CN110083871B - Thermal runaway simulation method and device based on lithium ion battery thermal runaway prediction model - Google Patents
Thermal runaway simulation method and device based on lithium ion battery thermal runaway prediction model Download PDFInfo
- Publication number
- CN110083871B CN110083871B CN201910237132.9A CN201910237132A CN110083871B CN 110083871 B CN110083871 B CN 110083871B CN 201910237132 A CN201910237132 A CN 201910237132A CN 110083871 B CN110083871 B CN 110083871B
- Authority
- CN
- China
- Prior art keywords
- lithium ion
- ion battery
- heat generation
- thermal runaway
- heat
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
- G06F2119/08—Thermal analysis or thermal optimisation
Abstract
The invention relates to a thermal runaway simulation method and device based on a lithium ion battery thermal runaway prediction model, wherein the method comprises the steps of establishing the lithium ion battery thermal runaway prediction model by utilizing a lithium ion battery SOC (state of charge) and a lithium ion battery SOH (health degree) and based on a lithium ion battery heat generation mechanism, calculating corresponding lithium ion battery instantaneous heat generation power by utilizing the lithium ion battery thermal runaway prediction model, acquiring temperature, heat generation element resistance value and control unit output current value in a mode of simulating heat generation by a control unit electrically controlled heat generation element to further calculate the instantaneous heat generation power of simulated heat generation, and comparing the calculated instantaneous heat generation power of the simulated heat generation with the lithium ion battery instantaneous heat generation power calculated by the lithium ion battery thermal runaway prediction model to finish the accurate simulation of the lithium ion battery thermal runaway process. The method provides an experimental platform for the research of mechanisms such as thermal runaway diffusion and the like, and also provides experimental environments for devices such as thermal runaway management and control and the like.
Description
Technical Field
The invention relates to the field of lithium ion battery safety, in particular to a thermal runaway simulation method and device based on a lithium ion battery thermal runaway prediction model.
Background
The electric vehicle thermal management technology has become one of the important factors restricting the electric vehicle technology development and safety improvement. With the continuous improvement of the performance requirements of the electric automobile, the thermal problem of the lithium ion battery can be caused in the using process due to factors such as large-current charging, high-capacity lithium ion battery, complex working condition use and the like, the possibility of thermal runaway exists, and the lithium ion battery pack is combusted when the thermal runaway occurs, so that the safety of the whole automobile is damaged.
Thermal runaway refers to the phenomenon that the temperature of a lithium ion battery rapidly rises due to the fact that a diaphragm inside the lithium ion battery is molten, an electrochemical reaction rapidly occurs and is converted into heat generation, and the lithium ion battery is subjected to puncture, over-temperature and the like. Usually, thermal runaway will occur on a single lithium ion battery first, and a large amount of heat released by the thermal runaway will cause the temperature of the lithium ion battery to rise sharply, and thermal diffusion to an adjacent lithium ion battery will cause the adjacent lithium ion battery to be over-heated, and thermal runaway will continue to occur, so that an avalanche effect is generated, and the whole lithium ion battery pack will start to burn, possibly causing serious consequences.
At present, a simulation and experiment device aiming at thermal runaway of a single lithium ion battery cannot well meet the requirement of a whole vehicle on safety. Some extreme conditions such as acupuncture of adoption of present thermal runaway experiments induce lithium ion battery thermal runaway, but this process is uncontrollable, and this process is more complicated, can't satisfy the experimental requirement, so adopt the development process of experimental apparatus simulation thermal runaway all to improve experimental precision, improve whole car security and all have important meaning.
Disclosure of Invention
The invention provides a thermal runaway simulation method based on a thermal runaway prediction model of a lithium ion battery, which aims to solve the problems that the existing thermal runaway simulation device of the lithium ion battery is mostly established according to the surface temperature condition or the temperature rise rate and the like of the lithium ion battery, the heat generation in the thermal runaway process of the lithium ion battery cannot be accurately simulated, and the phenomenon of non-uniform heat generation in the thermal runaway process of the lithium ion battery cannot be simulated. The invention also relates to a thermal runaway simulation device based on the lithium ion battery thermal runaway prediction model.
The technical scheme of the invention is as follows:
a thermal runaway simulation method based on a lithium ion battery thermal runaway prediction model is characterized in that a lithium ion battery thermal runaway prediction model is established by utilizing a lithium ion battery SOC and a lithium ion battery SOH and based on a lithium ion battery heat generation mechanism, corresponding lithium ion battery instantaneous heat generation power is calculated by utilizing the lithium ion battery thermal runaway prediction model, the temperature, the heat generation element resistance value and the control unit output current value are acquired in a mode that a control unit electrically controls a heat generation element to simulate heat generation so as to calculate the instantaneous heat generation power simulating the heat generation, the calculated instantaneous heat generation power simulating the heat generation is compared with the instantaneous heat generation power of the lithium ion battery calculated by the lithium ion battery thermal runaway prediction model, and if the two are equal, the lithium ion battery thermal runaway process is simulated according to the current value and the temperature; if the two are not consistent, the control unit is used for adjusting the output current to enable the output current to meet the consistency between the heat generation power acquired by the electric heating element in a heat generation simulating mode at the actual temperature and the instantaneous heat generation power of the lithium ion battery calculated by the lithium ion battery thermal runaway prediction model so as to simulate the heat generation condition of the resistance element in the lithium ion battery and finish the simulation of the lithium ion battery thermal runaway process.
