Method and system for suppressing thermal runaway of battery

Abstract

The invention discloses a method and a system for suppressing thermal runaway of a battery. The suppression method comprises the steps that when it is judged that a battery has a thermal runaway risk according to collected information of the battery, according to a preset energy transfer strategy, current SOC information of the battery and the current available discharge rate of the battery, a preset energy transfer mode is intelligently matched and started, and electric energy transfer is conducted till the SOC of the battery is reduced to the target SOC. According to the method, when the thermal runaway risk of the battery is predicted, the optimal energy transfer scheme is judged and executed after intelligent calculation by the battery management system according to the battery parameter state at the current moment, the battery energy is actively transferred, the SOC of the battery with the thermal runaway risk is reduced, and the thermal runaway risk and harm are reduced to the minimum; and the risk caused by energy transfer action is avoided, the thermal runaway risk of the battery is not accelerated, and the safety of the battery is improved.

Description

Technical Field

[0001] This invention relates to the field of battery system thermal management technology, and in particular to a method and system for suppressing battery thermal runaway. Background Technology

[0002] To address range anxiety and end-user charging anxieties, new energy vehicle manufacturers are increasingly adopting fast or ultra-fast charging technologies, which have almost become standard features in new energy vehicles. Under the same conditions, compared to slow charging, fast charging is more likely to trigger or increase the risk of thermal runaway in the power battery system. Thermal runaway occurs when the rate of heat generation within the power battery far exceeds its rate of heat dissipation. The accumulation of large amounts of heat causes a rapid rise in battery temperature, leading to a series of exothermic reactions such as melting of the internal separator, short circuits between the positive and negative electrodes, and electrolyte decomposition. Ultimately, this can result in uncontrollable phenomena such as battery fires and explosions. Thermal runaway can cause personal injury and property damage; therefore, prevention and control are essential. Current technologies for controlling thermal runaway in battery systems primarily focus on strengthening cell materials, improving module and system insulation and flame retardancy, structural protection, and enhancing physical barriers such as adding smoke ducts.

[0003] Patent publication CN114600301A discloses a method and system for preventing battery thermal runaway. The method includes: detecting or predicting whether there is a risk of thermal runaway in each battery cell or module of a battery pack; and in response to detecting or predicting a risk of thermal runaway in at least one battery cell or module of the battery pack, transferring the battery energy of at least one battery cell or module as thermal or electrical energy to the battery pack or another battery pack.

[0004] Patent document CN112590553A discloses a battery box and a method for controlling thermal runaway of the battery box. The battery box includes battery cells, a cooling system, a bypass circuit, a detection unit, and a control system. The cooling system is used to cool the battery cells. The bypass circuit is connected between the battery cells and the cooling system and is equipped with a discharge switch. The detection unit is used to detect the thermal runaway warning parameters of the battery cells. The control system is connected to the detection unit and the discharge switch to determine whether there is a risk of thermal runaway in the battery cells based on the thermal runaway warning parameters. When there is a risk of thermal runaway in the battery cells, the control system controls the discharge switch to discharge the battery cells and uses the discharged electricity to power the cooling system.

[0005] The patent document with publication number CN115275382A discloses a battery system including at least one battery module, a battery management device, and an energy transfer circuit. Each battery module includes at least two battery cells, and the energy transfer circuit is connected to the battery cells. The battery management device is used to control the energy transfer circuit to transfer the charge of the target battery cell group to other battery cells in the battery system or a load circuit connected to the battery system when the battery cell A experiences thermal runaway. Battery cell A is any battery cell, the target battery cell group is at least one battery cell in the battery module where battery cell A is located, and the other battery cells are the battery cells in the battery module where battery cell A is located excluding battery cell A and the target battery cell group and / or the battery cells in other battery modules other than the battery module where battery cell A is located.

[0006] The patent document with publication number CN117276710A discloses a power battery energy discharge device and energy discharge method. The power battery energy discharge method includes: acquiring the signal of thermal runaway of any single cell or module in the power battery; electrically connecting the power battery to a discharge module to discharge the power battery to the maximum state of charge or a lower state of charge under the condition of mild exothermic reaction in thermal runaway. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings and defects of the prior art and provide a method and system for suppressing battery thermal runaway. By using the big data model of the intelligent management system to provide early warning of the risk of thermal runaway of the cell module, the high charge of the risky cell module is transferred to reduce the impact of thermal runaway.

