Battery protection method and related device

Abstract

The embodiment of the present application discloses a battery protection method and related devices, the method comprising: determining the internal temperature of the battery and the surface temperature of the battery; if the difference between the internal temperature and the surface temperature is greater than a preset threshold, then determining the actual charging current, the actual discharging current and the current protection threshold; if the battery is determined to be in the first state according to the actual charging current, the actual discharging current and the current protection threshold, then performing current protection. In this way, it can be achieved that the current protection of the battery is realized by estimating the internal temperature of the battery and comparing and judging the current protection threshold corresponding to the internal / external temperature and the actual charging and discharging current, thereby improving the temperature application range of the battery and extending the battery life.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery protection method and related devices. Background Art

[0002] In the field of electric vehicles, the temperature sensor of the battery module is usually set on its surface, but the heat generated by the battery during use comes from the inside of the battery, which will cause the highest temperature point of the battery to be inside. In practical applications, the common battery protection method during battery charging and discharging is: based on the surface temperature data collected by the temperature sensor, judge whether the current battery temperature exceeds the threshold, and then execute the corresponding protection strategy for the battery based on the judgment result. However, in this way, the surface temperature of the battery has not reached the protection threshold, but its internal temperature is already seriously too high. If the battery continues to be charged or discharged, it will cause irreversible damage to the battery, and even cause thermal runaway of the battery.

[0003] Therefore, a battery protection method is urgently needed to solve the above problems. Summary of the invention

[0004] The embodiments of the present application provide a battery protection method and related devices, which can effectively improve the temperature application range of the battery and extend the battery life. At the same time, the retained surface temperature protection judgment can further ensure the battery safety.

[0005] In a first aspect, an embodiment of the present application provides a battery protection method, the method comprising:

[0006] determining an internal temperature of the battery and a surface temperature of the battery;

[0007] If the difference between the internal temperature and the surface temperature is greater than a preset threshold, determining an actual charging current, an actual discharging current, and a current protection threshold of the battery;

[0008] If it is determined that the battery is in the first state according to the actual charging current, the actual discharging current and the current protection threshold, current protection is performed on the battery.

[0009] In a second aspect, an embodiment of the present application provides a battery protection device, the device comprising: a calculation unit, an acquisition unit and an execution unit, wherein:

[0010] The calculation unit is used to determine the internal temperature of the battery and the surface temperature of the battery;

[0011] The acquisition unit is configured to determine an actual charging current, an actual discharging current, and a current protection threshold of the battery if a difference between the internal temperature and the surface temperature is greater than a preset threshold;

[0012] The execution unit is configured to execute current protection on the battery if it is determined that the battery is in a first state according to the actual charging current, the actual discharging current and the current protection threshold.

[0013] In a third aspect, an embodiment of the present application provides an electronic device, comprising a processor, a memory, a communication interface, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the processor, and the program includes instructions for executing the steps of any method in the first aspect of the embodiment of the present application.

[0014] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program for electronic data exchange, wherein the computer program enables a computer to execute part or all of the steps described in any method of the first aspect of the embodiment of the present application.

[0015] In a fifth aspect, an embodiment of the present application provides a computer program product comprising instructions, characterized in that when the computer program product is run on an electronic device, the electronic device executes some or all of the steps described in any method of the first aspect of the embodiment of the present application. The computer program product may be a software installation package.

[0016] In a sixth aspect, an embodiment of the present application provides a battery, comprising a battery module and a battery management system, wherein the battery management system is used to execute part or all of the steps described in any method of the first aspect of the embodiment of the present application.

[0017] It can be seen that a battery protection method and related device are disclosed in the embodiment of the present application, by determining the internal temperature of the battery and the surface temperature of the battery; if the difference between the internal temperature and the surface temperature is greater than the preset threshold, the actual charging current, the actual discharging current and the current protection threshold are determined; if the battery is determined to be in the first state according to the actual charging current, the actual discharging current and the current protection threshold, the current protection is performed. The method calculates the internal temperature of the battery, combines the internal temperature and the surface temperature of the battery to determine whether it is necessary to obtain current data and current protection thresholds, and makes current protection judgments based on the current data and the current protection thresholds, so that thermal runaway events of the battery can be discovered early. Furthermore, making current protection judgments based on the estimated internal temperature of the battery can effectively improve the temperature application range of the battery and extend the battery life, while retaining the current protection judgment based on the surface temperature can ensure the efficiency of the battery current protection, thereby improving the battery safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 It is a schematic diagram of an internal module of a battery protection provided by an embodiment of the present application;

[0020] Figure 2 It is a flowchart of a battery protection method provided in an embodiment of the present application;

[0021] Figure 3 It is a schematic diagram of a calculation process provided by an embodiment of the present application;

[0022] Figure 4 It is a schematic diagram of the overall process of a battery protection method provided in an embodiment of the present application;

[0023] Figure 5 It is a structural schematic diagram of an electronic device provided in an embodiment of the present application;

[0024] Figure 6 It is a schematic diagram of the functional unit structure of a battery protection device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0026] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0027] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0028] In order to better understand the solutions of the embodiments of the present application, the electronic devices, related terms, concepts and related backgrounds that may be involved in the embodiments of the present application are first introduced below.