Preferably, the method utilizes the SOC of the lithium ion battery, the SOH of the lithium ion battery, the appearance of the lithium ion battery and the nominal voltage of the lithium ion battery, establishes an electrochemical model of the lithium ion battery, a heat generation and heat transfer model of the lithium ion battery and an aging model of the lithium ion battery based on a heat generation mechanism of the lithium ion battery, and further couples the electrochemical model, the heat generation and heat transfer model and the aging model of the lithium ion battery into a thermal runaway prediction.
Preferably, the lithium ion battery thermal runaway prediction model established by the method is based on a lithium ion battery heat generation mechanism which comprises heat conduction of an internal material of the lithium ion battery, heat exchange in a radiation mode and coupling heat exchange in an external air or cold plate heat dissipation mode.
Preferably, the method obtains the internal heat generation power of the lithium ion battery and the temperature field distribution in the lithium ion battery according to the lithium ion battery thermal runaway prediction model, and provides theoretical parameters for determining the simulated heat generation of the electric control heat generation element.
Preferably, the method is characterized in that the control unit adopts a control unit and a resistance wire structure which is connected with the control unit and used for simulating an electric heating element in the lithium ion battery, the resistance wire structure is sequentially connected with a heating power supply and a current sensor to form a heating loop, and the instantaneous heat generation power simulating heat generation is calculated by acquiring the temperature and resistance value of the resistance wire structure and the output current value of the control unit.
Preferably, the resistance wire structure is layered or partitioned to respectively fill the resistance wire layer and the heat conduction material layer to simulate non-uniform heat generation of the lithium ion battery, the resistance wire layer is used for simulating a heat source inside the lithium ion battery, and the heat conduction material layer is filled with a material with a coefficient which is adaptive to the coefficient of heat conductivity inside the lithium ion battery and is used for simulating the heat transfer phenomenon inside the lithium ion battery.
A thermal runaway simulation device based on a lithium ion battery thermal runaway prediction model is characterized by comprising a lithium ion battery thermal runaway prediction model establishing module, a lithium ion battery instantaneous heat generation power theoretical calculation module, an electric control heat generation element simulation heat generation module, a lithium ion battery instantaneous heat generation power simulation calculation module, a data comparison processing module and a current regulation module, wherein the electric control heat generation element simulation heat generation module comprises a control unit and a resistance wire structure which is connected with the control unit and used for simulating an electric heating element in a lithium ion battery;
the lithium ion battery thermal runaway prediction model building module utilizes a lithium ion battery SOC and a lithium ion battery SOH and builds a lithium ion battery thermal runaway prediction model based on a lithium ion battery heat generation mechanism, the lithium ion battery instantaneous heat generation power theoretical calculation module utilizes the lithium ion battery thermal runaway prediction model to calculate corresponding lithium ion battery instantaneous heat generation power, the electric control heat generation element simulated heat generation module simulates heat generation through a control unit electric control resistance wire structure, the lithium ion battery instantaneous heat generation power simulated calculation module collects the temperature and resistance of the resistance wire structure and the output current value of the control unit according to the result of the electric control resistance wire structure simulated heat generation to calculate the instantaneous heat generation power of simulated heat generation, and the data comparison processing module compares the calculated instantaneous heat generation power of the simulated heat generation with the lithium ion battery instantaneous heat generation power calculated by the lithium ion battery thermal runaway prediction model, if the current value and the temperature are equal, simulating a thermal runaway process of the lithium ion battery according to the current value and the temperature; if the two are not consistent, the current regulation module utilizes the control unit to regulate the output current to ensure that the consistency of the heat generation power acquired by the electric heating element in a heat generation simulating mode at the actual temperature and the instantaneous heat generation power of the lithium ion battery calculated by the lithium ion battery thermal runaway prediction model is met so as to simulate the heat generation condition of the resistance element in the lithium ion battery to complete the simulation of the lithium ion battery thermal runaway process.
Preferably, the electric control heat generating element simulation heat generating module further comprises a heating power supply and a current sensor, the resistance wire structure, the heating power supply and the current sensor are sequentially connected to form a heating loop, the heating power supply is a direct current power supply or an alternating current power supply, and the output current value of the control element is acquired through the current sensor; the resistance wire structure is internally divided into a plurality of layers with different thicknesses or a plurality of regions with different sizes, and resistance wires or heat conduction materials with the heat conduction coefficients matched with those of the interior of the lithium ion battery are respectively filled in the layers or the regions, so that the resistance wire structure simulates non-uniform heat generation of the lithium ion battery.
Preferably, the electric control heat generating element simulation heat generating module adopts a sliding network mode to enable the resistance wire structure to move according to requirements so as to simulate a thermal runaway process when short circuit occurs at different positions in the lithium ion battery.
Preferably, the lithium ion battery thermal runaway prediction model establishing module establishes a lithium ion battery electrochemical model, a lithium ion battery heat generation model and a lithium ion battery aging model by utilizing the lithium ion battery SOC, the lithium ion battery SOH, the lithium ion battery appearance and the lithium ion battery nominal voltage based on a lithium ion battery heat generation mechanism, and further couples the lithium ion battery electrochemical model, the lithium ion battery heat generation model and the lithium ion battery aging model into a lithium ion battery thermal runaway prediction model;
and/or the lithium ion battery thermal runaway prediction model building module is based on a lithium ion battery heat generation mechanism which comprises heat conduction of an internal material of the lithium ion battery, heat exchange in a radiation mode and coupling heat exchange in an external air or cold plate heat dissipation mode;
and/or the lithium ion battery thermal runaway prediction model building module is connected with the electric control heat generating element simulation heat generating module, so that the electric control heat generating element simulation heat generating module obtains the internal heat generating power of the lithium ion battery and the temperature field distribution of the lithium ion battery according to the lithium ion battery thermal runaway prediction model, and provides theoretical parameters for determining the electric control heat generating element simulation heat generation.
