium-ion batteries are commonly used as power sources for electric vehicles due to their high energy and power density, no memory effect, and long cycle life. However, the safety of power batteries is the first issue to be considered and solved in the development process of electric vehicles, as battery energy density continues to increase. Thermal runaway accidents of electric vehicle batteries occur frequently, which limits the large-scale application of electric vehicles. Therefore, research on power battery thermal management needs to be carried out.

The battery pack of electric vehicles needs to apply real-time thermal management methods to ensure and predict the safe use of the battery. At present, the thermal management methods of battery packs under normal operating conditions at room temperature have been relatively complete, including air cooling, liquid cooling, phase change materials and other thermal management methods. management methods and a combination of multiple thermal management methods.

According to the inventor's understanding, there are currently unreasonable problems with the thermal management structure that suppresses the spread of thermal runaway. If the heat dissipation direction is consistent with the direction of thermal runaway spread, it may even aggravate the spread of thermal runaway; in addition, existing thermal runaway devices that incorporate thermal management systems Most of the spread models are finite element models, which results in slow calculation speed. It is difficult to apply to actual vehicles; currently, none of the existing models for quickly predicting the spread of thermal runaway has incorporated a thermal management system. Existing models for quickly predicting the spread of thermal runaway use heat transfer functions based on equivalent heat transfer experiments to quickly predict The spread of battery thermal runaway and the rapid prediction of thermal runaway by building a circuit model based on thermal resistance cannot be organically combined, and there is a lack of models that can quickly predict the spread of thermal runaway under the suppression of a thermal management system.

Contents of the invention

In order to solve the above problems, the present disclosure proposes a power battery thermal management and thermal spread suppression method based on a lumped model. A structure based on a combination of phase change materials and liquid-cooled small micro-channels is used as a thermal management system to suppress the spread of thermal runaway. , fully consider the possible spreading direction of thermal runaway, the liquid cooling flow direction is vertical direction, there is no possibility of aggravating the spread of thermal runaway, and the effect of suppressing thermal runaway is fast and effective.

According to some embodiments, the solution of the present disclosure provides a lumped model-based power battery thermal management and thermal spread suppression method, adopting the following technical solution:

A lumped model-based power battery thermal management and thermal spread suppression method includes the following steps:

The thermal management geometry of the power battery is constructed based on liquid-cooled small micro-channels and phase change materials;

Obtain the physical parameters of the thermal management geometric structure and establish a single cell heat generation model;

Construct a lumped model of the power battery based on multiple single cell heat production models;

A management module to suppress the spread of thermal runaway is added to the lumped model, predicts the temperature change of the power battery based on the lumped model, determines the conditions for triggering thermal runaway of the power battery, and starts all the thermal runaway triggering conditions of the power battery before reaching it. The liquid-cooled small micro-channels suppress the spread of thermal runaway and achieve thermal management of power batteries.

As a further technical limitation, in the process of constructing the thermal management geometry of the power battery, the phase change material is wrapped around each single cell, and the liquid cooling small micro-channels are arranged along the single cell. Vertical arrangement of batteries.

Further, when the single battery is operating normally, the thermal management geometry uses the phase change material to dissipate heat; when the single battery enters a thermal runaway state, the thermal management geometry restarts the liquid-cooled small micro-channel for heat dissipation. Suppress the spread of thermal runaway in power batteries.

As a further technical limitation, the single cell heat production model includes the heat production of the single cell during normal operation and the heat production of the single cell when thermal runaway occurs.

As a further technical limitation, the physical parameters of the thermal management geometric structure include the heat capacity of the single cell, the thermal resistance of the single cell, the contact thermal resistance between single cells, the heat capacity of the thermal management material, the thermal resistance of the single cell, The contact thermal resistance to the thermal management material, the convective thermal resistance of the single cell, and the convective thermal resistance of the thermal management material.

Furthermore, in the process of constructing the lumped model of the power battery, the lumped thermal resistance network of the power battery is established based on the established single battery heat generation model and physical parameters, and the lumped thermal resistance of the power battery is established based on the equivalent circuit. Model.

