Vehicle Power Battery State Detection Method and Cooling Control System

Abstract

This application belongs to the technical field of power battery state control, and particularly relates to a method for detecting the state of a vehicle-mounted power battery and a cooling control system. It includes step 1 of determining the operating conditions of the power battery system, establishing SOH monitoring devices for all power batteries, obtaining SOH parameters of all power batteries, and real-time monitoring and feedback of SOH parameters of each individual power battery; step 2 of determining the overheated state of the power battery system; evaluating and warning the overheated state of the system based on the SOH data of all power batteries in the system. The power battery cooling control system includes a direct injection emergency cooling module and a shell-type heat exchange cooling module. The implementation of this application is more convenient with fewer operating steps, and it can quickly determine the operating state of the system through some parameters measured by the SOH system of the power battery. Through the improved scheme, it can also predict the expected working window of the battery system in advance for early warning and planned use.

Description

Technical Field

[0001] This application belongs to the technical field of power battery state control, and particularly relates to a method for detecting the state of a vehicle power battery and a cooling control system. Background Art

[0002] With the rapid development of battery technology, its performance has developed rapidly, the battery's endurance and stability have been continuously improved, and it has been widely used in various aspects such as logistics, transportation, and production and processing. Batteries can be divided into two categories: storage batteries and power batteries according to their different usage requirements. Among them, power batteries are mainly used as energy storage function devices for electric vehicles and other electric vehicles. During the use of power batteries, in addition to ensuring sufficient energy storage capacity, they also need to be able to output electrical energy stably and efficiently. During this process, power batteries need to frequently change their working modes, and the internal temperature of the battery changes complexly during use. Therefore, it is necessary to effectively monitor and control its temperature. Summary of the Invention

[0003] The purpose of this application is to provide a method for detecting the state of a vehicle power battery and its cooling control system that is more convenient to implement, more flexible and intelligent, and can effectively feedback and detect the state and usage of the vehicle power battery.

[0004] To achieve the above purpose, this application adopts the following technical solutions.

[0005] A method for detecting the state of a vehicle power battery includes steps 1 and 2:

[0006] Step 1. A step for determining the operating conditions of the power battery system; specifically, it refers to establishing an SOH monitoring device for all power batteries based on the power battery system, obtaining the SOH parameters of all power batteries, and real-time monitoring and feedback of the SOH parameters of each single power battery, specifically including A1;

[0007] A1. Obtaining the SOH parameters of each single power battery; extracting the battery temperature T of each single power battery within the current detection cycle t t i ; counting the number C of single power batteries with T t i ≥T max ; i = 1, 2,..., I refers to the serial number of the single power battery, and t refers to the measurement cycle number; T t refers to the preset overheat temperature threshold of the power battery; max is the preset overheat temperature threshold of the power battery;

[0008] Step 2. A step for determining the overheat state of the power battery system; specifically, it refers to evaluating and warning the overheat state of the system based on the SOH data of all power batteries in the system, including B1 and B2;

[0009] B1. Determine the current overheat coefficient of the power battery system C refers to the total number of all power batteries in the system; determine the expected temperature of a single power battery Determine the overheat risk coefficient of the power battery system C t+1 refers to T i+1,i ≥T max The number C of single power batteries t+1 ; System average temperature Determine the expected average temperature change of the system

[0010] B2. Determine the overheat state of the power battery system;

[0011] If the current overheat coefficient That is, more than 80% of the single power batteries in the system are in an overheat state, and That is, the overheat states of the single batteries in the system are inconsistent, and the temperature difference between adjacent batteries exceeds within five degrees, then it is determined that the system is in an abnormal state; where |ΔT t nera | refers to the temperature difference between any two adjacent single power batteries;

[0012] If the current overheat coefficient That is, more than 80% of the single power batteries in the system are in an overheat state, and |ΔT t nera | max ≤5, that is, the overheat states of the single batteries in the system are consistent, and the temperature difference between adjacent batteries is within five degrees, then it is determined that the system is in an overall overheat state

