Diagnosis Method for Temperature Abnormal State of Battery Cells Utilizing Temperature Sensors of Battery Management System (BMS)

Abstract

To provide a system and a method for diagnosing the temperature condition of a battery cell or a module.SOLUTION: More particularly, the present invention relates to a system and a method for diagnosing an abnormal state of the temperature of a battery cell or a module on the basis of relative temperature change of the battery cell using a difference between the temperatures of the cell or module surface compared to a temperature sensor in a battery management system (BMS).SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a diagnostic system and method for the temperature state of a battery cell or module. More specifically, the present invention relates to a system and method for diagnosing an abnormal temperature state of a battery cell or module in accordance with a change in the relative temperature of the battery cell or module by utilizing a temperature sensor of a battery management system (BMS).

Background Art

[0002] Batteries used as energy sources for various portable electronic devices such as smartphones, notebook computers, and personal digital assistants (PDAs) may have their temperatures rise above the reference temperature under certain circumstances. For example, when a short circuit occurs inside a cell incorporated in the battery, when an abnormally large amount of power is consumed in an electronic device with a battery, or when an electronic device with a battery is exposed to a high-temperature environment.

[0003] When the temperature of the battery rises above the reference temperature in this way, a large amount of gas is released due to the decomposition of the electrolyte or active material built into the battery cell, and there is a risk that the internal pressure of the cell will rise rapidly and the cell will explode. In addition, there is a disadvantage that the electrochemical characteristics of the battery cell are deteriorated and the life of the battery is shortened.

[0004] To eliminate such disadvantages, the temperature of the battery cell is measured, and if it increases above a predetermined reference value, it is diagnosed as an abnormal temperature state, and the current of the battery is cut off to prevent further temperature rise.

[0005] However, in the case of the conventional technology as described above, the change in the temperature around the battery cell is not reflected at all, and the abnormal state of the temperature is judged only based on the absolute temperature of the battery cell itself. In this regard, as long as the temperature of the battery cell itself does not rise, it is impossible to detect abnormal temperature behavior in advance, so there is a disadvantage that the abnormal state of the temperature of the battery cell cannot be diagnosed promptly.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] The present invention is for solving the above-mentioned disadvantages, and diagnoses an abnormal state with the relative cell temperature state reflecting the change in the temperature around the battery cell, and further aims to diagnose and take measures for the abnormal state of the temperature more promptly.

Means for Solving the Problems

[0008] A system for diagnosing an abnormal state of the temperature of a battery cell according to the present invention includes a first temperature measurement unit that is arranged around the battery cell and measures the temperature of the cell periphery at a predetermined cycle, a second temperature measurement unit that is arranged on the surface of the battery cell and measures the surface temperature of the cell at a predetermined cycle, a temperature difference calculation unit that calculates the difference between the temperature of the cell periphery measured by the first temperature measurement unit and the surface temperature of the cell measured by the second temperature measurement unit, an abnormal state primary diagnosis unit that compares the temperature difference calculated by the temperature difference calculation unit with an abnormal state condition of a predetermined temperature and primarily diagnoses an abnormal state of the temperature of the battery cell based on the comparison result, an abnormal state secondary diagnosis unit that finally diagnoses the abnormal state of the temperature of the battery cell based on whether or not the state continues for a predetermined duration from the time when the abnormal state primary diagnosis unit diagnoses the abnormal state of the temperature, an abnormal treatment unit that takes a measure corresponding to the final diagnosis result of the abnormal state secondary diagnosis unit, a timer that measures the duration of the state from the time when the abnormal state primary diagnosis unit diagnoses the abnormal state of the temperature, and a memory unit that stores reference data for diagnosing the abnormal state of the temperature of the battery cell in the abnormal state primary diagnosis unit and the abnormal state secondary diagnosis unit.

[0009] On the one hand, a system for diagnosing an abnormal state of the temperature of a battery module according to the present invention includes a first temperature measurement unit disposed around the battery module and measuring the temperature of the periphery of the module at a predetermined period, a second temperature measurement unit disposed on the surface of the battery module and measuring the surface temperature of the module at a predetermined period, a temperature difference calculation unit calculating the difference between the temperature of the periphery of the module measured by the first temperature measurement unit and the surface temperature of the module measured by the second temperature measurement unit, an abnormal state primary diagnosis unit comparing the temperature difference calculated by the temperature difference calculation unit with abnormal state conditions of a predetermined temperature and primarily diagnosing the abnormal state of the temperature of the battery module based on the comparison result, an abnormal state secondary diagnosis unit finally diagnosing the abnormal state of the temperature of the battery module based on whether the state continues for a predetermined duration from the time when the abnormal state primary diagnosis unit diagnoses the abnormal state of the temperature, an abnormal treatment unit taking a treatment corresponding to the final diagnosis result of the abnormal state secondary diagnosis unit, a timer measuring the duration of continuation of the state from the time when the abnormal state primary diagnosis unit diagnoses the abnormal state of the temperature, and a memory unit storing reference data for diagnosing the abnormal state of the temperature of the battery module in the abnormal state primary diagnosis unit and the abnormal state secondary diagnosis unit.

[0010] Here, the abnormal state primary diagnosis unit includes a difference comparison unit comparing the temperature difference with at least two or more predetermined difference reference values set in order from a low value, and an abnormal signal output unit outputting an abnormal signal based on the comparison result in the difference comparison unit.

[0011] On the other hand, the difference comparison unit compares whether the temperature difference is equal to or greater than or less than a predetermined first difference reference value, and in subsequent cycles, based on the abnormal signal output from the abnormal signal output unit, sequentially compares whether the state where the temperature difference is equal to or greater than the predetermined first difference reference value continues and is equal to or greater than a predetermined second difference reference value and a third difference reference value.

[0012] On the one hand, if the temperature difference is equal to or greater than a predetermined first difference reference value, the abnormal signal output unit outputs a first abnormal signal indicating that fact. If, while the temperature difference is equal to or greater than the predetermined first difference reference value, it subsequently becomes equal to or greater than a predetermined second difference reference value, the abnormal signal output unit outputs a second abnormal signal indicating that fact. If, while the temperature difference is equal to or greater than the predetermined second difference reference value, it subsequently becomes equal to or greater than a predetermined third difference reference value, the abnormal signal output unit outputs a third abnormal signal indicating that fact.

