Battery cell diagnostic device and method

Abstract

The present invention relates to a battery cell diagnostic device and method, and a battery cell diagnostic device according to one embodiment of the present invention may include a reference cell module including at least one reference cell formed of a supercapacitor, a measuring device that measures a reference impedance of the reference cell and a battery impedance of the battery cell, and a processor that compares the battery impedance with the reference impedance to determine whether or not an abnormality exists in the battery cell.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0125853, filed September 30, 2022, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a battery cell diagnostic device and diagnostic method, and more particularly to a battery cell diagnostic device and method capable of diagnosing the state of a battery cell. [Background technology]

[0003] In recent years, the demand for portable electronic products such as laptops, video cameras, and mobile phones has increased sharply, and the development of electric vehicles, energy storage batteries, robots, satellites, and other products has progressed in earnest. As a result, much research has been conducted on secondary batteries, which are used as the driving power sources for these products.

[0004] If at least one of the multiple battery cells included in a battery pack experiences a performance degradation or failure, the performance of the entire battery pack may be degraded, and stable operation may not be possible.

[0005] Therefore, in recent years, there has been a demand for innovations to diagnose the performance of battery cells and determine whether or not there is an abnormality in the battery cells. Summary of the Invention [Problem to be solved by the invention]

[0006] The embodiments of the present invention provide a battery cell diagnostic device and method that can diagnose the state of a battery cell.

[0007] The technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0008] A battery cell diagnostic device according to an embodiment of the present invention may include a reference cell module including at least one reference cell formed of a supercapacitor, a measuring device that measures a reference impedance of the reference cell and a battery impedance of the battery cell, and a processor that compares the battery impedance with the reference impedance to determine whether or not an abnormality exists in the battery cell.

[0009] According to one embodiment, the reference cell module may include a housing having an internal space formed therein to accommodate the at least one reference cell, a protective cover covering the internal space, and a first bus bar and a second bus bar spaced apart by the protective cover.

[0010] According to one embodiment, at least one of the first bus bar and the second bus bar may protrude from the protective cover.

[0011] According to one embodiment, the reference cell may include a body accommodated in the internal space and storing an electric charge, a first conductive terminal disposed on the body and electrically connected to the first bus bar, and a second conductive terminal disposed on the body spaced apart from the first conductive terminal and electrically connected to the second bus bar.

[0012] According to one embodiment, the reference cell module may further include a first conductive bar disposed inside the housing and bent from the first bus bar, and a second conductive bar disposed inside the housing opposite the first conductive bar and bent from the second bus bar.

[0013] According to one embodiment, the first bus bar may be electrically connected to a first conductive terminal via the first conductive bar, and the second bus bar may be electrically connected to the second conductive terminal via the second conductive bar.

[0014] According to an embodiment, the battery cell diagnostic device may further include a charger / discharger that charges and discharges the reference cell and is in electrical contact with the first bus bar and the second bus bar.

[0015] According to one embodiment, the charger / discharger may be mounted on the protective cover.

[0016] According to one embodiment, the length of the charger / discharger may be the same as the separation distance between the first bus bar and the second bus bar.

[0017] According to one embodiment, the battery cells may include lithium-ion battery cells that utilize oxidation-reduction reactions to generate electricity.

[0018] According to one embodiment, the processor may determine that the battery cell is good if the difference between the battery impedance and the reference impedance is within a threshold value, and may determine that the battery cell is bad if the difference between the battery impedance and the reference impedance exceeds the threshold value.

[0019] According to one embodiment, the impedance measuring device remeasures the battery impedance of the battery cell determined to be defective, and the processor may determine that the battery cell is defective if the difference between the remeasured battery impedance and the reference impedance exceeds a threshold, and may determine that the measurement environment of the diagnostic device is abnormal if the difference between the remeasured battery impedance and the reference impedance is within the threshold.

[0020] According to one embodiment, when the measurement environment is determined to be abnormal, the impedance measuring instrument may remeasure the reference impedance, and the remeasured reference impedance may be updated in memory.

[0021] According to one embodiment, the reference cell module may be formed in a portable kit form.

[0022] A method for diagnosing a battery cell according to an embodiment of the present invention may include the steps of measuring a reference impedance of at least one reference cell including a supercapacitor, measuring a battery impedance of a battery cell including at least one battery cell, and comparing the battery impedance with the reference impedance to determine whether or not the battery cell is abnormal. [Effects of the Invention]

[0023] According to an embodiment of the present invention, it is possible to determine whether or not a battery cell has an abnormality based on a reference impedance measured using a reference cell that has a higher charge / discharge efficiency and a longer lifespan than a battery cell. The reference impedance of the reference cell can be maintained at a reliable level for a longer period of time compared to the battery impedance of the battery cell, thereby improving reliability.