[0029] The electronic device may be a portable electronic device that also includes other functions such as a personal digital assistant and / or a music player function, such as a mobile phone, a tablet computer, a wearable electronic device with a wireless communication function (such as a smart watch), etc. Exemplary embodiments of portable electronic devices include but are not limited to portable electronic devices equipped with an IOS system, an Android system, a Microsoft system, or other operating systems. The above-mentioned portable electronic device may also be other portable electronic devices, such as a laptop computer (Laptop), etc. It should also be understood that in some other embodiments, the above-mentioned electronic device may also be an electronic device used for battery protection in the present application scheme.

[0030] It should be noted that the use scenario of the battery protection method proposed in this application is the vehicle-mounted electronic controller unit (Electronic Control Unit, ECU). Based on the characteristics of vehicle-mounted ECU products, the solution with simple calculation, relatively small resource consumption and the ability to calculate relatively accurate results is the optimal solution.

[0031] Specifically, see Figure 1 , Figure 1 Schematic diagram of the internal modules of a battery module provided in an embodiment of the present application. Figure 1 As shown, the battery module includes: a thermal runaway calculation unit and a current protection unit, wherein the thermal runaway calculation unit includes an OCV voltage calculation module and an internal temperature calculation module.

[0032] For example, the current charge and discharge SOC of the battery is calculated by the OCV voltage calculation module, and the current open circuit voltage E(OCV) of the battery is calculated according to the SOC. At the same time, the internal heat capacity Cm and the internal thermal resistance Rm are calculated according to the ambient temperature fitting.

[0033] Furthermore, the internal temperature calculation module simultaneously calculates the current internal temperature of the battery according to the SOC, E(OCV), the surface temperature of the battery and the corresponding single cell voltage.

[0034] Further, the thermal runaway calculation unit determines whether to be activated according to the internal temperature and the surface temperature.

[0035] Furthermore, if it is determined to activate the thermal runaway calculation unit, the actual charging current, actual discharging current and current protection threshold of the battery are obtained, and the current protection unit determines whether to perform current protection based on the actual charging current, actual discharging current and current protection threshold.

[0036] It can be seen that the present application scheme is based on the above-mentioned functional modules, by determining the internal temperature of the battery and the surface temperature of the battery; if the difference between the internal temperature and the surface temperature is greater than the preset threshold, the actual charging current, the actual discharging current and the current protection threshold are determined; if the battery is determined to be in the first state according to the actual charging current, the actual discharging current and the current protection threshold, the current protection is performed. This method calculates the internal temperature of the battery, combines the internal temperature and the surface temperature of the battery to determine whether it is necessary to obtain current data and current protection thresholds, and makes current protection judgments based on the current data and the current protection thresholds, so that thermal runaway events of the battery can be discovered early. Furthermore, making current protection judgments based on the estimated internal temperature of the battery can effectively improve the applicable temperature range of the battery and extend the battery life, while retaining the current protection judgment based on the surface temperature can ensure the efficiency of the battery current protection, thereby improving the battery safety.

[0037] In order to better understand the above process, the present application is described in detail below in conjunction with specific embodiments.

[0038] See also Figure 2 , Figure 2 The present application provides a flowchart of a battery protection method. Figure 2 As shown, the battery protection method specifically includes the following steps:

[0039] S201: Determine the internal temperature of the battery and the surface temperature of the battery.

[0040] Specifically, the battery Figure 1 The thermal runaway calculation unit calculates the internal temperature of the battery based on the operating data of the battery, wherein the battery is a battery module, the battery module includes multiple battery cells, and the operating data of the battery includes but is not limited to: the surface temperature Ts of the battery module, the internal ambient temperature Ta, the battery cell voltage V, and the current I.

[0041] Specifically, in the solution of the present application, a plurality of NTC temperature sensors are arranged on a plurality of battery cells in a battery pack, and the surface temperature Ts of the battery is obtained through the NTC temperature sensors.

[0042] Exemplarily, the internal temperature Tc of the battery is calculated by establishing a target equation based on the above-obtained operating data and relevant parameters such as the lithium battery simulation heat generation formula and the battery open circuit voltage, and using the state data as input data of the target equation.

[0043] S202: If the difference between the internal temperature and the surface temperature is greater than a preset threshold, determine an actual charging current, an actual discharging current, and a current protection threshold of the battery.

[0044] For example, the difference between the internal temperature and the surface temperature is calculated. When the difference between the calculated Tc and the Ts measured by the NTC temperature sensor is greater than a preset threshold value Tg (where Tg is a threshold value determined according to the worst case), it is necessary to activate the following Figure 1 The thermal runaway calculation unit.

[0045] Furthermore, a current protection threshold is obtained through a thermal runaway calculation unit, wherein the current protection threshold includes a first current protection threshold corresponding to the internal temperature and a second current protection threshold corresponding to the surface temperature. The battery includes a charging state and a discharging state during use, because the current protection threshold also corresponds to a charging protection threshold and a discharging threshold, respectively.

[0046] S203: If it is determined that the battery is in a first state according to the actual charging current, the actual discharging current and the current protection threshold, perform current protection on the battery.

[0047] Exemplarily, when the thermal runaway calculation unit is activated, by combining the actual charging current, the actual discharging current, the first current protection threshold corresponding to the internal temperature, and the second current protection threshold corresponding to the surface temperature, it is determined that the battery is in the first state, and current protection is performed on the battery. The first state is used to indicate that the current battery module may be in a thermal runaway state, and current protection needs to be performed to ensure the safety and normal use of the battery module.