Specifically, after establishing the lumped thermal resistance network, the heat transfer characteristics of the battery such as the heat capacity of the single cell, the conductive thermal resistance inside the single cell, and the contact thermal resistance between single cells were obtained. The obtained lumped thermal resistance network is represented by an equivalent circuit, the output of the equivalent current source is used to represent the heat generation model of the single cell; the equivalent capacitance is used to represent the heat capacity of the single cell; the equivalent resistance is used Indicates the thermal conduction resistance inside the battery, the contact thermal resistance between batteries, etc. The final equivalent circuit is built using MATLAB Simulink.

Further, the lumped thermal resistance network of the power battery includes a battery thermal resistance network for normal operation of the power battery and a power battery thermal resistance network containing small micro-channels.

Further, the lumped model is represented by an equivalent circuit composed of an equivalent current source, an equivalent resistance and an equivalent capacitance; wherein the output of the equivalent current source represents the single cell heat generation model; The equivalent capacitance represents the heat capacity of the single cell; the equivalent resistance represents the thermal resistance.

As a further technical limitation, the management module for suppressing the spread of thermal runaway includes a phase change material module and a liquid cooling module; the phase change material module around the single cell is treated as a whole. When the phase change The phase change material undergoes a phase change from solid to liquid when the material is heated to the melting temperature.

Specifically, the thermal management module consists of a phase change material module and a liquid cooling module. When the battery is operating normally, only the phase change material model is running in the thermal management, that is, only the phase change material dissipates heat; when the single battery enters the thermal In the runaway state, the thermal management starts the liquid cooling module. At this time, the phase change material model and the liquid cooling module run at the same time. The liquid cooling and phase change materials jointly dissipate heat to inhibit the spread of thermal runaway of the power battery; the thermal management module is added to the equivalent The method in the circuit model is as follows. For the phase change material module, the phase change material around a battery is considered as a whole. At the same time, because the phase change material will undergo a phase change from solid to liquid when heated to the melting temperature, so The heat capacity of the phase change material around a battery is represented by a variable capacitor, and the contact thermal resistance between the battery and the thermal management material is represented by a resistance; for the liquid cooling module, in order to allow the model to simulate the effect of the liquid cooling flow, a small micro The liquid in the channel is divided into two parts. Two capacitors are used to represent the heat capacity of the entire small microchannel. The heat dissipation cycle is realized through the switch control of the circuit and the simulation of liquid cooling is realized.

As a further technical limitation, when it is determined that the power battery triggers thermal runaway conditions, when the power battery temperature exceeds the preset value of the thermal runaway temperature or the power battery temperature rise rate exceeds the preset value of the thermal runaway temperature rise rate, the power battery undergoes thermal runaway.

Compared with the existing technology, the beneficial effects of the present disclosure are:

This disclosure is based on a structure that combines phase change materials and liquid-cooled small micro-channels as a thermal management system to suppress the spread of thermal runaway. It fully considers the possible spread direction of thermal runaway. The liquid cooling flow direction is in the vertical direction, and there is no aggravation of the spread of thermal runaway. The possibility of suppressing thermal runaway is fast and effective.

Description of drawings

The description drawings that form a part of the present disclosure are used to provide a further understanding of the present disclosure. The illustrative embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation of the present disclosure.

Figure 1 is a flow chart of a power battery thermal management and thermal spread suppression method based on a lumped model in an embodiment of the present disclosure;

Figure 2 is a structural schematic diagram of the thermal management geometry of a power battery in an embodiment of the present disclosure;

Figure 3 is another structural schematic diagram of the thermal management geometry of the power battery in an embodiment of the present disclosure;

Figure 4 is a schematic structural diagram of a thermal resistance network of a power battery in an embodiment of the present disclosure;

Figure 5 is a schematic structural diagram of a thermal resistance network of small microchannels in an embodiment of the present disclosure;

Figure 6 is an equivalent circuit diagram of a lumped model in an embodiment of the present disclosure;

Figure 7 is a schematic diagram of a simulation of a small microchannel in an embodiment of the present disclosure;

Figure 8(a) is a schematic diagram of temperature changes of a thermal runaway triggered battery in an embodiment of the present disclosure;

Figure 8(b) is a schematic diagram of temperature changes of adjacent batteries in an embodiment of the present disclosure;

