Battery diagnostic device and method, battery diagnostic system and battery pack containing the device

Abstract

A battery diagnostic device according to an embodiment of the present disclosure includes: a measuring unit configured to measure a voltage and a temperature of a battery; an ohmic resistance determining unit configured to determine the ohmic resistance of the battery based on an impedance curve generated for the battery; and a control unit configured to calculate a voltage change by comparing the voltage of the battery measured by the measuring unit with a reference voltage, calculate a resistance change rate by comparing the ohmic resistance determined by the ohmic resistance determining unit with a reference resistance, determine a degree of internal gas generation in the battery by comparing the calculated resistance change rate with a reference resistance change rate, and determine a cause of internal gas generation in the battery by comparing the calculated voltage change with a standard voltage change.

Description

Technical Field

[0001] This application claims priority to Korean Patent Application No. 10-2020-0131450 filed in Korea on October 12, 2020, the disclosure of which is incorporated herein by reference.

[0002] The present disclosure relates to a battery diagnosis apparatus and method, and more particularly, to a battery diagnosis apparatus and method capable of diagnosing an internal gas generation level and a cause of the internal gas generation of a battery. Background Art

[0003] Recently, the demand for portable electronic products such as notebook computers, video cameras, and portable phones has increased dramatically, and electric vehicles, energy storage batteries, robots, satellites, etc. have been developed in earnest. Therefore, high-performance batteries that allow repeated charging and discharging are being actively studied.

[0004] Currently commercially available batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, lithium batteries, etc. Among them, lithium batteries have attracted much attention because they have almost no storage effect compared to nickel-based batteries, and also have extremely low self-charging rates and high energy density.

[0005] As the battery deteriorates, various side reactions occur with the generation of internal gas. If the side reactions continue and the amount of internal gas exceeds an allowable value, the joint portion of the battery is disconnected and the battery reaches an EOL (End of Life) state.

[0006] Therefore, in order to diagnose the state of the battery, it is necessary to measure the amount of internal gas, but in the prior art, it is difficult to measure the amount of internal gas of the battery in a non-destructive manner. Summary of the invention

[0007] Technical issues

[0008] The present disclosure is designed to solve the problems of the related art, and thus the present disclosure is directed to providing a battery diagnosis apparatus and method for diagnosing an internal gas generation level and an internal gas generation cause of a battery in a non-destructive manner based on an impedance curve of the battery.

[0009] These and other objects and advantages of the present disclosure can be understood from the following detailed description and more fully apparent from the exemplary embodiments of the present disclosure.In addition, it will be easily understood that the objects and advantages of the present disclosure can be achieved by the means and combinations thereof shown in the appended claims.

[0010] Technical Solution

[0011] A battery diagnostic device according to an aspect of the present disclosure may include: a measuring unit configured to measure a voltage and a temperature of a battery; an ohmic resistance determining unit configured to determine the ohmic resistance of the battery based on an impedance curve generated for the battery; and a control unit configured to calculate a voltage change by comparing the voltage of the battery measured by the measuring unit with a reference voltage, calculate a resistance change rate by comparing the ohmic resistance determined by the ohmic resistance determining unit with a reference resistance, determine a level of internal gas generation in the battery by comparing the calculated resistance change rate with a standard resistance change rate, and determine a cause of internal gas generation in the battery by comparing the calculated voltage change with a standard voltage change.

[0012] The ohmic resistance determination unit may be configured to determine the ohmic resistance based on an impedance curve generated for the battery when the temperature of the battery measured by the measurement unit during a predetermined period is equal to or higher than a standard temperature.

[0013] The control unit may be configured to judge that an amount of internal gas of the battery equal to or greater than a standard amount is generated when the calculated resistance change rate is equal to or greater than the standard resistance change rate.

[0014] The control unit may be configured to judge that the internal gas of the battery is generated in a smaller amount than the standard amount when the calculated resistance change rate is smaller than the standard resistance change rate.

[0015] The control unit may be configured to determine that the internal gas generation cause is a side reaction of the positive electrode of the battery when the calculated voltage change amount is equal to or greater than the standard voltage change amount.

[0016] The control unit may be configured to determine that the internal gas generation cause is other than a side reaction of the positive electrode when the calculated voltage change amount is smaller than the standard voltage change amount.

[0017] The control unit may be configured to diagnose a state of the battery based on the internal gas generation level and the internal gas generation cause.

[0018] The control unit may be configured to diagnose that the state of the battery is a normal state when it is judged that the internal gas less than the standard amount is generated due to the other cause.

[0019] When it is determined that the internal gas equal to or greater than the standard amount is generated due to the other cause, the control unit may be configured to diagnose that the state of the battery is a first warning state and lower an upper limit temperature of the battery.

[0020] When it is determined that the internal gas equal to or greater than the standard amount is generated due to the side reaction of the positive electrode, the control unit may be configured to diagnose the battery state as a second warning state and lower at least one of an upper limit temperature and an upper limit SOC of the battery.

[0021] When it is judged that the internal gas is generated in a smaller amount than the standard amount due to the side reaction of the positive electrode, the control unit may be configured to judge that an internal short circuit occurs in the battery and diagnose that the state of the battery is an unusable state.

[0022] A battery diagnostic system according to another aspect of the present disclosure may include: a battery diagnostic device according to one aspect of the present disclosure; an EIS unit, which is configured to output AC current to the battery, generate an impedance curve representing the impedance of the battery as a corresponding relationship between a real part and an imaginary part based on the output result of the AC current, and output the generated impedance curve to the battery diagnostic device.

[0023] A battery diagnosis system according to another aspect of the present disclosure may further include a heating unit configured to increase a temperature of the battery so that the temperature of the battery becomes equal to or higher than a standard temperature.

[0024] A battery pack according to still another aspect of the present disclosure may include the battery diagnosis device according to one aspect of the present disclosure.