[0048] Exemplarily, the current protection of the battery is a measure to ensure the safety and stability of the battery during use, with the aim of preventing the battery from overheating, short circuiting, catching fire or even exploding due to excessive current during charging or discharging. Current protection is mainly achieved through the battery management system (BMS). The current protection function of the battery management system includes the following aspects: Overcurrent protection: The BMS monitors the charging and discharging current of the battery. If the current exceeds the set safety threshold (usually formulated according to the battery type and specification), the BMS will protect the battery by cutting off the connection between the battery and the external circuit or limiting the current; Short circuit protection: When a battery short circuits, the current will increase rapidly to a very high level, which can cause the battery to overheat or even catch fire. The BMS can quickly detect this situation and immediately cut off the connection between the battery and the external circuit to avoid danger; Overcharge protection: Overcharging can cause serious damage to the battery. The BMS monitors the charging current and voltage of the battery, and once the charging upper limit is reached, the BMS will stop charging; Overdischarge protection: Excessive discharge can also damage the battery. BMS monitors the discharge current and voltage of the battery. Once the lower limit of discharge is reached, BMS stops discharging. Temperature monitoring: The battery may generate heat during the charging and discharging process. BMS monitors the battery temperature. If the temperature exceeds the safety threshold, BMS will take measures, such as reducing the current or cutting off the power supply, to prevent the battery from overheating.

[0049] Through the above measures, the safety and stability of the battery can be effectively protected, the battery life can be extended, and the battery can be ensured to work normally in various environments.

[0050] It can be seen that the battery protection method described in the embodiment of the present application determines the internal temperature of the battery and the surface temperature of the battery; if the difference between the internal temperature and the surface temperature is greater than the preset threshold, the actual charging current, the actual discharging current and the current protection threshold are determined; if the battery is determined to be in the first state based on the actual charging current, the actual discharging current and the current protection threshold, the current protection is performed. This method calculates the internal temperature of the battery, combines the internal temperature and the surface temperature of the battery to determine whether it is necessary to obtain current data and current protection thresholds, and makes current protection judgments based on the current data and the current protection thresholds, so that thermal runaway events of the battery can be discovered early. Furthermore, making current protection judgments based on the estimated internal temperature of the battery can effectively improve the applicable temperature range of the battery and extend the battery life, while retaining the current protection judgment based on the surface temperature can ensure the efficiency of the battery current protection, thereby improving the battery safety.

[0051] In one possible example, the current protection threshold includes a first current protection threshold corresponding to the internal temperature, the first current protection threshold includes a first charging current threshold and a first discharging current threshold, and the method of determining that the battery is in the first state also includes the following steps: if the actual charging current is greater than or equal to the first charging current threshold, and / or the actual discharging current is greater than or equal to the first discharging current threshold, then determine that the battery is in the first state.

[0052] Exemplarily, the battery module includes two states, charging and discharging, in actual application scenarios, so the first current protection threshold corresponding to the internal temperature includes a first charging current threshold in the charging state and a second discharging current threshold in the discharging state.

[0053] Specifically, the first current protection threshold and the second discharge current threshold are different. In actual application scenarios, the internal temperature of the battery module may have reached a higher temperature value, while the surface temperature of the battery module will delay this phenomenon. If it is judged only based on the surface temperature, the battery may be damaged due to the delay between the two. Therefore, the current operating status of the battery module is first judged based on the first current protection threshold corresponding to the internal temperature.

[0054] Specifically, if the actual charging current of the battery is greater than or equal to a first charging current threshold, and / or the actual discharging current is greater than or equal to a first discharging current threshold, it is determined that the battery is in the first state.

[0055] Furthermore, when it is determined that the battery module is in the first state, a current protection strategy needs to be executed to allow the system to enter a safe state.

[0056] It can be seen that in this example, the first discharge current threshold and the first charge current threshold corresponding to the calculated internal temperature are compared with the actual charge current and the actual discharge current of the battery to determine the current operating state of the battery. In this way, before the surface temperature triggers the activation of the thermal runaway calculation module in time, the thermal runaway event warning judgment is first performed based on the internal temperature and its corresponding current threshold, so that the state of the battery module can be determined more accurately and timely, and the battery safety can be guaranteed to the greatest extent based on multiple levels of current protection strategies.

[0057] In a possible example, the current protection threshold also includes a second current protection threshold corresponding to the surface temperature, the second current protection threshold includes a second charging current threshold and a second discharging current threshold, and the method also includes the following steps: if it is determined that the battery is not in the first state based on the internal temperature, and the first charging current threshold and the first discharging current threshold, then when the actual charging current is greater than or equal to the second charging current threshold, and / or the actual discharging current is greater than or equal to the second discharging current threshold, it is determined that the battery is in the first state.

[0058] Exemplarily, if it is determined that the battery is not in the first state according to the first charging current threshold and the first discharging current corresponding to the internal temperature, a judgment is made according to the actual charging current and the current threshold corresponding to the surface temperature.

[0059] Specifically, if the actual charging current is greater than or equal to the second charging current threshold, and / or the actual discharging current is greater than or equal to the second discharging current threshold, it is determined that the battery is in the first state.

[0060] It can be seen that in this example, when the internal temperature cannot determine that the battery module is in the first state, the battery module further judges the state of the battery module according to the second charging current threshold and the second discharging current threshold corresponding to the surface temperature. In this way, it is possible to retain the judgment method of the battery module state based on the second current threshold corresponding to the surface temperature. The dual judgment process can more accurately and timely warn the battery of thermal runaway events, thereby determining the state of the battery module more accurately and timely, and based on multiple levels of current protection strategies, ensuring battery safety to the greatest extent.