Figure 9 is a schematic diagram comparing the calculation time of the model in the embodiment of the present disclosure;

Figure 10 is a schematic diagram of temperature changes of a thermal runaway triggered battery (Battery-1) and an adjacent battery (Battery-2) in an embodiment of the present disclosure;

Figure 11 is a schematic diagram of the temperature changes of a thermal runaway triggered battery and adjacent batteries when liquid cooling is added or not in an embodiment of the present disclosure;

Figure 12 is a schematic diagram of temperature changes when multiple batteries simultaneously trigger thermal runaway in an embodiment of the present disclosure;

Among them, No. 1 and No. 1 batteries, No. 2 and No. 2 batteries, No. 3 and No. 3 batteries, No. 4 and No. 4 batteries, No. 5 and No. 5 batteries, No. 6 and No. 6 batteries, No. 7 and No. 7 batteries, No. 8 and No. 8 batteries , 9. AA battery, 10. AA battery, 11. AA battery, 12. AA battery, 13. Battery, 14. Phase change material, 15. Liquid cooling channel, 16. Coolant inlet, 17. Cooling Liquid outlet, 18. Coolant heat capacity, 19. Circuit switch, 20. Contact thermal resistance with the battery, 21. Contact thermal resistance with the outside world.

Detailed ways

The present disclosure will be further described below in conjunction with the accompanying drawings and examples.

It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present disclosure. Unless otherwise defined, all technical and scientific terms used herein have common meaning in the technical fields to which this disclosure belongs. have the same meaning as commonly understood by those skilled in the art.

It should be noted that the terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the exemplary embodiments according to the present disclosure. As used herein, the singular forms are also intended to include the plural forms unless the context clearly indicates otherwise. Furthermore, it will be understood that when the terms "comprises" and/or "includes" are used in this specification, they indicate There are features, steps, operations, means, components and/or combinations thereof.

The embodiments and features of the embodiments in the present disclosure may be combined with each other without conflict.

Embodiment 1 of the present disclosure introduces a power battery thermal management and thermal spread suppression method based on a lumped model.

As shown in Figure 1, a power battery thermal management and thermal spread suppression method based on a lumped model includes the following steps:

As one or more embodiments, the thermal management geometry consists of small liquid-cooled microchannels and a phase change material. Paraffin is selected as a filler for the phase change material. The phase change material is wrapped around the battery. The phase change material is wrapped around each battery. It is 20g. Small liquid-cooled micro-channels are arranged along the vertical direction of the battery. The material of the micro-channel is an aluminum shell, and water is used as the coolant. The total flow rate around each battery is 10L/min. As shown in Figures 2 and 3, the thermal Manage geometry Structure, the battery pack consists of a total of 12 batteries; when the batteries are working normally, only the PCM model is used for heat dissipation. When a battery enters a thermal runaway state, the system starts the liquid cooling module to inhibit the spread of thermal runaway of the battery.

The characteristic of the liquid-cooling micro-channel design is that it is composed of multiple small liquid-cooling channels. There are 12 channels distributed on both sides of the wide surface of each battery. The distribution method is that 6 channels are evenly distributed on both sides of the wide surface between each battery. channel, the liquid cooling flow direction is vertical.

As one or more embodiments, the heat transfer relationship is established based on the connection mode between the battery and the thermal management system, and the thermal parameters of the lumped model are determined based on the heat transfer relationship. The thermal parameters include the heat capacity of the battery, the thermal resistance inside the battery, Contact thermal resistance between batteries, heat capacity of thermal management materials, contact thermal resistance between batteries and thermal management materials, convection thermal resistance of batteries, and convection thermal resistance of thermal management materials.

The heat capacity of the battery is determined by the mass and specific heat capacity of the battery. The thermal resistance inside the battery is determined by the axial thermal conductivity of the battery, the radial thermal conductivity of the battery and the geometric size of the battery. The heat capacity of the thermal management material is determined by the thermal management material. The mass and specific heat capacity of the battery are determined. The thermal conduction resistance between the batteries is determined by the thermal conductivity and contact area between the batteries. The thermal conduction resistance between the battery and the thermal management material is determined by the thermal conductivity and contact area of the battery and the thermal management material. The thermal conductivity of the battery The convection thermal resistance is determined by the thermal conductivity and contact area between the battery and the air. The convection thermal resistance of the thermal management material is determined by the thermal conductivity and contact area between the thermal management material and the air.