[0025] According to another aspect of the present disclosure, a battery diagnostic method may include the following steps: a measuring step, the measuring step measures the voltage and temperature of the battery; an ohmic resistance determining step, the ohmic resistance of the battery is determined based on an impedance curve generated for the battery; a voltage change calculating step, the voltage change calculating step calculates the voltage change by comparing the voltage of the battery measured in the measuring step with a reference voltage; a resistance change rate calculating step, the resistance change rate calculating step calculates the resistance change rate by comparing the ohmic resistance determined in the ohmic resistance determining step with a reference resistance; an internal gas generation level judging step, the internal gas generation level judging step judges the internal gas generation level of the battery by comparing the calculated resistance change rate with the standard resistance change rate; and an internal gas generation cause judging step, the internal gas generation cause judging step judges the internal gas generation cause of the battery by comparing the calculated voltage change with the standard voltage change.

[0026] Beneficial Effects

[0027] According to an aspect of the present disclosure, an internal gas generation level and an internal gas generation cause of a battery may be diagnosed in a non-destructive manner.

[0028] The effects of the present disclosure are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art through the description of the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings illustrate preferred embodiments of the present disclosure, and together with the above disclosure are used to provide a further understanding of the technical features of the present disclosure. Therefore, the present disclosure is not interpreted as being limited to the accompanying drawings.

[0030] Figure 1 is a diagram schematically illustrating a battery diagnosis apparatus according to an embodiment of the present disclosure.

[0031] Figure 2 is a diagram schematically showing an impedance curve according to an embodiment of the present disclosure.

[0032] Figure 3 is a diagram schematically showing an example of a voltage change amount calculated by a battery diagnosis apparatus according to an embodiment of the present disclosure.

[0033] Figure 4 is a diagram schematically showing an example of a resistance change rate calculated by a battery diagnosis device according to an embodiment of the present disclosure.

[0034] Figure 5is a diagram schematically showing a battery state diagnosed by a battery diagnosis apparatus according to an embodiment of the present disclosure.

[0035] Figure 6 is a diagram schematically showing a battery diagnosis system according to another embodiment of the present disclosure.

[0036] Figure 7 is a diagram showing an exemplary configuration of a battery pack including a battery diagnostic apparatus according to an embodiment of the present disclosure.

[0037] Figure 8 is a diagram schematically illustrating a battery diagnosis method according to still another embodiment of the present disclosure. DETAILED DESCRIPTION

[0038] It should be understood that the terms used in the specification and the appended claims should not be interpreted as limited to the general meanings and dictionary meanings, but should be interpreted based on the meanings and concepts corresponding to the technical aspects of the present disclosure based on the principle of allowing the inventor to define terms suitable for the best description.

[0039] Therefore, the descriptions presented herein are merely preferred examples for illustrative purposes only and are not intended to limit the scope of the present disclosure, so it should be appreciated that other equivalent forms and modifications may be obtained without departing from the scope of the present disclosure.

[0040] Furthermore, in describing the present disclosure, when it is considered that a detailed description of related known elements or functions makes the key subject matter of the present disclosure unclear, the detailed description is omitted herein.

[0041] Terms including ordinal numbers such as “first,” “second,” etc. may be used to distinguish one element from another among various elements, but are not intended to limit the elements by the terms.

[0042] Throughout the specification, when a part is referred to as “comprising” or “including” any elements, it means that the part may further include other elements, without excluding the other elements, unless specifically stated otherwise.

[0043] In addition, terms such as a control unit described in the specification mean a unit that processes at least one function or operation, which can be implemented as hardware, software, or a combination of hardware and software.

[0044] In addition, throughout the specification, when a part is referred to as being “connected” to another part, it is not limited to the case where they are “directly connected” but also includes the case where they are “indirectly connected” with another element interposed therebetween.

[0045] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0046] Figure 1 is a diagram schematically illustrating a battery diagnosis apparatus 100 according to an embodiment of the present disclosure.

[0047] Reference Figure 1 , the battery diagnosis apparatus 100 according to an embodiment of the present disclosure may include a measuring unit 110 , an ohmic resistance determining unit 120 , and a control unit 130 .

[0048] The measuring unit 110 may be configured to measure the voltage and temperature of the battery.

[0049] Here, a battery means a single independent cell having a negative terminal and a positive terminal and is physically separable. For example, a pouch-type lithium polymer cell can be regarded as a battery. In addition, a battery may include one or more battery modules in which batteries are connected in series and / or in parallel. However, hereinafter, for ease of explanation, a battery will be described as meaning an independent cell.

[0050] For example, the measuring unit 110 may be electrically connected to the positive terminal and the negative terminal of the battery to measure the voltage of the battery. In addition, the measuring unit 110 may measure the voltage of the battery by measuring the positive electrode voltage and the negative electrode voltage of the battery, and calculate the difference between the measured positive electrode voltage and the measured negative electrode voltage. Preferably, the measuring unit 110 may measure the OCV (open circuit voltage) of the battery.

[0051] In addition, the measuring unit 110 may be connected to the battery to measure the current temperature of the battery.

[0052] The ohmic resistance determination unit 120 may be configured to determine the ohmic resistance of the battery based on an impedance curve generated for the battery.

[0053] Figure 2 is a diagram schematically showing an impedance curve according to an embodiment of the present disclosure.

[0054] Reference Figure 2 , when X is set to the real part (Zre) and Y is set to the imaginary part (-Zim), the impedance curve can be expressed as an XY plane graph. Figure 2 In the embodiment of the present invention, the ohmic resistance (Ro) of the battery may be the starting resistance value of the impedance curve. Specifically, in the impedance curve, when the value of the imaginary part (-Zim) is 0, the resistance value of the real part (Zre) may be the ohmic resistance (Ro) of the battery. Since the ohmic resistance (Ro) is a well-known factor, it should be noted that the description of the ohmic resistance (Ro) will be omitted.

[0055] For example, the impedance curve of the battery may be generated outside the battery diagnostic apparatus 100. In addition, the ohmic resistance determination unit 120 may directly receive the impedance curve of the battery generated externally, or may acquire the impedance curve by accessing a memory in which the impedance curve of the battery is stored.

[0056] Then, the ohmic resistance determination unit 120 may determine a starting resistance value from the received impedance curve, and determine the determined starting resistance value as the ohmic resistance of the battery.

[0057] The control unit 130 may be configured to calculate a voltage variation amount by comparing the battery voltage measured by the measurement unit 110 with a reference voltage.