[0008] One aspect of the present invention provides a method for suppressing battery thermal runaway, comprising the steps of:

[0009] Real-time collection of battery information;

[0010] Based on the collected battery information, when it is determined that the battery is at risk of thermal runaway, a preset energy transfer strategy is implemented. Based on the battery's current SOC information and the battery's current available discharge rate, the preset energy transfer method is intelligently matched and activated to transfer electrical energy until the battery's SOC drops to the target SOC.

[0011] Preferably, when the current SOC of the battery is greater than the preset SOC threshold, energy transfer is performed using the first energy transfer method or the third energy transfer method; otherwise, energy transfer is performed using the second energy transfer method or the third energy transfer method.

[0012] The first energy transfer method is to use a high-precision power module for energy transfer; the second energy transfer method is to use a bidirectional DC-DC module to transfer electrical energy to a safe energy storage device; and the third energy transfer method is to transfer electrical energy to the vehicle's electrical equipment.

[0013] Preferably, the SOC threshold is SOC 70%.

[0014] Specifically, when the electrical equipment is available, a third energy transfer method is used; otherwise, a first or second energy transfer method is used. The electrical equipment includes at least one of a liquid cooling device, an OBC module, a DC-DC module, and a motor. The availability of the electrical equipment refers to whether the available current of the electrical equipment meets the energy transfer requirements of the battery at risk of thermal runaway. It is determined whether the current required by the electrical equipment is within the available discharge rate range. If it is, the third energy transfer method is used; otherwise, the first or second energy transfer method is used.

[0015] Preferably, the safe energy storage device is one of a safe battery cell, a safe battery module, or a safe battery system.

[0016] Preferably, the high-precision, high-power module includes multiple power modules and a power module controller. The power module controller includes a control chip and multiple control switches. The multiple power modules are connected in series, and each power module is connected to a control switch of the power module controller at both ends. The power module controller, based on the available rate model in the intelligent battery management system, responds to discharge demand and intelligently matches different high-precision, high-power modules based on the battery's available discharge rate. By controlling the switching action of the control switches, the power modules connected to the control switches are in a preset state, including working or not working, thereby enabling different numbers of power modules to start and work in rotation.

[0017] Preferably, when the high-precision, high-power module is operating, before performing discharge, the following steps are performed using the available rate model:

[0018] Based on the current SOC, target SOC, and available discharge rate of the risk battery, determine the discharge time required for the risk battery to discharge to the target SOC;

[0019] The number of power modules required for discharge is determined based on the resistance value of each power module and the resistance value required for the discharge of the risky battery.

[0020] Based on the relationship between discharge current, power module resistance, temperature rise, and discharge time, and according to the preset temperature rise threshold of the power module, the single-operation discharge time of each power module is determined.

[0021] The number of discharge cycles is determined based on the single-operation discharge time of each power module, the discharge time required to discharge to the target SOC, and the number of power modules required for discharge.

[0022] Based on the number of discharges, the number of power modules required for a single operation, and the discharge time for a single operation, the discharge time required to discharge to the target SOC is matched in stages to the power modules that perform the discharge, and the power modules are dynamically controlled to perform the discharge operation.

[0023] Preferably, within the discharge time required for the risk battery to discharge to the target SOC, if the discharge time of the power module that performed the discharge in the previous period ends and the number of discharges has not been reached, the same number of power modules are started in the next period to continue discharging. At least one power module that performed the discharge in the previous period enters a cooling period, and so on, until the number of discharges is reached and then stops. The power discharge modules activated in the next period include at least one power module that performed the discharge in the previous period, or other power modules other than the power modules that performed the discharge in the previous period, until the number of discharges is reached and then stops.

[0024] Preferably, in the second energy transfer method, in a main battery system, the bidirectional DC-DC module is connected to multiple battery modules through a control circuit. The control circuit is equipped with a switch, which controls the transfer of electrical energy from the risky battery module to other safe battery modules. Alternatively, an auxiliary battery system is set up, and the bidirectional DC-DC module connected to the main battery system is electrically connected through a control switch to control the transfer of electrical energy from the main battery system to the auxiliary battery system.

[0025] Preferably, the collected battery information includes one of the following: voltage, temperature, temperature rise rate, and internal resistance of the battery cell, and / or at least one of the following: pressure, gas type, and gas concentration information in the battery system.

[0026] Another aspect of the present invention provides a battery system thermal runaway suppression system, used to implement the battery thermal runaway suppression method, implemented through an intelligent battery management system, comprising:

[0027] The information acquisition unit is used to collect battery information in real time;

[0028] The energy conversion decision execution unit is used to determine the risk of thermal runaway of the battery based on the collected battery information. Then, according to the preset energy transfer strategy, it adopts an energy transfer method that matches the current SOC information of the battery to transfer electrical energy until the battery SOC drops to the target SOC.