[0013] On the one hand, if the time during which the temperature difference continues in the state from the time when the first abnormal signal is output from the abnormal signal output unit is equal to or greater than a predetermined first duration, the abnormal state secondary diagnosis unit finally diagnoses that the current temperature state of the battery cell or module is in a first abnormal warning state, and outputs a first abnormal warning signal indicating that fact. In subsequent cycles, if the time during which the temperature difference continues in the state from the time when the second abnormal signal is output from the abnormal signal output unit is equal to or greater than the predetermined first duration, the abnormal state secondary diagnosis unit finally diagnoses that the current temperature state of the battery cell or module is in a second abnormal warning state, and outputs a second abnormal warning signal indicating that fact. In subsequent cycles, if the time during which the temperature difference continues in the state from the time when the second abnormal signal is output from the abnormal signal output unit is equal to or greater than a predetermined second duration, the abnormal state secondary diagnosis unit finally diagnoses that the current temperature state of the battery cell or module is in a first abnormal danger state, and outputs a first abnormal danger signal indicating that fact. In subsequent cycles, if the time during which the temperature difference continues in the state from the time when the third abnormal signal is output from the abnormal signal output unit is equal to or greater than a predetermined third duration, the abnormal state secondary diagnosis unit finally diagnoses that the current temperature state of the battery cell or module is in a second abnormal danger state, and outputs a second abnormal danger signal indicating that fact.

[0014] On the one hand, when a first abnormal warning signal or a second abnormal warning signal is output from the abnormal state secondary diagnosis unit, the abnormal handling unit is characterized by cutting off the inflow of current from the outside to the battery pack. In subsequent cycles, when a first abnormal danger signal or a second abnormal danger signal is output from the abnormal state secondary diagnosis unit, the power line inside the battery pack is further cut off.

[0015] The method for diagnosing an abnormal state of the temperature of a battery cell according to the present invention includes, at each predetermined cycle, a temperature measurement step of measuring the temperature of the periphery of the cell and the surface temperature of the cell of the battery cell, a temperature difference calculation step of calculating the difference between the temperature of the periphery of the cell measured in the temperature measurement step and the surface temperature of the cell, and comparing whether the calculated temperature difference continues for a predetermined first duration in a state where the temperature difference is equal to or greater than a predetermined first difference reference value, and diagnosing, based on the comparison result, whether the state of the temperature of the battery cell is a first abnormal warning state. An abnormal handling step of cutting off the inflow of current from the outside to the battery pack if the state of the current temperature of the battery cell is diagnosed as a first abnormal warning state by the first abnormal warning state diagnosis step. The first abnormal warning state diagnosis step includes a difference comparison step of comparing whether the current temperature difference calculated in the temperature difference calculation step is equal to or greater than a predetermined first difference reference value, and a duration confirmation step of confirming whether the temperature difference is maintained for a predetermined first duration in the state where the temperature difference is equal to or greater than a predetermined first difference reference value if the temperature difference is equal to or greater than a predetermined first difference reference value as a result of the comparison in the difference comparison step. If the temperature difference is maintained for a predetermined first duration in a state where the temperature difference is equal to or greater than a predetermined first difference reference value, it is characterized in that the state of the current temperature of the battery cell is diagnosed as a first abnormal warning state.

[0016] On the one hand, a method for diagnosing an abnormal state of the temperature of a battery module according to the present invention includes a temperature measurement step of measuring the temperature of the peripheral part of the module and the surface temperature of the module of the battery module at a predetermined cycle, a temperature difference calculation step of calculating the difference between the temperature of the peripheral part of the module and the surface temperature of the module measured in the temperature measurement step, and comparing whether the calculated temperature difference is maintained for a predetermined first duration in a state where the temperature difference is equal to or greater than a predetermined first difference reference value, and diagnosing whether the temperature state of the battery module is in a first abnormal warning state based on the comparison result. An abnormal treatment step of cutting off the flow of current from the outside to the battery pack if the temperature state of the current battery module is diagnosed as being in the first abnormal warning state by the first abnormal warning state diagnosis step. The first abnormal warning state diagnosis step includes a difference comparison step of comparing whether the current temperature difference calculated in the temperature difference calculation step is equal to or greater than a predetermined first difference reference value, and a duration confirmation step of confirming whether the temperature difference is maintained for a predetermined first duration in the state where the temperature difference is equal to or greater than a predetermined first difference reference value as a result of the comparison in the difference comparison step. If the temperature difference is maintained for a predetermined first duration in a state where the temperature difference is equal to or greater than a predetermined first difference reference value, it is characterized in that the temperature state of the current battery module is diagnosed as being in the first abnormal warning state.

[0017] Specifically, after diagnosing that the temperature state of the battery cell or module is in the first abnormal warning state in the first abnormal warning state diagnosis step, it is compared whether the current temperature difference calculated using the temperature difference calculation step is maintained for a predetermined first duration in a state where it is equal to or higher than a predetermined second difference reference value that is higher than the predetermined first difference reference value. Based on the comparison result, a second abnormal warning state diagnosis step for diagnosing whether the temperature state of the battery cell or module is in the second abnormal warning state is performed. If it is diagnosed by the second abnormal warning state diagnosis step that the current temperature state of the battery cell or module is in the second abnormal warning state, an abnormal handling step for maintaining the cut-off state of the current flowing into the battery pack from the outside during the diagnosis of the first abnormal warning state is performed. The second abnormal warning state diagnosis step includes a difference comparison step for comparing whether the current temperature difference calculated in the temperature difference calculation step is equal to or higher than a predetermined second difference reference value, and a duration confirmation step for confirming whether, as a result of the comparison in the difference comparison step, if the temperature difference is equal to or higher than the predetermined second difference reference value, it is maintained for a predetermined first duration in that state. If it is maintained for a predetermined first duration in a state where the temperature difference is equal to or higher than the predetermined second difference reference value, it is characterized in that it is diagnosed that the current temperature state of the battery cell or module is in the second abnormal warning state.