[0058] Here, the reference voltage may be a voltage value pre-measured for a battery in a BOL (Beginning of Life) state. More preferably, the reference voltage may be an OCV value measured when the SOC (State of Charge) of the battery in the BOL state is 100%.

[0059] Specifically, the control unit 130 may calculate the difference between the reference voltage and the measured voltage of the battery to calculate the voltage variation of the battery. For example, the control unit 130 may calculate the voltage variation of the battery by using the calculation formula “reference voltage-measured voltage of the battery”.

[0060] Figure 3 is a diagram schematically showing an example of a voltage variation amount calculated by the battery diagnosis apparatus 100 according to an embodiment of the present disclosure.

[0061] For example, in Figure 3 In an embodiment of the present invention, the control unit 130 may calculate the voltage variation of the first battery B1 to the sixth battery B6. Here, a reference voltage may be preset for each of the first battery B1 to the sixth battery B6. That is, a first reference voltage for the first battery B1 and a second reference voltage for the second battery B2 may be preset. In addition, a third reference voltage for the third battery B3 and a fourth reference voltage for the fourth battery B4 may be preset. In addition, a fifth reference voltage for the fifth battery B5 and a sixth reference voltage for the sixth battery B6 may be preset.

[0062] That is, the control unit 130 does not calculate the voltage variation of the first to sixth batteries B1 to B6 by using one preset reference voltage, but can calculate the voltage variation of each of the first to sixth batteries B1 to B6 by calculating the difference between the corresponding reference voltage and the measured voltage of the battery. Therefore, the degree of degradation of each battery can be reflected in the voltage variation of the battery calculated by the control unit 130.

[0063] For example, in Figure 3In the embodiment of the present invention, the voltage change amount of the first battery B1 may be 86.9 mV, and the voltage change amount of the second battery B2 may be 148.1 mV. In addition, the voltage change amount of the third battery B3 may be 97.3 mV, and the voltage change amount of the fourth battery B4 may be 83.8 mV. In addition, the voltage change amount of the fifth battery B5 may be 119.8 mV, and the voltage change amount of the sixth battery B6 may be 87.3 mV.

[0064] The control unit 130 may be configured to calculate a resistance change rate by comparing the ohmic resistance determined by the ohmic resistance determination unit 120 with a reference resistance.

[0065] Here, the reference resistance may be a resistance value pre-measured for the battery in the BOL state. More preferably, the reference resistance may be an ohmic resistance value measured when the SOC (State of Charge) of the battery in the BOL state is 100%.

[0066] Specifically, the control unit 130 can calculate the resistance change rate of the battery by calculating the ratio of the difference between the reference resistance and the measured ohmic resistance of the battery for the reference resistance. For example, the control unit 130 can calculate the resistance change rate of the battery by the calculation formula "(measured ohmic resistance of the battery-reference resistance)÷reference resistance×100".

[0067] Figure 4 is a diagram schematically showing an example of a resistance change rate calculated by the battery diagnosis apparatus 100 according to an embodiment of the present disclosure.

[0068] For example, in Figure 4 In an embodiment, the control unit 130 may calculate the resistance change rate of the first battery B1 to the sixth battery B6. Like the reference voltage, a reference resistance may be preset for each of the first battery B1 to the sixth battery B6. That is, a first reference resistance for the first battery B1 and a second reference resistance for the second battery B2 may be preset. In addition, a third reference resistance for the third battery B3 and a fourth reference resistance for the fourth battery B4 may be preset. In addition, a fifth reference resistance for the fifth battery B5 and a sixth reference resistance for the sixth battery B6 may be preset. In addition, the control unit 130 may calculate the resistance change rate of each of the first battery B1 to the sixth battery B6 based on the corresponding reference resistance and the ohmic resistance of the battery.

[0069] For example, in Figure 4In an embodiment of the present invention, the resistance change rate of the first battery B1 may be 16.4%, and the resistance change rate of the second battery B2 may be 13.8%. In addition, the resistance change rate of the third battery B3 may be 17.1%, and the resistance change rate of the fourth battery B4 may be 16.1%. In addition, the resistance change rate of the fifth battery B5 may be 24.2%, and the resistance change rate of the sixth battery B6 may be 25.2%.

[0070] The control unit 130 may be configured to judge the internal gas generation level of the battery by comparing the magnitude of the calculated resistance change rate with the magnitude of a standard resistance change rate.

[0071] Specifically, the control unit 130 may be configured to determine that an amount of internal gas of the battery equal to or greater than a standard amount is generated when the calculated resistance change rate is equal to or greater than a standard resistance change rate. In addition, the control unit 130 may be configured to determine that an amount of internal gas of the battery less than a standard amount is generated when the calculated resistance change rate is less than the standard resistance change rate. Here, the case where an amount of internal gas of the battery less than a standard amount is generated may include both a case where an amount of internal gas of the battery less than a standard amount is generated and a case where no internal gas is generated.

[0072] For example, in Figure 4 In the embodiment of the present invention, it is assumed that the standard resistance change rate is preset to 20%. Since the resistance change rate of the first battery B1 to the fourth battery B4 is less than the standard resistance change rate, the control unit 130 can judge that the internal gas of the first battery B1 to the fourth battery B4 is generated in a smaller amount than the standard amount. In addition, since the resistance change rate of the fifth battery B5 and the sixth battery B6 is greater than the standard resistance change rate, the control unit 130 can judge that the internal gas of the fifth battery B5 and the sixth battery B6 is generated in a larger amount than the standard amount.

[0073] The control unit 130 may be configured to determine the cause of internal gas generation of the battery by comparing the calculated voltage variation with the standard voltage variation.

[0074] Specifically, the control unit 130 may be configured to determine that the cause of the internal gas generation is a side reaction of the positive electrode of the battery when the calculated voltage variation is greater than or equal to the standard voltage variation. More preferably, the control unit 130 may be configured to determine that the cause of the internal gas generation is a side reaction of the positive electrode of the battery and the electrolyte when the calculated voltage variation is greater than or equal to the standard voltage variation.

[0075] In addition, the control unit 130 may be configured to determine that the internal gas generation cause is other than the positive electrode side reaction when the calculated voltage variation is less than the standard voltage variation. For example, other causes may include the negative electrode side reaction of the battery.