The formula for calculating the heat capacity of the battery is:

C＝ρVC _p (1)

Among them, ρ represents the battery density, C _p represents the battery specific heat capacity, and V represents the battery volume.

The thermal resistance calculation formula inside the battery is:

Among them, δ _{x, y, z} represents the thickness in the x, y, and z directions inside the battery, and λ _{x, y, z} represents the thermal conductivity in the x, y, and z directions inside the battery.

The calculation formula for conductive thermal resistance between batteries and between batteries and thermal management materials is:

Among them, h _c represents the convection heat transfer coefficient between batteries and between batteries and thermal management materials, and A represents the contact area between batteries and between batteries and thermal management materials.

The calculation formula of the battery's convection thermal resistance is:

Among them, h _cov is the convection heat transfer coefficient between the battery surface and the environment, and A _cov represents the contact area between the battery surface and the environment.

As one or more embodiments, the thermal power of a single battery is composed of the heat generated when the battery is operating normally and the heat generated when the battery is thermally runaway.

The heat production rate of the battery during normal operation is determined by the Bernardi formula, and the expression is as follows:

Among them, I is the current, U is the battery terminal voltage, U _oc is the battery open circuit voltage, V is the battery volume, is the battery entropy thermal coefficient, and T represents the thermodynamic temperature.

The heat generated by the battery during thermal runaway is measured through a single cell adiabatic thermal runaway experiment. Under the adiabatic test environment, the heat generated by the battery is completely absorbed by the battery and causes a temperature rise of ΔT. When the heat capacity C _p of the battery is known, the thermal runaway heat production ΔH=MC _p ΔT in an adiabatic environment can be accurately obtained. The adiabatic thermal runaway model can be fitted based on the experimentally measured heat production and various chemical components of the battery.

The heat-generating power of chemical reactions of various materials inside the battery can be expressed by a unified formula, namely

Among them, Q _x (t) represents the reaction heat power of each battery component x, and the subscript x can be SEI, anode, electrolyte, cathode, etc.; c _x ^d (t) represents the normalized concentration of the reactant. ΔH _x is the enthalpy of chemical reaction of reactant x, that is, the total heat released after the reactant reacts completely.

The heat generated by the internal short circuit during thermal runaway is

Among them, ΔH _e represents the total electric energy of the battery when an internal short circuit occurs; Δt represents the average time for electric energy release. In the adiabatic thermal runaway model, Δt is set to 10 seconds.

Therefore, the heat generated by a single battery when it is thermally runaway is:

Q(t)＝Q _e (t)+Q _x (t) (7)

As one or more embodiments, a battery lumped thermal resistance parameter network is established; a lumped thermal resistance network is established based on the heat transfer relationship between the battery and the thermal management system.

(1) Battery thermal resistance network during normal operation

The thermal resistance network of the battery during normal operation consists of the battery pack and the phase change material module. The thermal resistance network of the power battery is shown in Figure 4. Heat is transferred between the thermal resistance and adjacent batteries, the external environment and the phase change material module. The phase change material around a battery is also considered as a whole, represented by a temperature node, and heat is transferred between the battery and the external environment through thermal resistance. where T _c represents the temperature of the central cell; T _neight represents the temperature of adjacent cells; R _c represents the contact resistance between cells; R _h represents the convection resistance between the cell surface and the surrounding environment; R _x , R _y , R _z means respectively in the battery cell part and The conductive resistance in the x, y and z directions between the cell surfaces; R _pcm represents the conductive thermal resistance inside the phase change material.

According to the thermal resistance network, the energy balance equation at the battery node is, as follows

Among them, Q represents the heat generation rate when the battery is thermally runaway. M _c and C _p,cell represent the mass and specific heat capacity of the battery respectively.

(2) Adding small micro-channels to the battery thermal resistance network

Taking a section of small microchannels as an example, their thermal resistance network structure is shown in Figure 5. A section of small microchannels is considered as a whole and represented by a temperature node, which transfers heat to adjacent cells through thermal resistance.