[0018] After diagnosing in the second abnormal warning state diagnosis step that the current temperature state of the battery cell or module is in the second abnormal warning state, if it is maintained for a second duration that is longer than the predetermined first duration in a state where the temperature difference in the second abnormal warning state diagnosis step is equal to or higher than the predetermined second difference reference value, a first abnormal danger state diagnosis step for diagnosing that the current temperature state of the battery cell or module is in the first abnormal danger state is performed. If it is diagnosed by the first abnormal danger state diagnosis step that the current temperature state of the battery cell or module is in the first abnormal danger state, an abnormal handling step for further cutting off the power line inside the battery pack is performed.

[0019] And after diagnosing that the temperature state of the current battery cell or module is in the first abnormal dangerous state in the first abnormal dangerous state diagnosis step, it is compared whether the current temperature difference calculated using the temperature difference calculation step is maintained for a predetermined third duration in a state where it is equal to or greater than a predetermined third difference reference value, and based on the comparison result, a second abnormal dangerous state diagnosis step for diagnosing whether the temperature state of the battery cell or module is in the second abnormal dangerous state is performed. The second abnormal dangerous state diagnosis step includes a difference comparison step of comparing whether the current temperature difference calculated in the temperature difference calculation step is equal to or greater than a third difference reference value which is a value higher than a predetermined second difference reference value, and a duration confirmation step of confirming whether, as a result of the comparison in the difference comparison step, if the temperature difference is equal to or greater than the predetermined third difference reference value, it is maintained for a third duration which is longer than a predetermined second duration in this state. If the temperature difference is maintained for a predetermined third duration in a state where it is equal to or greater than the predetermined third difference reference value, it is characterized in that it is diagnosed that the temperature state of the current battery cell or module is in the second abnormal dangerous state.

Advantages of the Invention

[0020] The present invention can sense abnormal temperature behavior in advance by diagnosing an abnormal state based on the relative cell temperature state reflecting the change in the temperature around the battery cell, rather than the absolute temperature state of the battery cell itself.

[0021] Therefore, the abnormal state of the temperature of the battery cell can be diagnosed and treated more quickly. Furthermore, the stability and lifespan of the battery can be improved.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0023] Hereinafter, based on the accompanying drawings, embodiments of the present invention will be described in detail so that those having ordinary knowledge in the technical field to which the present invention pertains can easily implement it. However, the present invention can be embodied in various different forms and is not limited to the embodiments described herein. In the drawings, for the purpose of clearly explaining the present invention, parts irrelevant to the explanation are omitted, and similar reference numerals are given to similar parts throughout the specification.

[0024] Hereinafter, the present invention will be described in detail based on the accompanying drawings.

[0025] 1. Diagnostic System for Temperature Abnormal State According to the Present Invention FIG. 1 is a block diagram schematically showing the overall configuration of a diagnostic system for a temperature abnormal state according to the present invention. The diagnostic system for a temperature abnormal state may include a first temperature measurement unit 100, a second temperature measurement unit 200, a temperature difference calculation unit 300, a primary abnormal state diagnosis unit 400, a secondary abnormal state diagnosis unit 500, an abnormal treatment unit 600, a timer 700, and a memory unit 800.

[0026] 1.1. First Temperature Measurement Unit 100 The first temperature measurement unit is a component that is arranged in the peripheral part of the battery cell and measures the temperature of the cell peripheral part at a predetermined cycle.

[0027] More specifically, the first temperature measurement unit is a component mounted on the printed circuit board (PCB) of the battery management system (BMS) to indirectly measure the temperature of the battery cell. For example, it is located near heat sources such as the cell balancing circuit section or the pre-charge circuit section, and measures the temperature in that area. As described above, the temperature sensor of the first temperature measurement unit may be mounted on the printed circuit board (PCB). According to another example, it may be arranged on the battery case so as to approach the heat source.

[0028] On the other hand, in the case of a battery module / battery pack composed of a plurality of battery cells, the first temperature measurement unit can be arranged adjacent to electrical / chemical heat sources such as the BMS of the battery module, the BMS of the pack, or the bus bar and circuit section connecting the internal battery cells and modules.

[0029] 1.2. The second temperature measurement unit 200 The second temperature measurement unit is a component arranged on the surface of the battery cell 10 to measure the surface temperature of the cell at a predetermined cycle.

[0030] Unlike the first temperature measurement unit 100 arranged in the area around the battery cell to measure the temperature of the cell periphery, the second temperature measurement unit is arranged on the battery cell itself to measure its surface temperature.

[0031] On the other hand, in the case of a battery module / battery pack composed of a plurality of battery cells, the second temperature measurement unit may be arranged on the surface of the battery module or the battery pack to measure the surface temperature of the module or the pack.

[0032] 1.3. The temperature difference calculation unit 300 The temperature difference calculation unit is a component that calculates the difference between the temperature of the cell periphery measured by the first temperature measurement unit 100 and the surface temperature of the cell measured by the second temperature measurement unit 200.

[0033] 1.4. Primary Abnormality Diagnosis Unit 400 for Abnormal Conditions The primary abnormality diagnosis unit for abnormal conditions compares the difference between the temperature of the cell peripheral part and the surface temperature of the cell calculated by the temperature difference calculation unit 300 with the abnormal condition criteria of a predetermined temperature, and based on the comparison result, primarily diagnoses the abnormal condition of the temperature of the battery cell. Such a primary abnormality diagnosis unit for abnormal conditions may include the following detailed components.

[0034] a. Difference Comparison Unit 410 It is a component that compares the temperature difference calculated by the temperature difference calculation unit 300 with at least two or more predetermined difference reference values.

[0035] Here, the predetermined difference reference values may include first to third difference reference values set in order from a lower value.

[0036] First, it is compared whether the calculated temperature difference is greater than or less than a predetermined first difference reference value. Next, if a first abnormal signal is output from the abnormal signal output unit 420 described later, the temperature difference calculated by the temperature difference calculation unit 300 thereafter is compared with the first difference reference value and a second difference reference value set to a value higher than the first difference reference value. Next, when a second abnormal signal is output from the abnormal signal output unit 420 described later, the temperature difference calculated by the temperature difference calculation unit 300 thereafter may be compared with the second difference reference value and a third difference reference value set to a value higher than the second difference reference value.