[0061] In a possible example, the internal temperature calculation satisfies the following formula:

[0062]

[0063] Wherein, the Tc is used to characterize the internal temperature, the Cm is used to characterize the internal heat capacity of the battery, the Rm is used to characterize the internal thermal resistance of the battery, the Ts is used to characterize the surface temperature, the E is used to characterize the open circuit voltage, the V is used to characterize the single cell voltage, the I is used to characterize the current, and the k and the k+1 correspond to two adjacent moments.

[0064] Exemplarily, the internal temperature calculation module calculates the internal temperature of the battery at the current moment according to the acquired internal heat capacity, internal thermal resistance, surface temperature, open circuit voltage, and single cell voltage, current and other state data.

[0065] Among them, when the internal temperature calculation module calculates the internal temperature at the current time K+1, it uses the internal temperature Tc(1) calculated at the previous time K (adjacent time) as the input of Tc(k=1) for the next iterative calculation at time K+1, and at the same time, the input parameters required for the calculation are updated to the data at time k=1, and Tc(k+1) at the current time k+1 is obtained in real time. In particular, the initial value Tc(0) of Tc is equal to Ts(0).

[0066] It can be seen that in this example, based on the proposed temperature calculation method, the internal temperature of the battery is estimated by the battery surface temperature, and the calculated internal temperature and the measured surface temperature are used as parameters for temperature protection judgment, so that the status of the battery module can be determined more accurately and timely, and the battery safety can be guaranteed to the greatest extent based on multiple levels of current protection strategies.

[0067] In one possible example, before determining the internal temperature of the battery, the method further includes the following steps: obtaining status data of the battery, wherein the status data includes the ambient temperature of the battery operation, the single cell voltage and current of the battery; and calculating the internal thermal capacity, the internal thermal resistance and the open circuit voltage based on the status data.

[0068] Specifically, see Figure 3 , Figure 3 This is a schematic diagram of a calculation process provided by an embodiment of the present application. Figure 3 As shown, by taking the ambient temperature Ta as input data, the internal heat capacity and internal thermal resistance of the battery are fitted and calculated.

[0069] For example, by Figure 1 The OCV voltage calculation module calculates the open circuit voltage E(OCV) of the battery by taking the single cell voltage and surface temperature of the battery as input data, wherein E=Fun(Soc).

[0070] Furthermore, the internal temperature of the battery is calculated based on the internal heat capacity, internal thermal resistance, surface temperature and open circuit voltage of the battery.

[0071] It can be seen that in the example of the present application, the open circuit voltage, internal heat capacity and internal thermal resistance of the battery are calculated respectively, and the calculated parameters are used as input parameters for finally calculating the internal temperature of the battery, so as to realize the estimated calculation of the internal temperature of the battery based on the relevant parameters during the operation of the battery.

[0072] In a possible example, the internal heat capacity, the internal thermal resistance and the open circuit voltage are calculated according to the status data, and the method also includes the following steps: calculating the internal heat capacity and the internal thermal resistance according to the ambient temperature, wherein the internal heat capacity is used to characterize the ability of the battery material to absorb and dissipate heat, and the internal thermal resistance is used to characterize the rate of heat conduction inside the battery; calculating the state of charge of the battery according to the surface temperature and the single cell voltage; and calculating the open circuit voltage of the battery according to the state of charge.

[0073] For example, in the present application, the internal heat generation formula of the battery is first simplified according to the Bernadi formula (Formula 1) and the chemical characteristics of the battery. The internal heat generation of the battery includes reaction heat, polarization heat and Joule heat. Polarization heat and Joule heat are the main components of the heat source, corresponding to I (EV). Among them, the reaction heat accounts for a relatively low proportion in the heat source, so it is negligible.

[0074]

[0075] Further, according to the above description, the Bemadi formula is finally simplified to Formula 2, where I is the current flowing through the battery, E is the open circuit voltage E (OCV), and V is the terminal voltage (Vcell) of the battery cell.

[0076] Q=I(EV) (Formula 2)

[0077] Furthermore, according to the energy conservation equation inside and outside the battery, Fourier's heat law and Newton's heat dissipation law, formula 3 is obtained:

[0078]

[0079] Furthermore, in order to reflect the dynamic characteristics of the lithium battery thermal model system, the internal temperature Tc of the system is taken as the system state variable, and the current I is taken as the system input. Formula 3 is described to obtain the state equation formula 4:

[0080]

[0081] Furthermore, a relatively simple single-cell battery thermal model is established based on the internal heat generation mechanism and heat transfer mechanism of the lithium battery. Cc represents the internal heat capacity of the battery, which is used to characterize the ability of the battery material to absorb and dissipate heat. Ri represents the internal thermal resistance, which is used to characterize the rate of heat conduction inside the battery. Considering that Ts is a measurable point in the actual usage scenario, the time t is defined here as a unit time 1, then Formula 4 can be further simplified to Formula 5:

[0082]

[0083] In a possible example, the method for calculating the open circuit voltage of the battery further includes the following steps: calculating the state of charge of the battery according to the surface temperature and the single cell voltage; and calculating the open circuit voltage of the battery according to the state of charge.