[0013] If the current overheat coefficient That is, more than 80% of the single power batteries in the system are in an overheat state, and |ΔT t nera | max >5, that is, the temperatures of the single power batteries in the system are uneven and the local temperature difference exceeds 8 degrees, then it is determined that the system is in a local overheat state;

[0014] If the current overheat coefficient That is, the proportion of single power batteries in the system in an overheat state is less than 0.5, and |ΔT t nera | max ≤5, that is, the overheat states of the single batteries in the system are consistent, and the temperature difference between adjacent batteries is within five degrees, then it is determined that the system is in a stable state.

[0015] For a further improvement or preferred implementation of the foregoing method for detecting the state of a vehicle's power battery, for a device using an independent temperature control system for individual batteries, if it is determined in step B2 that the system is in a locally overheated state, the following steps are continued:

[0016] Judge whether the current overheat coefficient satisfies β t ∈[0.5, 0.8). If it is satisfied, the determination result of the locally overheated state is maintained; if β t <0.5, then further calculate the maximum value of the difference between the highest temperature of the individual power batteries in the system and the preset overheat temperature threshold of the power battery (T t i -T max ) max , if (T t i -T max ) max ≥10, that is, the temperature of the individual power batteries in the system far exceeds the preset overheat temperature threshold of the power battery, then correct the locally overheated state to an abnormal alarm state.

[0017] For a further improvement or preferred implementation of the foregoing method for detecting the state of a vehicle's power battery, for a power battery system using an overall cooling system, step 1 further includes A2;

[0018] A2. Specifically, it includes: determining the expected temperature change value of the power battery where a = 1, 2,..., A refers to several working modes of the power battery i, is the average slope of the temperature change curve of the individual power battery in the corresponding mode, is the average duration of the individual power battery i in mode a, is the probability that the power battery i will be in mode a in the next detection cycle; determining the expected temperature of the individual power battery Determining the overheat risk coefficient of the power battery system C t+1 refers to T i+1,i ≥T max of the number of individual power batteries; determining the expected average temperature change of the system

[0019] In step B2, if it is determined that the system is in a stable state, the following steps are continued to determine the overheat risk coefficient β of the battery system t+1 ; if the overheat risk coefficient β of the system t+1 ≥0.8 and ΔT t+1 ≥0.5T max ; then correct the system state to the expected overheated state;

[0020] If the system is in an overheated state, further determine the expected maximum temperature of the single power battery in the system and the preset power battery overheating temperature threshold T max The maximum value of the difference If (T t i -T max ) max ≥10, the expected overheating state is corrected to the abnormal alarm state.

[0021] A power battery cooling control system for a vehicle power battery status detection method includes a direct injection emergency cooling module and a shell-type heat exchange cooling module. The direct injection emergency cooling module cools each single power battery independently, and the shell-type heat exchange module cools the power battery system as a whole.

[0022] Its beneficial effects are:

[0023] The vehicle power battery status detection method and its power battery cooling control system of the present application are easier to implement, have fewer operating steps, and can quickly determine the system operating status through some parameters measured by the SOH system of the power battery. Through the improved scheme, the expected working window of the battery system can also be predicted in advance to facilitate early warning and planned use. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a flow chart of a vehicle power battery status detection method. DETAILED DESCRIPTION

[0025] The present application is described in detail below in conjunction with specific embodiments.