[0076] For example, in Figure 3 In the embodiment of the present invention, it is assumed that the standard voltage variation is preset to 110 mV. Since the voltage variation of the first battery B1, the third battery B3, the fourth battery B4 and the sixth battery B6 is less than the standard voltage variation, the control unit 130 can determine that the internal gas of the first battery B1, the third battery B3, the fourth battery B4 and the sixth battery B6 is caused by other reasons. In addition, since the voltage variation of the second battery B2 and the fifth battery B5 is greater than the standard voltage variation, the control unit 130 can determine that the internal gas of the second battery B2 and the fifth battery B5 is generated by the side reaction of the positive electrode of the corresponding battery.

[0077] That is, the battery diagnostic apparatus 100 according to the embodiment of the present disclosure can determine whether the internal gas of the battery is generated equal to or greater than the standard amount and whether the internal gas of the battery is generated due to any side reaction. In particular, the battery diagnostic apparatus 100 has the advantage of diagnosing in a non-destructive manner whether the internal gas of the battery is generated due to the side reaction of the positive electrode of the battery.

[0078] For example, when diagnosing the state of one or more batteries collected for reuse, the battery diagnostic device 100 according to an embodiment of the present disclosure may be used. The battery diagnostic device 100 may diagnose the internal gas generation level and the internal gas generation cause for each of the one or more batteries in a non-destructive manner. Therefore, according to an embodiment of the present disclosure, since the internal gas generation level and the internal gas generation cause of the battery can be quickly and easily diagnosed based on the ohmic resistance and voltage of the battery, it is possible to quickly and accurately determine whether the collected battery is reusable.

[0079] In addition, the control unit 130 provided for the battery diagnostic device 100 may optionally include a processor, an application-specific integrated circuit (ASIC), another chipset, a logic circuit, a register, a communication modem, a data processing device, etc., known in the art for executing various control logics performed in the present disclosure. In addition, when the control logic is implemented by software, the control unit 130 may be implemented as a collection of program modules. In this case, the program module may be stored in a memory and executed by the control unit 130. The memory may be provided inside the control unit 130 or outside the control unit 130, and may be connected to the control unit 130 through various well-known means.

[0080] In addition, refer to Figure 1, the battery diagnostic device 100 may further include a storage unit 140. The storage unit 140 may store data or programs necessary for the operation and function of each component of the battery diagnostic device 100, data generated in the process of performing the operation or function, and the like. The type of the storage unit 140 is not particularly limited as long as it is a known information storage device that can record, erase, update, and read data. As an example, the information storage device may include a RAM, a flash memory, a ROM, an EEPROM, a register, and the like. In addition, the storage unit 140 may store a program code in which a process that can be executed by the control unit 130 is defined.

[0081] For example, the storage unit 140 may store a reference voltage and a reference resistance of each battery. In addition, the storage unit 140 may store an impedance curve of the battery. In this case, the ohmic resistance determination unit 120 may access the storage unit 140 to obtain the impedance curve of the battery.

[0082] Preferably, the ohmic resistance determination unit 120 may be configured to determine the ohmic resistance based on an impedance curve generated for the battery when the battery temperature measured by the measurement unit 110 during a predetermined period is equal to or higher than a standard temperature.

[0083] Here, the predetermined period may be a minimum period during which the battery temperature must be maintained at or above the standard temperature so that the change in the ohmic resistance of the battery can be correlated with the internal gas generation of the battery. That is, if the battery temperature is maintained at or above the standard temperature only for too short a period, the generated battery internal gas may not have a significant relationship with the change in the ohmic resistance of the battery. Therefore, in the present disclosure, by maintaining the temperature of the battery at or above the standard temperature during the predetermined period, it is possible to make a judgment by correlating the change in the ohmic resistance of the battery with the internal gas generation level of the battery.

[0084] For example, the standard temperature may be set to any one of 40° C. to 60° C. Preferably, the standard temperature may be set to 40° C. In addition, the predetermined period may be set to any one of 3 days to 8 days. Preferably, the predetermined period may be set to 3 days.

[0085] As a specific example, assuming that the standard temperature is set to 40° C. and the predetermined period is set to 3 days, when the temperature of the battery measured by the measuring unit 110 remains at 40° C. or above for 3 days, the ohmic resistance determining unit 120 can determine the ohmic resistance of the corresponding battery by acquiring an impedance curve of the corresponding battery.

[0086] In addition, the measuring unit 110 may measure only the voltage with respect to the corresponding battery, and the control unit 130 may diagnose the internal gas generation level and the internal gas generation cause only with respect to the corresponding battery.

[0087] Generally, the higher the SOC and temperature of the battery, the greater the internal gas generation of the battery. That is, in order to diagnose the internal gas generation level and the internal gas generation cause for the purpose of judging whether the battery is reusable, the battery diagnostic apparatus 100 according to an embodiment of the present disclosure can perform diagnosis on a battery maintained at or above a standard temperature during a predetermined period of time.

[0088] In addition, preferably, the battery can be initially fully charged to a SOC 100% state. In addition, the fully charged battery can be maintained at a standard temperature or above for a predetermined period of time. That is, during the predetermined period of time, the fully charged battery can be naturally gradually discharged, but the temperature of the battery can be configured to be maintained at a standard temperature or above.

[0089] That is, only when the fully charged battery is maintained at a standard temperature or above for a predetermined period of time so as to form a test environment in which the internal gas of the battery can be generated, the battery diagnostic device 100 can determine whether the internal gas of the battery is generated, and if the internal gas of the battery is generated, determine the cause of the generation of the internal gas of the battery.

[0090] Hereinafter, an embodiment in which the battery diagnosis apparatus 100 diagnoses a battery state according to a diagnosed internal gas generation level and an internal gas generation cause of a battery will be described in detail.

[0091] The control unit 130 may be configured to diagnose the state of the battery based on the internal gas generation level and the internal gas generation cause.