[0037] b. Abnormal Signal Output Unit 420 The abnormal signal output unit may output an abnormal signal based on the result of the comparison in the difference comparison unit 410.

[0038] First, if the temperature difference is greater than or equal to a predetermined first difference reference value, a first abnormal signal indicating that may be output.

[0039] On the one hand, after the output of the first abnormal signal, if the calculated temperature difference, for which the tendency of the increase in the temperature difference between the cell peripheral part and the cell surface part is alleviated, is less than a predetermined first difference reference value, a first abnormal release signal indicating that fact is output.

[0040] On the other hand, after the output of the first abnormal signal, if the state where the temperature difference between the cell peripheral part and the cell surface part continues to increase and the calculated temperature difference becomes equal to or more than a predetermined second difference reference value, a second abnormal signal indicating that fact may be output.

[0041] After the output of the second abnormal signal, if the tendency of the increase in the temperature difference between the cell peripheral part and the cell surface part is alleviated and the calculated temperature difference becomes less than the predetermined second difference reference value, a second abnormal release signal indicating that fact is output.

[0042] On the one hand, even after the output of the second abnormal signal, if the state where the temperature difference between the cell peripheral part and the cell surface part continues to increase and the calculated temperature difference becomes equal to or more than a predetermined third difference reference value, a third abnormal signal indicating that fact may be output.

[0043] 1.5. Abnormal state secondary diagnosis unit 500 The abnormal state secondary diagnosis unit finally diagnoses the abnormal state of the temperature of the battery cell based on whether or not the abnormal signal output from the abnormal signal output unit 420 continues in that state for a predetermined time from the output time point. Here, whether or not it continues for a predetermined time in the state corresponding to the output abnormal signal can be confirmed using the time measured by a timer 700 described later.

[0044] FIG. 2 is a table showing an example of the conditions of the temperature abnormal state for diagnosing the abnormal state of the temperature of the battery cell step by step in the abnormal state secondary diagnosis unit, and FIG. 3 is a graph showing an example of the state of the temperature of the cell peripheral part and the surface temperature of the cell of the battery cell. With reference to these, the following detailed components will be described.

[0045] A. First abnormal warning state determination unit 510 If a first abnormal warning signal indicating that the temperature difference between the current cell periphery and the cell surface from the abnormal signal output unit 420 is equal to or greater than a predetermined first difference reference value is output, the first abnormal warning state determination unit checks whether the time measured by the timer 700 is equal to or greater than a predetermined first duration. If so, it may finally diagnose that the current battery cell temperature state is in the first abnormal warning state and output a first abnormal warning signal indicating the same. For example, as shown in the table of FIG. 2, if the first difference reference value is set to 10 °C and the first duration is set to 1 second, if the temperature difference is maintained at 10 °C or more for 1 second, it is diagnosed as being in the first abnormal warning state. At this time, the timer 700, which will be described later, measures the duration from the point when the first abnormal signal is output.

[0046] On the other hand, if the time measured by the timer 700 is less than the predetermined first duration, even if the first abnormal signal is output, it is not diagnosed that the current battery cell temperature state is in the first abnormal warning state.

[0047] On the other hand, after determining that it is in the first abnormal warning state, if a first abnormal cancellation signal indicating that the temperature difference between the cell periphery and the cell surface from the abnormal signal output unit 420 is less than the predetermined first difference reference value is output, and if the time measured by the timer 700 is equal to or greater than the predetermined first duration, it may be determined that the first abnormal warning state initially diagnosed by the battery is cancelled by the treatment of the abnormal treatment unit 600, which will be described later, and a first abnormal warning cancellation signal indicating the same may be output. For example, as shown in the table of FIG. 2, if the first difference reference value is set to 10 °C and the first duration is set to 1 second, if the temperature difference is maintained at less than 10 °C for 1 second, it is diagnosed that the first abnormal warning state initially diagnosed has been cancelled.

[0048] i. Second abnormal warning state determination unit 520 As shown in FIG. 3, the second abnormal warning state determination unit, even after the first abnormal warning state determination unit 510 finally diagnoses that the current temperature state of the battery cell is in the first abnormal warning state, if the temperature difference between the cell peripheral part and the cell surface continues to increase and a second abnormal signal indicating that the temperature difference between the current cell peripheral part and the cell surface is equal to or greater than a predetermined second difference reference value is output from the abnormal signal output unit 420, then, in the same manner as the method described above, if the duration from the time when the second abnormal signal measured by the timer 700 is output reaches a predetermined first duration, it may be finally diagnosed that the current temperature state of the battery cell is in the second abnormal warning state, and a second abnormal warning signal indicating the same may be output. For example, as shown in the table of FIG. 2, when the second difference reference value is set to 20° C. and the first duration is set to 1 second, if the temperature difference is maintained at 20° C. or more for 1 second, it is diagnosed that it is in the second abnormal warning state.

[0049] On the other hand, if the time measured by the timer 700 is less than the predetermined first duration, even if the second abnormal signal is output, it is not diagnosed that the current temperature state of the battery cell is in the second abnormal warning state.

[0050] On the other hand, after determining that it is in the second abnormal warning state, if a second abnormal cancellation signal indicating that the temperature difference between the cell peripheral part and the cell surface is less than a predetermined second difference reference value is output from the abnormal signal output unit 420, it is confirmed whether the time measured by the timer 700 is equal to or greater than the predetermined first duration. If so, it is determined that the second abnormal warning state initially diagnosed for the battery is cancelled by the treatment of the abnormal treatment unit 600 described later, etc., and a second abnormal warning cancellation signal indicating the same may be output. For example, as shown in the table of FIG. 2, when the second difference reference value is set to 20° C. and the first duration is set to 1 second, if the temperature difference is maintained at less than 20° C. for 1 second, it is diagnosed that the second abnormal warning state initially diagnosed has been cancelled.