The invention has the following technical effects:
the invention provides a thermal runaway simulation method based on a lithium ion battery thermal runaway prediction model, which is characterized in that a lithium ion battery thermal runaway prediction model is established by utilizing a lithium ion battery SOC and a lithium ion battery SOH and based on a lithium ion battery heat generation mechanism, so that a lithium ion battery thermal runaway accurate prediction model can be established, the lithium ion battery thermal runaway prediction heat generation model can also be called as a lithium ion battery thermal runaway prediction heat generation model, the lithium ion battery instantaneous heat generation power is calculated by utilizing the thermal runaway prediction model, the current is a lithium ion battery instantaneous heat generation power theoretical value, a control unit is used for electrically controlling a heat generation element to simulate the heat generation mode, the heat generation is simulated and the heat generation power of the lithium ion battery in the thermal runaway process is analyzed according to the lithium ion battery heat generation and heat transfer processes, the simulated detection value is a simulated detection value, the simulated detection value is compared with the theoretical value and is adjusted when the simulation detection value is inconsistent The method can accurately simulate the heat generation of the lithium ion battery thermal runaway process, provides an experimental platform for the research of mechanisms such as thermal runaway diffusion and the like, and also provides an experimental environment for devices such as thermal runaway management and control and the like.
The method provided by the invention has a reliable principle, can repeatedly simulate the thermal runaway process of the lithium ion battery, and can simulate the thermal runaway process of the lithium ion battery under different SOC, SOH and environments. Furthermore, the position of the resistance wire structure in the mode of simulating heat generation by adjusting the electric control heat generating element can simulate the heat generation condition of thermal runaway caused by internal short circuit of the lithium ion battery at different positions. The invention can accurately simulate the heat generation of the lithium ion battery in the thermal runaway process, and can even simulate the non-uniform heat generation of the lithium ion battery in the thermal runaway process by respectively filling the resistance wire layer and the heat conduction material layer, thereby solving the problem that the prior art can not simulate the non-uniform heat generation phenomenon of the lithium ion battery in the thermal runaway process and further improving the thermal runaway simulation precision.
The invention also relates to a thermal runaway simulation device based on the lithium ion battery thermal runaway prediction model, which corresponds to the thermal runaway simulation method based on the lithium ion battery thermal runaway prediction model and can be understood as a device for realizing the method, the device comprises a lithium ion battery thermal runaway prediction model establishing module, a lithium ion battery instantaneous heat generation power theoretical calculation module, an electric control heat generation element simulated heat generation module, a lithium ion battery instantaneous heat generation power simulated calculation module, a data comparison processing module and a current regulation module, all the modules are mutually matched and cooperatively work to realize the thermal runaway accurate simulation of the lithium ion battery thermal runaway prediction heat generation model, the electric control heat generation element simulated heat generation module comprises a control unit and a resistance wire structure which is connected with the control unit and is used for simulating an electric heating element in the lithium ion battery, and the module is designed by utilizing the heat generation principle of the electric control element, the device has the advantages of simple structure, easy manufacture and lower cost, can meet the requirements of the invention, accurately simulates the internal power supply and heat transfer of the lithium ion battery, and simulates the heat loss process.
Drawings
Fig. 1 is a flow chart of a thermal runaway simulation method based on a lithium ion battery thermal runaway prediction model.
Fig. 2 is a circuit diagram of a manner of simulating heat generation by the electrically controlled heat generating element using a direct current power supply.
Fig. 3 is a circuit diagram of a manner of simulating heat generation by the electrically controlled heat generating element using an ac power supply.
Fig. 4 is a first order model diagram of a lithium ion battery.
Fig. 5 is a block diagram of a thermal runaway simulator based on a lithium ion battery thermal runaway prediction model.
Detailed Description
The principle of the invention is based on the thermal runaway prediction model of the lithium ion battery and the heat generation of the electric control element. And after accurate lithium ion battery heating power and temperature field distribution are obtained through the established lithium ion battery thermal runaway prediction model, simulating a thermal runaway process according to the heat generation of the electric control element.
The heat generation of the electric control element of the invention is realized by simulating the heat generation of the electric control heat generating element through the control unit, namely, by adopting an electric heating mode,the main heat generating element is preferably a resistance wire, other heat generating elements may also fulfill the function. When current flows through the resistance wire, the current is converted into heat output according to the electric work, and the heat output is converted into heat output according to Joule's law Q ═ I2RT, when the heat generating power and the resistance of the heat generating element are known, the required heating current transient can be calculated. The thermal runaway process of the lithium ion battery can be simulated by adjusting the instantaneous value of the heating current to meet the requirements of heat generation power and the surface temperature of the lithium ion battery.
The technical scheme of the invention is explained in detail in the following with the accompanying drawings.
Fig. 1 shows a flow chart of a thermal runaway simulation method based on a lithium ion battery thermal runaway prediction model according to the invention. The method comprises the steps of utilizing parameters such as SOC (residual electric quantity) of a lithium ion battery, SOH (health degree) of the lithium ion battery and the like to estimate and establish a thermal runaway prediction model of the lithium ion battery (or called a thermal runaway prediction heat generation model of the lithium ion battery, or called a thermal runaway model for short) based on a heat generation mechanism of the lithium ion battery, utilizing the thermal runaway prediction model of the lithium ion battery to calculate the instantaneous heat generation power of the corresponding lithium ion battery, wherein the instantaneous heat generation power is a theoretical value of the instantaneous heat generation power of the lithium ion battery or called ideal heat generation power of the lithium ion battery, acquiring temperature, resistance value of the heat generation element and the output current value of a control unit in a mode that the control unit electrically controls the heat generation element to simulate heat generation, calculating the instantaneous heat generation power of the simulated heat generation, wherein the instantaneous heat generation power of the simulated heat generation is a simulated detection, namely, the actual heat generation power of the lithium ion battery is compared with the ideal heat generation power, and the adjustment is carried out when the actual heat generation power is inconsistent with the ideal heat generation power, specifically: if the current value and the temperature are equal, the thermal runaway process of the lithium ion battery can be simulated according to the current value and the temperature; if the two are not consistent, the control unit is used for adjusting the output current to enable the output current to meet the consistency between the heat generation power acquired by the electric heating element in a mode of simulating heat generation and the lithium ion battery instantaneous heat generation power calculated by the lithium ion battery thermal runaway prediction model at the actual temperature so as to simulate the heat generation condition of the resistance element in the lithium ion battery to complete the lithium ion battery thermal runaway process.