[0024] Furthermore, according to the embodiment of the present invention, it is possible to determine whether or not there is an abnormality in the measurement environment based on a change in the impedance value of the battery cell.

[0025] In addition, various other effects can be provided that can be understood directly or indirectly through this document. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a block diagram showing a battery cell diagnostic device according to the present invention; [Figure 2] FIG. 2 is a perspective view showing the reference cell module shown in FIG. [Figure 3] FIG. 3 is an exploded perspective view showing the reference cell module shown in FIG. 2. [Figure 4] 3 is a flowchart showing a battery cell diagnostic method according to the first embodiment of the present invention. [Figure 5] 4 is a graph showing a reference impedance and a battery impedance measured by the impedance measuring device according to the first embodiment of the present invention. [Figure 6] 6 is a flowchart showing a battery cell diagnostic method according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] The present invention will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can easily understand the preferred embodiments of the present invention. However, the present invention can be realized in various different forms and is not limited to the following embodiments.

[0028] In order to clearly explain the present invention, detailed descriptions of parts that are not relevant to the explanation or related known technologies that may obscure the gist of the present invention will be omitted, and when assigning reference symbols to components in each drawing in this specification, the same or similar reference symbols will be assigned to the same or similar components throughout the specification.

[0029] Furthermore, the terms and words used in this specification and claims should not be interpreted in a limited way to their ordinary or dictionary meanings, but should be interpreted in a way that is consistent with the technical idea of ​​the present invention, in accordance with the principle that an inventor can appropriately define the concept of a term in order to best explain his or her invention.

[0030] FIG. 1 is a block diagram showing a battery cell diagnostic device according to the present invention.

[0031] Referring to FIG. 1, the battery cell diagnostic device may include a charger / discharger 320, an impedance measurer 330, a processor 360, and a memory 340.

[0032] The charger / discharger 320 can charge or discharge the reference cell module 310 when measuring the reference impedance of the reference cell module 310. One end of the charger / discharger 320 may be connected to the positive terminal of the reference cell module 310, and the other end may be connected to the negative terminal of the reference cell module 310. The reference cell module 310 may include at least one reference cell. The reference cell may be an energy storage device that has higher charge / discharge efficiency and a longer lifespan than a battery cell. For example, the reference cell may be a supercapacitor.

[0033] The charger / discharger 320 can charge or discharge the battery cell module 350 while measuring the battery impedance of the battery cell module 350. One end of the charger / discharger 320 may be connected to the positive terminal of the battery cell module 350, and the other end may be connected to the negative terminal of the battery cell module 350. The battery cell module 350 may include at least one battery cell. The battery cell may be a battery cell that generates electricity using an oxidation-reduction reaction. For example, the battery cell may be a lithium-ion battery cell.

[0034] The charger / discharger 320 may be configured to apply an AC voltage to the reference cell module 310 to measure the reference impedance of the reference cell module 310. As an example, the charger / discharger 320 may charge the reference cell module 310 by applying an AC voltage while changing the frequency. During this charging process, the impedance measurer 330 may be configured to measure the internal impedance (or reference impedance) of the reference cell module 310. As another example, the charger / discharger 320 may charge and discharge the reference cell module. During this charging / discharging process, the impedance measurer 330 may be configured to measure the internal impedance of the reference cell module 310.

[0035] The impedance measuring device 330 can measure the reference impedance of the reference cell module 310 including a plurality of supercapacitors as well as the battery impedance of the battery cell module 350. The impedance measuring device 330 can measure the reference impedance and the battery impedance using, for example, electrochemical impedance spectroscopy (EIS).

[0036] The reference impedance and the battery impedance can be measured simultaneously or sequentially. Alternatively, a plurality of impedance measuring devices 330 may be provided so as to measure the reference impedance of the reference cell module 310 and the battery impedance of the battery cell module 350, respectively.

[0037] The memory 340 may store the reference impedance for each frequency. The memory 340 may divide a predetermined frequency range into a plurality of frequencies and store the corresponding reference impedance for each divided frequency in a preset format. The reference impedance is a value to be compared with the battery impedance of the battery cell module 350 and may be a value obtained in advance by at least one previous measurement. The reference impedance may be periodically updated by re-measuring the reference impedance at a predetermined period in the memory 340.

[0038] The processor 360 can determine whether or not there is an abnormality in the battery cell module 350 based on the comparison result between the battery impedance and the reference impedance. If the difference between the battery impedance measured by the impedance measuring instrument 330 and the reference impedance stored in the memory 340 is within a preset threshold, the processor 360 can determine that the battery cell module 350 is a good product. If the difference between the battery impedance measured by the impedance measuring instrument 330 and the reference impedance stored in the memory 340 exceeds the preset threshold, the processor 360 can determine that the battery cell module 350 is defective.

[0039] FIG. 2 is a perspective view showing the reference cell module shown in FIG. 1, and FIG. 3 is an exploded perspective view showing the reference cell module shown in FIG.

[0040] 2 and 3, a reference cell module 110 (e.g., the reference cell module 310 of FIG. 1) according to an embodiment may be formed in the form of a portable kit. The reference cell module 110 may include a reference cell 200, a housing 140, first and second conductive bars 121, 131, first and second bus bars 120, 130, and a protective cover 150.

[0041] The housing 140 may include at least one recessed or hole-shaped internal space 141. At least one reference cell 200 may be accommodated in the internal space 141 of the housing 140. The housing 140 may be formed to surround the side and bottom surfaces of the reference cell 200, or may be formed to surround the side surfaces of the reference cell 200. When a plurality of reference cells 200 are accommodated in the housing 140, the plurality of reference cells 200 may be connected in series, parallel, or series-parallel.

[0042] The first and second bus bars 120, 130 may be electrically connected to a charger / discharger (e.g., charger / discharger 320 in FIG. 1). The first bus bar 120 may be electrically connected to a positive terminal of the charger / discharger, and the second bus bar 130 may be electrically connected to a negative terminal of the charger / discharger.

[0043] The first bus bar 120 and the second bus bar 130 may be formed to protrude from the protective cover 150. The first bus bar 120 may protrude from the first conductive bar 121. The second bus bar 130 may protrude from the second conductive bar 131. The first bus bar 120 and the second bus bar 130 may be spaced apart via the protective cover 150. The distance between the first bus bar 120 and the second bus bar 130 may correspond to (e.g., be the same as) the length of the charger / discharger mounted on the protective cover 150.

[0044] The first conductive bar 121 and the second conductive bar 131 may be disposed inside the housing 140 formed of an insulating material. The first conductive bar 121 and the second conductive bar 131 may be disposed opposite each other. The first conductive bar 121 may be bent from the first bus bar 120. The second conductive bar 131 may be bent from the second bus bar 130. As an example, the first conductive bar 121 may be formed of the same conductive material as the first bus bar 120 and integrated with the first bus bar 120. The second conductive bar 131 may be formed of the same conductive material as the second bus bar 130 and integrated with the second bus bar 130. As another example, the first conductive bar 121 may be formed of the same or a different conductive material as the first bus bar 120 and electrically connected to the first bus bar 120 by a fastening member (e.g., a bolt and / or a nut). The second conductive bar 131 may be formed of the same or different conductive material as the second bus bar 130 and may be electrically connected to the second bus bar 130 by a fastening member (e.g., a bolt and / or a nut).

[0045] The protective cover 150 may be formed as a single plate-like structure that is coupled to the housing 140 and covers the internal space 141 in which the reference cell 200 is housed. The protective cover 150 and the housing 140 may be coupled by welding or fastened with fastening members (e.g., bolts and / or nuts) with corresponding edges in contact with each other. The protective cover 150 and the housing 140 can cover the reference cell 200 from above, below, left, and right. The protective cover 150 and the housing 140 can physically protect the reference cell 200. The protective cover 150 and the housing 140 may be formed of an insulating material having a predetermined strength.

[0046] The reference cell 200 may include a body 210, a first conductive terminal 220, and a second conductive terminal 230. For example, the first conductive terminal 220 may be a positive terminal, and the second conductive terminal 230 may be a negative terminal.

[0047] An electric charge can be stored in the body 210. The body 210 may be formed in a shape corresponding to the internal space 141 of the housing 140 and may be accommodated in the internal space 141 of the housing 140.

[0048] The first conductive terminal 220 may be disposed on the body 210 and extend in one direction from one side of the body 210. The first conductive terminal 220 may be electrically connected to the first bus bar 120 via a first conductive bar 121. The second conductive terminal 230 may be disposed on the body 210 at a distance from the first conductive terminal 220 and extend in one direction from one side of the body 210. The second conductive terminal 230 may be electrically connected to the second bus bar 130 via a second conductive bar 131.

[0049] The reference cell 200 may be a supercapacitor, which has the advantages of better charge / discharge efficiency and a longer cycle life than battery cells (e.g., lithium-ion battery cells). Supercapacitors are capable of rapid charge / discharge, high charge / discharge efficiency, and semi-permanent cycle life. Supercapacitors can store several tens of times more energy per unit area than conventional capacitors. Because they have a large storage capacity, supercapacitors are also called ultracapacitors or ultra-high-capacity capacitors. Supercapacitors may be composed of electrodes attached to a conductor and an electrolyte solution impregnated therein. A pair of charge layers (electric double layers) with opposite polarities may be formed at the electrode interface. Unlike battery cells that use chemical reactions, supercapacitors may be energy storage devices that utilize a charging phenomenon due to simple ion migration or surface chemical reactions at the interface between the electrode and electrolyte. The impedance of a supercapacitor does not fluctuate with repeated charge / discharge cycles or degradation over time, making it more reliable than a lithium-ion battery cell.

[0050] FIG. 4 is a flowchart showing a battery cell diagnostic method according to the first embodiment of the present invention.

[0051] In operation S11, an impedance measuring device (e.g., impedance measuring device 330 in FIG. 1) can measure the impedance of a reference cell module (e.g., reference cell module 310 in FIG. 1) including a supercapacitor. The measured impedance of the reference cell module can be stored in a memory (e.g., memory 340 in FIG. 1) as a reference impedance.

[0052] In operation S12, the impedance measurer can measure the battery impedance of a battery cell module (eg, battery cell module 350 in FIG. 1) that includes lithium-ion battery cells.

[0053] In operation S13, a processor (e.g., processor 360 of FIG. 1) can compare the measured battery impedance with a reference impedance stored in memory. The processor can determine whether the difference between the battery impedance and the reference impedance stored in memory is within a threshold value.

[0054] In operation S14, if the comparison shows that the difference between the battery impedance and the reference impedance is within a preset threshold, the battery cell module can be determined to be a non-defective product.

[0055] In operation S15, if the comparison result shows that the difference between the measured impedance and the reference impedance is outside (or exceeds) the threshold value, the battery cell module can be determined to be defective.

[0056] FIG. 5 is a diagram showing the reference impedance and the battery impedance measured by the impedance measuring device according to the first embodiment of the present invention.

[0057] In FIG. 5, the horizontal axis represents the real component of impedance (Zreal), and the vertical axis represents the imaginary component of impedance (Zimag). The units of the horizontal and vertical axes can be mΩ or Ω. Each point can be considered an impedance point corresponding to a respective frequency. The real and imaginary values ​​of the impedance change with changes in frequency, and their intersections are displayed as points on the coordinate system, i.e., impedance points.

[0058] Referring to FIG. 5, the processor can receive and acquire frequency-specific battery impedances for a battery cell and frequency-specific reference impedances for a reference cell from an impedance measuring device (e.g., impedance measuring device 330 in FIG. 1). The processor can compare battery impedance points and reference impedance points corresponding to the same or similar frequencies. If the battery impedance points are the same as the reference impedance points or within a threshold value (or error range), the processor can determine the battery cell as a non-defective product. If the battery impedance points are outside the threshold range relative to the reference impedance points, the processor can determine the battery cell as a defective product. In this way, the processor can diagnose the performance of the battery cell based on the acquired frequency-specific impedance points.

[0059] FIG. 6 is a flowchart showing a battery cell diagnostic method according to a second embodiment of the present invention.

[0060] In operation S21, an impedance measuring device (e.g., impedance measuring device 330 in FIG. 1) can measure the impedance of a reference cell module (e.g., reference cell module 310 in FIG. 1) including a supercapacitor. The measured impedance of the reference cell module can be stored in a memory (e.g., memory 340 in FIG. 1) as a reference impedance.

[0061] In operation S22, the impedance measurer can measure the battery impedance of a battery cell module (eg, battery cell module 350 in FIG. 1) that includes lithium-ion battery cells.

[0062] In operation S23, a processor (e.g., processor 360 of FIG. 1) may compare the measured battery impedance with a reference impedance stored in memory. The processor may determine whether the difference between the measured battery impedance and the reference impedance stored in memory is within a threshold value.

[0063] In operation S24, if the comparison shows that the difference between the measured battery impedance and the reference impedance is within a preset threshold, the battery cell module can be determined to be a non-defective product.

[0064] In operation S25, if the comparison result indicates that the difference between the measured battery impedance and the reference impedance is outside the threshold, the impedance measuring device can remeasure at least one of the battery impedance of the battery cell module and the reference impedance of the reference cell module. For example, the impedance measuring device can remeasure the battery impedance of the battery cell module.

[0065] In operation S26, the processor may compare the re-measured battery impedance with the reference impedance stored in memory, and the processor may again determine whether the difference between the re-measured battery impedance and the reference impedance stored in memory is within the threshold value.

[0066] In operation S27, if the comparison shows that the difference between the re-measured battery impedance and the reference impedance is outside the threshold, the processor can determine that the battery cell module is faulty.

[0067] In operation S28, if the comparison shows that the difference between the re-measured battery impedance and the reference impedance is within the threshold, the processor can determine that the measurement environment of the diagnostic device is abnormal. If the measurement environment is determined to be abnormal, the inspector can check for abnormalities in the reference cell module, the battery cell module, and the diagnostic device. If the reference cell module is determined to be abnormal, the reference cell module can be inspected. After inspecting the reference cell module, the impedance measuring device 330 can re-measure the reference impedance and update the re-measured reference impedance in memory.

[0068] The battery cell module described above can be applied to various devices, including, but not limited to, transportation means such as electric bicycles, electric cars, and hybrid vehicles, and can be applied to various devices in which a battery cell module can be used.

[0069] Although the present invention has been described above using limited embodiments and drawings, the present invention is not limited thereto, and various implementations within the technical spirit of the present invention and the scope of equivalents of the appended claims can be made by a person having ordinary skill in the art to which the present invention pertains. [Explanation of symbols]

[0070] 110, 310 reference cell module 120, 130 busbars 140 Housing 150 Protective Cover 200 reference cells 320 charger / discharger 330 Impedance Measuring Instrument 340 memory 350 Battery Cell Module 360 processor

Claims

1. A diagnostic device for inspecting the state of a battery cell, a reference cell module including at least one reference cell made of a supercapacitor; a measuring instrument for measuring the reference impedance of the reference cell and the battery impedance of the battery cell; a processor that compares the battery impedance with the reference impedance to determine whether or not an abnormality exists in the battery cell.

2. The reference cell module comprises: a housing having an interior space formed therein for accommodating the at least one reference cell; a protective cover that covers the internal space; The diagnostic device of claim 1 , further comprising: a first bus bar and a second bus bar spaced apart by the protective cover.

3. The diagnostic device according to claim 2 , wherein at least one of the first bus bar and the second bus bar protrudes from the protective cover.

4. The reference cell is a body contained in the interior space and capable of storing an electric charge; a first conductive terminal disposed on the body and electrically connected to the first bus bar; 4. The diagnostic device of claim 3, further comprising: a second electrically conductive terminal disposed on the body spaced apart from the first electrically conductive terminal and electrically connected to the second bus bar.

5. The reference cell module comprises: a first conductive bar disposed inside the housing and bent from the first bus bar; The diagnostic device of claim 4 , further comprising: a second conductive bar disposed inside the housing opposite the first conductive bar and bent from the second bus bar.

6. the first bus bar is electrically connected to a first conductive terminal via the first conductive bar; The diagnostic device according to claim 5 , wherein the second bus bar is electrically connected to the second conductive terminal via the second conductive bar.

7. The diagnostic device of claim 2 , further comprising a charger / discharger that charges and discharges the reference cell and that is in electrical contact with the first bus bar and the second bus bar.

8. The diagnostic device of claim 7 , wherein the charger / discharger is mounted on the protective cover.

9. The diagnostic device according to claim 7 , wherein the length of the charger / discharger is the same as the separation distance between the first bus bar and the second bus bar.

10. The diagnostic device according to claim 1 , wherein the battery cell includes a lithium-ion battery cell that generates electricity using an oxidation-reduction reaction.

11. The processor: If the difference between the battery impedance and the reference impedance is within a threshold value, the battery cell is determined to be a non-defective product; The diagnostic device according to claim 1 , wherein the battery cell is determined to be defective when a difference between the battery impedance and the reference impedance exceeds a threshold value.

12. The measuring instrument is re-measuring the battery impedance of the battery cell determined to be defective; The processor: If the difference between the re-measured battery impedance and the reference impedance exceeds a threshold, the battery cell is determined to be defective; The diagnostic device according to claim 11 , wherein if the difference between the re-measured battery impedance and the reference impedance is within a threshold value, it is determined that the measurement environment of the diagnostic device is abnormal.

13. The measuring instrument is If it is determined that the measurement environment is abnormal, the reference impedance is measured again. The diagnostic device of claim 12 , wherein the re-measured reference impedance is updated in a memory.

14. The diagnostic device of claim 1 , wherein the reference cell module is configured in a portable kit form.

15. A diagnostic method for diagnosing the state of a battery cell, comprising: measuring a reference impedance of at least one reference cell including a supercapacitor; measuring a battery impedance of the battery cells including at least one battery cell; A diagnostic method for a battery cell, comprising: a step of comparing the battery impedance with the reference impedance to determine whether or not an abnormality exists in the battery cell.

Images