The energy balance equation of the small microchannel is as follows:

Among them, _TL represents the temperature of the small microchannel; _RL represents the contact resistance between the battery and the small microchannel.

Establish a lumped model based on the established battery lumped thermal resistance network

The model is represented by an equivalent circuit, which consists of an equivalent current source, an equivalent thermal resistance and an equivalent capacitance, as shown in Figure 6. In the model, the heat-generating power of the battery is represented by the output of the current source, and the heat capacity of the battery is represented by the capacitance. The conductive thermal resistance between the battery and the battery is represented by resistance, and the convection thermal resistance between the battery and the air is represented by resistance.

The thermal management module is added based on the battery lumped thermal resistance parameter model. In the model, because the phase change material will undergo a phase change from solid to liquid when heated to the melting temperature, the heat capacity is represented by a variable capacitance, and the thermal resistance between the battery and the thermal management material is represented by a resistance; for the liquid cooling module , in order for the model to simulate the effect of liquid cooling flow, the liquid in a small microchannel is divided into two parts, Two capacitors are used to represent the heat capacity of the entire small microchannel, and the heat dissipation cycle is realized through the switch control of the circuit to realize the simulation of liquid cooling, as shown in Figure 7.

Start the model to determine whether the battery reaches thermal runaway conditions. If it reaches thermal runaway conditions, start the liquid cooling module that suppresses thermal runaway, observe the spread of thermal runaway, and calculate when it will drop to a safe temperature.

The battery reaches thermal runaway condition. When the power battery temperature exceeds 150°C, or the temperature rise rate dT/dt exceeds 1°C/s, the power battery is considered to have thermal runaway.

In order to verify the accuracy of the thermal resistance model, COMSOL was used to establish a three-dimensional thermal management model that suppresses the spread of thermal runaway. The thermal runaway of the battery is triggered by acupuncture. The thermal management model consists of liquid-cooled small micro-channels and phase change materials. The phase change material Wrapped around the battery, liquid-cooled small micro-channels are arranged along the vertical direction of the battery; the same thermal management model for suppressing the spread of thermal runaway is established using the lumped thermal resistance model of the present invention, and the results of the two models for suppressing the spread of thermal runaway are compared. A comparison was made. Figure 8(a) and Figure 8(b) respectively show the temperature changes of the thermal runaway triggered battery and adjacent batteries. It can be seen that the thermal management system inhibits the spread of thermal runaway. At the same time, the results of the two models are very close, proving that Reliability of lumped models.

By comparing the calculation times of the two methods, the COMSOL three-dimensional model and the lumped thermal resistance model, as shown in Figure 9, it can be seen that the calculation speed of the lumped thermal resistance network method of the present invention is significantly faster than the calculation speed of the COMSOL model. , which will greatly improve the prediction efficiency of thermal runaway processes.

To demonstrate the specific operation of this thermal management system, first, when the battery is working normally, assume that the temperature of one battery (battery-1) rises sharply due to acupuncture. At this time, the system begins to predict the temperature of each battery cell. The simulation results It shows that after the thermal runaway occurs in the battery (Battery-1), the heat gradually spreads to the adjacent batteries. At 410s, the thermal runaway of the adjacent batteries has been triggered. As shown in Figure 10, the thermal runaway triggers the battery (Battery-1) and the adjacent battery ( Schematic diagram of temperature changes of battery-2). At this time, the system determines If it is determined that the battery is about to reach a thermal runaway condition, the thermal management system that suppresses thermal runaway will be activated immediately.

After starting the thermal management system to suppress thermal runaway, the liquid-cooled small micro-channel module also started to work. At this time, the system began to predict the temperature of each battery cell based on the current cooling situation, and observed the thermal runaway triggered battery (Battery-1 ) and the temperature change of the adjacent battery (battery-2) of the thermal runaway triggered battery, as shown in Figure 11. The maximum temperature of the adjacent battery is predicted to be 83°C. After 700s, the thermal runaway triggered battery drops below 100°C, indicating thermal runaway. Spread is well suppressed.