Particularly, the lithium ion battery thermal runaway prediction model is a model established based on simulation results, and mainly comprises heat generation quantity of each point inside the lithium ion battery during thermal runaway and surface temperature of the lithium ion battery. The method for establishing the thermal runaway model is various, and a new model can be established along with the change of the input quantity. The input quantities may include: the lithium ion battery has a plurality of variables such as the shape (size), the capacity, the nominal voltage, an OCV-SOC curve and an SOH curve. For example, the shape of the lithium ion battery, the capacity of the lithium ion battery, the nominal voltage, the charge-discharge cycle process, an SOC curve and the temperature of the outer wall are used as input, wherein the temperature of the outer wall is used as a correction quantity, a thermal runaway prediction model of the lithium ion battery is established, and the influence of the SOC on the heat generation quantity of the lithium ion battery in the thermal runaway process can be reflected.
The control unit regulates the output current, as exemplified by the control method of the current. For example, one: taking 18650 cylindrical lithium ion battery with the capacity of 2Ah as an example, the electric heating elements are arranged in a ring shape, the heating is controlled in a segmented mode by using a plurality of current sources, and the ideal heating power is calculated by a lithium ion battery thermal runaway prediction model. Such as: the heating power of the electric heating element 1 is 10W, the heating power of the electric heating element 2 is 15W, and the heating power of the electric heating element 3 is 13W. And detecting the temperature of the shell at a corresponding temperature point of the outer wall of the lithium ion battery, feeding the temperature as an input quantity back to the thermal runaway prediction model, and recalculating the thermal runaway thermal power. Under the ideal condition, the shell temperature of the lithium ion battery is 50 ℃, 65 ℃ and 55 ℃, but the detection values of the temperature sensors at the moment are 45 ℃, 60 ℃ and 50 ℃, the detection values of the temperature sensors are input into a lithium ion battery thermal runaway model, and the actual heat generation power is calculated again to be 12W, 18W and 15W. The control unit adjusts the output current to enable the output current to meet a new heat generation power value, namely, the consistency between the heat generation power collected by the electric heating element in a simulated heat generation mode at the actual temperature and the instantaneous heat generation power of the lithium ion battery calculated by the lithium ion battery thermal runaway prediction model is met, so that the heat generation condition of the resistance element in the lithium ion battery is simulated to complete the lithium ion battery thermal runaway process.
Example two: taking an 217000 square lithium ion battery with the capacity of 26Ah as an example, resistance wires are arranged into a laminated structure, and a plurality of current sources are used for controlling the heating of the resistance wires in a segmented mode. The heating power is calculated by a lithium ion battery thermal runaway prediction model. Such as: the heating power of the resistance wire 1 is 200W, the heating power of the resistance wire 2 is 300W, and the heating power of the resistance wire 3 is 160W. And detecting the temperature of the shell at a corresponding temperature point of the outer wall of the lithium ion battery, feeding the temperature as an input quantity back to the thermal runaway prediction model, and recalculating the thermal runaway thermal power. Under the ideal condition, the shell temperature of the lithium ion battery is 100 ℃, 130 ℃ and 95 ℃, but the detection values of the temperature sensors at the moment are 105 ℃, 134 ℃ and 100 ℃, the detection values of the temperature sensors are input into a thermal runaway model, and the heat generation power is recalculated to be 180W, 270W and 130W. The output current is adjusted to meet the new heat generation power value.
Preferably, a lithium ion battery electrochemical model, a lithium ion battery heat generation model, a lithium ion battery aging model and other models can be established by utilizing various indexes such as a lithium ion battery SOC, a lithium ion battery SOH, a lithium ion battery appearance and a lithium ion battery nominal voltage based on a lithium ion battery heat generation mechanism, and then the models are further coupled into a lithium ion battery thermal runaway prediction model. The lithium ion battery heat generation mechanism based on the lithium ion battery thermal runaway prediction model comprises heat conduction of internal materials of the lithium ion battery, heat exchange in a radiation mode and heat exchange in a coupling mode of external air or a cold plate. The lithium ion battery thermal runaway prediction model is used for obtaining the internal heating power of the lithium ion battery and the temperature field distribution in the lithium ion battery and providing theoretical parameters for determining the simulated heat generation of the electric control heat generating element.
Wherein, the lithium ion battery electrochemical model is as follows: a first order RC model, such as the model diagram shown in fig. 4, is used.
The mathematical expression of the first-order RC model of the lithium ion battery is as follows:
in the above formula: u shapepTo polarize electricityPressure, CpIs a polarization capacitance, RpIs a polarization resistance, IlIs main current, UtIs the actual voltage, UocIs an open circuit voltage, R0Is the internal resistance of the lithium ion battery.