[0084] For example, the unknown parameters Cc and Ri in the above-mentioned state equation are identified according to the actual experimental process. Generally, the least square method is used to identify and fit the parameters Cc and Ri as a function related to the ambient temperature Ta according to the experimental data:

[0085] Ri=Func1(Ta) (Formula 6)

[0086] Cc=Func2(Ta) (Formula 7)

[0087] It should be noted that the simplified model represents the process of heat diffusion from the internal heat source Q of the battery to the surface of the battery. Since the surface temperature Ts can be measured in the usage scenario, the process of heat diffusion from the surface to the environment is not modeled here. When Ta is low, the composition range of the internal central thermal characteristic similarity area is small, which makes the internal structure heat capacity composed of the two poles and the central area smaller. As Ta increases, the composition range of the internal central thermal characteristic similarity area becomes larger.

[0088] According to the above calculation formula, all the parameters required to calculate the internal temperature of the single cell have been completed, but in actual use scenarios, the battery generally appears in the form of a module. Therefore, in this application, the internal thermal resistance Rm = Func1′ (Ta) and the internal heat capacity Cm = Func2′ (Ta) of the battery module are calculated by using the volume average method and the mass average method, and the parameters Rm and Cm are substituted into Formula 6. The final required Ri and Cc are obtained.

[0089] Specifically, the ECU of the battery module collects the current status data of the battery, including the surface temperature Tsn of the battery module, the internal ambient temperature Ta, the battery cell voltage Vn and the battery current I, etc.

[0090] Further, according to Figure 3 The OCV voltage calculation module in the schematic diagram shown calculates the current SOC of the battery and calculates the current open circuit voltage E(OCV) based on the SOC; at the same time, Cm and Rm are calculated by substituting the ambient temperature Ta into the fitting formula.

[0091] Further, the above state data is substituted into the formula satisfied by the internal temperature calculation. Figure 1 The internal temperature calculation module performs the internal temperature calculation process and outputs the highest internal temperature Tc(1). In particular, the initial value Tc(0) of Tc is equal to Ts(0).

[0092] It should be noted that Tc(1) calculated at the current moment will be used as the input of Tc(k=1) for the next iterative calculation. At the same time, the input state data required for the calculation are updated to the data at moment k=1, so as to obtain Tc(k+1) at the current moment k+1 in real time.

[0093] Further, the surface temperature and the internal temperature are input into the temperature calculation protection module (such as Figure 3 dotted box).

[0094] Furthermore, when the difference between the calculated Tc and the measured Ts is greater than the preset threshold Tg, the thermal runaway calculation unit needs to be activated. At this time, the state of the cell temperature and cell voltage sampling system can be combined to predict in advance whether a thermal runaway event will occur in the battery.

[0095] It can be seen that in the example of the present application, a corresponding calculation formula is created and stored in the ECU for subsequent calculation of the open circuit voltage, internal heat capacity and internal thermal resistance based on the battery status data, and the calculated parameters are used as input parameters for the final calculation of the internal temperature of the battery, so as to realize the estimation and calculation of the internal temperature of the battery based on the relevant parameters during the operation of the battery.

[0096] In one possible example, the battery includes at least one battery cell. Before calculating the internal temperature of the battery, the method further includes the following steps: determining a target battery cell based on the surface temperatures corresponding to the at least one battery cell, wherein the target battery cell is the battery cell corresponding to the maximum surface temperature; and determining a voltage corresponding to the target battery cell as the cell voltage.

[0097] For example, in the present application, an NTC temperature sensor is set on the surface of one or more cells of the battery module to collect the surface temperature of the battery during use. However, in the actual calculation process, not every battery cell's corresponding data needs to be used in the internal temperature calculation. Specifically, in the present application, by obtaining the surface temperature data of multiple cells, the battery cell with the highest surface temperature value is determined as the target battery cell.

[0098] Furthermore, the voltage corresponding to the target battery cell is obtained, and is input into the above formula as the cell voltage required for calculating the internal temperature for calculation.

[0099] It can be seen that in the example of this application, due to the hysteresis of the surface temperature, when the internal temperature has reached a certain value, the surface temperature may be lower than the internal temperature. Therefore, in order to more accurately calculate the internal temperature, the battery cell corresponding to the maximum surface temperature is determined as the target battery cell, thereby ensuring that the calculation of the internal temperature is more accurate, and more timely discovering whether the battery is currently in a thermal runaway state, ensuring the safety of the battery and increasing the battery life.

[0100] To better understand the entire process of this application solution, please refer to Figure 4 , Figure 4 Schematic diagram of the overall process of a battery protection method provided by an embodiment of the present application. Figure 4 As shown:

[0101] Step S401, Ts, Tc validity determination.

[0102] Step S402: determine whether the difference between Ts and Tc is greater than a preset threshold value Tg. If yes, proceed to step S303.

[0103] Step S403: Activate the thermal runaway calculation unit.

[0104] Step S404: Acquire the actual current and the current protection threshold.

[0105] The actual current includes the actual charging current and the actual discharging current. The current protection threshold includes a first current protection threshold corresponding to the internal temperature and a second current protection threshold corresponding to the surface temperature. The first current protection threshold includes a first charging current threshold and a first discharging current threshold; the second current protection threshold includes a second charging current threshold and a second discharging current threshold.

[0106] Step S405: determine whether the actual current is greater than or equal to the first current protection threshold. If yes, proceed to step S406; if no, proceed to step S407.

[0107] Step S406: Execute current protection.

[0108] Step S407, determine whether the actual current is greater than or equal to the second current protection threshold. If yes, proceed to step S406; if no, end the current determination process.

[0109] Specifically, all the processing steps S401-S407 above can be compared with the above Figure 2 The contents of steps S201-S203 correspond to each other and are not described in detail here.

[0110] It can be seen that the battery protection method described in the embodiment of the present application determines the internal temperature of the battery and the surface temperature of the battery; if the difference between the internal temperature and the surface temperature is greater than the preset threshold, the actual charging current, the actual discharging current and the current protection threshold are determined; if the battery is determined to be in the first state based on the actual charging current, the actual discharging current and the current protection threshold, the current protection is performed. This method calculates the internal temperature of the battery, combines the internal temperature and the surface temperature of the battery to determine whether it is necessary to obtain current data and current protection thresholds, and makes current protection judgments based on the current data and the current protection thresholds, so that thermal runaway events of the battery can be discovered early. Furthermore, making current protection judgments based on the estimated internal temperature of the battery can effectively improve the applicable temperature range of the battery and extend the battery life, while retaining the current protection judgment based on the surface temperature can ensure the efficiency of the battery current protection, thereby improving the battery safety.

[0111] See also Figure 5 , Figure 5 It is a schematic diagram of the structure of an electronic device, such as Figure 5 As shown, the electronic device includes a processor, a memory, a communication interface, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the processor, and the above-mentioned program of the electronic device includes instructions for executing the following steps:

[0112] determining an internal temperature of the battery and a surface temperature of the battery;

[0113] If the difference between the internal temperature and the surface temperature is greater than a preset threshold, determining an actual charging current, an actual discharging current, and a current protection threshold of the battery;

[0114] If it is determined that the battery is in the first state according to the actual charging current, the actual discharging current and the current protection threshold, current protection is performed on the battery.

[0115] It can be seen that the battery protection method described in the embodiment of the present application determines the internal temperature of the battery and the surface temperature of the battery; if the difference between the internal temperature and the surface temperature is greater than the preset threshold, the actual charging current, the actual discharging current and the current protection threshold are determined; if the battery is determined to be in the first state based on the actual charging current, the actual discharging current and the current protection threshold, the current protection is performed. This method calculates the internal temperature of the battery, combines the internal temperature and the surface temperature of the battery to determine whether it is necessary to obtain current data and current protection thresholds, and makes current protection judgments based on the current data and the current protection thresholds, so that thermal runaway events of the battery can be discovered early. Furthermore, making current protection judgments based on the estimated internal temperature of the battery can effectively improve the applicable temperature range of the battery and extend the battery life, while retaining the current protection judgment based on the surface temperature can ensure the efficiency of the battery current protection, thereby improving the battery safety.

[0116] In a possible example, the current protection threshold includes a first current protection threshold corresponding to the internal temperature, the first current protection threshold includes a first charging current threshold and a first discharging current threshold, and the determining that the battery is in the first state, the program includes instructions for performing the following steps:

[0117] If the actual charging current is greater than or equal to the first charging current threshold, and / or the actual discharging current is greater than or equal to the first discharging current threshold, it is determined that the battery is in the first state.

[0118] In a possible example, the current protection threshold further includes a second current protection threshold corresponding to the surface temperature, the second current protection threshold includes a second charging current threshold and a second discharging current threshold, and the above program includes instructions for performing the following steps:

[0119] If the battery is determined to be not in the first state based on the internal temperature, the first charging current threshold and the first discharging current threshold, then the battery is determined to be in the first state when the actual charging current is greater than or equal to the second charging current threshold, and / or the actual discharging current is greater than or equal to the second discharging current threshold.

[0120] In a possible example, the internal temperature calculation satisfies the following formula:

[0121]

[0122] Wherein, the Tc is used to characterize the internal temperature, the Cm is used to characterize the internal heat capacity of the battery, the Rm is used to characterize the internal thermal resistance of the battery, the Ts is used to characterize the surface temperature, the E is used to characterize the open circuit voltage, the V is used to characterize the single cell voltage, the I is used to characterize the current, and the k and the k+1 correspond to two adjacent moments.

[0123] In a possible example, before determining the internal temperature of the battery, the program includes instructions for performing the following steps:

[0124] Acquiring status data of the battery, wherein the status data includes an ambient temperature of the battery, a single cell voltage and a current of the battery;

[0125] The protected internal thermal capacitance, the internal thermal resistance and the open circuit voltage are calculated according to the status data.

[0126] In a possible example, the calculating the internal thermal capacity, the internal thermal resistance and the open circuit voltage according to the state data, the program includes instructions for executing the following steps:

[0127] Calculating the internal heat capacity and the internal thermal resistance according to the ambient temperature, wherein the internal heat capacity is used to characterize the ability of the battery material to absorb and dissipate heat, and the internal thermal resistance is used to characterize the rate of heat conduction inside the battery;

[0128] Calculating the state of charge of the battery according to the surface temperature and the cell voltage;

[0129] The open circuit voltage of the battery is calculated according to the state of charge.

[0130] In a possible example, the battery includes at least one battery cell, and before calculating the internal temperature of the battery, the program includes instructions for performing the following steps:

[0131] Determine a target battery cell according to the surface temperature respectively corresponding to the at least one battery cell, wherein the target battery cell is the battery cell corresponding to the maximum surface temperature;

[0132] The voltage corresponding to the target battery cell is determined as the cell voltage.

[0133] The above mainly introduces the scheme of the embodiment of the present application from the perspective of the execution process on the method side. It is understandable that, in order to realize the above functions, the electronic device includes a hardware structure and / or software module corresponding to the execution of each function. It should be easily appreciated by those skilled in the art that, in combination with the units and algorithm steps of each example described in the embodiments provided herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present application.

[0134] The embodiment of the present application can divide the electronic device into functional units according to the above method example. For example, each functional unit can be divided according to each function, or two or more functions can be integrated into one processing unit. The above integrated unit can be implemented in the form of hardware or in the form of software functional units. It should be noted that the division of units in the embodiment of the present application is schematic and is only a logical function division. There may be other division methods in actual implementation.

[0135] It should be noted that all relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module and will not be repeated here.

[0136] In the case of dividing each functional module into corresponding functional modules, Figure 6 A battery protection device is shown, characterized in that the device comprises: a calculation unit 601, an acquisition unit 602 and an execution unit 603, wherein:

[0137] The calculation unit 601 is used to determine the internal temperature of the battery and the surface temperature of the battery;

[0138] The acquisition unit 602 is configured to acquire an actual charging current, an actual discharging current, and a current protection threshold of the battery if the difference between the internal temperature and the surface temperature is greater than a preset threshold;

[0139] The execution unit 603 is configured to execute current protection on the battery if it is determined that the battery is in the first state according to the actual charging current, the actual discharging current and the current protection threshold.

[0140] It can be seen that in the battery protection device described in the embodiment of the present application, the calculation unit determines the internal temperature of the battery and the surface temperature of the battery; if the difference between the internal temperature and the surface temperature is greater than the preset threshold, the determination unit obtains the actual charging current, the actual discharging current and the current protection threshold; if the battery is determined to be in the first state according to the actual charging current, the actual discharging current and the current protection threshold, the execution unit executes current protection. This method calculates the internal temperature of the battery, combines the internal temperature and the surface temperature of the battery to determine whether it is necessary to obtain current data and current protection threshold, and makes current protection judgments based on the current data and the current protection threshold, so that thermal runaway events of the battery can be discovered early. Furthermore, making current protection judgments based on the estimated internal temperature of the battery can effectively improve the temperature application range of the battery and extend the battery life, while retaining the current protection judgment based on the surface temperature can ensure the efficiency of the battery current protection, thereby improving the battery safety.

[0141] In a possible example, the current protection threshold includes a first current protection threshold corresponding to the internal temperature, the first current protection threshold includes a first charging current threshold and a first discharging current threshold, and the determining that the battery is in the first state, the execution unit 603 is further used to perform the following steps:

[0142] If the actual charging current is greater than or equal to the first charging current threshold, and / or the actual discharging current is greater than or equal to the first discharging current threshold, it is determined that the battery is in the first state.

[0143] In a possible example, the current protection threshold further includes a second current protection threshold corresponding to the surface temperature, the second current protection threshold includes a second charging current threshold and a second discharging current threshold, and the execution unit 603 is further used to perform the following steps:

[0144] If the battery is determined to be not in the first state based on the internal temperature, the first charging current threshold and the first discharging current threshold, then the battery is determined to be in the first state when the actual charging current is greater than or equal to the second charging current threshold, and / or the actual discharging current is greater than or equal to the second discharging current threshold.

[0145] In a possible example, the internal temperature calculation satisfies the following formula:

[0146]

[0147] Wherein, the Tc is used to characterize the internal temperature, the Cm is used to characterize the internal heat capacity of the battery, the Rm is used to characterize the internal thermal resistance of the battery, the Ts is used to characterize the surface temperature, the E is used to characterize the open circuit voltage, the V is used to characterize the single cell voltage, the I is used to characterize the current, and the k and the k+1 correspond to two adjacent moments.

[0148] In a possible example, before determining the internal temperature of the battery, the execution unit 603 is further configured to execute the following steps:

[0149] Acquiring status data of the battery, wherein the status data includes an ambient temperature of the battery, a single cell voltage and a current of the battery;

[0150] The protected internal thermal capacitance, the internal thermal resistance and the open circuit voltage are calculated according to the status data.

[0151] In a possible example, the calculating the internal thermal capacity, the internal thermal resistance and the open circuit voltage according to the state data, the execution unit 603 is further used to perform the following steps:

[0152] Calculating the internal heat capacity and the internal thermal resistance according to the ambient temperature, wherein the internal heat capacity is used to characterize the ability of the battery material to absorb and dissipate heat, and the internal thermal resistance is used to characterize the rate of heat conduction inside the battery;

[0153] Calculating the state of charge of the battery according to the surface temperature and the cell voltage;

[0154] The open circuit voltage of the battery is calculated according to the state of charge.

[0155] In a possible example, the battery includes at least one battery cell. Before calculating the internal temperature of the battery, the execution unit 603 is further configured to execute the following steps:

[0156] Determine a target battery cell according to the surface temperature respectively corresponding to the at least one battery cell, wherein the target battery cell is the battery cell corresponding to the maximum surface temperature;

[0157] The voltage corresponding to the target battery cell is determined as the cell voltage.

[0158] In the case of an integrated unit, the electronic device may include a processing module, a storage module and a communication module. The processing module may be used to control and manage the actions of the electronic device, for example, it may be used to support the electronic device to perform all the above steps. The storage module may be used to support the electronic device to execute stored program codes and data, etc. The communication module may be used to support the electronic device to communicate with other devices.

[0159] Among them, the processing module can be a processor or a controller. It can implement or execute various exemplary logic boxes, modules and circuits described in conjunction with the disclosure of this application. The processor can also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of digital signal processing (DSP) and a microprocessor, etc. The storage module can be a memory. The communication module can specifically be a device that interacts with other electronic devices, such as a radio frequency circuit, a Bluetooth chip, a Wi-Fi chip, etc.

[0160] An embodiment of the present application also provides a computer storage medium, wherein the computer storage medium stores a computer program for electronic data exchange, wherein the computer program enables a computer to execute part or all of the steps of any method described in the above method embodiments, and the above computer includes an electronic device.

[0161] The embodiment of the present application also provides a computer program product, the computer program product includes a non-transitory computer-readable storage medium storing a computer program, the computer program is operable to cause a computer to execute some or all of the steps of any method described in the method embodiment. The computer program product may be a software installation package, and the computer includes an electronic device.

[0162] It should be noted that, for the aforementioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the described order of actions, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0163] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0164] In the several embodiments provided in the present application, it should be understood that the disclosed device can be implemented in other ways. For example, the device embodiments described above are only schematic, such as the division of the above-mentioned units, which is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection of devices or units can be electrical or other forms.

[0165] The units described above as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0166] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0167] If the above-mentioned integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable memory. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a memory, including a number of instructions to enable a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of the above-mentioned methods of each embodiment of the present application. The aforementioned memory includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, disk or CD-ROM and other media that can store program codes.

[0168] A person skilled in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable memory, and the memory can include: a flash drive, a read-only memory (English: Read-Only Memory, abbreviated as: ROM), a random access memory (English: Random Access Memory, abbreviated as: RAM), a magnetic disk or an optical disk, etc.

[0169] The embodiments of the present application are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for general technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A battery protection method, characterized in that: The method comprises: determining an internal temperature of the battery and a surface temperature of the battery; If the difference between the internal temperature and the surface temperature is greater than a preset threshold, determining an actual charging current, an actual discharging current, and a current protection threshold of the battery; If it is determined that the battery is in the first state according to the actual charging current, the actual discharging current and the current protection threshold, current protection is performed on the battery.

2. The method according to claim 1, characterized in that The current protection threshold comprises a first current protection threshold corresponding to the internal temperature, the first current protection threshold comprises a first charging current threshold and a first discharging current threshold, and determining that the battery is in the first state comprises: If the actual charging current is greater than or equal to the first charging current threshold, and / or the actual discharging current is greater than or equal to the first discharging current threshold, it is determined that the battery is in the first state.

3. The method according to claim 2, characterized in that The current protection threshold further includes a second current protection threshold corresponding to the surface temperature, the second current protection threshold includes a second charging current threshold and a second discharging current threshold, and the method further includes: If the battery is determined to be not in the first state based on the internal temperature, the first charging current threshold and the first discharging current threshold, then the battery is determined to be in the first state when the actual charging current is greater than or equal to the second charging current threshold, and / or the actual discharging current is greater than or equal to the second discharging current threshold.

4. The method according to claim 3, characterized in that The internal temperature calculation satisfies the following formula: Wherein, the Tc is used to characterize the internal temperature, the Cm is used to characterize the internal heat capacity of the battery, the Rm is used to characterize the internal thermal resistance of the battery, the Ts is used to characterize the surface temperature, the E is used to characterize the open circuit voltage, the V is used to characterize the single cell voltage, the I is used to characterize the current, and the k and the k+1 correspond to two adjacent moments.

5. The method according to claim 4, characterized in that Before determining the internal temperature of the battery, the method further includes: Acquiring status data of the battery, wherein the status data includes an ambient temperature of the battery, a single cell voltage and a current of the battery; The protected internal thermal capacitance, the internal thermal resistance and the open circuit voltage are calculated according to the status data.

6. The method according to claim 5, characterized in that The calculating the internal thermal capacity, the internal thermal resistance and the open circuit voltage according to the state data comprises: Calculating the internal heat capacity and the internal thermal resistance according to the ambient temperature, wherein the internal heat capacity is used to characterize the ability of the battery material to absorb and dissipate heat, and the internal thermal resistance is used to characterize the rate of heat conduction inside the battery; Calculating the state of charge of the battery according to the surface temperature and the cell voltage; The open circuit voltage of the battery is calculated according to the state of charge.

7. The method according to claim 6, characterized in that The battery includes at least one battery cell. Before calculating the internal temperature of the battery, the method further includes: Determine a target battery cell according to the surface temperature respectively corresponding to the at least one battery cell, wherein the target battery cell is the battery cell corresponding to the maximum surface temperature; The voltage corresponding to the target battery cell is determined as the cell voltage.

8. A battery protection device, characterized in that: The device comprises: a calculation unit, an acquisition unit and an execution unit, wherein: The calculation unit is used to determine the internal temperature of the battery and the surface temperature of the battery; The acquisition unit is configured to determine an actual charging current, an actual discharging current, and a current protection threshold of the battery if a difference between the internal temperature and the surface temperature is greater than a preset threshold; The execution unit is configured to execute current protection on the battery if it is determined that the battery is in a first state according to the actual charging current, the actual discharging current and the current protection threshold.

9. An electronic device, characterized in that: The method comprises a processor, a memory, a communication interface, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the processor, and the programs include instructions for executing the steps in the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: A computer program for electronic data exchange is stored, wherein the computer program causes a computer to execute the method according to any one of claims 1 to 7.

11. A computer program product comprising instructions, characterized in that When the computer program product runs on an electronic device, the electronic device is enabled to execute the method according to any one of claims 1 to 7.

12. A battery, characterized in that: The battery includes a battery module and a battery management system, and the battery management system is used to execute the method according to any one of claims 1-7.

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