An ultrasonic battery sorting method and battery sorting system

Abstract

The application discloses an ultrasonic battery sorting method and a battery sorting system, which comprises the following steps: S1, direct current charging a battery pack for a first predetermined time; S2, obtaining the SOC state of each battery to be detected in the battery pack by using ultrasonic waves; S3, comparing the SOC state of each battery to be detected with the SOC standard of a full battery, marking the batteries that do not meet the SOC standard of the full battery, and obtaining unqualified batteries according to the marked batteries; and S4, removing the unqualified batteries. Since the batteries that are unqualified due to aging cannot reach a full state within a specified charging time, the SOC state of the batteries cannot meet the SOC standard of the full battery. According to this principle, if the SOC state of the batteries after direct current charging for the first predetermined time does not meet the SOC standard of the full battery, the batteries are marked. The unqualified batteries that cannot be fully charged within the specified time can be screened out, and compared with a discharging detection sorting method, the sorting efficiency of the batteries is greatly improved.

Description

Technical Field

[0001] This invention relates to, and more specifically to, an ultrasonic battery sorting method and a battery sorting system. Background Technology

[0002] Lithium-ion batteries, as the power source for electric vehicles, determine the reliability and safety of transportation. With the increasing number of electric vehicles, the number of retired batteries is also growing, making the handling and utilization of these batteries a pressing issue. Simply scrapping them without maximizing their residual value would increase the operating costs of electric vehicles. Typically, retired batteries are reused, utilizing their remaining capacity and performance in other applications where their performance meets the requirements. However, the health status of retired batteries from electric vehicles is inconsistent, preventing direct reuse. Strict screening is essential to remove batteries with poor consistency and substandard health conditions. Only through proper screening can their full value be realized during reuse.

[0003] Existing battery sorting methods, as described in patent application CN202110620187.5, typically involve charging the batteries and then discharging them to obtain voltage drop and impedance data. These data are then used to evaluate the battery's health and filter out substandard batteries. This method requires discharging each battery individually, necessitating real-time monitoring of voltage and current output during discharge. This continuous discharge process is a necessary step in the battery sorting method, slowing down the overall sorting speed.

[0004] Therefore, how to efficiently sort batteries is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned technical deficiencies and propose an ultrasonic battery sorting method and battery sorting system to solve the technical problem that the existing technology requires a long time to discharge the battery, which slows down the battery sorting speed.

[0006] To achieve the above-mentioned technical objectives, the technical solution of the present invention includes an ultrasonic battery sorting method, which includes:

[0007] S1. DC charge the battery pack for a first predetermined time;

[0008] S2. Use ultrasound to obtain the SOC state of each battery to be tested in the battery pack;

[0009] S3. Compare the SOC status of each battery to be tested with the SOC standard of a fully charged battery, and mark the batteries that do not meet the SOC standard of a fully charged battery. Based on the marked batteries, determine the unqualified batteries.

[0010] S4. Remove defective batteries.

[0011] Preferably, the marked battery and the batteries adjacent to the marked battery are defined as unqualified batteries.

[0012] Preferably, step S1 includes:

[0013] S11. Discharge the battery pack until the stored power in the battery pack is completely consumed;

[0014] S12, DC charge the battery pack for a first predetermined time.

[0015] Preferably, the first predetermined time is the charging time for a brand-new battery pack to go from 0% to 100%.

[0016] Preferably, step S2 includes:

[0017] S21, The battery pack remains stationary for the second predetermined time;

[0018] S22. Use ultrasonic waves to detect the porosity of the negative electrode of the battery under test.

[0019] S23. Calculate the SOC state of the battery under test based on the porosity of the negative electrode of the battery under test.

[0020] Preferably, step S23 includes:

[0021] S231. Obtain the relationship between the negative electrode porosity and negative electrode temperature of a fully charged battery.

[0022] S232. Obtain the negative electrode porosity and negative electrode temperature of the battery to be tested;

[0023] S233. Compare the porosity of the negative electrode of the battery under test with that of a fully charged battery at the same temperature.

[0024] S234. Calculate the SOC state of the battery to be tested based on the comparison results.

[0025] Preferably, the negative electrode temperatures of the fully charged battery and the battery under test are obtained using an infrared detector.

[0026] Preferably, the second predetermined time is not less than half an hour.

[0027] Preferably, the first predetermined time increases as the ambient temperature decreases.

[0028] A battery sorting system that applies the ultrasonic battery sorting method described above.