[0051] c. First Abnormal Danger State Determination Unit 530 The first abnormal danger state determination unit determines that, in the second abnormal warning state determination unit 520, even after finally diagnosing that the current temperature state of the battery cell is in the second abnormal warning state, if the temperature difference between the cell peripheral part and the cell surface continues to be in the second abnormal warning state and the duration from the time when the second abnormal signal measured by the timer 700 is output becomes equal to or longer than a predetermined second duration set to be longer than a predetermined first duration, it is finally diagnosed that the current temperature state of the battery cell is in a first abnormal danger state meaning a higher risk level than the second abnormal warning state, and outputs a first abnormal danger signal indicating that fact. For example, as shown in the table of FIG. 2, when the second difference reference value is 20°C and the second duration is set to 3 seconds, if the temperature difference is maintained at 20°C for a period exceeding 1 second and within 3 seconds, it is diagnosed as being in the first abnormal danger state.

[0052] Here, if the time measured by the timer 700 is less than the predetermined second duration, it is not finally diagnosed as being in the first abnormal danger state, and the second abnormal warning state diagnosed by the second abnormal warning state determination unit 520 is maintained.

[0053] On the other hand, after determining that it is in the second abnormal warning state, if the duration from the time when a second abnormal cancellation signal indicating that the temperature difference between the cell peripheral part and the cell surface is less than a predetermined second difference reference value is output from the abnormal signal output unit 420 becomes equal to or longer than the predetermined second duration, it may be determined that the battery is in a state where the first abnormal warning state initially diagnosed is cancelled by means such as the treatment of an abnormal treatment unit 600 described later, and a first abnormal danger cancellation signal indicating that fact is output. For example, as shown in the table of FIG. 2, when the second difference reference value is set to 20°C and the second duration is set to 3 seconds, if the temperature difference after the diagnosis of the first abnormal danger state is maintained at less than 20°C for 3 seconds, it is diagnosed that the first abnormal danger state initially diagnosed has been cancelled.

[0054] E. Second abnormal danger state determination unit 540 If the temperature difference between the cell periphery and the cell surface continues to increase even after the first abnormal risk state determination unit 530 finally diagnoses the current battery cell temperature state as the first abnormal risk state, and the abnormal signal output unit 420 outputs a third abnormal signal indicating that the current temperature difference between the cell periphery and the cell surface is equal to or greater than a third difference reference value, the second abnormal risk state determination unit may check whether the duration measured by the timer 700 from the time when the third abnormal signal was output is equal to or greater than the third duration, and if so, may finally diagnose the current battery cell temperature state as the second abnormal risk state and output a second abnormal risk signal indicating the same. For example, as shown in the table of FIG. 2, if the third difference reference value is set to 40° C. and the third duration is set to 25 seconds, if the current temperature difference is maintained at 40° C. or more for 25 seconds, the second abnormal risk state, which is the most dangerous state, is diagnosed.

[0055] As described above, the first abnormality warning state, the second abnormality warning state, the first abnormal danger state, and the second abnormal danger state indicate, in order, the degree of danger regarding the current temperature state of the battery cell.

[0056] Therefore, if the second abnormal danger condition judgment unit diagnoses that the current temperature state of the battery cell is the second abnormal danger state, this is a state that requires additional improvement measures in addition to the abnormality treatment by the abnormality treatment unit 600, so unlike the first and second abnormal warning state judgment units 510, 520 and the first abnormal danger condition judgment unit 530 described above, it does not judge whether the initially diagnosed second abnormal state has been resolved.

[0057] 1.6. Abnormality Treatment Unit 600 The abnormality treatment unit is a component that takes measures corresponding to the diagnosis signal output from the secondary abnormality diagnosis unit 500 to prevent the temperature difference between the periphery of the battery cell and the cell surface from increasing, i.e., to prevent the temperature state of the battery cell from worsening.

[0058] If a first abnormal warning signal or a second abnormal warning signal is output from the abnormal state secondary diagnosis unit 500, measures may be taken to cut off the relay outside the battery pack so that no more current flows into the battery pack from the outside.

[0059] On the other hand, as described above, after taking the measure of cutting off the relay outside the battery pack, if a first abnormal warning cancellation signal or a second abnormal warning cancellation signal is output from the abnormal state secondary diagnosis unit 500, the cutoff of the relay outside the battery pack may be cancelled.

[0060] On the other hand, if a first abnormal danger signal or a second abnormal danger signal is output from the abnormal state secondary diagnosis unit 500, measures may be taken to cut off the relay inside the battery pack and cut off the internal power line of the pack. As described above, the output of the first and second abnormal danger signals indicates that the danger level of the temperature state of the battery cells is further deteriorated compared to the first and second abnormal warning signals. Therefore, by preventing current from flowing inside the pack and suppressing heat generation due to the flow of current as much as possible, the temperature of the battery cells is lowered.

[0061] Next, if a first abnormal danger cancellation signal is output from the abnormal state secondary diagnosis unit 500, the cutoff of the relay inside the battery pack may be cancelled and the flow of current inside the pack may be opened.

[0062] Furthermore, the abnormal handling unit may notify the external upper-level system of the diagnosis results of each abnormal state of the abnormal state secondary diagnosis unit 500.

[0063] 1.7. Timer 700 When an abnormal signal or an abnormal cancellation signal is output from the abnormal signal output unit 420, the timer measures the time elapsed since the output time point.

[0064] For example, if a first abnormal signal is output from the abnormal signal output unit 420, the duration held in that state is measured from the output time point. Thus, as described above, the duration measured by the timer is used as a criterion for finally diagnosing the abnormal state of the temperature corresponding to the abnormal signal in the abnormal state secondary diagnosis unit 500.

[0065] 1.8. Memory unit 800 The memory unit stores reference data for diagnosing the abnormal state of the temperature of the battery cell in the abnormal state primary diagnosis unit 400 and the abnormal state secondary diagnosis unit 500.

[0066] Here, the reference data may include predetermined first to third difference reference values and predetermined first to third duration values.

[0067] On the other hand, in the above, only the diagnosis of the abnormal state of the temperature of the battery cell has been specifically described, but the present invention is not limited thereto at all. Even in the case of a battery module / battery pack composed of a plurality of battery cells, the same method as described above can be applied to configure the diagnosis of the abnormal state of the temperature of the battery module / battery pack.