[0029] The battery thermal runaway suppression method and system of the present invention, when predicting the risk of thermal runaway in a battery, intelligently calculates and executes the optimal energy transfer scheme based on the current battery parameter status, such as SOC, SOH, temperature rise, and other available information, according to the battery management system. It actively transfers energy to reduce the SOC of the battery at risk of thermal runaway, thereby minimizing the risk and harm of thermal runaway and ensuring that the energy transfer action does not cause any risk or accelerate the risk of battery thermal runaway. This improves the safety of the battery system and can be applied to any product using lithium-ion batteries. Attached Figure Description

[0030] Figure 1 This is a flowchart of the method for controlling thermal runaway in a battery system according to the present invention.

[0031] Figure 2 This is a schematic diagram of the power module connecting to the battery module in an embodiment of the present invention.

[0032] Figure 3 This is a schematic diagram of the power module connecting to the power module controller and the risk battery module in an embodiment of the present invention.

[0033] Figure 4 This is a schematic diagram of the first polling operation mode of the power module according to an embodiment of the present invention.

[0034] Figure 5 This is a schematic diagram of the second polling operation mode of the power module in an embodiment of the present invention.

[0035] Figure 6 This is a schematic diagram of the DC-DC module connecting multiple battery modules and a battery management system according to an embodiment of the present invention. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0037] Studies have shown that the rate of thermal runaway in lithium batteries varies significantly under different SOCs (State of Charge). Higher SOCs result in lower thermal runaway trigger temperatures, faster temperature rise rates, and higher risks. Furthermore, discharging at an appropriate rate can reduce the thermochemical heat generated by the negative electrode interface reaction, thereby lowering the battery temperature and suppressing thermal runaway. Based on this understanding, this application proposes a technology for actively suppressing thermal runaway. This involves actively reducing the battery's SOC to decrease the risk of thermal runaway without accelerating it due to energy consumption. The main idea is that when an intelligent battery management system predicts a risk of thermal runaway in a single cell or battery module, it intelligently calculates and processes available state parameters such as SOC, SOH, temperature, and voltage to determine the optimal energy transfer scheme. This allows the battery system to actively transfer energy from the at-risk cell or battery module, minimizing the energy of the at-risk cell or module.

[0038] See Figure 1 As shown in the exemplary embodiment of this application, the method for controlling thermal runaway of the battery system is implemented using the following steps:

[0039] S1. Real-time acquisition of battery information;

[0040] S2. Based on the collected battery information, if it is determined that the battery has a risk of thermal runaway, according to the preset energy transfer strategy, based on the current SOC information of the battery and the current available discharge rate of the battery, the preset energy transfer mode is intelligently matched and activated to transfer electrical energy until the battery SOC drops to the target SOC.

[0041] In one embodiment, the collected battery information includes one of the following: voltage, temperature, temperature rise rate, and internal resistance of the battery cell. It may also include other information of the battery system, such as single or multiple information such as pressure, gas type, and gas concentration in the battery system. Only the collected information can be used to judge or identify battery thermal runaway. Based on the big data model in the intelligent management system, by collecting preset information, the battery cells, battery modules, or battery systems at risk of thermal runaway can be predicted and locked in advance.

[0042] In a preferred embodiment, this application selects an intelligent battery management system to identify or predict in advance, based on the built-in big data model and real-time battery status information, whether there are cells or modules in the battery system with thermal runaway risk, so as to control the risk from the initial state and minimize the risk. Preferably, according to the three stages of battery thermal runaway: T1 stage (self-heating initiation stage), T2 stage (thermal runaway trigger temperature), and T3 stage (thermal runaway maximum temperature), this application prioritizes the prediction and locking of risky cells or modules based on the state information of the battery's self-heating stage. Therefore, this invention prioritizes the identification of whether the cell is in the T1 initiation stage. The T1 initiation stage can be determined based on a large number of cell simulation models and measured big data.

[0043] In the T1 stage (the initial stage of self-generated heat) of battery thermal runaway, the battery's SEI film begins to decompose, metal ions dissolve, and the battery begins to generate abnormal heat. The chemical reactions inside the battery gradually intensify, generating a large amount of heat that cannot be dissipated, causing the temperature to rise rapidly. At this time, the intelligent management system can identify the abnormal temperature rise rate of the battery, that is, judge or predict that the battery is at risk of thermal runaway. Since the active energy release action is initiated during the battery's self-generated heat T1 stage, the high energy of the battery predicted to be at risk of thermal runaway is transferred to other safe batteries. After the energy transfer, the normal batteries will not be at risk of overcharging or overheating due to energy absorption.