[0029] Compared with existing technologies, the beneficial effects of this invention include: firstly, the battery pack is charged using DC charging for a first predetermined time; then, the State of Charge (SOC) of each battery under test is obtained using ultrasonic detection and compared with the SOC standard of a fully charged battery. Since aged, substandard batteries cannot reach full charge within the specified charging time, their SOC does not meet the SOC standard for a fully charged battery. Based on this principle, if the SOC of a battery after DC charging for the first predetermined time does not meet the SOC standard for a fully charged battery, these batteries are marked. The marked batteries are used to identify substandard batteries, thus ultimately removing them. Using the ultrasonic battery sorting method provided by this invention, substandard batteries that cannot be fully charged within a specified time can be screened out, significantly improving battery sorting efficiency compared to discharge detection sorting methods. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the ultrasonic battery sorting method according to an embodiment of the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0032] See also Figure 1 This invention provides an ultrasonic battery sorting method, which belongs to the field of battery recycling. The ultrasonic battery sorting method is used to screen unqualified batteries in a battery pack. The ultrasonic battery sorting method improves the efficiency of battery sorting by detecting the SOC state of the battery after charging and then judging whether the battery is qualified.

[0033] In some preferred embodiments, the ultrasonic battery sorting method includes:

[0034] S1. DC charge the battery pack for a first predetermined time;

[0035] S2. Use ultrasound to obtain the SOC state of each battery to be tested in the battery pack;

[0036] S3. Compare the SOC status of each battery to be tested with the SOC standard of a fully charged battery, and mark the batteries that do not meet the SOC standard of a fully charged battery. Based on the marked batteries, determine the unqualified batteries.

[0037] S4. Remove defective batteries.

[0038] First, the battery pack is charged using DC charging for a predetermined time. Then, the State of Charge (SOC) of each battery is obtained using ultrasonic testing and compared with the SOC standard of a fully charged battery. Because aged, substandard batteries cannot reach full charge within the specified charging time, their SOC does not meet the standard for a fully charged battery. Based on this principle, if the SOC of a battery after the first predetermined time of DC charging does not meet the standard for a fully charged battery, these batteries are marked. The marked batteries are then used to identify substandard batteries, which are ultimately removed. Using the ultrasonic battery sorting method provided by this invention, substandard batteries that cannot be fully charged within a specified time can be screened out, significantly improving battery sorting efficiency compared to discharge detection sorting methods.

[0039] It is important to emphasize that the present invention utilizes ultrasonic waves to detect the SOC state of lithium batteries. During the charging process of lithium-ion batteries, Li+ ions first escape from the positive electrode, diffuse onto the surface of the negative electrode, and then embed into the lattice of the graphite negative electrode. As Li+ ions embed, the graphite particles undergo a certain degree of volume expansion, which causes a change in the porosity of the negative electrode sheet. Ultrasonic waves are very sensitive to changes in porosity, thus enabling highly sensitive detection of the battery's SOC state.

[0040] In some preferred embodiments, the marked battery and its adjacent batteries are defined as defective batteries. In a battery pack, when a battery ages and develops a quality problem, adjacent batteries often age rapidly as well. This means that even if batteries around a clearly defective battery pass inspection, their lifespan will be significantly shortened. Therefore, batteries surrounding the marked battery are also considered defective. Although this may incorrectly identify some objectively acceptable batteries as defective, it can significantly improve the efficiency of battery sorting.

[0041] In some preferred embodiments, step S1 includes:

[0042] S11. Discharge the battery pack until the stored power in the battery pack is completely consumed;

[0043] S12, DC charge the battery pack for a first predetermined time.

[0044] The ultrasonic battery sorting method of the present invention charges the battery packs within a first predetermined time period, and then evaluates the health of the batteries by detecting their State of Charge (SOC). However, to ensure the accuracy of the detection, it is necessary to ensure that all battery packs have the same initial charge before charging. Therefore, the easiest way to accurately control the initial charge of the battery packs is to discharge the battery packs to be tested, thereby completely consuming the charge stored in the battery packs.

[0045] Based on the above embodiment, the first predetermined time is the charging time for a brand-new battery pack from 0% to 100%. If the battery is not fully charged within the first predetermined time, it indicates a quality problem. Specifically, this means there is a difference between the State of Charge (SOC) of the battery under test and that of a fully charged battery. Based on this principle, unqualified batteries can be sorted out.

[0046] In some preferred embodiments, step S2 includes:

[0047] S21, The battery pack remains stationary for the second predetermined time;

[0048] S22. Use ultrasonic waves to detect the porosity of the negative electrode of the battery under test.

[0049] S23. Calculate the SOC state of the battery under test based on the porosity of the negative electrode of the battery under test.

[0050] It's understandable that batteries will lose some charge after charging, and if the rate of charge loss is too rapid, it indicates that the battery's DC current is not up to standard. After charging, batteries are left to rest. Batteries that lose charge too quickly will lose a significant amount of charge during this resting period, causing a change in their State of Charge (SOC) and thus leading to their rejection.

[0051] In some preferred embodiments, step S23 includes:

[0052] S231. Obtain the relationship between the negative electrode porosity and negative electrode temperature of a fully charged battery.

[0053] S232. Obtain the negative electrode porosity and negative electrode temperature of the battery to be tested;

[0054] S233. Compare the porosity of the negative electrode of the battery under test with that of a fully charged battery at the same temperature.