[0068] 2. Diagnostic method for temperature abnormal state according to the present invention Based on FIG. 4, a method for diagnosing the abnormal state of the temperature of the battery cell according to the present invention will be described.

[0069] 2.1. Temperature measurement step (S100) The temperature measurement step is a step of measuring the temperature of the cell peripheral part and the surface temperature of the cell of the battery cell at a predetermined cycle. Different from the conventional technology that diagnoses the abnormal state of the temperature only based on the surface temperature of the cell of the battery cell, in the present invention, the abnormal state of the temperature of the battery cell is diagnosed by reflecting the change in the surface temperature of the cell and the temperature of the cell peripheral part.

[0070] This step is performed by a first temperature measurement unit 100 that is disposed near a heat source such as a cell balancing circuit unit or a precharge circuit unit to measure the temperature of the cell peripheral portion, and a second temperature measurement unit 200 that is disposed on the cell surface of the battery cell to measure the temperature of the cell itself.

[0071] 2.2. Temperature difference calculation step (S200) The temperature difference calculation step is a step of calculating the difference between the temperature of the cell peripheral portion measured in the temperature measurement step (S100) and the surface temperature of the cell, and is performed by the temperature difference calculation unit 300 described above.

[0072] 2.3. First abnormal warning state diagnosis step (S300) The first abnormal warning state diagnosis step diagnoses whether the temperature state of the battery cell is in the first abnormal warning state based on whether the temperature difference between the cell peripheral portion and the cell surface calculated in the temperature difference calculation step (S200) is maintained for a predetermined first duration in a state where it is equal to or greater than a predetermined first difference reference value.

[0073] A. Difference comparison step (S310) First, the temperature difference calculated in the temperature difference calculation step (S200) is compared with a predetermined first difference reference value, which is performed in the difference comparison unit 410 of the abnormal state primary diagnosis unit 400 described above.

[0074] B. Duration confirmation step (S320) As a result of the comparison in the difference comparison step (S310), if the temperature difference is equal to or greater than a predetermined first difference reference value, it is checked whether it is held in that state for a predetermined first duration. If it is held for a predetermined first duration in a state where the temperature difference is equal to or greater than the first difference reference value, it may be diagnosed that the current temperature state of the battery cell corresponds to a first abnormal warning state, which is the step with the lowest risk among the overall four steps for diagnosing an abnormal temperature state. For example, as shown in the table of FIG. 2, if the first difference reference value is set to 10°C and the first duration is set to 1 second, if it is held for 1 second in a state where the temperature difference is 10°C or more, it is diagnosed (S332) as being in the first abnormal warning state.

[0075] Then, in the abnormal handling step (S700) described later, in response to the current temperature state of the battery cell being in the first abnormal warning state, in order to mitigate the increase in the temperature difference between the cell periphery and the cell surface of the battery cell, measures such as shutting off the relay outside the battery pack may be taken to cut off the flow of current from the outside to the battery pack.

[0076] On the other hand, as described above, after diagnosing that the current temperature state of the battery cell is in the first abnormal warning state, if the calculated temperature difference between the cell periphery and the cell surface is less than the first difference reference value and is held for a predetermined first duration, it may be diagnosed that the diagnosed first abnormal warning state has been released. For example, as shown in the table of FIG. 2, if the first difference reference value is set to 10°C and the first duration is set to 1 second, if it is held for 1 second in a state where the temperature difference is less than 10°C, it is diagnosed that the initially diagnosed first abnormal warning state has been released (S334).

[0077] Then, in the abnormal handling step (S700), the cutoff of the relay outside the battery pack that has been taking measures according to the diagnosis of the first abnormal warning state may be released.

[0078] Such steps are performed by the first abnormal warning state determination unit 510 of the abnormal state secondary diagnosis unit 500 and the timer 700.

[0079] 2.4. Second Abnormal Warning State Diagnosis Step (S400) The second abnormal warning state diagnosis step is a step of diagnosing whether, as shown in FIG. 3, the temperature difference between the cell peripheral part and the cell surface has increased and shifted to the second abnormal warning state even after diagnosing that the temperature state of the battery cell is in the first abnormal warning state in the first abnormal warning state diagnosis step (S300).

[0080] A. Difference Comparison Step (S410) The difference comparison step compares whether the current temperature difference calculated after the first abnormal warning state diagnosis step (S400) is equal to or higher than a predetermined second difference reference value that is higher than a predetermined first difference reference value (difference comparison unit 410).

[0081] B. Duration Confirmation Step (S420) As a result of the comparison in the difference comparison step (S410), if the current temperature difference is equal to or higher than the predetermined second difference reference value, it is confirmed whether it is maintained for a predetermined first duration in that state. If it is maintained for the predetermined first duration in a state where the current temperature difference is equal to or higher than the predetermined second difference reference value, it may be diagnosed that the current temperature state of the battery cell is in a second abnormal warning state with a higher risk level than the first abnormal warning state. For example, as shown in the table of FIG. 2, when the second difference reference value is set to 20°C and the first duration is set to 1 second, if it is maintained for 1 second in a state where the temperature difference is 20°C or higher, it is diagnosed (S432) as being in the second abnormal warning state.

[0082] Then, in the abnormal handling step (S700) described later, the cutoff state of the relay outside the battery pack that has taken measures according to the diagnosis of the first abnormal warning state in the first abnormal warning state diagnosis step (S300) is maintained, and the inflow of current from the outside to the battery pack is still blocked.

[0083] On the one hand, after diagnosing that the current temperature state of the battery cell is in the second abnormal warning state as described above, if the temperature difference between the calculated cell peripheral part and the cell surface is maintained for a predetermined first duration in a state where it is less than the second difference reference value, it may be diagnosed that the diagnosed second abnormal warning state has been released. For example, as shown in the table of FIG. 2, when the second difference reference value is set to 20° C. and the first duration is set to 1 second, if the temperature difference is maintained for 1 second in a state where it is less than 20° C., it is diagnosed that the initially diagnosed second abnormal warning state has been released (S434).

[0084] Then, in the abnormal handling step (S700), the disconnection of the relay outside the battery pack that has been held according to the diagnosis of the second abnormal warning state may be released.