[0026] A vehicle power battery status detection method includes steps 1 and 2:

[0027] Step 1. A step for determining the operating condition of the power battery system; specifically, establishing a SOH monitoring device for all power batteries based on the power battery system, obtaining SOH parameters of all power batteries, and real-time monitoring and feedback of SOH parameters of each single power battery, specifically including A1 and A2;

[0028] A1. Obtain the SOH parameters of each power battery; extract the battery temperature T of each power battery in the current detection cycle t t i ; Statistics T t i ≥T max The number of single power batteries C t ; i = 1, 2, ..., I refers to the number of the single power battery, t refers to the measurement cycle number; T maxrefers to the preset overheat temperature threshold of the power battery;

[0029] A2. Specifically, it includes: determining the expected temperature change value of the power battery where a = 1, 2,..., A refers to several working modes of the i-th power battery, refers to the average slope of the temperature change curve of the single power battery in the corresponding mode, refers to the average duration period of the single power battery i in the a mode, is the probability that the i-th power battery is in the a mode in the next detection cycle; determining the expected temperature of the single power battery Determining the overheat risk coefficient of the power battery system C t+1 refers to T i+1,i ≥T max is the number of single power batteries; determining the expected average temperature change of the system

[0030] Step 2. Steps for determining the overheat state of the power battery system; specifically, it refers to evaluating and warning the overheat state of the system based on the SOH data of all power batteries in the system, including B1 and B2;

[0031] B1. Determining the current overheat coefficient of the power battery system C refers to the total number of all power batteries in the system; determining the expected temperature of the single power battery Determining the overheat risk coefficient of the power battery system C t+1 refers to T i+1,i ≥T max is the number C of single power batteries; the average temperature of the system t+1 ; Determining the expected average temperature change of the system

[0032] B2. Determining the overheat state of the power battery system;

[0033] If the current overheat coefficient that is, more than 80% of the single power batteries in the system are in an overheat state, and |ΔT t nera | max > 5, that is, the overheat states of the single batteries in the system are inconsistent, and the temperature difference between adjacent batteries exceeds five degrees, then it is determined that the system is in an abnormal state; where |ΔT t nera | refers to the temperature difference between any two adjacent single power batteries;

[0034] If the current overheat coefficient That is, more than 80% of the single-cell power batteries in the system are in an overheated state, and |ΔT t nera | max ≤5, that is, the overheated states of the single cells in the system are consistent, and the temperature difference between adjacent batteries is within five degrees, then it is determined that the system is in an overall overheated state

[0035] If the current overheat coefficient That is, more than 80% of the single-cell power batteries in the system are in an overheated state, and |ΔT t nera | max >5, that is, the temperatures of the single-cell power batteries in the system are uneven and the local temperature difference exceeds 8 degrees, then it is determined that the system is in a local overheated state;

[0036] If the current overheat coefficient That is, the proportion of single-cell power batteries in the system in an overheated state is less than 0.5, and |ΔT t nera | max ≤5, that is, the overheated states of the single cells in the system are consistent, and the temperature difference between adjacent batteries is within five degrees, then it is determined that the system is in a stable state, and continue to execute the following steps to determine the overheat risk coefficient β of the battery system t+1 ; If the system overheat risk coefficient β t+1 ≥0.8 and ΔT t+1 ≥0.5T max ; Then correct the system state to the expected overheated state;

[0037] If the system is in the overdue overheated state, then further determine the expected highest temperature of the single-cell power batteries in the system The maximum value of the difference from the preset overheat temperature threshold T of the power battery max If (T t i -T max ) max ≥10, then correct the expected overheated state to the abnormal alarm state.

[0038] For the equipment with an independent temperature control system for single cells, if it is determined in step B2 that the system is in a local overheated state, then continue to execute the following steps:

[0039] Judge whether the current overheat coefficient satisfies β t ∈[0.5, 0.8), if it is satisfied, then maintain the determination result of the local overheated state; if β t <0.5, then further calculate the maximum value of the difference between the highest temperature of the single-cell power batteries in the system and the preset overheat temperature threshold of the power battery (T t i -T max )​max , if (T t i - T max ) max ≥ 10, that is, the temperature of the single battery in the system far exceeds the preset overheat temperature threshold of the power battery, then correct the local overheat state to the abnormal alarm state.