[0044] Because a higher state of charge (SOC) of a battery results in a greater chemical energy reserve, the severity and hazard of thermal runaway are also higher. The technology in this application, by actively reducing the SOC of the battery, such as from 100% to 50% or even lower, can significantly "passivate" the battery, greatly reducing the intensity of the reaction even if an internal short circuit occurs. Other methods for predicting battery thermal runaway may exist, and the specific methods used to determine battery thermal runaway in the embodiments of this invention are not limited.

[0045] In one embodiment, considering the battery's rechargeable rate and usable discharge rate, a State of Charge (SOC) threshold, such as 70% of the SOC, is set as the basis for executing a preset energy transfer strategy. When the battery's current SOC is greater than the preset SOC threshold, energy transfer is performed using either the first or third energy transfer method; otherwise, energy transfer is performed using either the second or third energy transfer method. That is, when the SOC is greater than or equal to 70%, the first or third energy transfer method is used; when the SOC is less than 70%, the second or third energy transfer method is used. Other combinations of energy transfer methods may also be used, and this is not limited to these. In some embodiments, when the third energy transfer method is available, it is preferentially selected. The energy transfer method of this application can be the discharge of a risky battery to a high-precision, high-power module, or the transfer of energy from a risky battery to other safe batteries via a bidirectional DC-DC converter; it can also be used to power other available electrical equipment in the system or vehicle.

[0046] In this application, the determination of whether the third energy transfer method is available, that is, the determination of whether the electrical equipment is available, can be made by determining whether the current required by the electrical equipment is within the range of the battery's available discharge rate. If it is, the third energy transfer method is preferred; otherwise, the first energy transfer method or the second energy transfer method is used.

[0047] The technology in this application embodiment can determine potential thermal runaway risks by monitoring single or multiple pieces of information such as voltage, temperature, temperature rise rate, and internal resistance of each individual battery cell, or by monitoring single or multiple pieces of information such as pressure, gas type, and gas concentration in the battery system. The intelligent management system, based on information such as SOC (State of Charge), controls the switch to match the corresponding energy transfer method. Simultaneously, it determines the discharge rate range according to the available discharge rate model. For example, if the first energy transfer method is used, the intelligent management system needs to control the switch to match an appropriate number of high-precision, high-power modules. Simultaneously, the power module controller enables the high-precision, high-power modules to work in rotation, preventing excessive current and prolonged operation from causing the high-precision, high-power modules to overheat. If the second energy transfer method is used, the discharge current needs to be adjusted via bidirectional DC-DC converters to transfer energy from the risky battery to the safe battery. If the third energy transfer method is used, the intelligent management system needs to determine whether the current required by the electrical equipment is within the available discharge rate range. If it is, the third energy transfer method can be used; if it is not, the first or second energy transfer method needs to be switched to prevent exacerbating the thermal runaway risk.

[0048] In one embodiment, the high-precision, high-power module includes multiple power modules and a power module controller. The power module controller includes a control chip and multiple control switches. The multiple power modules are connected in series, and each power module is connected to a control switch of the power module controller at both ends. The power module controller, based on the available rate model in the intelligent battery management system, responds to discharge demand and intelligently matches different high-precision, high-power modules based on the battery's available discharge rate. By controlling the switching action of the control switches, the power modules connected to the control switches are in a preset state, including working or not working, thereby enabling different numbers of power modules to start and work in rotation.

[0049] In one embodiment, when the high-precision, high-power module is operating, before performing discharge, the following steps are performed using the available rate model:

[0050] Based on the current SOC, target SOC, and available discharge rate of the risk battery, determine the discharge time required for the risk battery to discharge to the target SOC;

[0051] The number of power modules required for discharge is determined based on the resistance value of each power module and the resistance value required for the discharge of the risky battery.

[0052] Based on the relationship between discharge current, power module resistance, temperature rise, and discharge time, and according to the preset temperature rise threshold of the power module, the single-operation discharge time of each power module is determined.

[0053] The number of discharge cycles is determined based on the single-operation discharge time of each power module, the discharge time required to discharge to the target SOC, and the number of power modules required for discharge.

[0054] Based on the number of discharges, the number of power modules required for a single operation, and the discharge time for a single operation, the discharge time required to discharge to the target SOC is matched in stages to the power modules that perform the discharge, and the power modules are dynamically controlled to perform the discharge operation.