[0085] 2.5. First Abnormal Danger State Diagnosis Step (S500) In the first abnormal danger state diagnosis step, if the temperature difference in the duration confirmation step (S420) of the second abnormal warning state diagnosis step (S400) is maintained for a predetermined second duration set to be longer than the predetermined first duration in a state where it is equal to or greater than the predetermined second difference reference value, it may be diagnosed that the current temperature state of the battery cell is in a first abnormal danger state with a higher degree of danger than the second abnormal warning state. For example, as shown in the table of FIG. 2, when the second difference reference value is 20° C. and the second duration is set to 3 seconds, if the temperature difference is maintained for 3 seconds exceeding 1 second in a state where it is 20° C., it is diagnosed (S512) that it is in the first abnormal danger state.

[0086] Then, in the abnormal handling step (S700) described later, the cut-off state of the relay of the battery pack that has been held according to the diagnosis of the second abnormal warning state in the second abnormal warning state diagnosis step (S400) may still be maintained, and the relay inside the battery pack may be cut off to also cut off the flow of current inside the pack.

[0087] On the one hand, as described above, after diagnosing that the current temperature state of the battery cell is in the first abnormal dangerous state, if the temperature difference between the cell periphery and the cell surface calculated is less than the second difference reference value and is maintained for a predetermined second duration, it may be diagnosed that the diagnosed first abnormal dangerous state has been released. For example, as shown in the table of FIG. 2, when the second difference reference value is set to 20° C. and the second duration is set to 3 seconds, if the temperature difference after the diagnosis of the first abnormal dangerous state is less than 20° C. and is maintained for 3 seconds, it is diagnosed that the first abnormal dangerous state initially diagnosed has been released (S514).

[0088] Then, in the abnormal treatment step (S700), the cut-off state of the relay outside the battery pack may be maintained, but a treatment may be taken to open the relay inside the battery pack that was cut off according to the diagnosis of the first abnormal dangerous state.

[0089] 2.6. Second Abnormal Dangerous State Diagnosis Step (S600) The second abnormal dangerous state diagnosis step is a step of diagnosing whether the temperature difference between the cell periphery and the cell surface has increased and shifted to the second abnormal dangerous state even after diagnosing in the first abnormal dangerous state diagnosis step (S500) that the temperature state of the battery cell is in the first abnormal dangerous state.

[0090] A. Difference Comparison Step (S610) In the difference comparison step, it is compared whether the current temperature difference calculated after the first abnormal dangerous state diagnosis step (S500) is equal to or higher than a predetermined third difference reference value that is higher than a predetermined second difference reference value (difference comparison unit 410).

[0091] B. Duration Confirmation Step (S620) If, as a result of the comparison in the difference comparison step (S610), the current temperature difference is equal to or greater than a predetermined third difference reference value, it is confirmed whether or not it is held for a predetermined third duration, which is longer than a predetermined second duration, in that state. If it is held for the predetermined third duration in a state where the current temperature difference is equal to or greater than the predetermined third difference reference value, it may be diagnosed that the state of the current battery cell temperature is more dangerous than the first abnormal dangerous state, that is, the second abnormal dangerous state, which is the most dangerous state. For example, as shown in the table of FIG. 2, when the third difference reference value is set to 40° C. and the third duration is set to 25 seconds, if it is held for 25 seconds in a state where the current temperature difference is 40° C. or more, it is diagnosed (S630) as the second abnormal dangerous state with the highest degree of danger.

[0092] Then, in the abnormality handling step (S700) described later, the cutoff state of the relay inside the battery pack that had taken measures according to the diagnosis of the first abnormal dangerous state in the first abnormal dangerous state diagnosis step (S500) is maintained, and eventually, a state where all currents to the inside / outside of the battery pack are cut off is maintained.

[0093] On the other hand, in the above-described first abnormal warning state diagnosis step (S300), second abnormal warning state diagnosis step (S400), and first abnormal dangerous state diagnosis step (S500), re-diagnosis was performed by canceling the initially diagnosed abnormal state in response to a decrease in the width of the temperature difference calculated after each diagnosis. In contrast, in the second abnormal dangerous state diagnosis step (S600) for diagnosing that it is the state with the highest degree of danger, after diagnosing that it is the second abnormal dangerous state, an operation for diagnosing whether or not to cancel is not separately performed.

[0094] 2.7. Abnormality Handling Step (S700) In the abnormality handling step, as described above, measures corresponding to the diagnosis results of the abnormal states of the temperature performed for each step are taken.

[0095] When it is diagnosed as the first abnormal warning state in the first abnormal warning state diagnosis step (S300), and when it is diagnosed as the second abnormal warning state in the second abnormal warning state diagnosis step (S400), the relay outside the battery pack is cut off and held. When it is diagnosed as the first abnormal dangerous state in the first abnormal dangerous state diagnosis step (S500), and when it is diagnosed as the second abnormal dangerous state in the second abnormal dangerous state diagnosis step (S600), measures may be taken to further cut off and hold the relay inside the battery pack.

[0096] Here, the diagnosis results in each abnormal state diagnosis step may be further notified to an external upper-level system.

[0097] On the other hand, in the above, only the process of diagnosing the abnormal state of the temperature of the battery cell has been specifically described. However, the present invention is not limited thereto, and even in the case of a battery module / battery pack composed of a plurality of battery cells, the same method as described above can be applied to diagnose the abnormal state of the temperature of the battery module / battery pack.

[0098] On the other hand, although the technical idea of the present invention has been specifically described based on the above embodiments, it should be noted that the above embodiments are for the purpose of explanation and not for limitation. Those skilled in the technical field of the present invention should be able to understand that various embodiments can be implemented within the scope of the technical idea of the present invention.