Even if multiple batteries trigger thermal runaway at the same time, the combination of phase change materials and liquid cooling in this model can well suppress this extreme situation. Two batteries (Battery-1, 7) were set to trigger thermal runaway, and the temperature changes of the thermal runaway-triggered battery (Battery-1) and the adjacent batteries (Battery-2, 3, 4) of the thermal runaway-triggered battery were observed. As shown in Figure 12, the adjacent battery did not trigger thermal runaway, and the thermal runaway triggered the battery to drop below 100°C after 900 seconds, proving the good effect of the thermal management system in inhibiting the spread of thermal runaway.

The above descriptions are only preferred embodiments of the present disclosure and are not intended to limit the present disclosure. For those skilled in the art, the present disclosure may have various modifications and changes. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this disclosure shall be included in the protection scope of this disclosure.

Claims

A power battery thermal management and thermal spread suppression method based on a lumped model, which is characterized by including the following steps:

The thermal management geometry of the power battery is constructed based on liquid-cooled small micro-channels and phase change materials;

Obtain the physical parameters of the thermal management geometric structure and construct a lumped model of the power battery;

A management module to suppress the spread of thermal runaway is added to the lumped model, predicts the temperature change of the power battery based on the lumped model, determines the conditions for triggering thermal runaway of the power battery, and starts all the thermal runaway triggering conditions of the power battery before reaching it. The liquid-cooled small micro-channels suppress the spread of thermal runaway and achieve thermal management of power batteries.
A power battery thermal management and thermal spread suppression method based on a lumped model as claimed in claim 1, characterized in that, in the process of constructing the thermal management geometry of the power battery, the phase change material is Wrapped around each single cell, the liquid-cooled small micro-channels are arranged to be arranged along the vertical direction of the single cell.
A power battery thermal management and thermal spread suppression method based on a lumped model as claimed in claim 2, characterized in that when the single battery is operating normally, the thermal management geometry uses the phase change material to dissipate heat; When a single battery enters a thermal runaway state, the thermal management geometry restarts the liquid-cooled small micro-channels for heat dissipation to inhibit the spread of thermal runaway of the power battery.
A power battery thermal management and thermal spread suppression method based on a lumped model as claimed in claim 1, characterized in that the single cell heat production model includes the heat production of the single cell in normal operation and the heat spread of the single cell. Heat production during thermal runaway.
A power battery thermal management and thermal spread suppression method based on a lumped model as claimed in claim 1, characterized in that the physical parameters of the thermal management geometric structure include the heat capacity of a single battery, Thermal resistance, thermal contact resistance between single cells, thermal capacity of thermal management materials, single cells and thermal management Contact thermal resistance of materials, convection thermal resistance of monomers, and convection thermal resistance of thermal management materials.
A power battery thermal management and heat spread suppression method based on a lumped model as claimed in claim 5, characterized in that, in the process of constructing a lumped model of the power battery, based on the established single battery heat generation The model and physical parameters are used to establish the lumped thermal resistance network of the power battery, and the equivalent circuit is combined to establish the lumped thermal resistance model of the power battery.
A power battery thermal management and heat spread suppression method based on a lumped model as claimed in claim 6, characterized in that the lumped thermal resistance network of the power battery includes a battery thermal resistance network of a normal working battery of the power battery and Power battery thermal resistance network containing small microchannels.
A power battery thermal management and thermal spread suppression method based on a lumped model as claimed in claim 7, characterized in that the lumped model consists of an equivalent current source, an equivalent resistance and an equivalent capacitance. Equivalent circuit representation; wherein, the output of the equivalent current source represents the heat generation model of the single cell; the equivalent capacitance represents the heat capacity of the single cell; and the equivalent resistance represents the thermal resistance.
A power battery thermal management and thermal spread suppression method based on a lumped model as claimed in claim 8, characterized in that the thermal runaway spread suppression management module includes a phase change material module and a liquid cooling module; The phase change material module surrounding the volume cell as a whole, when the phase change material is heated to the melting temperature, the phase change material produces a phase change from solid to liquid.
A power battery thermal management and thermal spread suppression method based on a lumped model as claimed in claim 1, characterized in that when the power battery trigger thermal runaway conditions are determined, when the power battery temperature exceeds the thermal runaway temperature preset value Or when the temperature rise rate of the power battery exceeds the preset value of the thermal runaway temperature rise rate, the power battery will experience thermal runaway.