Analysis of heat generation inside lithium ion battery:
the heat generation inside the lithium ion battery belongs to the heat effect of electrochemical reaction, and accords with the heat balance equation:
in the above formula, the first and second carbon atoms are,
the heat conduction rate, Q, the total heat generation rate of the lithium ion battery, ρ, the density, c, the lithium ion concentration, t, and τ are time constants. Wherein, the two terms on the right are heat conduction rate, Q is total heat generation rate of the lithium ion battery, and the total heat generation rate Q is related to the electrochemical-thermal model of the lithium ion battery. The commonly used lithium ion battery heating power formula is as follows:
wherein E is the open-circuit voltage of the lithium ion battery in a balanced state, U is the actual working voltage, I is the working current, and dE/dT is the entropy coefficient of the lithium ion battery reaction and represents the change relation of the lithium ion battery voltage along with the temperature; the specific value can be measured by an equilibrium potential method or a calorimetry method; t is the temperature of the lithium ion battery, and the formula is simplified to obtain:
the first term on the right of the above equation is resistance heat of the lithium ion battery, also called irreversible heat, which is the heat generated by the resistance (polarization resistance and ohmic resistance) in the lithium ion battery. The other side of the formula is entropy heating of the lithium ion battery, and belongs to reversible heat.
In addition to normal reversible heat and irreversible heat, side reaction heat generated by temperature rise is generated in the thermal runaway process of the lithium ion battery, and the part of the side reaction heat is the most important heat generation source. The side reactions mainly include SEI film decomposition, reaction of negative electrode lithium with a binder, reaction of a positive electrode material with an electrolyte, decomposition reaction of an electrolyte, and the like. Therefore, a thermal runaway prediction model of the lithium ion battery can be established by coupling an SEI film decomposition mathematical model, a cathode lithium and binder reaction mathematical model, an anode material and electrolyte reaction mathematical model, an electrolyte decomposition reaction mathematical model and the like.
The invention adopts a mode that a control unit electrically controls a heat generating element to simulate heat generation, adopts the control unit and a resistance wire structure which is connected with the control unit and is used for simulating an electric heating element in a lithium ion battery, and sequentially connects the resistance wire structure with a heating power supply and a current sensor to form a heating loop, as shown in figures 2 and 3, adopts circuit diagrams of a direct current power supply and an alternating current power supply respectively for the mode that the electrically controlled heat generating element simulates heat generation, and further calculates the instantaneous heat generation power simulating heat generation by acquiring the temperature and resistance value of the resistance wire structure and the output current value of the control unit.
Furthermore, the resistance wire structure adopted in the method can adopt a layered or block mode to respectively fill a resistance wire layer and a heat conduction material layer to simulate the non-uniform heat generation of the lithium ion battery, the resistance wire layer is used for simulating the internal heat source of the lithium ion battery, the heat conduction material layer is filled with a material with a heat conduction coefficient matched with the internal heat conduction coefficient of the lithium ion battery, such as a heat conduction material layer, a resistance wire layer, a heat conduction material layer, another resistance wire layer, another heat conduction material layer and the like, which are sequentially arranged at intervals to simulate the internal environment of the lithium ion battery and simulate the internal heat transfer phenomenon of the lithium ion battery. Meanwhile, in order to simulate the thermal runaway process when short circuit occurs at different positions in the lithium ion battery, the invention can adopt a simple and convenient network sliding mode and the like to ensure that the heating resistor can move according to the experiment requirement.
The invention also relates to a thermal runaway simulation device based on the lithium ion battery thermal runaway prediction model, which corresponds to the thermal runaway simulation method based on the lithium ion battery thermal runaway prediction model and can be understood as a device for realizing the method, and the structural diagram of the device is shown in figure 5, and the device comprises a lithium ion battery thermal runaway prediction model establishing module, a lithium ion battery instantaneous heat generation power theoretical calculation module, an electric control heat generation element simulation heat generation module, a lithium ion battery instantaneous heat generation power simulation calculation module, a data comparison processing module and a current regulation module, wherein the electric control heat generation element simulation heat generation module comprises a control unit and a resistance wire structure which is connected with the control unit and is used for simulating an electric heating element in the lithium ion battery.
The lithium ion battery thermal runaway prediction model building module utilizes a lithium ion battery SOC and a lithium ion battery SOH and builds a lithium ion battery thermal runaway prediction model based on a lithium ion battery heat generation mechanism, the lithium ion battery instantaneous heat generation power theoretical calculation module utilizes the lithium ion battery thermal runaway prediction model to calculate corresponding lithium ion battery instantaneous heat generation power, the electric control heat generation element simulated heat generation module simulates heat generation through a control unit electric control resistance wire structure, the lithium ion battery instantaneous heat generation power simulated calculation module collects the temperature and resistance of the resistance wire structure and the output current value of the control unit according to the result of the electric control resistance wire structure simulated heat generation to calculate the instantaneous heat generation power of simulated heat generation, and the data comparison processing module compares the calculated instantaneous heat generation power of the simulated heat generation with the lithium ion battery instantaneous heat generation power calculated by the lithium ion battery thermal runaway prediction model, if the current value and the temperature are equal, simulating a thermal runaway process of the lithium ion battery according to the current value and the temperature; if the two are not consistent, the current regulation module utilizes the control unit to regulate the output current to ensure that the consistency of the heat generation power acquired by the electric heating element in a heat generation simulating mode at the actual temperature and the instantaneous heat generation power of the lithium ion battery calculated by the lithium ion battery thermal runaway prediction model is met so as to simulate the heat generation condition of the resistance element in the lithium ion battery to complete the simulation of the lithium ion battery thermal runaway process.