Explanation of Reference Numerals

[0099] 100: First temperature measurement unit 200: Second temperature measurement unit 300: Temperature difference calculation unit 400: Abnormal state primary diagnosis unit 410: Difference comparison unit 420: Abnormal signal output unit 500: Abnormal state secondary diagnosis unit 510: First abnormal warning state determination unit 520: Second Abnormality Warning State Judgment Unit 530: First Abnormality Danger State Judgment Unit 540: Second Abnormality Danger State Judgment Unit 600: Abnormality Handling Unit 700: Timer

Claims

1. A method for diagnosing an abnormal state of temperature of a battery cell constituting a battery pack, comprising: a temperature measuring step of measuring a temperature around the battery cell and a surface temperature of the battery cell at each predetermined period; a temperature difference calculation step of calculating a difference between the temperature of the periphery of the cell and the surface temperature of the cell, both measured in the temperature measurement step; a first abnormality warning state diagnosis step of comparing whether the calculated temperature difference is equal to or greater than a predetermined first difference reference value and continues for a predetermined first duration, and diagnosing whether the temperature state of the battery cell is a first abnormality warning state based on the comparison result; a second abnormality warning state diagnosis step of diagnosing the temperature state of the battery cell as a second abnormality warning state when the first abnormality warning state is diagnosed and the temperature difference is maintained for a predetermined first duration in a state equal to or greater than a predetermined second difference reference value, and diagnosing that the second abnormality warning state has been released when the temperature difference is maintained for the first duration less than the predetermined second difference reference value after diagnosing the second abnormality warning state; an abnormality handling step of cutting off current inflow from the outside to the battery pack when the first abnormality warning state diagnosis step determines that the current temperature state of the battery cell is the first abnormality warning state, maintaining the cut-off of the current inflow when the second abnormality warning state diagnosis step determines that the current state is the second abnormality warning state, and thereafter, canceling the cut-off of the current inflow when it is determined that the second abnormality warning state has been released.

2. A method for diagnosing an abnormal temperature state of a battery module constituting a battery pack, comprising: a temperature measuring step of measuring a temperature around the module and a surface temperature of the module at each predetermined period; a temperature difference calculation step of calculating a difference between the temperature of the periphery of the module and the surface temperature of the module, both of which are measured in the temperature measurement step; a first abnormality warning state diagnosis step of comparing whether the calculated temperature difference is maintained at or above a predetermined first difference reference value for a predetermined first duration, and diagnosing whether the temperature state of the battery module is a first abnormality warning state based on a comparison result; a second abnormality warning state diagnosis step of diagnosing the temperature state of the battery module as a second abnormality warning state when the first abnormality warning state is diagnosed and the temperature difference is maintained for a predetermined first duration in a state equal to or greater than a predetermined second difference reference value, and diagnosing that the second abnormality warning state has been released when the temperature difference is maintained for the first duration less than the predetermined second difference reference value after diagnosing the second abnormality warning state; an abnormality handling step of cutting off current inflow from outside to the battery pack when the first abnormality warning state diagnosis step determines that the current temperature state of the battery module is the first abnormality warning state, maintaining the cut-off of the current inflow when the second abnormality warning state diagnosis step determines that the current state is the second abnormality warning state, and thereafter, releasing the cut-off of the current inflow when it is determined that the second abnormality warning state has been released.

3. a first abnormal danger state diagnosis step of diagnosing the current temperature state of the battery cell as a first abnormal danger state if the temperature difference in the second abnormal warning state diagnosis step is maintained at or above a predetermined second difference reference value for a second duration that is longer than a predetermined first duration after diagnosing the current temperature state of the battery cell as a second abnormal danger state in the second abnormal warning state diagnosis step; an abnormality processing step of further cutting off a power line inside the battery pack if the current temperature state of the battery cell is diagnosed as a first abnormal or dangerous state by the first abnormal or dangerous state diagnosis step; 2. The method according to claim 1, further comprising:

4. performing a second abnormal and dangerous condition diagnosis step of diagnosing whether the current temperature state of the battery cell is a first abnormal and dangerous condition in the first abnormal and dangerous condition diagnosis step, comparing whether the current temperature difference calculated using the temperature difference calculation step is maintained at or above a third predetermined difference reference value for a third duration, and diagnosing whether the temperature state of the battery cell is a second abnormal and dangerous condition based on a comparison result; The second abnormal or dangerous condition diagnosis step includes: a difference comparison step of comparing whether or not the current temperature difference calculated in the temperature difference calculation step is equal to or greater than a third difference reference value, which is a value higher than a predetermined second difference reference value; a duration confirmation step of confirming whether or not the temperature difference is maintained for a third duration, which is a time longer than the second duration, in the abnormal state, if the temperature difference is equal to or greater than a third predetermined difference reference value as a result of the comparison in the difference comparison step; Including, 4. The method of claim 3, further comprising diagnosing a current battery cell temperature condition as a second abnormal or dangerous condition if the temperature difference is maintained at or above a third predetermined difference reference value for a third predetermined duration.

5. A first abnormal danger condition diagnosis step of diagnosing the current temperature state of the battery module as a first abnormal danger condition if, after diagnosing the current temperature state of the battery module as a second abnormal warning state in the second abnormal warning state diagnosis step, the temperature difference in the second abnormal warning state diagnosis step is maintained at or above a predetermined second difference reference value for a second duration that is longer than the predetermined first duration; an abnormality processing step of further cutting off a power line inside the battery pack if the current temperature state of the battery module is diagnosed as a first abnormal or dangerous state by the first abnormal or dangerous state diagnosis step; 3. The method according to claim 2, further comprising:

6. After diagnosing the current temperature state of the battery module as a first abnormal hazard state in the first abnormal hazard state diagnosis step, a second abnormal hazard state diagnosis step is performed in which a comparison is made as to whether the current temperature difference calculated using the temperature difference calculation step is maintained at or above a predetermined third difference reference value for a predetermined third duration, and based on the comparison result, a diagnosis is made as to whether the temperature state of the battery module is a second abnormal hazard state; The second abnormal or dangerous condition diagnosis step includes: a difference comparison step of comparing whether or not the current temperature difference calculated in the temperature difference calculation step is equal to or greater than a third difference reference value, which is a value higher than a predetermined second difference reference value; a duration confirmation step of confirming whether or not the temperature difference is maintained for a third duration, which is a time longer than the second duration, in the abnormal state, if the temperature difference is equal to or greater than a third predetermined difference reference value as a result of the comparison in the difference comparison step; Including, 6. The method of claim 5, further comprising diagnosing a current battery module temperature state as a second abnormal or dangerous state if the temperature difference is maintained at or above a third predetermined difference reference value for a third predetermined duration.

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