[0092] Hereinafter, for the sake of convenience of explanation, the state of the battery that can be judged by the control unit 130 is divided into a normal state, a first warning state, a second warning state, or an unusable state. However, the state of the battery that can be judged by the control unit 130 can be further subdivided according to the internal gas generation level and the cause of the internal gas generation of the battery. For example, the control unit 130 can specifically subdivide and diagnose the internal gas generation level of the battery by comparing the calculated resistance change rate of the battery with the standard resistance range divided into multiple segments. In addition, the control unit 130 can compare the calculated voltage change amount of the battery with the standard voltage range divided into multiple voltage segments to subdivide and diagnose the cause of the internal gas generation of the battery in more detail. In addition, it should be noted that the state of the battery can be specifically diagnosed in more various aspects by subdividing and diagnosing the internal gas generation level and the cause of the internal gas generation.

[0093] Figure 5 is a diagram schematically illustrating a battery state diagnosed by the battery diagnosis apparatus 100 according to an embodiment of the present disclosure.

[0094] Reference Figure 5, the control unit 130 may be configured to diagnose that the state of the battery is a normal state when it is judged that the internal gas is generated in an amount less than a standard amount due to another reason.

[0095] That is, even if a fully charged battery is placed at a standard temperature or above for a predetermined period of time, if less than a standard amount of internal gas is generated and the generated internal gas is not caused by a side reaction of the positive electrode, the control unit 130 can diagnose that the state of the battery is a normal state. In addition, the control unit 130 can classify the battery as a reusable battery.

[0096] In addition, refer to Figure 5 , the control unit 130 may be configured to diagnose that the state of the battery is the first warning state when it is determined that the internal gas equal to or greater than the standard amount is generated due to other reasons. In addition, the control unit 130 may classify the battery as a reusable battery.

[0097] Thereafter, the control unit 130 may be configured to lower the upper limit temperature of the battery so as to reduce the amount of internal gas generation of the battery diagnosed as the first warning state. That is, the battery diagnosed as the first warning state may be set by the control unit 130 so that the allowable upper limit temperature is lowered. That is, when the battery diagnosed as the first warning state is reused, the allowable upper limit temperature of the battery may be limited to the temperature set by the control unit 130.

[0098] In addition, refer to Figure 5 The control unit 130 may be configured to diagnose that the state of the battery is the second warning state when it is determined that the internal gas generated by the side reaction of the positive electrode is equal to or greater than the standard amount. In addition, the control unit 130 may classify the battery as a reusable battery.

[0099] Thereafter, the control unit 130 may be configured to reduce at least one of the upper limit temperature and the upper limit SOC of the battery so as to reduce the amount of internal gas generated by the battery diagnosed as the second warning state. That is, the battery diagnosed as the second warning state may be set by the control unit 130 so that at least one of the allowable upper limit temperature and the allowable upper limit SOC is reduced. Preferably, the control unit 130 may reduce both the upper limit temperature and the upper limit SOC of the battery so as to effectively reduce the amount of internal gas generated by the battery diagnosed as the second warning state. That is, when the battery diagnosed as the second warning state is reused, at least one of the allowable upper limit temperature and the upper limit SOC of the corresponding battery may be limited to the value set by the control unit 130.

[0100] Specifically, the control unit 130 may diagnose that the state of the battery having the internal gas generation level equal to or greater than the standard amount is a warning state, and lower the upper limit temperature and / or the upper limit SOC in order to reduce the internal gas generation amount.

[0101] In addition, refer to Figure 5 When it is determined that the amount of internal gas generated by the side reaction of the positive electrode is less than the standard amount, the control unit 130 can be configured to determine that an internal short circuit occurs in the battery and diagnose that the battery is in an unusable state. In addition, the control unit 130 can classify the battery as a non-reusable battery.

[0102] That is, when less than the standard amount of battery internal gas is generated but a positive electrode side reaction is determined to have occurred, the control unit 130 can determine that an internal short circuit has occurred in the battery. In addition, the control unit 130 can diagnose that the battery state is an unusable state, thereby preventing the battery from being reused.

[0103] In summary, the control unit 130 can classify the battery diagnosed as a normal state, a first warning state, or a second warning state as a reusable battery, and classify the battery diagnosed as an unusable state as an unusable battery. In addition, the control unit 130 can reduce the amount of internal gas generated by the battery when the battery is reused by appropriately limiting the operation of the battery diagnosed as the first warning state or the second warning state.

[0104] In this way, the battery diagnostic device 100 according to the embodiment of the present disclosure can diagnose the state of the battery by focusing on whether the battery is reusable based on the internal gas generation level of the battery and the internal gas generation cause. In addition, in order to reduce the generation of internal gas during reuse, the operation of each battery can be limited based on the diagnosis state. Therefore, the battery diagnostic device 100 is advantageous in that it not only determines whether the battery is reusable, but also sets appropriate control conditions so that the battery can be used for a longer period of time.

[0105] Figure 6 is a diagram schematically showing a battery diagnosis system 10 according to another embodiment of the present disclosure.

[0106] Reference Figure 6 , the battery diagnosis system 10 may include a battery diagnosis apparatus 100 and an EIS unit 200 according to an embodiment of the present disclosure.

[0107] The EIS unit 200 may be configured to output an AC current to the battery, and generate an impedance curve representing the impedance of the battery as a corresponding relationship between a real part (Zre) and an imaginary part (-Zim) according to the output result of the AC current.

[0108] Specifically, the EIS unit 200 may be configured to perform EIS (Electrochemical Impedance Spectroscopy). Therefore, the EIS unit 200 may apply a small AC current to the battery to measure the impedance of the battery and generate an impedance curve representing the impedance as a corresponding relationship between a real part (Zre) and an imaginary part (-Zim).

[0109] For example, when the temperature of the battery is equal to or higher than the standard temperature, the impedance of the battery measured by the EIS unit 200 may be inaccurate due to the influence of temperature. Therefore, when the temperature of the battery becomes close to the room temperature, the EIS unit 200 may measure the impedance of the battery.

[0110] The EIS unit 200 may be configured to output the generated impedance curve to the battery diagnostic apparatus 100 .

[0111] For example, the EIS unit 200 may transmit the generated impedance curve to the ohmic resistance determination unit 120 of the battery diagnostic apparatus 100 .

[0112] As another example, the EIS unit 200 may transmit the generated impedance curve to the storage unit 140 of the battery diagnosis apparatus 100. In this case, the ohmic resistance determination unit 120 may access the storage unit 140 to acquire the impedance curve generated by the EIS unit 200.

[0113] In addition, refer to Figure 6 The battery diagnosis system 10 may further include a heating unit 300 .

[0114] The heating unit 300 may be configured to increase the temperature of the battery so that the temperature of the battery is equal to or higher than the standard temperature. That is, the heating unit 300 may increase and maintain the temperature of the battery so that the temperature of the battery may be maintained at or above the standard temperature within a predetermined period of time.

[0115] Therefore, the battery diagnosis system 10 has the advantage of diagnosing whether the battery is reusable by satisfying the test conditions that can generate gas inside the battery.

[0116] In addition, refer to Figure 6 The battery diagnosis system 10 may further include a charging and discharging unit 400 .

[0117] The charging and discharging unit 400 may be configured to be connected to a battery to charge or discharge the battery.

[0118] For example, the battery may be fully charged by the charging and discharging unit 400. In addition, the temperature of the battery may be maintained at or above a standard temperature for a predetermined period of time by the heating unit 300. In this case, the battery diagnostic device 100 may diagnose the internal gas generation level, the internal gas generation cause, and the state of the battery.

[0119] On the other hand, when the cause of the internal gas generation of the battery is diagnosed as other than the side reaction of the positive electrode, the battery diagnosis system 10 may perform additional diagnosis to specifically diagnose the cause of the internal gas generation of the battery.

[0120] The charge and discharge unit 400 may be configured to fully discharge the battery after fully charging the battery again.

[0121] For example, a battery maintained at a temperature equal to or higher than a standard temperature within a predetermined period of time may be naturally discharged to reduce its capacity. Therefore, the charging and discharging unit 400 may fully charge the battery again at a first time point after a predetermined period of time has passed. That is, at the first time point, the SOC of the battery may be 100%. In addition, at a second time point later than the first time point, the charging and discharging unit 400 may fully discharge the battery. That is, at the second time point, the SOC of the battery may be 0%. The measuring unit 110 may measure the discharge capacity of the battery from the first time point to the second time point.

[0122] The control unit 130 may calculate the capacity change rate by comparing the discharge capacity of the battery calculated by the measuring unit 110 with the standard capacity. Here, the standard capacity may be the discharge capacity of the battery in the BOL state. That is, the standard capacity may be the discharge capacity when the battery in the BOL state is discharged from 100% SOC to 0% SOC.

[0123] Specifically, the control unit 130 can calculate the capacity change rate by calculating the difference between the standard capacity and the calculated discharge capacity. For example, the control unit 130 can calculate the capacity change rate of the battery by the calculation formula "(standard capacity-calculated discharge capacity)÷standard capacity×100".

[0124] Furthermore, the control unit 130 may be configured to determine that the internal gas generation cause of the battery is a side reaction of the negative electrode if the calculated capacity change rate is greater than or equal to a standard capacity change rate.

[0125] In addition, the control unit 130 may be configured to diagnose that the state of the battery is the third warning state when it is determined that the battery internal gas is generated in an amount equal to or greater than a standard amount due to the side reaction of the negative electrode. In addition, the control unit 130 may classify the battery as a reusable battery.

[0126] Thereafter, the control unit 130 may be configured to lower at least one of the upper limit temperature and the upper limit C rate of the battery so as to reduce the amount of internal gas generation of the battery diagnosed as the third warning state. That is, the battery diagnosed as the third warning state may be set by the control unit 130 so that at least one of the allowable upper limit temperature and the upper limit C rate is lowered. That is, when the battery diagnosed as the third warning state is reused, the allowable upper limit temperature and / or the upper limit C rate of the battery may be limited to the value set by the control unit 130.

[0127] The battery diagnostic device 100 according to the present disclosure may be applied to a BMS (battery management system). That is, the BMS according to the present disclosure may include the above-mentioned battery diagnostic device 100. In this configuration, at least some components of the battery diagnostic device 100 may be implemented by supplementing or adding functions of the configuration included in a conventional BMS.

[0128] In addition, the battery diagnostic device 100 according to the present disclosure may be configured for a battery pack. That is, the battery pack according to the present disclosure may include the battery diagnostic device 100 described above and at least one battery. In addition, the battery pack may further include electrical devices (relays, fuses, etc.) and a housing.

[0129] Figure 7 is a diagram schematically showing an exemplary configuration of a battery pack 1 according to another embodiment of the present disclosure. Figure 7 , the battery pack 1 may include a battery diagnosis device 100 , an EIS unit 200 , a heating unit 300 , and a charge and discharge unit 400 . That is, the battery pack 1 may include a battery diagnosis system 10 .

[0130] For example, in Figure 7 In the embodiment of the present invention, the battery diagnosis apparatus 100 may be connected to the first to fourth sensing lines SL1 to SL4. Preferably, the first to fourth sensing lines SL1 to SL4 may be connected to the measurement unit 110 of the battery diagnosis apparatus 100.

[0131] The measuring unit 110 may measure the temperature of the battery B through the first sensing line SL1 .

[0132] In addition, the measuring unit 110 can measure the positive electrode voltage of the battery B through the second sensing line SL2, and measure the negative electrode voltage of the battery B through the third sensing line SL3. In addition, the measuring unit 110 can measure the voltage of the battery B by calculating the difference between the measured positive electrode voltage and negative electrode voltage of the battery B.

[0133] In addition, the measuring unit 110 may be connected to the current measuring element A through the fourth sensing line SL4. Here, the current measuring element A may be a current system or a shunt resistor. Therefore, the measuring unit 110 may measure the current of the battery B through the fourth sensing line SL4. Figure 7 An embodiment in which the current measuring element A is disposed between the negative electrode of the battery B and the negative terminal P− of the battery pack 1 is shown as a preferred embodiment, but the current measuring element A may also be disposed between the positive electrode of the battery B and the positive terminal P+ of the battery pack 1 .

[0134] One end of the EIS unit 200 may be connected between the positive terminal P+ of the battery pack 1 and the positive electrode of the battery B, and the other end may be connected between the negative terminal P− of the battery pack 1 and the negative electrode of the battery B. In addition, the EIS unit 200 may measure the impedance of the battery B after outputting a tiny AC current. Thereafter, the EIS unit 200 may generate an impedance curve of the battery B and transmit it to the battery diagnostic apparatus 100.

[0135] One end of the heating unit 300 may be connected to the positive electrode of the battery B, and the other end may be connected to the negative electrode of the battery B. In addition, the operation of the heating unit 300 is controlled by the battery diagnostic apparatus 100 (particularly, the control unit 130), and when the heating unit 300 operates, the temperature of the battery B may increase.

[0136] One end of the charge and discharge unit 400 may be connected to the positive terminal P+ of the battery pack 1, and the other end may be connected to the negative terminal P- of the battery pack 1. In another embodiment, one end of the charge and discharge unit 400 may be directly connected to the positive electrode of the battery B, and the other end may be directly connected to the negative electrode of the battery B, similar to the heating unit 300. The operation of the charge and discharge unit 400 may be controlled by the battery diagnostic device 100 (specifically, the control unit 130), and when the charge and discharge unit 400 operates, the battery B may be charged or discharged.

[0137] For example, the battery B may be fully charged by the charging and discharging unit 400. In addition, the temperature of the battery B may be maintained at or above the standard temperature for a predetermined period of time by the heating unit 300. Thereafter, the internal gas generation level, internal gas generation cause, and state of the battery B may be diagnosed by the battery diagnostic apparatus 100.

[0138] Figure 8 is a diagram schematically illustrating a battery diagnosis method according to still another embodiment of the present disclosure.

[0139] Here, each step of the battery diagnosis method may be performed by the battery diagnosis apparatus 100. Hereinafter, for the convenience of explanation, contents repeated with the previously described contents will be briefly described or omitted.

[0140] Reference Figure 8 According to an embodiment of the present disclosure, the battery diagnosis method may include a measuring step (S100), an ohmic resistance determining step (S200), a voltage change amount calculating step (S300), a resistance change rate calculating step (S400), an internal gas generation level judging step (S500), and an internal gas generation cause judging step (S600).

[0141] The measuring step ( S100 ) is a step of measuring the voltage and temperature of the battery, and may be performed by the measuring unit 110 .

[0142] For example, refer to Figure 1 and Figure 7 , the measuring unit 110 may be connected to the battery through the first to third sensing lines SL1 to SL3. In addition, the measuring unit 110 may measure the temperature of the battery through the first sensing line SL1, and measure the voltage of the battery through the second and third sensing lines SL2 and SL3.

[0143] The ohmic resistance determining step ( S200 ) is a step of determining the ohmic resistance of the battery based on the impedance curve generated for the battery, and may be performed by the ohmic resistance determining unit 120 .

[0144] For example, the ohmic resistance determining unit 120 may directly receive an impedance curve generated for the battery from the outside, or may access the storage unit 140 to obtain the impedance curve stored in the storage unit 140. In addition, the ohmic resistance determining unit 120 may determine the ohmic resistance of the battery according to the impedance curve.

[0145] Preferably, the ohmic resistance determination unit 120 may determine the ohmic resistance only for a battery whose temperature measured by the measurement unit 110 is equal to or higher than the standard temperature and this state is maintained for a predetermined period of time.

[0146] The voltage variation calculation step ( S300 ) is a step of calculating the voltage variation by comparing the voltage of the battery measured in the measurement step ( S100 ) with a reference voltage, and may be performed by the control unit 130 .

[0147] For example, the control unit 130 may calculate the voltage variation of the battery by using a calculation formula of “reference voltage−measured voltage of the battery”.

[0148] The resistance change rate calculation step ( S400 ) is a step of calculating the resistance change rate by comparing the ohmic resistance determined in the ohmic resistance determination step ( S200 ) with a reference resistance, and may be performed by the control unit 130 .

[0149] For example, the control unit 130 may calculate the resistance change rate of the battery by a calculation formula of “(determined ohmic resistance−reference resistance)÷reference resistance×100”.

[0150] The internal gas generation level judging step ( S500 ) is a step of judging the internal gas generation level of the battery by comparing the calculated resistance change rate with the standard resistance change rate, and may be performed by the control unit 130 .

[0151] For example, if the calculated resistance change rate is greater than or equal to the standard resistance change rate, the control unit 130 may determine that an amount of battery internal gas equal to or greater than the standard amount is generated. Conversely, if the calculated resistance change rate is less than the standard resistance change rate, the control unit 130 may determine that an amount of battery internal gas less than the standard amount is generated.

[0152] The internal gas generation cause determination step ( S600 ) is a step of determining the internal gas generation cause of the battery by comparing the calculated resistance variation with the standard voltage variation, and may be performed by the control unit 130 .

[0153] For example, if the calculated voltage variation is greater than or equal to the standard voltage variation, the control unit 130 may determine that the internal gas of the battery is generated due to the side reaction of the positive electrode of the battery. On the contrary, if the calculated voltage variation is less than the standard voltage variation, the control unit 130 may determine that the internal gas of the battery is generated due to other reasons besides the side reaction of the positive electrode of the battery.

[0154] In addition, despite the Figure 8 Although not shown in the figure, the battery diagnosis method may further include a battery state diagnosis step after the internal gas generation cause determination step (S600).

[0155] The battery state diagnosis step is a step of diagnosing the battery state based on the internal gas generation level and the internal gas generation cause, and may be performed by the control unit 130 .

[0156] Reference Figure 5 , the control unit 130 may diagnose the state of the battery as a normal state, a first warning state, a second warning state, or an unusable state based on the internal gas generation level and the internal gas generation cause.

[0157] For example, the control unit 130 may classify a battery diagnosed as a normal state, a first warning state, or a second warning state as a reusable battery, and classify a battery diagnosed as an unusable state as an unreusable battery. In addition, the control unit 130 may reduce the amount of internal gas generated by the battery when the battery is reused by appropriately limiting the operation of the battery diagnosed as the first warning state or the second warning state.

[0158] In addition, after the battery state diagnosis step, only when the battery is judged to be in the first warning state, an additional diagnosis step may be performed to confirm the cause of internal gas generation of the battery more specifically.

[0159] The additional diagnosis step is a step of diagnosing whether the cause of the internal gas generation of the battery is a side reaction of the negative electrode, and may be performed by the control unit 130 .

[0160] The embodiments of the present disclosure described above can be implemented not only by devices and methods, but also by programs that implement functions corresponding to the configurations of the embodiments of the present disclosure or recording media on which the programs are recorded. Based on the above description of the embodiments, those skilled in the art can easily implement the programs or recording media.

[0161] The present disclosure has been described in detail. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the present disclosure, are given by way of illustration only, since various changes and modifications within the scope of the present disclosure will be apparent to those skilled in the art from the detailed description.

[0162] In addition, those skilled in the art may make many substitutions, modifications and changes to the disclosure described above without departing from the technical aspects of the disclosure, and the disclosure is not limited to the above-mentioned embodiments and drawings, and the various embodiments may be selectively combined in part or in whole to allow various modifications.

[0163] (reference symbol)

[0164] 1: Battery Pack

[0165] 10: Battery diagnostic system

[0166] 100: Battery diagnostic equipment

[0167] 110: Measurement unit

[0168] 120: Ohm resistance determination unit

[0169] 130: Control unit

[0170] 140: Storage unit

[0171] 200: EIS unit

[0172] 300: Heating unit

[0173] 400: Charging and discharging unit

Claims

1. A battery diagnostic device, comprising: a measuring unit configured to measure a voltage and a temperature of the battery; an ohmic resistance determination unit configured to determine an ohmic resistance of the battery based on an impedance curve generated for the battery; as well as A control unit configured to calculate a voltage change by comparing the voltage of the battery measured by the measuring unit with a reference voltage, calculate a resistance change rate by comparing the ohmic resistance determined by the ohmic resistance determining unit with a reference resistance, judge the internal gas generation level of the battery by comparing the calculated resistance change rate with the standard resistance change rate, and judge the cause of the internal gas generation of the battery by comparing the calculated voltage change rate with the standard voltage change rate.

2. The battery diagnostic device according to claim 1, wherein: The reference voltage is a voltage value pre-measured for a battery in a state at the beginning of its life.

3. The battery diagnostic device according to claim 1, wherein: The reference resistance is a resistance value pre-measured for a battery in a state at the beginning of its life.

4. The battery diagnostic device according to claim 1, in, The ohmic resistance determination unit is configured to determine the ohmic resistance based on an impedance curve generated for the battery when the temperature of the battery measured by the measurement unit during a predetermined period is equal to or higher than a standard temperature.

5. The battery diagnostic device according to claim 1, in, The control unit is configured to judge that an amount of internal gas of the battery equal to or greater than a standard amount is generated when the calculated resistance change rate is equal to or greater than the standard resistance change rate, and The control unit is configured to determine that a smaller amount of internal gas of the battery than the standard amount is generated when the calculated resistance change rate is smaller than the standard resistance change rate.

6. The battery diagnostic device according to claim 5, in, The control unit is configured to determine that the internal gas generation cause is a side reaction of the positive electrode of the battery when the calculated voltage change amount is equal to or greater than the standard voltage change amount, and The control unit is configured to determine that the internal gas generation cause is other than the side reaction of the positive electrode when the calculated voltage change amount is smaller than the standard voltage change amount.

7. The battery diagnostic device according to claim 6, in, The control unit is configured to diagnose a state of the battery based on the internal gas generation level and the internal gas generation cause.

8. The battery diagnostic device according to claim 7, in, The control unit is configured to diagnose that the state of the battery is a normal state when it is judged that the internal gas less than the standard amount is generated due to the other cause.

9. The battery diagnostic device according to claim 7, in, When it is determined that the internal gas equal to or greater than the standard amount is generated due to the other cause, the control unit is configured to diagnose that the state of the battery is a first warning state and lower an upper limit temperature of the battery.

10. The battery diagnostic device according to claim 7, in, When it is determined that the internal gas is generated in an amount equal to or greater than the standard amount due to the side reaction of the positive electrode, the control unit is configured to diagnose the state of the battery as a second warning state and lower at least one of an upper limit temperature and an upper limit SOC of the battery.

11. The battery diagnostic device according to claim 7, in, When it is judged that the internal gas is generated in an amount less than the standard amount due to a side reaction of the positive electrode, the control unit is configured to judge that an internal short circuit occurs in the battery and diagnose a state of the battery as an unusable state.

12. The battery diagnostic device according to claim 9, wherein: The measuring unit measures the discharge capacity of the battery from a first time point to a second time point, the control unit calculates a capacity change rate by comparing the discharge capacity of the battery calculated by the measuring unit with a standard capacity, If the calculated capacity change rate is greater than or equal to a standard capacity change rate, the control unit determines that the internal gas generation of the battery is caused by a side reaction of the negative electrode.

13. The battery diagnostic device according to claim 12, wherein: When it is determined that an amount of internal gas of the battery equal to or greater than the standard amount is generated due to a side reaction of the negative electrode, the control unit is configured to diagnose that the state of the battery is a third warning state and reduce at least one of an upper limit temperature and an upper limit C rate of the battery.

14. A battery diagnostic system, comprising: The battery diagnostic device according to any one of claims 1 to 13; as well as An electrochemical impedance spectroscopy (EIS) unit is configured to output an AC current to the battery, generate an impedance curve representing the impedance of the battery as a correspondence between a real part and an imaginary part according to the output result of the AC current, and output the generated impedance curve to the battery diagnostic device.

15. The battery diagnosis system according to claim 14, further comprising: A heating unit is configured to increase the temperature of the battery so that the temperature of the battery becomes equal to or higher than a standard temperature.

16. A battery pack comprising the battery diagnostic device according to any one of claims 1 to 13.

17. A battery diagnosis method, the battery diagnosis method comprising the following steps: a measuring step, wherein the measuring step measures the voltage and temperature of the battery; an ohmic resistance determining step of determining the ohmic resistance of the battery based on an impedance curve generated for the battery; a voltage variation calculation step, wherein the voltage variation calculation step calculates the voltage variation by comparing the voltage of the battery measured in the measuring step with a reference voltage; a resistance change rate calculation step of calculating a resistance change rate by comparing the ohmic resistance determined in the ohmic resistance determination step with a reference resistance; an internal gas generation level judging step of judging the internal gas generation level of the battery by comparing the calculated resistance change rate with a standard resistance change rate; and The internal gas generation cause determination step determines the internal gas generation cause of the battery by comparing the calculated voltage variation with the standard voltage variation.

Images