The electric control heat generating element simulation heat generating module of the thermal runaway simulator also comprises a heating power supply and a current sensor, as shown in fig. 2 and 3, the resistance wire structure R, the heating power supply E and the current sensor are sequentially connected to form a heating loop, the heating power supply can be a direct current power supply as shown in fig. 2 or an alternating current power supply as shown in fig. 3, and the output current value of the control element is acquired through the current sensor; the resistance wire structure is internally divided into a plurality of layers with different thicknesses or a plurality of regions with different sizes, and resistance wires or heat conduction materials with the heat conduction coefficients matched with those of the interior of the lithium ion battery are respectively filled in the layers or the regions, so that the resistance wire structure simulates non-uniform heat generation of the lithium ion battery. Electric control heat generating element simulation heat generating module
Therefore, fig. 2 may also be referred to as a circuit diagram of a lithium ion battery thermal runaway simulator dc power supply device, and fig. 3 may also be referred to as a circuit diagram of a lithium ion battery thermal runaway simulator ac power supply device. And regulating the output heating current by using the control unit, wherein the heating current is calculated according to Joule's law as follows:
because the actual resistance R of the resistance wires is related to the temperature I, and the temperature functions of different resistance wires are different, the functional relation between the resistance and the temperature is expressed by the following formula:
R＝F(T)
according to the lithium ion battery thermal runaway prediction model, the heat generation power and the temperature distribution of the point blockage are known, so that the calculation formula of the current I is as follows:
the electric control heat generating element simulation heat generating module in the thermal runaway simulation device adopts a sliding network mode to enable the resistance wire structure to move as required to simulate the thermal runaway process when short circuit occurs in different positions in the lithium ion battery.
Also preferably, the lithium ion battery thermal runaway prediction model adopted by the thermal runaway simulation device of the invention is established depending on the SOC of the lithium ion battery, the SOH of the lithium ion battery, the appearance of the lithium ion battery and the nominal voltage of the lithium ion battery, and is further coupled into the lithium ion battery thermal runaway prediction model after establishing the lithium ion battery electrochemical model, the lithium ion battery heat generation heat transfer model and the lithium ion battery aging model based on the lithium ion battery heat generation mechanism;
the lithium ion battery thermal runaway prediction model building module is based on a lithium ion battery heat generation mechanism and comprises heat conduction of internal materials of the lithium ion battery, heat exchange in a radiation mode and coupling heat exchange in an external air or cold plate heat dissipation mode;
the lithium ion battery thermal runaway prediction model building module is connected with the electric control heat generating element simulated heat generating module, so that the electric control heat generating element simulated heat generating module obtains the internal heat generating power of the lithium ion battery and the temperature field distribution in the lithium ion battery according to the lithium ion battery thermal runaway prediction model, and theoretical parameters are provided for determining the simulated heat generation of the electric control heat generating element.
The principle of non-uniform heat generation of the lithium ion battery in the scheme of the invention is as follows: dividing the interior of the thermal runaway simulation device into a plurality of sheet layers with different thicknesses or a plurality of areas with different sizes, and respectively filling an electric heating element or a heat conduction material, wherein the heat conduction material is made of a material with a coefficient similar to that of the heat conduction coefficient of the interior of the lithium ion battery. In the invention, a layering method is adopted to simulate a non-uniform heat generation process, such as simulation of a thermal runaway phenomenon of the lithium ion battery caused by reasons such as extrusion and the like; the thermal runaway process of the lithium ion battery caused by piercing and other causes can be simulated by using the zone division method. In the using process of the device, the thickness of each sheet layer is inconsistent, so the heat generation power of the sheet layers of the electric heating element is inconsistent; the thickness of the heat conducting material sheet layer is inconsistent, the heat resistance of the heat conducting material sheet layer is inconsistent, and a temperature gradient exists during heat conduction, so that the heat generation power in the device is non-uniform.
The invention discloses a thermal runaway simulator of a lithium ion battery thermal runaway prediction model.A lithium ion battery thermal runaway prediction model building module builds a simulation model, and on the basis of the simulation model based on thermal runaway accurate prediction, by combining factors such as heat generation and heat dissipation of a single lithium ion battery in a thermal runaway process, a thermal runaway simulation module is simulated by an electric control heat generating element to control heat generation through a group of electric control elements to realize thermal runaway device simulation. And the thermal runaway process can be used repeatedly; the thermal runaway process under different SOCs, SOHs and working conditions can be simulated; by adjusting the position of the internal heating element in the external heat transfer component, the heat generation condition of thermal runaway caused by internal short circuit of the lithium ion battery at different positions can be simulated; the temperature distribution of the outer surface of the lithium ion battery in the thermal runaway process can be sensed conveniently in any modes of a plurality of temperature sensors, any number of temperature sensors and the like.
It should be noted that the above-mentioned embodiments enable a person skilled in the art to more fully understand the invention, without restricting it in any way. Therefore, although the present invention has been described in detail with reference to the drawings and examples, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention.
Claims (9)
1. A thermal runaway simulation method based on a lithium ion battery thermal runaway prediction model is characterized in that a lithium ion battery electrochemical model, a lithium ion battery heat generation heat transfer model and a lithium ion battery aging model are established by utilizing a lithium ion battery SOC, a lithium ion battery SOH, a lithium ion battery appearance and a lithium ion battery nominal voltage based on a lithium ion battery heat generation mechanism and are further coupled into the lithium ion battery thermal runaway prediction model, corresponding lithium ion battery instantaneous heat generation power is calculated by utilizing the lithium ion battery thermal runaway prediction model, the temperature, the heat generation element resistance value and the control unit output current value are collected in a mode that a control unit electrically controls a heat generation element to simulate heat generation so as to calculate the simulated heat generation instantaneous heat generation power, and the calculated simulated heat generation instantaneous heat generation power is compared with the lithium ion battery instantaneous heat generation power calculated by the lithium ion battery thermal runaway prediction model, if the current value and the temperature are equal, simulating a thermal runaway process of the lithium ion battery according to the current value and the temperature; if the two are not consistent, the control unit is used for adjusting the output current to enable the output current to meet the consistency between the heat generation power acquired by the electric heating element in a heat generation simulating mode at the actual temperature and the instantaneous heat generation power of the lithium ion battery calculated by the lithium ion battery thermal runaway prediction model so as to simulate the heat generation condition of the resistance element in the lithium ion battery and finish the simulation of the lithium ion battery thermal runaway process.