[0055] Furthermore, within the discharge time required for the risk battery to discharge to the target SOC, if the discharge time of the power module that performed the discharge in the previous period ends and the number of discharges has not been reached, the same number of power modules will be activated in the next period to continue discharging. At least one power module that performed the discharge in the previous period will enter a cooling period, and so on, until the number of discharges is reached and then stops. The power discharge modules activated in the next period include at least one power module that performed the discharge in the previous period, or other power modules besides the power modules that performed the discharge in the previous period, until the number of discharges is reached and then stops.

[0056] For details, see Figure 2 As shown, Figure 2The diagram illustrates a structure where four modules and a power module are connected via five switches K13-K17 to form a discharge recovery circuit. Taking the risk of thermal runaway in the battery module as an example, during the execution of the first energy transfer mode, if there is a risk of thermal runaway in the cells of module M1, switches K16 and K17 are closed, and module M1 discharges to the high-precision, high-power module. The discharge rate is determined by the discharge rate model written into the intelligent management system. Since different cells have different discharge rates at different SOCs, according to Ohm's law I=V / R, the resistance of the power module and the discharge current are inversely proportional. That is, if the discharge current is large, the resistance of the power module needs to be smaller. Therefore, it is necessary to dynamically adjust the resistance of the power module.

[0057] Additionally, the discharge time t = (SOC - SOC1) / C at the target SOC state can be calculated as a time parameter for controlling discharge. Here, SOC is the current remaining battery capacity, SOC1 is the target remaining battery capacity after discharge, and C is the available discharge rate of the battery. This can be determined and calculated by the intelligent battery management system based on the battery state, such as SOH state, battery type, and other state parameters.

[0058] As shown in Figure 3, the high-precision, high-power module in this application is arranged with N power modules W1-WN to discharge module MX. The power module resistance is adjusted by a power module controller (correspondingly configured with N switches S1-S2N). Taking active suppression of battery module thermal runaway as an example, when it is determined that battery module MX (risk module) has a risk of thermal runaway, the intelligent management system and the power module controller interact through unrestricted communication methods such as daisy chain or CAN communication to determine the number of power modules to be used, i.e., the number of power modules to perform discharge.

[0059] See Figure 3 as well as Figure 4 As shown in the embodiment, assuming the resistance of a single power module W1-WN is Rp, and the required resistance of the power module to achieve the discharge rate of the risky cell module is R=2Rp, then the power module control closes switches S1-S4, causing power modules W1 and W2 to act as loads in the discharge circuit of the thermal runaway risky cell module, absorbing energy and performing the discharge operation. The discharge energy of a single power module... ,in, For the specific heat capacity of the power module, For the quality of the power module, This is the discharge current. This refers to the resistance value of the power module. For the overcurrent time of the power module, This is due to the temperature rise of the power module; therefore, in , , and When constant, and The temperature rise is directly proportional to the temperature. To avoid overheating and damaging the power module or affecting other components, the temperature rise needs to be controlled when the power module is discharging. Within a certain range, it is necessary to control the overcurrent time of a single power module during operation. During the discharge operation, the total discharge time t is divided into m*n equal parts, where m is the number of repeated discharges, n = N / d, N is the number of power modules, and d is the power output of each single discharge, such that t / m*n ≤ Within a time period of (0, t / m*n), when switches S1 and S4 are closed, power modules W1 and W2 experience a large current flow, causing their temperatures to rise. Within a time period of (t / m*n, 2t / m*n), when switches S5 and S8 are closed, power modules W3 and W4 are connected in series into the discharge circuit. Simultaneously, switches S1 and S4 are opened, and no current flows through power modules W1 and W2. At this time, power modules W3 and W4 experience a large current flow, causing their temperatures to rise, while power modules W1 and W2 enter the cooling period. Following the above logic sequentially, until within the time interval [(n-1)t / (m*n), t / m], power modules W(N-1) and WN are closed, and power modules W(N-1) and WN are connected in series into the discharge circuit. At this time, power modules W(N-1) and WN experience a large current and their temperature rises. Simultaneously, S(2N-7) and S(2N-4) are opened, and power modules W(N-3) and W(N-2) no longer have current flowing through them, entering the cooling period. This process is repeated, with power modules W1 to WN alternately experiencing a large current and their temperature rising, and then alternately stopping the current flow and their temperature decreasing, thus controlling the temperature rise of the power modules. This process is repeated m times until the discharge time t requirement is met, at which point the SOC of the thermal runaway cell module reaches the target SOC1.

[0060] In some embodiments, see Figure 3 as well as Figure 5As shown, when using power modules for energy transfer, the following second implementation scheme can also be used for polling operation: During the time interval (0, t / (m*n)], switches S1 and S4 are closed, and modules W1 and W2 experience a large current and their temperatures rise. During the time interval (t / (m*n), 2t / (m*n)], switches S2 and S7 are closed, and modules W2 and W3 are connected in series into the discharge circuit. At this time, modules W2 and W3 experience a large current and their temperatures rise. Simultaneously, switches S1 and S4 are opened, and no current flows through W1, which enters the cooling period. During the time interval (2t / (m*n), 3t / (m*n)], switches S5 and S8 are closed, and modules W3 and W4 are connected in series into the discharge circuit. At this time, modules W3 and W4 experience a large current and their temperatures rise; simultaneously, switches S2 and S7 are opened, and no current flows through module W2. Module W2 enters the cooling period. The above process is continued sequentially until, within the time interval [(n-1)t / (m*n), t / m], W(N-1) / 2 and WN / 2 are closed, and modules W(N-1) / 2 and WN / 2 are connected in series into the discharge circuit. At this time, modules W(N-1) / 2 and WN / 2 experience a large current and their temperature rises. Simultaneously, S(2N-6) and S(2N-1) are opened, and no current flows through module W(N-2) / 2, which enters the cooling period. This process is repeated, with modules W1 to WN / 2 alternately experiencing a large current and their temperature rising, and then alternately stopping the current flow and their temperature decreasing, thus controlling the temperature rise of the power module. This process is repeated m times until the required discharge time t is met, at which point the SOC of the thermal runaway cell module reaches the target SOC1.

[0061] When using power modules for energy transfer, compared to the first polling operation scheme, the second polling operation scheme has a longer time for each power module to operate under the same current. This is mainly due to the current magnitude, the overcurrent temperature rise rate, and the cooling rate of the power module. These parameters are written into a big data model. Figures 4 and 5 of this application show the operating modes of the power modules in the first and second polling operation schemes, respectively. Under the same conditions, the number of power modules in the second scheme can be reduced to half that of the first scheme.

[0062] The operation of the power modules described above is achieved through a power module controller, which includes a control chip and high-power switches (S1 to S2N). The control chip interacts with the intelligent management system to confirm the number of power modules connected in series at the same time. The high-power switches (S1 to S2N) are used to control the on / off state of the circuit, meeting the requirements of high-current, high-frequency closing and opening. Similarly, depending on the discharge current, one or more power modules can be connected in series simultaneously to achieve compatibility with battery systems of different cell types.

[0063] The control process of the power module is achieved through the power module controller, which includes a control chip and a high-power, high-frequency switch, and can meet the requirements of high-current, high-frequency closing and opening.

[0064] In this embodiment, the BMS intelligent management system matches different numbers of power modules according to the discharge current of different battery cells, avoiding accelerated thermal runaway risks due to uncontrollable current. Multiple power modules operate in a rotating manner, reducing temperature rise and preventing other hazards. Simultaneously, the same power module group can be matched with different battery systems, modules, or cells, achieving universality and standardization.

[0065] In one embodiment, using the second energy transfer method, in a main battery system, the bidirectional DC-DC module is connected to multiple battery modules via a control circuit. The control circuit has a switch that controls the transfer of energy from the at-risk battery module to other safe battery modules. Alternatively, an auxiliary battery system can be set up, and the bidirectional DC-DC module connected to the main battery system is electrically connected via a control switch to control the transfer of energy from the main battery system to the auxiliary battery system. Specifically, when using a bidirectional DC-DC module, if the battery is at risk of thermal runaway, the bidirectional DC-DC module needs to adjust the discharge current to transfer energy to safe batteries, such as safe cells, modules, or other battery systems. Figure 6 The safety battery module shown. Figure 6 In the example, there are four battery modules in the battery system. The following explains how to transfer energy by adjusting the current through DC-DC converter when different battery modules are at risk of thermal runaway.

[0066] When module M1 is at risk of thermal runaway, the intelligent management system and DC-DC converter interact via CAN communication or other unrestricted communication methods to determine the closure of K7 and K8. Module M1 serves as the input of DC-DC converter, while K11 and K12 are closed simultaneously. Modules M3 and M4 serve as the output of DC-DC converter. The discharge current of module M1 is adjusted by DC-DC converter to transfer energy to modules M3 and M4.

[0067] When module M2 is at risk of thermal runaway, the intelligent management system and DC-DC converter interact via CAN communication or other unrestricted communication methods to determine the closure of K5 and K6. Module M2 serves as the input of DC-DC converter, while K11 and K12 are closed simultaneously. Modules M3 and M4 serve as the output of DC-DC converter. The discharge current of M2 is adjusted by DC-DC converter to transfer energy to modules M3 and M4.

[0068] When module M3 is at risk of thermal runaway, the intelligent management system and DC-DC converter interact via CAN communication or other unrestricted communication methods to determine the closure of K3 and K4. Module M3 serves as the input of DC-DC converter, while K9 and K10 are closed simultaneously. Modules M1 and M2 serve as the output of DC-DC converter. The discharge current of module M3 is adjusted by DC-DC converter to transfer energy to modules M1 and M2.

[0069] When module M4 is at risk of thermal runaway, the intelligent management system and DC-DC converter interact via CAN communication or other unrestricted communication methods to determine the closing of K1 and K2. Module M4 serves as the input of DC-DC converter, while K9 and K10 are closed simultaneously. Modules M1 and M2 serve as the output of DC-DC converter. The discharge current of module M3 is adjusted by DC-DC converter to transfer energy to modules M1 and M2.

[0070] The above ensures that if any module in the battery system is at risk of thermal runaway, energy can be transferred to other modules via the DC-DC converter. Furthermore, because the charge from one module can be evenly distributed between the two modules, the energy levels of these two modules will not exceed safe limits. Switches K1 to K12 can be relatively small MOSFETs integrated into the DC-DC converter to meet the space requirements of the battery system.

[0071] In this scenario, if more than one single-cell module in battery system A is at risk of thermal runaway, the intelligent management system and the DC-DC converter interact via CAN communication or other unrestricted communication methods to determine the closing of switches K1 and K8. Battery system A serves as the input to the DC-DC converter, while simultaneously closing switches K18 and K19. The DC-DC converter then regulates the discharge current of battery system A, transferring energy to battery system B. Under normal conditions, battery system B can also function as a range extender battery pack, increasing the vehicle's overall capacity to achieve increased range.

[0072] In this embodiment, the third energy transfer method is activated by the intelligent management system when it identifies whether there are available electrical devices in the battery system or the vehicle. These electrical devices may include liquid cooling devices, OBC modules, DC-DC modules, motors, and other electrical equipment. The activation of this third energy transfer method is determined by whether the available current of the electrical device meets the energy transfer requirements of the cell module at risk of thermal runaway. If it does, this method can be used; otherwise, it is not recommended. Using this method may not achieve the goal of reducing the maximum temperature of thermal runaway and suppressing thermal runaway.

[0073] The technology in this application employs multiple energy transfer methods and adaptive adjustment control to avoid exacerbating thermal runaway due to energy transfer or to prevent damage to the energy transfer module due to energy accumulation, thereby improving the reliability of energy transfer.

[0074] In this application embodiment, the battery can be any of a single cell, a battery module, or a battery system. The technology of this application can be used for the independent active suppression and control of thermal runaway in a single cell, a battery module, or a battery system.

[0075] This application embodiment also provides a battery system thermal runaway suppression system, used to implement the battery thermal runaway suppression method, implemented through an intelligent battery management system. The intelligent battery management system has an available rate model, including an information acquisition unit for real-time acquisition of battery information; and an energy conversion decision execution unit for, based on the acquired battery information, determining that the battery has a risk of thermal runaway, and intelligently matching and initiating a preset energy transfer mode according to a preset energy transfer strategy, based on the battery's current SOC information and the battery's current available discharge rate, to transfer electrical energy until the battery SOC drops to the target SOC.

[0076] For specific techniques for suppressing thermal runaway in battery systems, please refer to the aforementioned methods for suppressing thermal runaway in batteries.

[0077] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention.

[0078] Therefore, the embodiments should be regarded as exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of the equivalents of the claims be included within the invention.

[0079] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for suppressing battery thermal runaway, characterized in that, Includes the following steps: Real-time collection of battery information; Based on the collected battery information, when it is determined that the battery is at risk of thermal runaway, a preset energy transfer strategy is implemented. Based on the battery's current SOC information and the battery's current available discharge rate, the preset energy transfer method is intelligently matched and activated to transfer electrical energy until the battery's SOC drops to the target SOC.