[0055] S234. Calculate the SOC state of the battery to be tested based on the comparison results.

[0056] It should be noted that the battery sorting method of this invention calculates the state of charge (SOC) of the battery by ultrasonically detecting the porosity of the negative electrode. However, the porosity of the negative electrode changes with its temperature. To avoid the influence of temperature on the detection results, the relationship between the porosity of the negative electrode of a fully charged battery and its temperature can be obtained. By comparing the porosity of the negative electrode of the battery under test with that of a fully charged battery at the same temperature, the influence of temperature changes on the porosity of the negative electrode can be avoided, thus allowing the calculation of the SOC of the battery under test.

[0057] Any method that can obtain the negative electrode temperature of the battery to be tested is feasible. In some preferred embodiments, the negative electrode temperatures of the fully charged battery and the battery to be tested are obtained by an infrared detector.

[0058] Based on the above embodiments, the second predetermined time is not less than half an hour.

[0059] It is understood that the lower the ambient temperature, the longer it takes for the battery pack to be fully charged. In some preferred embodiments, the first predetermined time increases as the ambient temperature decreases.

[0060] In addition, the present invention also provides a battery sorting system that applies the above-described ultrasonic battery sorting method.

[0061] To ensure accurate testing, all battery packs must have the same initial charge level before charging. Therefore, the easiest way to precisely control the initial charge level is to discharge the battery packs under test, completely depleting their stored charge. The battery packs are charged using DC charging for a predetermined time, and then left to rest. Batteries that lose charge too quickly will suffer significant charge loss during this resting period. Subsequently, ultrasonic testing is used to obtain the State of Charge (SOC) of each battery under test, and this is compared to the SOC standard of a fully charged battery. Because aging batteries cannot reach full charge within the specified charging time, their SOC does not meet the standard for a fully charged battery. Based on this principle, if the SOC of a battery after the first predetermined DC charging time does not meet the standard for a fully charged battery, these batteries are marked. The marked batteries are used to identify the unqualified batteries, which are then removed. The ultrasonic battery sorting method provided by this invention can screen out unqualified batteries that cannot be fully charged within a specified time, which greatly improves the battery sorting efficiency compared with the sorting method based on discharge detection.

[0062] Finally, it must be emphasized again that the State of Charge (SOC) of a battery within the specified charging time is insufficient to comprehensively evaluate its health, and it cannot be arbitrarily assumed that a battery with a satisfactory SOC is ready for reuse. However, the SOC within the specified charging time is one of the important indicators for judging battery health. The purpose of the ultrasonic battery method of this invention is to provide a means to quickly screen out unqualified batteries, thereby improving the efficiency of battery screening. Batteries sorted by this invention can be used in some less demanding application scenarios, or combined with other testing methods to obtain more accurate screening results.

[0063] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. An ultrasonic battery sorting method, characterized in that, include: S1. DC charge the battery pack for a first predetermined time; S2. Use ultrasound to obtain the SOC state of each battery to be tested in the battery pack; S3. Compare the SOC status of each battery to be tested with the SOC standard of a fully charged battery, and mark the batteries that do not meet the SOC standard of a fully charged battery. Based on the marked batteries, determine the unqualified batteries. S4. Remove defective batteries; Step S2 includes: S21, The battery pack remains stationary for the second predetermined time; S22. Use ultrasonic waves to detect the porosity of the negative electrode of the battery under test. S23. Calculate the SOC state of the battery under test based on the porosity of the negative electrode of the battery under test.

2. The ultrasonic battery sorting method according to claim 1, characterized in that, The marked battery and the adjacent marked battery are defined as non-compliant batteries.

3. The ultrasonic battery sorting method according to claim 1, characterized in that, Step S1 includes: S11. Discharge the battery pack until the stored power in the battery pack is completely consumed; S12, DC charge the battery pack for a first predetermined time.

4. The ultrasonic battery sorting method according to claim 3, characterized in that, The first predetermined time is the charging time for a brand new battery pack from 0% to 100%.

5. The ultrasonic battery sorting method according to claim 1, characterized in that, Step S23 includes: S231. Obtain the relationship between the negative electrode porosity and negative electrode temperature of a fully charged battery. S232. Obtain the negative electrode porosity and negative electrode temperature of the battery to be tested; S233. Compare the porosity of the negative electrode of the battery under test with that of a fully charged battery at the same temperature. S234. Calculate the SOC state of the battery to be tested based on the comparison results.

6. The ultrasonic battery sorting method according to claim 5, characterized in that, The negative electrode temperatures of the fully charged battery and the battery under test are obtained using an infrared detector.

7. The ultrasonic battery sorting method according to claim 4, characterized in that, The second scheduled time shall not be less than half an hour.

8. The ultrasonic battery sorting method according to claim 1, characterized in that, The first predetermined time increases as the ambient temperature decreases.

9. A battery sorting system, characterized in that, Its application is the ultrasonic battery sorting method as described in any one of claims 1 to 8.

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