2. The thermal runaway simulation method of claim 1, wherein the lithium ion battery thermal runaway prediction model established by the method is based on a lithium ion battery heat generation mechanism comprising heat conduction of an internal material of the lithium ion battery, heat exchange in a radiation mode, and heat exchange in a coupling mode in an external air or cold plate heat dissipation mode.
3. The thermal runaway simulation method of claim 1, wherein the method obtains internal thermal power generation and temperature field distribution in the lithium ion battery according to a lithium ion battery thermal runaway prediction model to provide theoretical parameters for determining simulated thermal generation of the electrically controlled heat generating element.
4. The thermal runaway simulation method as claimed in any one of claims 1 to 3, wherein the control unit is used for electrically controlling the heat generating element to simulate heat generation by adopting the control unit and a resistance wire structure connected with the control unit and used for simulating an electric heating element in the lithium ion battery, the resistance wire structure is connected with a heating power supply and a current sensor in sequence to form a heating loop, and the instantaneous heat generating power for simulating heat generation is calculated by acquiring the temperature and resistance value of the resistance wire structure and the output current value of the control unit.
5. The thermal runaway simulation method of claim 4, wherein an adopted resistance wire structure is formed by respectively filling a resistance wire layer and a heat conduction material layer in a layered or block-wise manner so as to simulate non-uniform heat generation of the lithium ion battery, the resistance wire layer is used for simulating a heat source inside the lithium ion battery, and the heat conduction material layer is filled with a material with a coefficient of heat conductivity suitable for the heat conductivity inside the lithium ion battery and is used for simulating a heat transfer phenomenon inside the lithium ion battery.
6. A thermal runaway simulation device based on a lithium ion battery thermal runaway prediction model is characterized by comprising a lithium ion battery thermal runaway prediction model establishing module, a lithium ion battery instantaneous heat generation power theoretical calculation module, an electric control heat generation element simulation heat generation module, a lithium ion battery instantaneous heat generation power simulation calculation module, a data comparison processing module and a current regulation module, wherein the electric control heat generation element simulation heat generation module comprises a control unit and a resistance wire structure which is connected with the control unit and used for simulating an electric heating element in a lithium ion battery;
the lithium ion battery thermal runaway prediction model building module utilizes a lithium ion battery SOC, a lithium ion battery SOH, a lithium ion battery appearance and a lithium ion battery nominal voltage to build a lithium ion battery electrochemical model, a lithium ion battery heat generation and heat transfer model and a lithium ion battery aging model based on a lithium ion battery heat generation mechanism and is further coupled into a lithium ion battery thermal runaway prediction model, the lithium ion battery instantaneous heat generation power theoretical calculation module utilizes the lithium ion battery thermal runaway prediction model to calculate corresponding lithium ion battery instantaneous heat generation power, the electric control heat generation element simulated heat generation module simulates heat generation through a control unit electric control resistance wire structure, the lithium ion battery instantaneous heat generation power simulated calculation module collects the temperature and resistance of the resistance wire structure and the output current value of the control unit according to the result of simulated heat generation of the electric control resistance wire structure to further calculate the simulated heat generation instantaneous heat generation, the data comparison processing module compares the calculated instantaneous heat generation power of the simulated heat generation with the instantaneous heat generation power of the lithium ion battery calculated by a lithium ion battery thermal runaway prediction model, and if the calculated instantaneous heat generation power of the simulated heat generation is equal to the instantaneous heat generation power of the lithium ion battery calculated by the lithium ion battery thermal runaway prediction model, a lithium ion battery thermal runaway process is simulated according to the current value and the temperature; if the two are not consistent, the current regulation module utilizes the control unit to regulate the output current to ensure that the consistency of the heat generation power acquired by the electric heating element in a heat generation simulating mode at the actual temperature and the instantaneous heat generation power of the lithium ion battery calculated by the lithium ion battery thermal runaway prediction model is met so as to simulate the heat generation condition of the resistance element in the lithium ion battery to complete the simulation of the lithium ion battery thermal runaway process.
7. The thermal runaway simulator of claim 6, wherein the electrically controlled heat generating element simulated heat generating module further comprises a heating power supply and a current sensor, the resistance wire structure, the heating power supply and the current sensor are sequentially connected to form a heating loop, the heating power supply is a direct current power supply or an alternating current power supply, and the output current value of the control element is acquired by the current sensor; the resistance wire structure is internally divided into a plurality of layers with different thicknesses or a plurality of regions with different sizes, and resistance wires or heat conduction materials with the heat conduction coefficients matched with those of the interior of the lithium ion battery are respectively filled in the layers or the regions, so that the resistance wire structure simulates non-uniform heat generation of the lithium ion battery.
8. The thermal runaway simulator of claim 7, wherein the electrically controlled heat generating element simulated heat generating module employs a sliding network to move a resistance wire structure as needed to simulate a thermal runaway process when a short circuit occurs in different locations within the lithium ion battery.