[0040] The present application also provides a power battery cooling control system for a vehicle power battery state detection method, including a direct injection emergency cooling module and a shell heat exchange cooling module. The direct injection emergency cooling module independently cools each single power battery, and the shell heat exchange module cools the power battery system as a whole.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than limiting the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A method for detecting the state of a vehicle power battery, characterized in that, Including steps 1 and 2: Step 1. A step for determining the operating conditions of the power battery system; specifically, it refers to establishing an SOH monitoring device for all power batteries based on the power battery system, obtaining the SOH parameters of all power batteries, and real-time monitoring and feedback of the SOH parameters of each single power battery, specifically including A1; A1. Obtain the SOH parameters of each single battery cell; extract the battery temperature T of each single battery cell within the current detection period t t i ; Statistical T t i ≥T max The number C of single cell power batteries t ; i = 1, 2,..., I refers to the serial number of the single cell power battery, and t refers to the measurement cycle number; T max Refers to the preset overheat temperature threshold of the power battery Step 2. A step for determining the overheat state of the power battery system; specifically, it refers to evaluating and warning the overheat state of the system based on the SOH data of all power batteries in the system, including B1 and B2; B1. Determine the current overheat coefficient of the power battery system C refers to the total number of all power batteries within the system; B2. Determine the overheat state of the power battery system; If the current overheat coefficient and |ΔT t nera | max ≥ 5, it is determined that the system is in an abnormal state; where |ΔT t nera | refers to the temperature difference between any two adjacent single battery cells within the system; If the current overheat coefficient and |ΔT t nera | max <5, it is determined that the system is in an overall overheat state If the current overheat coefficient and |ΔT t nera | max ≥ 5, it is determined that the system is in a local overheat state; If the current overheat coefficient and |ΔT t nera | max <5, it is determined that the system is in a stable state.

2. The method for detecting the state of a vehicle power battery according to claim 1, wherein, For a power battery system adopting an independent cooling system for single cells, if it is determined in the step B2 that the system is in a local overheat state, then continue to execute the following steps: Determine whether the current overheat coefficient satisfies β t ∈[0.5, 0.8). If it is satisfied, maintain the determination result of the local overheat state; if β t <0.5, then further calculate the maximum value of the difference between the highest temperature T t i of the single power battery in the system and the preset overheat temperature threshold T max of the power battery, (T t i - T max ). max If (T t i - T max ) max ≥10, then correct the local overheat state to the abnormal alarm state.

3. A method for detecting the state of a vehicle power battery according to claim 1, characterized in that, The step 1 further includes A2; A2. Specifically include: determining the expected temperature change value of the power battery where a = 1, 2,..., A refers to several working modes of the power battery i refers to the average slope of the temperature change curve of the single power battery in the corresponding mode refers to the average duration period of the single power battery i in the a mode is the probability that the power battery i is in the a mode in the next detection period; determining the expected temperature of the single power battery Determining the overheat risk coefficient of the power battery system C t+1 refers to T i+1,i ≥T max is the number of single power batteries; determining the expected average temperature change of the system In step B2, if it is determined that the system is in a stable state, continue to execute the following steps to determine the overheat risk coefficient β of the battery system t+1 ; if the system overheat risk coefficient β t+1 ≥0.8 and ΔT t+1 ≥0.5T max ; then correct the system state to the expected overheat state; If the system is in an overdue overheating state, further determine the expected maximum temperature of the single power battery within the system The maximum value of the difference from the preset overheating temperature threshold T of the power battery max If (T t i - T max ) ma ≥ 10, correct the expected overheating state to an abnormal alarm state.​ 4. The power battery cooling control system of the vehicle power battery state detection method according to claim 3, characterized in that Including a direct injection type emergency cooling module and a shell type heat exchange cooling module. The direct injection type emergency cooling module independently cools each single power battery, and the shell type heat exchange module cools the power battery system as a whole.

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