2. The method for suppressing battery thermal runaway according to claim 1, characterized in that, When the current SOC of the battery is greater than the preset SOC threshold, energy transfer is performed using either the first or third energy transfer method; otherwise, energy transfer is performed using either the second or third energy transfer method. The first energy transfer method is to use a high-precision power module for energy transfer; the second energy transfer method is to use a bidirectional DC-DC module to transfer electrical energy to a safe energy storage device; and the third energy transfer method is to transfer electrical energy to the vehicle's electrical equipment. Preferably, the SOC threshold is SOC 70%.

3. The method for suppressing battery thermal runaway according to claim 2, characterized in that, in, When the electrical equipment is available, the third energy transfer method is used; otherwise, the first or second energy transfer method is used. The electrical equipment includes at least one of a liquid cooling device, an OBC module, a DC-DC module, and a motor. The availability of the electrical equipment refers to whether the available current of the electrical equipment meets the energy transfer requirements of the battery at risk of thermal runaway. It is determined whether the current required by the electrical equipment is within the range of the available discharge rate. If it is, the third energy transfer method is used; otherwise, the first or second energy transfer method is used.

4. The method for suppressing battery thermal runaway according to claim 2, characterized in that, The safe energy storage device is one of a safe battery cell, a safe battery module, or a safe battery system.

5. The method for suppressing battery thermal runaway according to claim 2, characterized in that, The high-precision, high-power module includes multiple power modules and a power module controller. The power module controller includes a control chip and multiple control switches. The multiple power modules are connected in series, and each power module is connected to a control switch of the power module controller at both ends. The power module controller, based on the available rate model in the intelligent battery management system, responds to discharge demand and intelligently matches different high-precision, high-power modules based on the battery's available discharge rate. By controlling the switching action of the control switches, the power modules connected to the control switches are in a preset state, including working or not working, thereby enabling different numbers of power modules to start and work in rotation.

6. The method for suppressing battery thermal runaway according to claim 5, characterized in that, When the high-precision, high-power module is working, before discharging, the following steps are performed using the available rate model: Based on the current SOC, target SOC, and available discharge rate of the risk battery, determine the discharge time required for the risk battery to discharge to the target SOC; The number of power modules required for discharge is determined based on the resistance value of each power module and the resistance value required for the discharge of the risky battery. Based on the relationship between discharge current, power module resistance, temperature rise, and discharge time, and according to the preset temperature rise threshold of the power module, the single-operation discharge time of each power module is determined. The number of discharge cycles is determined based on the single-operation discharge time of each power module, the discharge time required to discharge to the target SOC, and the number of power modules required for discharge. Based on the number of discharges, the number of power modules required for a single operation, and the discharge time for a single operation, the discharge time required to discharge to the target SOC is matched in stages to the power modules that perform the discharge, and the power modules are dynamically controlled to perform the discharge operation.

7. The method for suppressing battery thermal runaway according to claim 6, characterized in that, If, within the discharge time required for the risk battery to discharge to the target SOC, the discharge time of the power module that performed the discharge in the previous period ends and the number of discharges has not been reached, the same number of power modules will be activated in the next period to continue discharging. At least one power module that performed the discharge in the previous period will enter a cooling period, and so on, until the number of discharges is reached and then stops. The power discharge modules activated in the next period include at least one power module that performed the discharge in the previous period, or other power modules besides the power modules that performed the discharge in the previous period, until the number of discharges is reached and then stops.

8. The method for suppressing battery thermal runaway according to claim 2, characterized in that, In the second energy transfer method, in a main battery system, the bidirectional DC-DC module is connected to multiple battery modules through a control circuit. The control circuit is equipped with a switch, which controls the transfer of electrical energy from the risky battery module to other safe battery modules. Alternatively, an auxiliary battery system can be set up, and the bidirectional DC-DC module connected to the main battery system is electrically connected through a control switch to control the transfer of electrical energy from the main battery system to the auxiliary battery system.

9. The method for suppressing battery thermal runaway according to claim 1, characterized in that, The collected battery information includes one of the following: voltage, temperature, temperature rise rate, and internal resistance of the battery cell, and / or at least one of the following: pressure, gas type, and gas concentration information in the battery system.

10. A battery system thermal runaway suppression system, characterized in that, The method for suppressing battery thermal runaway as described in any one of claims 1-9 is implemented through an intelligent battery management system, comprising: The information acquisition unit is used to collect battery information in real time; The energy conversion decision execution unit is used to determine the risk of thermal runaway of the battery based on the collected battery information. Then, according to the preset energy transfer strategy, the battery's current SOC information and the battery's current available discharge rate, the preset energy transfer mode is intelligently matched and activated to transfer electrical energy until the battery SOC drops to the target SOC.

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