9. The thermal runaway simulation device of one of claims 6 to 8, wherein the lithium ion battery thermal runaway prediction model building module is based on a lithium ion battery heat generation mechanism comprising heat conduction of an internal material of the lithium ion battery, heat exchange in a radiation mode, and heat exchange in a coupling mode in an external air or cold plate heat dissipation mode;
and/or the lithium ion battery thermal runaway prediction model building module is connected with the electric control heat generating element simulation heat generating module, so that the electric control heat generating element simulation heat generating module obtains the internal heat generating power of the lithium ion battery and the temperature field distribution of the lithium ion battery according to the lithium ion battery thermal runaway prediction model, and provides theoretical parameters for determining the electric control heat generating element simulation heat generation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910237132.9A CN110083871B (en) | 2019-03-27 | 2019-03-27 | Thermal runaway simulation method and device based on lithium ion battery thermal runaway prediction model |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910237132.9A CN110083871B (en) | 2019-03-27 | 2019-03-27 | Thermal runaway simulation method and device based on lithium ion battery thermal runaway prediction model |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110083871A CN110083871A (en) | 2019-08-02 |
| CN110083871B true CN110083871B (en) | 2021-03-30 |
Family
ID=67413693
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910237132.9A Active CN110083871B (en) | 2019-03-27 | 2019-03-27 | Thermal runaway simulation method and device based on lithium ion battery thermal runaway prediction model |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110083871B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112644336B (en) * | 2019-10-11 | 2022-11-04 | 北京车和家信息技术有限公司 | Power battery thermal runaway prediction method and device |
| CN113497281B (en) * | 2020-04-01 | 2023-02-03 | 北京新能源汽车股份有限公司 | Method and detection system for determining thermal runaway boundary condition of lithium ion battery |
| CN112467236B (en) * | 2020-09-17 | 2021-11-05 | 北京理工大学 | Grading safety early warning method under lithium ion battery life cycle |
| CN112485674B (en) * | 2020-11-20 | 2021-12-10 | 清华大学 | Modeling method for short circuit thermal runaway in forward lithium ion battery |
| CN115309202B (en) * | 2022-07-12 | 2023-08-11 | 东风汽车集团股份有限公司 | Heat simulation device and control method thereof |
| CN116826254A (en) * | 2023-08-17 | 2023-09-29 | 中南大学 | Battery direct-current self-heating method, system, medium and terminal under low temperature of Ad hoc network of heavy-duty freight train |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20110250505A1 (en) * | 2010-04-09 | 2011-10-13 | Panasonic Corporation | Non-aqueous electrolyte secondary battery |
| CN104008243B (en) * | 2014-05-29 | 2017-06-06 | 清华大学 | The quantitative analysis method of power battery module thermal runaway expansion process heat output |
| CN104346524B (en) * | 2014-09-16 | 2017-05-31 | 清华大学 | A kind of modeling method of lithium ion battery thermal runaway |
| CN106569142A (en) * | 2016-11-11 | 2017-04-19 | 华中科技大学 | Power lithium ion battery thermal runaway early warning system and early warning method |
-
2019
- 2019-03-27 CN CN201910237132.9A patent/CN110083871B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN110083871A (en) | 2019-08-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110083871B (en) | Thermal runaway simulation method and device based on lithium ion battery thermal runaway prediction model | |
| Li et al. | Water cooling based strategy for lithium ion battery pack dynamic cycling for thermal management system | |
| Xia et al. | A reliability design method for a lithium-ion battery pack considering the thermal disequilibrium in electric vehicles | |
| CN106650134B (en) | Thermal simulation method for lithium ion battery system | |
| Lai et al. | Insight into heat generation of lithium ion batteries based on the electrochemical-thermal model at high discharge rates | |
| CN104991980B (en) | The electrochemical mechanism modeling method of lithium ion battery | |
| Samba et al. | Impact of tab location on large format lithium-ion pouch cell based on fully coupled tree-dimensional electrochemical-thermal modeling | |
| Yi et al. | Modeling the temperature dependence of the discharge behavior of a lithium-ion battery in low environmental temperature | |
| CN110110358A (en) | A kind of lithium ion battery thermal runaway sprawling analogy method and device | |
| Ganesan et al. | Physics based modeling of a series parallel battery pack for asymmetry analysis, predictive control and life extension | |
| CN107134604A (en) | A kind of power battery thermal management method based on working characteristicses | |
| Awarke et al. | Thermal analysis of a Li‐ion battery module under realistic EV operating conditions | |
| Du et al. | Multi-objective optimization discharge method for heating lithium-ion battery at low temperatures | |
| CN109614754B (en) | Simulation method of three-dimensional simplified model of lithium ion battery | |
| Tourani et al. | A multi scale multi-dimensional thermo electrochemical modelling of high capacity lithium-ion cells | |
| CN108417906A (en) | Battery management system with Intelligent heat management system control function | |
| CN108008308A (en) | A kind of test system and method for lithium ion battery caloric value | |
| CN111914503A (en) | Lithium ion battery power input electric heating coupling model building method | |
| Shen et al. | A comprehensive analysis and experimental investigation for the thermal management of cell-to-pack battery system | |
| CN105116338B (en) | A kind of parallel connection type battery system modeling method based on SOC compensators | |
| Huang et al. | A co-simulation method based on coupled thermoelectric model for electrical and thermal behavior of the lithium-ion battery | |
| Wang et al. | An experimental and numerical examination on the thermal inertia of a cylindrical lithium-ion power battery | |
| CN110148336B (en) | Method and device for simulating faults in charging process of lithium ion battery | |
| Wu et al. | Measurement of thermophysical parameters and thermal modeling of 21,700 cylindrical battery | |
| Shi et al. | Thermal analysis of rapid charging nickel/metal hydride batteries |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |