Battery temperature calculation method and device and battery

Abstract

The invention provides a battery temperature calculation method and device and a battery. The battery temperature calculation method comprises the following steps: acquiring charging parameters of a battery, wherein the charging parameters comprise charging current and charging temperature; obtaining a temperature rise rate model according to the charging current and the charging temperature; the initial temperature, the environment temperature and the temperature rise rate of the battery and the charging duration of the battery are obtained; and calculating the battery temperature according to the temperature rise rate, the initial temperature, the environment temperature and the charging duration. Through the method, the temperature of the battery during charging can be calculated, and the temperature of the battery is calculated based on the temperature rise rate, the initial temperature, the environment temperature and the charging duration, that is, the temperature of the battery can be calculated in real time based on dynamic conditions, reliable reference data is provided for thermal management of the battery, and the charging safety of the battery is improved.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to a Chinese patent application filed with the Chinese Patent Office on September 3, 2024, with application number 202411223448.X and application name “A method, device and battery for calculating battery temperature”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of energy storage technology, and in particular to a method and device for calculating battery temperature, and a battery. Background Art

[0004] A battery is a device that can be charged through an external power source and is reusable. It is charged through an external power source, converting electrical energy into chemical energy for storage, and then converting chemical energy into electrical energy for use by the device when needed.

[0005] Batteries are used in a wide range of applications. Batteries are important energy storage devices for electric and hybrid vehicles, providing long-lasting energy supply and efficient power output. Batteries play an important role in grid energy storage systems, storing excess electrical energy and releasing it when needed to balance grid loads, respond to sudden demands or unstable power supply. Batteries are used as power sources in portable electronic devices such as smartphones, tablets, and laptops. Batteries are also widely used in aerospace, medical equipment, wireless communication base stations and other fields.

[0006] However, in the process of implementing the embodiments of the present application, the inventors of the present application found that: batteries, as an important energy storage device, play an important role in modern society; calculating the temperature of the battery during the charging process is crucial to ensuring the safety and life of the battery. Summary of the invention

[0007] In view of the above problems, the present application provides a method, device and battery for calculating the battery temperature, which overcome the above problems or at least partially solve the above problem of needing to calculate the battery temperature.

[0008] According to one aspect of the present application, a method for calculating battery temperature is provided, comprising: obtaining charging parameters of the battery, the charging parameters comprising charging current and charging temperature; wherein the charging parameters are charging parameters of the battery tested by an experimental method; the charging temperature is the test temperature of the battery; according to the charging current and charging temperature, a temperature rise rate model is obtained; the initial temperature, ambient temperature, temperature rise rate and charging time of the battery are obtained; wherein, according to the initial temperature and the charging current corresponding to the initial temperature, the corresponding temperature rise rate is found by searching the temperature rise rate model; and the battery temperature is calculated according to the temperature rise rate, initial temperature, ambient temperature and charging time.

[0009] In an optional manner, the formula for calculating the battery temperature according to the temperature rise rate, initial temperature, ambient temperature and charging time is:

[0010]

[0011] Wherein, T(t) is the battery temperature, V is the temperature rise rate, and T Start is the initial temperature, the T env is the ambient temperature, t is the charging time, K is the cooling coefficient, and e is the base of the natural logarithm.

[0012] In an optional manner, the step of calculating the battery temperature according to the temperature rise rate, initial temperature, ambient temperature and charging time includes: establishing a charging model according to the charging parameters, the charging model including multiple charging stages; obtaining the front cut-off temperature of the previous charging stage; calculating the estimated duration of the battery in the current charging stage according to the charging model; correcting the initial temperature using the front cut-off temperature, correcting the charging time using the estimated duration, and calculating the cut-off temperature of the battery in the current charging stage.

[0013] In an optional manner, the calculation formula for the cut-off temperature is:

[0014]

[0015] Among them, the T n+1 is the cut-off temperature of the nth charging stage, and the t n is the estimated duration of the nth charging stage, V is the temperature rise rate, and T n is the previous cut-off temperature of the previous charging stage of the nth charging stage, and the T env is the ambient temperature, K is the cooling coefficient, and e is the base of the natural logarithm; wherein, when n is 1, T 1It is the starting temperature when the battery starts to be charged.

[0016] In an optional manner, the charging parameters also include SOC, and the step of calculating the estimated duration of the battery in the current charging stage includes: obtaining the theoretical cut-off temperature of the battery in the current charging stage according to the charging model; correcting the initial temperature using the previous cut-off temperature, and correcting the battery temperature using the theoretical cut-off temperature, and calculating the first charging duration of the battery in the current charging stage; obtaining the rated capacity of the battery; obtaining the starting SOC and the cutting-off SOC corresponding to the current charging stage according to the charging model; calculating the second charging duration of the battery in the current charging stage according to the rated capacity, the starting SOC and the cutting-off SOC; and obtaining the minimum value of the first charging duration and the second charging duration as the estimated duration.

[0017] In an optional manner, the calculation formula for the first charging time is:

[0018]

[0019] Among them, the is the first charging duration of the nth charging stage, and the T end(n+1) is the theoretical cut-off temperature of the nth charging stage, V is the temperature rise rate, and T n is the previous cut-off temperature of the previous charging stage of the nth charging stage, and the T env is the ambient temperature, K is the cooling coefficient, and ln is the logarithm with e as the base; wherein, when n is 1, T 1 It is the starting temperature when the battery starts to be charged.

[0020] In an optional manner, the step of calculating the second charging duration of the battery in the current charging stage according to the rated capacity, the starting SOC and the cutting-off SOC includes: obtaining the current current of the battery; obtaining the theoretical charging current of the battery limited by the SOC in the current charging stage according to the charging model, and obtaining the theoretical temperature current of the battery limited by the charging temperature in the current charging stage; obtaining the minimum value of the current current, the theoretical charging current and the theoretical temperature current as the current calculation value; calculating the second charging duration of the battery in the current charging stage according to the rated capacity, the starting SOC, the cutting-off SOC and the current calculation value.

[0021] In an optional manner, the battery has a charging efficiency, and the step of calculating the second charging time of the battery in the current charging stage according to the rated capacity, the starting SOC, the cutting-off SOC and the current calculated value includes: calculating the second charging time according to the charging efficiency, the rated capacity, the starting SOC, the cutting-off SOC and the current calculated value.

[0022] In an optional manner, the step of calculating the second charging duration based on the charging efficiency, rated capacity, starting SOC, ending SOC and current calculated value includes: obtaining the previous current calculated value and the previous starting SOC of the previous charging stage; calculating the starting SOC calculated value of the current charging stage based on the previous current calculated value, the previous estimated duration and the previous starting SOC; and replacing the starting SOC with the starting SOC calculated value to obtain the second charging duration.

[0023] In an optional manner, the formula for calculating the starting SOC value is:

[0024]

[0025] Among them, the SOC n is the starting SOC calculation value of the nth charging stage, the SOC n-1 is the previous starting SOC of the previous charging stage of the nth charging stage, n is the charging efficiency, and I n-1 is the calculated value of the previous current in the previous charging stage of the nth charging stage, and the t n-1 is the previous estimated duration of the charging stage before the nth charging stage, and C is the rated capacity.

[0026] In an optional manner, the calculation formula for the second charging time is:

[0027]

[0028] Among them, the is the second charging time of the nth charging stage, the SOC next is the cut-off SOC of the nth charging stage, the SOC n is the calculated starting SOC value of the nth charging stage, C is the rated capacity, and I n is the calculated current value of the nth charging stage, and η is the charging efficiency.

[0029] According to one aspect of an embodiment of the present application, a battery temperature calculation device is provided, including: a first acquisition module, used to obtain charging parameters of the battery, the charging parameters including charging current and charging temperature; wherein the charging parameters are charging parameters of the battery tested by an experimental method; the charging temperature is the test temperature of the battery; a second acquisition module, used to obtain a temperature rise rate model according to the charging current and the charging temperature; a third acquisition module, used to obtain the initial temperature, ambient temperature, temperature rise rate and charging time of the battery; wherein, according to the initial temperature and the charging current corresponding to the initial temperature, the corresponding temperature rise rate is found by searching the temperature rise rate model; a calculation module, used to calculate the battery temperature according to the temperature rise rate, initial temperature, ambient temperature and charging time.

[0030] According to one aspect of an embodiment of the present application, a battery is provided, comprising: at least one processor, and a memory, wherein the memory is communicatively connected to the at least one processor, the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the method as described above.

[0031] According to one aspect of an embodiment of the present application, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the processor performs the steps of the above method.

[0032] The beneficial effects of the present application include: the present application provides a method for calculating the battery temperature, including: obtaining the charging parameters of the battery, the charging parameters including the charging current and the charging temperature; wherein the charging parameters are the charging parameters of the battery tested by an experimental method; the charging temperature is the test temperature of the battery; according to the charging current and the charging temperature, a temperature rise rate model is obtained; the initial temperature, the ambient temperature and the charging time of the battery are obtained; wherein, according to the initial temperature and the charging current corresponding to the initial temperature, the corresponding temperature rise rate is found by searching the temperature rise rate model; according to the temperature rise rate, the initial temperature, the ambient temperature, the temperature rise rate and the charging time, the battery temperature is calculated. Through this method, not only the temperature of the battery during charging can be calculated, but also because the battery temperature is calculated based on the temperature rise rate, the initial temperature, the ambient temperature and the charging time, that is, based on dynamic conditions, the battery temperature can be calculated in real time, providing reliable reference data for the thermal management of the battery and improving the safety of charging the battery. In addition, since the battery temperature calculation method provided in the present application does not require the use of temperature testing equipment to detect the battery temperature, that is, no additional equipment costs are required, the battery temperature calculation method provided in the present application has good economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0034] Figure 1 is a schematic diagram of a system provided in an embodiment of the present application;

[0035] Figure 2 Schematic diagram of the hardware structure of the BMS module provided in the embodiment of the present application;

[0036] Figure 3 is a flow chart of a method for calculating battery temperature provided in an embodiment of the present application;

[0037] Figure 4 is the internal resistance of the battery represented by the first-order Thevenin equivalent circuit model of the battery provided in the embodiment of the present application;

[0038] Figure 5 is a schematic diagram of a flow chart of calculating battery temperature provided in an embodiment of the present application;

[0039] Figure 6 This is a flow chart of the estimated duration provided by the embodiment of the present application:

[0040] Figure 7It is a schematic diagram of an implementation method of the first model provided in the embodiment of the present application;

[0041] Figure 8 is a schematic diagram of an implementation method of the second model provided in an embodiment of the present application;

[0042] Fig. 9 It is a flowchart of an implementation method for calculating the second charging time provided in an embodiment of the present application;

[0043] Fig.10 is a flowchart of another implementation method for calculating the second charging time provided in an embodiment of the present application;

[0044] Fig.11 Schematic diagram of a battery temperature calculation device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme 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 part of the embodiments of the present application, rather than all of the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field belong to the scope of protection of this application.

[0046] In addition, the technical features involved in the embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0047] See also Figure 1 , Figure 1 1 is a schematic diagram of a system provided in an embodiment of the present application, and the system is applicable to the battery temperature calculation method and the battery temperature calculation device. The system includes a battery 100. The battery 100 can be specifically configured in a variety of ways, not limited to Figure 1 The situation shown.

[0048] The battery 100 may include only one battery cell 10 , that is, the battery 100 is formed of a single battery cell 10 .

[0049] The battery 100 may include a plurality of battery cells 10 , and the plurality of battery cells 10 are connected in series or in parallel.

[0050] The battery 100 may also include a plurality of groups of electrochemical devices, wherein one group of electrochemical devices includes a plurality of battery cells 10 , and the plurality of battery cells 10 are connected in series or in parallel.

[0051] The battery 100 may be a lithium-ion battery, which mainly includes consumer batteries, power batteries and energy storage batteries. Among them, the consumer battery usually requires small size, light weight, high energy density and long cycle life, and is widely used in personal electronic devices such as mobile phones, laptops, tablet computers, digital cameras and portable music players. Among them, the power battery is mainly used in transportation tools such as new energy vehicles, electric bicycles, electric trains, etc., to provide the instantaneous high power output required by the vehicle to support operations such as acceleration and climbing. Among them, the energy storage battery is mostly used as a battery energy storage system for renewable energy such as solar energy, wind power, and hydropower, as well as grid peak and frequency regulation, backup power supply, microgrid and other occasions, mainly for long-term storage and stable release of energy. No matter which type of battery, there is a charging and discharging process. Due to the inconsistency of each battery cell in the battery, the power in each battery cell is different, and it is necessary to balance the control of each battery cell to solve the problem of consistency of each battery cell. When the balance control of each battery cell in the battery is performed, it is necessary to obtain the balance time of a single battery cell, so as to further balance it according to the balance time of each battery cell.

[0052] It is understandable that, in some embodiments, the system further includes a BMS (Battery Management System) module 200, which is responsible for monitoring the operating status of the battery 100 and ensuring the safe and reliable operation of the battery 100. The BMS module 200 can monitor and collect the state parameters of the battery 100 (including but not limited to the voltage, current, temperature, insulation resistance, etc. of the battery 100) in real time, and perform necessary analysis and calculation on the relevant state parameters to obtain more state evaluation parameters, and realize effective control of the battery 100 according to a specific protection control strategy to ensure the safe and reliable operation of the entire battery 100. At the same time, the BMS module 200 can exchange information with other external devices 300 (PCS, EMS, fire protection system, etc.) through its own communication interface and analog / digital input interface to form a linkage control to ensure the safe, reliable and efficient operation of the battery 100.

[0053] In order to solve the technical problem that the battery temperature cannot be calculated in the prior art, an embodiment of the present application provides a method for calculating the battery temperature.

[0054] Embodiment 1

[0055] Before introducing the calculation method of the battery temperature in detail, the hardware structure of the BMS module 200 provided in the embodiment of the present application is described.

[0056] See also Figure 2 , Figure 22 is a schematic diagram of the hardware structure of the BMS module 200 provided in the embodiment of the present application, which can execute the battery temperature calculation method. The BMS module 200 includes at least one processor 21 and a memory 22 ( Figure 2 A bus connection and a processor are used as an example). A person skilled in the art can understand that Figure 2 The structure shown is for illustration only and does not limit the structure of the above-mentioned battery. Figure 2 More or fewer components as shown, or with Figure 2 Different configurations are shown.

[0057] The processor 21 is used to provide computing and control capabilities, and control the BMS module 200 to execute any method provided in the following application embodiments, thereby managing the battery 100 accordingly.

[0058] It can be understood that the processor 21 can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0059] The memory 22, as a non-transient computer-readable storage medium, can be used to store non-transient software programs, non-transient computer executable programs and modules, such as program instructions / modules corresponding to the various calculation methods in the embodiments of the present application. The processor 21 can implement the various calculation methods in any of the following method embodiments by running the non-transient software programs, instructions and modules stored in the memory 22. The memory 22 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage devices. In some embodiments, the memory 22 may also include a memory remotely arranged relative to the processor, and these remote memories may be connected to the processor via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network and a combination thereof.

[0060] Embodiment 2

[0061] The embodiment of the present application also provides a non-volatile computer-readable storage medium, wherein the non-volatile computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used by a battery to execute each calculation method in any of the following method embodiments.

[0062] An embodiment of the present application provides a computer program product, including a computing program stored on a non-volatile computer-readable storage medium, wherein the computer program includes program instructions, and when the program instructions are executed by a computer, the computer executes each computing method in any of the following method embodiments.

[0063] Through the description of the above implementation methods, ordinary technicians in this field can clearly understand that each implementation method can be implemented by means of software plus a general hardware platform, and of course it can also be implemented by hardware. Ordinary technicians in this field can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing related hardware through a computer program, and the program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, the storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

[0064] Embodiment 3

[0065] The following is a discussion of the battery temperature calculation method provided in the embodiment of the present application. Figure 3 , Figure 3 : is a flow chart of a method for calculating battery temperature provided in an embodiment of the present application, the method comprising the following steps:

[0066] Step S10, obtaining charging parameters of the battery, wherein the charging parameters include charging current and charging temperature.

[0067] The charging parameter may be a charging parameter of a battery tested by an experimental method, and the charging temperature may be a test temperature of the battery; or it may be a charging parameter of the battery during a historical charging process. In some embodiments, the charging parameter includes a charging current and a charging temperature; in other embodiments, the charging parameter also includes a battery's SOC (State of Charge), which is an indicator describing the current remaining power of the battery, usually shown in the form of a percentage.

[0068] It is understandable that the BMS module can obtain the charging parameters of the battery during the historical charging process. Specifically, the BMS module is provided with an AFE (Analog Front End), which is a series of circuits used to process analog signals in an electronic system. In the BMS module, the AFE is used to measure battery voltage, current and other parameters with high precision, and convert these analog signals into digital signals for further processing and analysis.

[0069] It is worth noting that the charging temperature in the charging parameter may be data tested by a sensor.

[0070] Step S20: obtaining a temperature rise rate model according to the charging current and the charging temperature.

[0071] For different batteries, the charging current range may be different. For batteries used as new energy vehicles, they are generally designed for high-power discharge and fast charging. Their charging current range can range from 0.2C to 0.5C for slow charging, to 1C or higher for fast charging. The development of fast charging technology has enabled some batteries to be charged at higher currents, which may reach 2C, 3C or higher to shorten the charging time. The "C" here refers to the battery capacity. For example, a 100Ah battery is charged at 1C, and the theoretical temperature current is 100A.

[0072] In contrast, batteries used in energy storage systems for renewable energy sources such as solar power, wind power, and hydropower usually do not need to be charged as quickly as batteries used in new energy vehicles. Therefore, the charging current range of batteries used in energy storage systems is usually lower, and the following charging currents may be set: 1.2C, 1C, 0.8C, 0.5C, 0.3C, 0.2C, and 0.1C.

[0073] The temperature rise rate model may be a temperature rise rate table as shown in Table 1 below. The temperature rise rate table may be established based on the charging temperature and charging current measured under experimental conditions.

[0074] As an example, assuming that the battery's operable charging temperature range is divided into 5 segments and the charging current is divided into 9 segments, the corresponding temperature rise rates are obtained as shown in Table 1:

[0075] Table 1 Temperature rise rate at different charging currents in each charging temperature range (℃)

[0076]

[0077] Step S30, obtaining the initial temperature, ambient temperature, temperature rise rate of the battery and charging time of the battery.

[0078] The ambient temperature in the embodiment of the present application refers to the ambient temperature when the battery is charging.

[0079] The initial temperature in the embodiment of the present application has multiple meanings. The initial temperature may be the starting temperature when the battery starts to be charged, and the initial temperature may be equal to the ambient temperature. The initial temperature may also be the temperature of the battery at the beginning of a certain time interval.

[0080] The temperature rise rate in the embodiment of the present application refers to the temperature rise rate of the battery corresponding to the initial temperature moment. According to the initial temperature and the charging current corresponding to the initial temperature moment, the corresponding temperature rise rate can be found by looking up the temperature rise rate model (temperature rise rate table). For example: the initial temperature T 0 In the temperature range of T1 to T2 in Table 1, the charging current I corresponding to the initial temperature T0 is 0 For I 3 , then its temperature rise rate is V T1I3 ; If the initial temperature is in the temperature range T L ~T H The corresponding charging current is between the charging current I L ~I H The calculation formula of the temperature rise rate is:

[0081]

[0082] Among them, the V n is the current temperature rise rate, In the temperature range T L ~T H And charging current I H The temperature rise rate is limited to In the temperature range T L ~T H And charging current I L The temperature rise rate is limited, the I n is the charging current corresponding to the initial temperature, and the I H and I L are the two ends of the charging current interval in which the charging current is located.

[0083] The charging time in the embodiments of the present application has multiple meanings. The charging time can be the start time from when the battery starts charging, and the target time when the battery temperature is calculated is the timing end time. The charging time can also be the start time from when the battery starts charging, and the battery temperature or the battery SOC reaches a certain value as the timing end time. The charging time can also be in terms of a certain time interval.

[0084] Step S40, calculating the battery temperature according to the temperature rise rate, initial temperature, ambient temperature and charging time.

[0085] In some embodiments, the formula for calculating the battery temperature based on the temperature rise rate, initial temperature, ambient temperature and charging time is:

[0086]

[0087] Wherein, T(t) is the battery temperature that changes with the charging time, V is the temperature rise rate, and T Start is the initial temperature, the T env is the ambient temperature, t is the charging time, K is the cooling coefficient, and e is the base of the natural logarithm.

[0088] It is worth noting that the cooling coefficient corresponds to Newton's law of cooling, and the value of cooling absorption depends on many factors, including the material properties of the object, the shape and size of the object, air flow conditions, etc. The value of the cooling coefficient will also be different in different environments and conditions. In practical applications, the value of the cooling coefficient is usually obtained through experimental measurements.

[0089] In order to help readers understand the inventive concept of the present application, the above battery temperature formula is now derived. The change in battery temperature satisfies the following formula (1):

[0090]

[0091] Among them, the is the change of the battery temperature over time, is the change of battery heating temperature over time, Cooling the battery to see how the temperature changes over time.

[0092] From Newton's law of cooling, we know the following formula (2):

[0093]

[0094] Among them, the is the change of battery heat dissipation, K is the cooling coefficient, T is the battery temperature, and T env is the ambient temperature.

[0095] According to Ohm's law, the formula for heat generation is:

[0096] Q 发热 =I2R Ω t

[0097] Among them, the Q 发热 is the heat generated, I is the current, and R Ω is the internal resistance of the battery, and t is the time.

[0098] According to the specific heat capacity formula, the change of battery heat over time is:

[0099]

[0100] Wherein, ΔTheat(t) is the change of battery heat with time, Qheat is the heat output, c is the specific heat capacity, m is the battery mass, I is the current, and R Ω is the internal resistance of the battery, and t is the time.

[0101] The change of battery heating temperature over time is shown in the following formula (3):

[0102]

[0103] Among them, the is the change of battery heating temperature over time, I is the current, R Ω is the internal resistance of the battery, c is the specific heat capacity, and m is the mass of the battery.

[0104] Combining equations (2) and (3), the change of battery temperature over time can be expressed as the following equation (4):

[0105]

[0106] Among them, the is the change of the battery temperature over time, I is the current, and R Ω is the battery internal resistance, c is the specific heat capacity, m is the battery mass, K is the cooling coefficient, T is the battery temperature, and T env is the ambient temperature.

[0107] Among them, the specific heat capacity c and the battery mass m are constants, but the battery internal resistance R Ω is not set in stone, see Figure 4 According to the first-order Thevenin equivalent circuit model of the battery, the battery internal resistance can be divided into polarization internal resistance and ohmic internal resistance.

[0108] Among them, the ohmic resistance R o is a constant, the polarization internal resistance R p It will change with the current and battery temperature.

[0109] Since the measurement of battery temperature change is based on 1°C, the accuracy requirement is not high. From the perspective of practical application, the formula for the temperature rise rate V can be as follows:

[0110]

[0111] Wherein, V is the temperature rise rate, I is the current, and R Ωis the internal resistance of the battery, c is the specific heat capacity, and m is the mass of the battery.

[0112] It is worth noting that, as mentioned above, the temperature rise rate is derived from a temperature rise rate table, which is established based on the charging temperature (battery test temperature) and charging current measured under experimental conditions.

[0113] Under experimental conditions, a high and low temperature chamber is usually used for testing, that is, the battery is placed in a high and low temperature chamber, which is also called a temperature cycle test chamber or a high and low temperature alternating humidity chamber, and is a device used to simulate environmental conditions. The high and low temperature chamber can provide a controllable temperature range, from extremely low temperature to high temperature, and can achieve rapid temperature changes within a certain period of time.

[0114] Since the internal space of the high and low temperature box is limited and isolated from the external environment, the temperature inside the high and low temperature box detected represents the charging temperature of the battery (battery test temperature), and the heat exchange with the external environment can be basically ignored. The temperature rise rate can be measured by experimental methods, and the temperature rise rate measured by the experimental method is close to the heating rate of the battery.

[0115] In actual working conditions, the battery is not placed in a sealed high and low temperature box, but may be placed in a container (the container can be large or small). However, in order to ensure the heat dissipation of the battery, it is usually necessary to use natural air convection, forced air cooling, liquid cooling and other means to make the environment in the container exchange or communicate with the external environment. Therefore, when calculating the change of battery temperature over time, it is necessary to consider the ambient temperature, that is, it is necessary to consider heat dissipation. Therefore, in actual working conditions, the temperature rise rate tested by experimental methods can be expressed as the following formula (4):

[0116]

[0117] Among them, the is the change of the battery temperature over time, V is the temperature rise rate, K is the cooling coefficient, T is the battery temperature, and T env is the ambient temperature.

[0118] Solve the differential equation (5) by separation of variables:

[0119] make

[0120] T′=TT env

[0121] because

[0122]

[0123] Among them, the and All of them are the changes of battery temperature over time:

[0124] Then the above formula (5) can be transformed into the following formula (6):

[0125]

[0126] Among them, the is the change of the battery temperature over time, V is the temperature rise rate, K is the cooling coefficient, and T′ is also the battery temperature.

[0127] Formula (6) is a linear first-order ordinary differential equation, and its standard solution is to find the sum of homogeneous solutions and special solutions.

[0128] The process of solving the aligned solution is briefly described as follows:

[0129] The homogeneous equation is

[0130]

[0131] Among them, the is the change of the battery temperature over time, K is the cooling coefficient, and T′ is also the battery temperature:

[0132] The homogeneous solution is

[0133] T h ′(t)=Me -Kt

[0134] Wherein, M is a constant, e is the base of the natural logarithm, K is a cooling coefficient, and t is time.

[0135] The process of solving the special solution is briefly described as follows:

[0136] Assume a special solution T p ′ is a constant, and let:

[0137]

[0138] Among them, the T p ′ is a special solution, V is the temperature rise rate, and K is the cooling coefficient.

[0139] Adding the above special solution and homogeneous solution gives the general solution:

[0140]

[0141] Convert T′(t) back to T(t), then

[0142]

[0143] Using T(0)=T Start , we can find M;

[0144] because

[0145]

[0146] but

[0147]

[0148] Then the formula for the above battery temperature can be obtained:

[0149]

[0150] Wherein, T(t) is the battery temperature that changes with the charging time, V is the temperature rise rate, and T Start is the initial temperature, the T env is the ambient temperature, t is the charging time, K is the cooling coefficient, and e is the base of the natural logarithm.

[0151] It is worth noting that the method for calculating the battery temperature according to the temperature rise rate, initial temperature, ambient temperature and charging time is not limited to the above formula, and may also be in other forms. For example, in some embodiments, refer to Figure 5 , the step of calculating the battery temperature, that is, the above step S40 includes:

[0152] Step S401: establishing a charging model according to the charging parameters, wherein the charging model includes multiple charging stages.

[0153] The charging model is established according to the charging parameters, and the charging model includes multiple charging stages.

[0154] Step S402, obtaining the front cut-off temperature of the previous charging stage.

[0155] The previous charging stage is a charging stage before the current charging stage, and the current charging stage is the charging stage in which the battery is when the battery temperature is calculated.

[0156] The battery will have a cut-off temperature in the current charging stage, that is, the temperature of the battery actually calculated at the end of the current charging stage, and the previous charging stage has a front cut-off temperature, which is actually the initial temperature of the battery at the beginning of the current charging stage.

[0157] It is worth noting that when the current charging stage is the first charging stage, the front cut-off temperature of the previous charging stage is the starting temperature when the battery starts charging. In some embodiments, the starting temperature when the battery starts charging can be equal to the ambient temperature, that is, when the current charging stage is the first charging stage, the front cut-off temperature of the previous charging stage is equal to the ambient temperature.

[0158] Step S403, calculating the estimated duration of the battery in the current charging stage according to the charging model.

[0159] In some embodiments, see Figure 6 , the step of calculating the estimated duration of the battery in the current charging stage according to the charging model, that is, step S403 includes:

[0160] Step S4031: acquiring a theoretical cutoff temperature of the battery in the current charging stage according to the charging model.

[0161] In some embodiments, see Figure 7 The charging model includes a first model, which is established based on the charging current and charging temperature. The charging current corresponding to each charging stage in the first model is a theoretical temperature current, which is a charging current after current limiting, that is, a maximum safe charging current or a maximum allowable current based on the charging temperature. Each charging stage in the first model corresponds to a theoretical starting temperature and a theoretical cut-off temperature. After the current charging stage is determined, the theoretical cut-off temperature corresponding to the current charging stage can be obtained.

[0162] As an example, in the first model, the theoretical temperature current (I Ti ) can set the following currents: 1.2C, 1C, 0.8C, 0.5C, 0.3C, 0.2C and 0.1C. The "C" here refers to the battery capacity.

[0163] The operating temperature range of the battery is usually -20℃ to 60℃. The optimal operating temperature range is 0℃ to 40℃. Within this range, the battery has better performance and can achieve normal charging and discharging efficiency. When the battery is at a lower temperature (for example, less than 25℃), the theoretical temperature current is usually set to a higher constant value (for example, 1.2C) because the battery can withstand a larger charging rate without generating too much heat or side reactions. When the temperature gradually rises (such as 25℃-35℃), the theoretical temperature current needs to gradually decrease, because the higher the temperature, the weaker the battery's acceptance capacity, and the charging rate must be slowed down to avoid overcharging and accumulation of internal pressure. When the battery approaches high temperature (such as close to 60℃), the theoretical temperature current will further decrease to a very low level. Figure 7 shows the theoretical temperature current (I Ti) and the battery temperature.

[0164] Step S4032: Use the previous cut-off temperature to correct the initial temperature, use the theoretical cut-off temperature to correct the battery temperature, and calculate the first charging time of the battery in the current charging stage.

[0165] The initial temperature is corrected using the previous cut-off temperature, and the battery temperature is corrected using the theoretical cut-off temperature, so that the formula for the corrected battery temperature is:

[0166]

[0167] Among them, the T end(n+1) is the theoretical cut-off temperature of the nth charging stage, the T env is the ambient temperature, the T n is the front cut-off temperature of the previous charging stage of the nth charging stage, V is the temperature rise rate, K is the cooling coefficient, e is the base of the natural logarithm, is the first charging duration of the nth charging stage;

[0168] When n is 1, that is, the current charging stage is the first charging stage, then T 1 It is the starting temperature when the battery starts to be charged.

[0169] According to the above corrected battery temperature formula, the formula for the first charging time of the battery in the current charging stage is:

[0170]

[0171] Among them, the is the first charging duration of the nth charging stage, and the T end(n+1) is the theoretical cut-off temperature of the nth charging stage, V is the temperature rise rate, and T n is the previous cut-off temperature of the previous charging stage of the nth charging stage, and the T env is the ambient temperature, K is the cooling coefficient, and ln is the logarithm with e as the base;

[0172] When n is 1, that is, the current charging stage is the first charging stage, then T 1 It is the starting temperature when the battery starts to be charged.

[0173] Step S4033, obtaining the rated capacity of the battery.

[0174] The rated capacity of a battery refers to the minimum amount of electricity that the battery should be able to discharge under certain discharge conditions (such as a certain temperature, discharge rate, and termination voltage), usually expressed in ampere-hours or milliampere-hours. This indicator reflects the amount of electricity stored in the battery and is one of the important parameters for measuring battery performance. In practical applications, the rated capacity of a battery is of great significance in determining the battery's service life and replacement cycle.

[0175] The specific value of the rated capacity of the battery is pre-set in the battery, for example, in a battery management system (BMS).

[0176] Step S4034: acquiring a starting SOC and an ending SOC corresponding to the current charging stage according to the charging model.

[0177] In some embodiments, see Figure 8 , Figure 8 Another implementation form of the charging model is shown. Specifically, the charging model includes a second model, which is established based on the charging current and the SOC of the battery. The charging current corresponding to each charging stage in the second model is a theoretical charging current. The theoretical temperature current is the charging current after current limiting, that is, the maximum safe charging current or the maximum allowable current based on the SOC of the battery. Since the second model is established based on the charging current and the SOC of the battery, the starting SOC and the ending SOC can be queried according to the second model.

[0178] As an example, in the second model, the theoretical charging current (I SOCi ) can be set to the following currents: 1.2C, 1C, 0.8C, 0.5C, 0.3C, 0.2C and 0.1C. The "C" here refers to the battery capacity, for example, a 100Ah battery is charged at 1C, the theoretical charging current is 100A.

[0179] When the battery is at a low SOC, the theoretical charge current is usually set to a higher constant value (such as 1.2C) because the battery can withstand a larger charge rate without generating too much heat or side reactions. When the battery SOC is larger (such as SOC reaches more than 80%), the theoretical charge current needs to be gradually reduced because the battery's acceptance capacity is weakened and the charging rate must be slowed down to avoid overcharging and internal pressure accumulation. When the battery is close to being fully charged (SOC is close to 100%), the theoretical charge current will be further reduced to a very low level, called trickle charge or float charge, to keep the battery in a fully charged state without causing overcharging. Figure 8 The theoretical charging current (I SOCi ) and SOC.

[0180] It is worth noting that each charging stage in the first model may be the same as or different from each charging stage in the second model, and the theoretical temperature current corresponding to each charging stage in the first model may be the same as or different from the theoretical charging current corresponding to each charging stage in the second model.

[0181] Step S4035: Calculate the second charging time of the battery in the current charging stage according to the rated capacity, the starting SOC and the ending SOC.

[0182] In some embodiments, when the charging efficiency of the battery is taken into consideration, the second charging time may be calculated according to the charging efficiency, the rated capacity, the starting SOC, and the ending SOC.

[0183] In some embodiments, the calculation formula of the second charging time may refer to the following formula:

[0184]

[0185] Among them, the t soci is the second charging time of the i-th charging stage, the SOC i+1 is the cut-off SOC of the i-th charging stage, the SOC i is the starting SOC of the i-th charging stage, C is the rated capacity, and I SOCi is the theoretical charging current of the i-th charging stage, and η is the charging efficiency.

[0186] In some embodiments, the charging efficiency is calculated as follows:

[0187]

[0188] Among them, the Q out is the charging efficiency, is the total discharge amount of the battery during the last full charge and discharge process, and is the Q in It is the total charge capacity of the battery during the last full charge and discharge process.

[0189] Here, "last time" refers to the most recent full filling and discharging process from the current moment.

[0190] Among them, the total discharge amount during the last full charge and discharge process and the total charge amount during the last full charge and discharge process can be obtained from the battery management system (BMS).

[0191] In some embodiments, the total charge capacity during the last full charge and discharge process can be obtained by the ampere-hour integration method, and the calculation formula is:

[0192]

[0193] Among them, the Q CellAccumulate is the total charge capacity of the battery during the last full charge and discharge process, t1 is the charging start time, t2 is the charging end time, and I(t) is the current during the last full charge process.

[0194] The total discharge amount during the last full charge and discharge process can be calculated by referring to the above formula for the total charge amount during the last full charge and discharge process.

[0195] It is worth noting that, in some embodiments, the charging efficiency may also be a preset fixed value, such as 96%, 97% or 98%.

[0196] It is understandable that, in some embodiments, the charging efficiency may not be introduced when calculating the second charging time, that is, the second charging time is calculated only based on the rated capacity, the starting SOC, the ending SOC and the theoretical charging current. When the charging efficiency is introduced, it is more in line with the actual situation of battery charging, so that the calculation of the second charging time is more accurate.

[0197] The second charging time calculated above uses the theoretical charging current of the battery. In order to more accurately reflect the situation of the battery during charging, the theoretical charging current can be corrected to obtain a more accurate second charging time. Specifically, in some embodiments, please refer to Fig. 9 , the step of calculating the second charging time of the battery in the current charging stage according to the rated capacity, the starting SOC and the ending SOC, that is, step S4035 includes:

[0198] Step S40351, obtaining the current current of the battery.

[0199] The current current is the external charging current input to the battery in the current charging stage, that is, the external input current to the battery at the moment of calculating the battery temperature. The current current is the external input current limit, that is, the maximum charging current that can be input to the battery externally. For example, when charging the battery with a charger, the current of the charger is between 5A and 20A, and the external input current limit is 20A.

[0200] Step S40352: According to the charging model, obtain the theoretical charging current of the battery limited by the SOC in the current charging stage, and obtain the theoretical temperature current of the battery limited by the charging temperature in the current charging stage.

[0201] The charging model includes a first model and a second model, wherein the first model is established based on the charging current and the battery temperature, and the charging current corresponding to each charging stage is the theoretical temperature current, and the theoretical temperature current corresponding to the current charging stage can be obtained according to the charging model. The second model is established based on the charging current and the SOC of the battery, and the charging current corresponding to each charging stage is the theoretical charging current, and the theoretical charging current corresponding to the current charging stage can be obtained according to the charging model.

[0202] Step S40353, obtaining the minimum value among the current current, the theoretical charging current and the theoretical temperature current as the current calculation value.

[0203] For safety reasons, the actual current calculation value should be the minimum value among the current current, theoretical charging current and theoretical temperature current.

[0204] The formula for calculating the current value is:

[0205]

[0206] Among them, the I n is the current calculation value, the is the theoretical charging current, is the theoretical temperature current, the I MAX is the current.

[0207] Step S40354, calculating the second charging time of the battery in the current charging stage according to the rated capacity, the starting SOC, the ending SOC and the current calculation value.

[0208] In some embodiments, if the current charging stage is the first charging stage in the charging model, the second duration is corrected according to the charging efficiency, rated capacity, starting SOC, ending SOC and current calculation value, and the formula for obtaining the second charging duration is:

[0209]

[0210] Among them, the is the second charging duration corresponding to the first charging stage, and the SOC 2 is the end SOC corresponding to the first charging stage, that is, the start SOC of the second charging stage. 1 is the starting SOC corresponding to the first charging stage, C is the rated capacity, and I 1 is the calculated value of the current in the first charging stage, and η is the charging efficiency.

[0211] In some embodiments, if the current charging stage is any charging stage starting from the second charging stage in the charging model, refer to Fig.10 The step of calculating the second charging time according to the charging efficiency, rated capacity, starting SOC, ending SOC and current calculation value, i.e. step S40354, includes:

[0212] Step S1, obtaining a previous current calculation value and a previous starting SOC of the previous charging stage;

[0213] The previous charging stage is a charging stage before the current charging stage.

[0214] The previous current calculation value is the current calculation value corresponding to the previous charging stage.

[0215] It is worth noting that, in some embodiments, if there is no corresponding current calculation value in the previous charging stage, the minimum value between the theoretical charging current and the theoretical temperature current corresponding to the previous charging stage is used as the previous current calculation value.

[0216] The previous starting SOC is the starting SOC corresponding to the previous charging stage in the second model.

[0217] The previous current calculation value and the previous starting SOC may be historical data stored in the battery. Specifically, they may be managed by a BMS module.

[0218] Step S2, calculating the starting SOC calculated value of the current charging stage according to the previous current calculated value, the previous estimated duration and the previous starting SOC.

[0219] In some embodiments, the formula for calculating the starting SOC value is:

[0220]

[0221] Among them, the SOC n is the starting SOC calculation value of the nth charging stage, the SOC n-1 is the previous starting SOC of the previous charging stage of the nth charging stage, n is the charging efficiency, and I n-1 is the calculated value of the previous current in the previous charging stage of the nth charging stage, and the t n-1 is the previous estimated duration of the charging stage before the nth charging stage, and C is the rated capacity.

[0222] Among them, the nth charging stage corresponds to the current charging stage mentioned in the embodiment of the present application.

[0223] When n is 1, that is, the current charging stage is the first charging stage, then the SOC n The starting SOC calculation value for the nth charging stage is taken as zero.

[0224] Step S3, using the calculated starting SOC value to replace the starting SOC, so as to correct the second charging time and obtain the second charging time.

[0225] In some embodiments, the calculation formula of the second charging time is:

[0226]

[0227] Among them, the is the second charging time of the nth charging stage, the SOC next is the cut-off SOC of the nth charging stage, the SOC n is the calculated starting SOC value of the nth charging stage, C is the rated capacity, and I n is the current calculated value of the nth charging stage, and η is the charging efficiency. The nth charging stage corresponds to the current charging stage mentioned in the embodiment of the present application.

[0228] Through the above steps S1 to S3, the second charging duration is obtained based on the charging efficiency, rated capacity, cut-off SOC and current calculation value of the current charging stage, and combined with historical data, that is, combined with the starting SOC calculation value of the current charging stage (that is, the cut-off SOC calculation value of the previous charging stage), thereby improving the accuracy of the calculated second charging duration.

[0229] Step S4036, obtaining the minimum value of the first charging time and the second charging time as the estimated time.

[0230] By obtaining the minimum value of the first charging duration and the second charging duration as the estimated duration, the formula for the actual time spent in the current charging stage is:

[0231]

[0232] Among them, the t n is the estimated duration of the nth charging stage, is the second charging time length of the nth charging stage, is the first charging duration of the nth charging stage, wherein the nth charging stage corresponds to the current charging stage mentioned in the embodiment of the present application.

[0233] It is worth noting that Figure 7 and Figure 8The first model and the second model are shown as examples. When the first charging time is shorter than the second charging time, that is, the charging temperature will reach the next charging stage first, then the theoretical temperature current will also enter the next charging stage. Similarly, when the second charging time is shorter than the first charging time, that is, the battery SOC will reach the next charging stage first, then the theoretical charging current will also enter the next charging stage. Based on this, when the charging model includes the first model and the second model, the estimated time takes the minimum value of the first charging time and the second charging time.

[0234] It is worth noting that the estimated duration of the battery in the current charging stage is not limited to the minimum value of the first charging duration and the second charging duration, but may also have other forms. For example, in some embodiments, the second charging duration may also be taken as the estimated duration to calculate the cut-off temperature of the battery in the current charging stage.

[0235] Step S404: using the previous cut-off temperature to correct the initial temperature, using the estimated charging time to correct the charging time, and calculating the cut-off temperature of the battery in the current charging stage.

[0236] In some embodiments, the calculation formula of the cut-off temperature is:

[0237]

[0238] Among them, the T n+1 is the cut-off temperature of the nth charging stage, and the t n is the estimated duration of the nth charging stage, V is the temperature rise rate, and T n is the previous cut-off temperature of the previous charging stage of the nth charging stage, and the T env is the ambient temperature, K is the cooling coefficient, and e is the base of the natural logarithm;

[0239] Wherein, when n is 1, T 1 It is the starting temperature when the battery starts to be charged.

[0240] It is worth noting that after calculating from the first charging stage to the last charging stage, the cut-off temperature of the last charging stage can be calculated, so as to obtain the temperature of the battery during the charging process, thereby providing a basis for temperature management of the battery in practical applications.

[0241] In order to facilitate readers to understand the inventive concept of the present application, a method for calculating the battery temperature provided in an embodiment of the present application is first described with a specific example:

[0242] Set the starting SOC of the first charging stage to 20%, set the starting temperature of the battery when charging starts to 25°C, and set the SOC of the next charging stage to 80%. The rated capacity of the battery is C. The theoretical charging current of the first charging stage Theoretical temperature current in the first charging stage The current of the battery I MAX =1.3C,

[0243]

[0244] The second charging time required for SOC to increase to the next charging stage is but

[0245]

[0246] Of this, 95% is charging efficiency.

[0247] Determine that the charging temperature of 25°C is in the temperature range of 25-40°C. At this time, the limited charging current I 1 =1.0C, between 0.8C and 1.2C, by looking up the temperature rise rate table shown in Table 1, for example, the temperature rise rate corresponding to 1.0C is 17.65°C / h, the ambient temperature is 25°C, the cooling coefficient K is 0.1 as measured in the laboratory, and the theoretical cut-off temperature of the current charging stage (the first charging stage) is set to 40°C, then the first charging time of the first charging stage is:

[0248]

[0249] The estimated duration of the first charging phase is t 1 for:

[0250]

[0251] Then the cut-off temperature of the first charging stage is:

[0252]

[0253] Based on the estimated duration of the first charging stage t 1 , then the SOC first enters the next stage of 80%. At this time, the starting SOC calculation value of the second charging stage is as follows:

[0254]

[0255] The theoretical temperature current of the second charging stage can be obtained through the first model, the theoretical charging current of the second charging stage can be obtained through the second model, and the current current of the second charging stage can be obtained. Then, the minimum value of the three can be taken to obtain the current calculation value corresponding to the second charging stage;

[0256] By obtaining the cut-off SOC of the second charging stage in the second model, the second charging duration corresponding to the second charging stage can be calculated through the calculated starting SOC value (80%) of the second charging stage, the rated capacity, the calculated current value of the second charging stage, and the charging efficiency;

[0257] The theoretical cut-off temperature of the second charging stage can be obtained through the first model. According to the cut-off temperature (35.8°C) of the first charging stage, the temperature rise rate table shown in Table 1 can be queried to obtain the corresponding temperature rise rate. According to the ambient temperature, the cut-off temperature (35.8°C) of the first charging stage, and the cooling coefficient measured in the laboratory, the first charging duration of the second charging stage can be obtained; by comparing the first charging duration and the second charging duration, the estimated duration corresponding to the second charging stage can be obtained; according to the estimated duration corresponding to the second charging stage, according to the cut-off temperature (35.8°C) of the first charging stage, the temperature rise rate table shown in Table 1 is queried to obtain the corresponding temperature rise rate. According to the cut-off temperature (35.8°C) of the first charging stage, according to the ambient temperature and the cooling coefficient measured in the laboratory, the cut-off temperature of the second charging stage can be calculated;

[0258] By repeating the above steps, the cut-off temperature of the last charging stage can be obtained, that is, the temperature of the battery at the end of the charging process can be obtained.

[0259] In an embodiment of the present application, a method for calculating the battery temperature includes: obtaining the charging parameters of the battery, the charging parameters including the charging current and the charging temperature; obtaining a temperature rise rate model according to the charging current and the charging temperature; obtaining the initial temperature, ambient temperature, temperature rise rate and charging time of the battery; and calculating the battery temperature according to the temperature rise rate, initial temperature, ambient temperature and charging time. Through this method, not only the temperature of the battery during charging can be calculated, but also because the battery temperature is calculated based on the temperature rise rate, initial temperature, ambient temperature and charging time, that is, based on dynamic conditions, the temperature of the battery can be calculated in real time, providing reliable reference data for the thermal management of the battery, and improving the safety of charging the battery. In addition, since the method for calculating the battery temperature provided in the present application does not require the use of temperature testing equipment to detect the temperature of the battery, that is, no additional equipment cost is required, the method for calculating the battery temperature provided in the present application has good economic benefits.

[0260] Embodiment 4

[0261] The following is a discussion of the battery temperature calculation device provided in the embodiment of the present application. Fig.11 , Fig.11It is a schematic diagram of a battery temperature calculation device provided in an embodiment of the present application, the battery temperature calculation device 1 includes a first acquisition module 11, which is used to obtain the charging parameters of the battery, and the charging parameters include charging current and charging temperature; wherein the charging parameters are charging parameters of the battery tested by an experimental method; the charging temperature is the test temperature of the battery; a second acquisition module 12, which is used to obtain a temperature rise rate model according to the charging current and the charging temperature; a third acquisition module 13, which is used to obtain the initial temperature, ambient temperature, temperature rise rate and charging time of the battery; wherein, according to the initial temperature and the charging current corresponding to the initial temperature, the corresponding temperature rise rate is found by searching the temperature rise rate model; a calculation module 14, which is used to calculate the battery temperature according to the temperature rise rate, initial temperature, ambient temperature and charging time.

[0262] In some embodiments, the calculation module 14 includes a model building unit 141, which is used to build a charging model according to the charging parameters, and the charging model includes multiple charging stages; a first acquisition unit 142, which is used to obtain the front cut-off temperature of the previous charging stage; a first calculation unit 143, which is used to calculate the estimated duration of the battery in the current charging stage according to the charging model; a second calculation unit 144, which is used to correct the initial temperature using the front cut-off temperature, correct the charging duration using the estimated duration, and calculate the cut-off temperature of the battery in the current charging stage.

[0263] In some embodiments, the charging parameters also include SOC, and the first calculation unit 143 is specifically used to obtain the theoretical cut-off temperature of the battery in the current charging stage according to the charging model; use the previous cut-off temperature to correct the initial temperature, use the theoretical cut-off temperature to correct the battery temperature, and calculate the first charging time of the battery in the current charging stage; obtain the rated capacity of the battery; according to the charging model, obtain the starting SOC and the cutting-off SOC corresponding to the current charging stage; according to the rated capacity, the starting SOC and the cutting-off SOC, calculate the second charging time of the battery in the current charging stage; obtain the minimum value of the first charging time and the second charging time as the estimated time.

[0264] In some embodiments, the first calculation unit 143 is also used to obtain the current current of the battery; according to the charging model, obtain the theoretical charging current of the battery limited by the SOC in the current charging stage, and obtain the theoretical temperature current of the battery limited by the charging temperature in the current charging stage; obtain the minimum value of the current current, the theoretical charging current and the theoretical temperature current as the current calculation value; calculate the second charging time of the battery in the current charging stage according to the rated capacity, the starting SOC, the ending SOC and the current calculation value.

[0265] In some embodiments, the first calculation unit 143 is further configured to calculate the second charging duration according to the charging efficiency, rated capacity, starting SOC, ending SOC and current calculation value.

[0266] In some embodiments, the first calculation unit 143 is also used to obtain the previous current calculation value and the previous starting SOC of the previous charging stage; calculate the starting SOC calculation value of the current charging stage according to the previous current calculation value, the previous estimated duration and the previous starting SOC; and use the starting SOC calculation value to replace the starting SOC to obtain the second charging duration.

[0267] In the embodiment of the present application, the charging parameters of the battery are obtained by the first acquisition module 11, and the charging parameters include the charging current and the charging temperature; the temperature rise rate model is obtained according to the charging current and the charging temperature by the second acquisition module 12; the initial temperature, ambient temperature, temperature rise rate and charging time of the battery are obtained by the third acquisition module 13; the battery temperature is calculated according to the temperature rise rate, initial temperature, ambient temperature and charging time by the calculation module 14, so that not only the temperature of the battery during charging can be calculated, but also because the battery temperature is calculated based on the temperature rise rate, initial temperature, ambient temperature and charging time, that is, based on dynamic conditions, the temperature of the battery can be calculated in real time, providing reliable reference data for the thermal management of the battery, and improving the safety of charging the battery. In addition, since the battery temperature calculation method provided in the present application does not require the use of temperature testing equipment to detect the temperature of the battery, that is, no additional equipment cost is required, the battery temperature calculation method provided in the present application has good economic benefits.

[0268] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Under the concept of the present application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes in different aspects of the present application as above, which are not provided in detail for the sake of simplicity. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for calculating battery temperature, characterized in that: Methods include: Obtaining charging parameters of the battery, wherein the charging parameters include charging current and charging temperature; wherein the charging parameters are charging parameters of the battery tested by an experimental method; and the charging temperature is a test temperature of the battery; Obtaining a temperature rise rate model according to the charging current and the charging temperature; Acquire the initial temperature, ambient temperature, temperature rise rate and charging time of the battery; wherein, according to the initial temperature and the charging current corresponding to the initial temperature, find the corresponding temperature rise rate by searching the temperature rise rate model; The battery temperature is calculated according to the temperature rise rate, the initial temperature, the ambient temperature and the charging time.

2. The method according to claim 1, characterized in that The formula for calculating the battery temperature according to the temperature rise rate, initial temperature, ambient temperature and charging time is: Wherein, T(t) is the battery temperature, V is the temperature rise rate, and T Start is the initial temperature, the T env is the ambient temperature, t is the charging time, K is the cooling coefficient, and e is the base of the natural logarithm.

3. The method according to claim 2, characterized in that The step of calculating the battery temperature according to the temperature rise rate, the initial temperature, the ambient temperature and the charging time includes: Establishing a charging model according to the charging parameters, wherein the charging model includes multiple charging stages; Get the previous cutoff temperature of the previous charging stage; Calculating the estimated duration of the battery in the current charging stage according to the charging model; The initial temperature is corrected using the previous cut-off temperature, the charging duration is corrected using the estimated duration, and the cut-off temperature of the battery in the current charging stage is calculated.

4. The method according to claim 3, characterized in that The calculation formula of the cut-off temperature is: Among them, the T n+1 is the cut-off temperature of the nth charging stage, and the t n is the estimated duration of the nth charging stage, V is the temperature rise rate, and T n is the previous cut-off temperature of the previous charging stage of the nth charging stage, and the T env is the ambient temperature, K is the cooling coefficient, and e is the base of the natural logarithm; Wherein, when n is 1, T1 is the starting temperature when the battery starts to be charged.

5. The method according to claim 3, characterized in that: The charging parameter also includes SOC, and the step of calculating the estimated duration of the battery in the current charging stage includes: According to the charging model, obtaining a theoretical cut-off temperature of the battery in the current charging stage; Correct the initial temperature using the previous cut-off temperature, correct the battery temperature using the theoretical cut-off temperature, and calculate the first charging time of the battery in the current charging stage; Obtaining the rated capacity of the battery; According to the charging model, obtaining a starting SOC and a stopping SOC corresponding to the current charging stage; Calculating a second charging time of the battery in the current charging stage according to the rated capacity, the starting SOC and the ending SOC; The minimum value of the first charging duration and the second charging duration is obtained as the estimated charging duration.

6. The method according to claim 5, characterized in that The calculation formula of the first charging time is: Among them, the t Tn is the first charging duration of the nth charging stage, and the T end(n+1) is the theoretical cut-off temperature of the nth charging stage, V is the temperature rise rate, and T n is the previous cut-off temperature of the previous charging stage of the nth charging stage, and the T env is the ambient temperature, K is the cooling coefficient, and ln is the logarithm with e as the base; Wherein, when n is 1, T1 is the starting temperature when the battery starts to be charged.

7. The method according to claim 5, characterized in that The step of calculating the second charging duration of the battery in the current charging stage according to the rated capacity, the starting SOC and the ending SOC comprises: Obtaining the current of the battery; According to the charging model, obtaining a theoretical charging current of the battery limited by the SOC at the current charging stage, and obtaining a theoretical temperature current of the battery limited by the charging temperature at the current charging stage; Obtaining the minimum value among the current current, the theoretical charging current and the theoretical temperature current as the current calculation value; The second charging duration of the battery in the current charging stage is calculated according to the rated capacity, the starting SOC, the ending SOC and the current calculation value.

8. The method according to claim 7, characterized in that The battery has a charging efficiency, and the step of calculating the second charging time of the battery in the current charging stage according to the rated capacity, the starting SOC, the ending SOC and the current calculation value includes: The second charging time is calculated according to the charging efficiency, rated capacity, starting SOC, ending SOC and current calculation value.

9. The method according to claim 8, characterized in that The step of calculating the second charging time according to the charging efficiency, rated capacity, starting SOC, ending SOC and current calculation value comprises: Obtaining a previous current calculation value and a previous starting SOC of the previous charging stage; Calculating a starting SOC calculated value of the current charging phase according to the previous current calculated value, the previous estimated duration and the previous starting SOC; The starting SOC is replaced by the starting SOC calculation value to obtain the second charging duration.

10. The method according to claim 9, characterized in that The formula for calculating the starting SOC value is: Among them, the SOC n is the starting SOC calculation value of the nth charging stage, the SOC n-1 is the previous starting SOC of the previous charging stage of the nth charging stage, n is the charging efficiency, and I n-1 is the calculated value of the previous current in the previous charging stage of the nth charging stage, and the t n-1 is the previous estimated duration of the charging stage before the nth charging stage, and C is the rated capacity.

11. The method according to claim 10, characterized in that The calculation formula of the second charging time is: Among them, the t SOCn is the second charging time of the nth charging stage, the SOC next is the cut-off SOC of the nth charging stage, the SOC n is the calculated starting SOC value of the nth charging stage, C is the rated capacity, and I n is the calculated current value of the nth charging stage, and η is the charging efficiency.

12. A battery temperature calculation device, characterized in that: include: A first acquisition module is used to acquire charging parameters of the battery, wherein the charging parameters include charging current and charging temperature; wherein the charging parameters are charging parameters of the battery tested by an experimental method; and the charging temperature is a test temperature of the battery; A second acquisition module, used for obtaining a temperature rise rate model according to the charging current and the charging temperature; A third acquisition module is used to acquire the initial temperature, ambient temperature, temperature rise rate and charging time of the battery; wherein, according to the initial temperature and the charging current corresponding to the initial temperature, the corresponding temperature rise rate is found by searching the temperature rise rate model; The calculation module is used to calculate the battery temperature according to the temperature rise rate, the initial temperature, the ambient temperature and the charging time.

13. A battery, characterized in that: include: at least one processor; as well as A memory, wherein the memory is communicatively connected to the at least one processor, the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the method according to any one of claims 1 to 11.

14. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the processor performs the steps of the method according to any one of claims 1 to 11.

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