Battery state of health based charging evaluation method and use thereof

Abstract

A charging assessment method based on battery health state and its use are disclosed. The charging assessment method based on battery health state includes the following steps: providing one or more batteries in multiple battery health states; charging one or more batteries using multiple charging methods; acquiring multiple battery parameters of the one or more batteries during the charging process; forming a radar chart corresponding to a single battery health state using the multiple battery parameters; calculating and comparing the area proportions of the multiple charging methods on the radar chart; and determining the charging method with the highest area proportion among the multiple charging methods as the applicable charging method for the battery health state range.

Description

Technical Field

[0001] This invention relates to a charging assessment method based on battery health status and its use. Background Technology

[0002] Current battery chargers are generally designed using a uniform charging method, without considering the gradual aging of batteries with increasing charge-discharge cycles. Therefore, using the same charging method on aged batteries may cause unexpected temperature rises during charging, increasing the risk of thermal runaway. Therefore, there is an urgent need to develop a charging assessment method based on battery health status to improve temperature rise during charging and enhance safety. Summary of the Invention

[0003] According to one aspect of the present invention, a charging evaluation method based on battery health state is proposed. The charging evaluation method based on battery health state includes the following steps: providing one or more batteries in various battery health states; charging the one or more batteries using various charging methods; acquiring various battery parameters of the one or more batteries during the charging process; forming a radar chart corresponding to a single battery health state using the various battery parameters; calculating and comparing the area percentages of the various charging methods on the radar chart; and determining the charging method with the highest area percentage among the various charging methods as the applicable charging method for the battery health state range.

[0004] To provide a better understanding of the above and other aspects of the present invention, specific embodiments are described below in conjunction with the accompanying drawings. Attached Figure Description

[0005] Figure 1A A flowchart illustrating a charging assessment method based on battery health status according to an embodiment of the present invention is shown;

[0006] Figure 1B for Figure 1A A detailed flowchart of step S120 in the process;

[0007] Figure 2 This illustration depicts one type of various charging methods involved in a charging assessment method based on battery health status according to an embodiment of the present invention.

[0008] Figure 3 This illustration depicts one type of various charging methods involved in a charging assessment method based on battery health status according to an embodiment of the present invention.

[0009] Figure 4 This illustration depicts one type of various charging methods involved in a charging assessment method based on battery health status according to an embodiment of the present invention.

[0010] Figure 5 This illustration depicts one type of various charging methods involved in a charging assessment method based on battery health status according to an embodiment of the present invention.

[0011] Figure 6 This illustration depicts one type of various charging methods involved in a charging assessment method based on battery health status according to an embodiment of the present invention.

[0012] Figure 7 An example of a radar chart generated by a charging assessment method based on battery health status according to an embodiment of the present invention;

[0013] Figure 8 An example of a radar chart generated by a charging assessment method based on battery health status according to an embodiment of the present invention;

[0014] Figure 9 An example of a radar chart generated by a charging assessment method based on battery health status according to an embodiment of the present invention is shown.

[0015] [Symbol Explanation]

[0016] S110, S120, S130, S140, S150, S160: Steps

[0017] CC: Charging current

[0018] CV: Rated Voltage

[0019] I1, I2: Current values

[0020] R1, R2: Equivalent resistance values ​​of the battery

[0021] T1, T2: Time points

[0022] +△V: Set a positive value

[0023] -△V: Set negative value Detailed Implementation

[0024] Please refer to Figure 1A The flowchart illustrates a charging evaluation method based on battery health status according to an embodiment of the present invention. The charging evaluation method based on battery health status in this embodiment mainly includes steps S110 to S160.

[0025] In step S110, one or more batteries in various states of health (SOH) are provided. For example, an ICR18650 lithium-ion battery can be used. In one embodiment, at least two batteries can be provided, each in a different state of health. For example, three batteries can be provided: one with an SOH of 100%, one with an SOH of 95%, and one with an SOH of 91%. In another embodiment, a single battery can be provided, which undergoes a battery aging process to achieve various states of health. For example, a single battery with an SOH of 100% can be provided, which is then aged to achieve an SOH of 95% or 91% to meet subsequent demands for different SOH values. The battery aging process can accelerate battery aging by charging and discharging the battery to reach a set charge-discharge cycle (e.g., 10 to 15 cycles, but not limited to this).

[0026] In step S120, a capacity test is performed on one or more batteries. Please refer to [link / reference needed]. Figure 1B , Figures 2-6 ,in Figure 1B This is a detailed flowchart of step S120, and Figures 2-6 This illustration depicts various charging methods involved in the charging assessment method based on battery health status according to embodiments of the present invention. In this embodiment, such as... Figure 1B As shown, step S120 can be further divided into steps S121 and S122. In step S121, the one or more batteries are charged using various charging methods. After step S121, step S122 is performed, in which the one or more batteries are discharged.

[0027] For example, step S121 can be achieved using five different charging methods. Figures 2-4 The diagram shows a constant current and constant voltage charging method. Figure 2 In the constant current and constant voltage charging method shown, the battery is first charged with a fixed charging current CC (this period is the constant current mode) until the battery terminal voltage is greater than or equal to the battery's rated voltage CV. Then, the battery switches to a fixed rated voltage CV for charging (this period is the constant voltage mode) until the current is less than a set current value, at which point the charging stops. Figure 3 In the constant current and constant voltage charging method shown, the battery is first charged with a fixed charging current CC (this period is the constant current mode) until the battery terminal voltage is greater than or equal to the sum of the battery's rated voltage CV and a set negative value -ΔV (i.e., [CV + (-ΔV)]). Then, the battery is charged with a fixed voltage value [CV + (-ΔV)] (this period is the constant voltage mode) until the current is less than a set current value, at which point the charging stops. Figure 4In the constant current and constant voltage charging method shown, the battery is first charged with a fixed charging current CC (this period is the constant current mode). When the battery terminal voltage is greater than or equal to the sum of the battery's rated voltage CV and a set positive value +ΔV (i.e., [CV + (+ΔV)]), the battery switches to a fixed voltage value [CV + (+ΔV)] for charging (this period is the constant voltage mode), and stops when the current is less than a set current value. Therefore, it can be seen that... Figure 2 ~

[0028] Figure 4 The charging methods shown all belong to the constant current and constant voltage charging method, but these constant current and constant voltage charging methods have different cut-off voltages and are therefore different types.

[0029] Figure 5 The diagram shows a constant power charging method using constant power and constant voltage charging. In this method, the battery... Figure 5 The diagram shows that charging is initially performed at a fixed charging power (this period is called constant power mode), where the charging power is the product of voltage and current. Figure 5 The product of the voltage value V1 and the corresponding current value I1 at time point T1 is equal to the product of the voltage value V2 and the corresponding current value I2 at time point T2. The battery continues to charge in a constant power mode until the battery terminal voltage is greater than or equal to a set voltage value. At this point, the battery switches to charging at the fixed set voltage value (this period is the aforementioned constant voltage mode) until the current is less than a set current value, at which point charging stops. The charging power can be determined according to the battery's rated power. In one embodiment, it can be set to, for example, 0.5 times the rated power.

[0030] Figure 6 The diagram shows a constant-loss charging method using constant-loss constant-voltage charging. In this method, the battery... Figure 6 The diagram shows initial charging with a fixed charging loss (this period is called constant loss mode), where the charging loss is the product of the square of the current and the battery's equivalent resistance. That is, during... Figure 6 The product of the square of the current value I1 at time point T1 and the corresponding equivalent battery resistance value R1 is equal to the product of the square of the current value I2 at time point T2 and the corresponding equivalent battery resistance value R2. The battery continues to be charged in a constant-loss mode until the battery terminal voltage is greater than or equal to a set voltage value. At this point, the battery switches to charging at a fixed set voltage value (this period is the aforementioned constant-voltage mode) until the current is less than a set current value, at which point the charging stops. Since the internal equivalent impedance of the battery is different under different states of charge (SOC), in order to maintain the same charging loss, the charging current in constant-loss mode varies with the SOC.

[0031] In an embodiment providing three batteries (a battery with a state of 100% SOH, a battery with a state of 95% SOH, and a battery with a state of 91% SOH, respectively), each of the three batteries can be charged using at least two of the five different charging methods described in Figures 2-6. In an embodiment providing a single battery (a battery with a state of 100% SOH, a battery with a state of 95% SOH, and a battery with a state of 91% SOH), this battery is charged using at a state of 100% SOH. Figures 2-6 At least two of the five different charging methods described herein; then, after the battery is aged to a state of SOH of 95%, the same at least two of the five different charging methods described above are performed again; then, after the battery is aged to a state of SOH of 91%, the same at least two of the five different charging methods described above are performed again.

[0032] Next, step S122 is performed to discharge the one or more batteries. In this embodiment, the one or more batteries are discharged using the same discharge method, but this is not a limitation. Therefore, in this embodiment, the capacity test in step S120 includes charging with multiple charging methods and discharging with the same discharge method. It should be noted that in other embodiments, step S120 may only include step S121 and omit step S122, meaning that only the charging process for the capacity test in step S120 is performed, but this is not a limitation.

[0033] In step S130, various battery parameters of the one or more batteries during the charging / discharging process are acquired. For example, battery parameters of a battery with a state of 100% SOH during various charging methods, battery parameters of a battery with a state of 95% SOH during various charging methods, and battery parameters of a battery with a state of 91% SOH during various charging methods can be acquired. The various battery parameters during the charging process include, for example, the reciprocal of a maximum temperature rise, the reciprocal of an average temperature rise, a charging rate, and a charging capacity. The reciprocal of the maximum temperature rise (in units such as °C) is the reciprocal of the difference between the battery surface temperature and the ambient temperature. The reciprocal of the average temperature rise (in units such as °C) is the reciprocal of the average difference between the battery surface temperature and the ambient temperature at multiple time points sampled during the charging process. The charging rate is the reciprocal of the charging time (in units such as hours). Correspondingly, battery parameters of the one or more batteries during the discharging process can be acquired, including, for example, a discharging capacity and a coulombic efficiency. Coulombic efficiency is the percentage of a battery's discharge capacity (e.g., ampere-hours) to its charge capacity (e.g., ampere-hours). Specifically, information about these battery parameters can be acquired by an acquisition unit. This acquisition unit can be integrated into a controller or a processor. Furthermore, the acquisition unit can be a physical circuit formed using at least one semiconductor process, such as a semiconductor wafer or semiconductor package.

[0034] Based on a practical test of a charging evaluation method based on battery health status, the following table (Tables 1-3) provides data on battery parameters corresponding to different battery health states:

[0035] Table 1 (Battery parameters obtained using five charging methods for batteries with a SOH of 100%)

[0036]

[0037]

[0038] Table 2 (Battery parameters obtained using five charging methods for batteries with a state of 95% SOH)

[0039]

[0040] Table 3 (Battery parameters obtained using five charging methods for a battery with a state of 91% SOH)

[0041]

[0042]

[0043] In step S140, a radar chart corresponding to the health state of a single battery is formed using the various battery parameters. As mentioned above, after charging one or more batteries using various charging methods, the one or more batteries can be further discharged, thus allowing the corresponding battery parameters for the charging and discharging processes to be captured. Since forming a radar chart requires at least three indicators (three indicators form a triangular radar chart, four indicators form a quadrilateral radar chart, five indicators form a pentagonal radar chart, six indicators form a hexagonal radar chart, and so on), the battery parameters for the charging and discharging processes can include at least three of the following: the reciprocal of the maximum temperature rise, the reciprocal of the average temperature rise, the charging rate, the charging capacity, the discharging capacity, and the coulombic efficiency. However, if the one or more batteries are not further discharged, only the battery parameters for the charging process are captured, where the battery parameters for the charging process include at least three of the following: the reciprocal of the maximum temperature rise, the reciprocal of the average temperature rise, the charging rate, and the charging capacity.

[0044] Please refer to [the website / reference] Figures 7-9 The example illustrates a radar chart generated based on a charging assessment method using battery health status, where... Figure 7 The plot is based on the data in Table 1. Figure 8 The plot is based on the data in Table 2. Figure 9 The data is plotted based on the data in Table 3.

[0045] In one embodiment, in step S130, for example, all six listed battery parameters—the reciprocal of the maximum temperature rise, the reciprocal of the average temperature rise, the charging rate, the charging capacity, the discharging capacity, and the coulombic efficiency—are extracted. Then, in step S140, these six battery parameters are used to form a hexagonal radar chart as shown in Figures 7-9. More specifically, Figures 7-9 The radar chart shown is a hexagonal radar chart corresponding to a single battery health state, formed by further normalizing various battery parameters. The normalization process can be the ratio of a single battery parameter data obtained by a certain charging method for a single battery health state in Tables 1-3 to the maximum data of the same battery parameter obtained by all different battery health states and all different charging methods. For example, in Table 1, batteries with a SOH of 100% are used... Figure 2 The reciprocal of the maximum temperature rise obtained by the charging method shown is 0.29, while the largest reciprocal of the maximum temperature rise obtained by all different battery health states and all different charging methods is 0.32 (in Table 2, batteries with a SOH of 95% are used). Figure 6 (The data obtained from the charging method shown) Therefore, the normalized value is 0.29 / 0.32 = 0.90625. For example... Figure 7As shown, a node of the radar chart is then plotted at a position between 0.7 and 1.0 based on a value of 0.90625. All battery parameter data in Tables 1-3 can undergo the aforementioned normalization process to generate the radar chart.

[0046] In step S150, the area percentages of the various charging methods on the radar chart are calculated and compared. The area percentage is the ratio of the area of ​​the outlines of the five charging methods on each radar chart to the total outline of the radar chart. Specifically, the area percentage information can be calculated and compared by a computing unit. The computing unit can be integrated into a controller or a processor. Furthermore, the computing unit can be a physical circuit formed using at least one semiconductor process, such as a semiconductor wafer or semiconductor package. Based on practical testing of the charging evaluation method based on battery health status, the area percentage data on the radar chart corresponding to different battery health states are provided in Table 4 below:

[0047] Table 4 (Ratio of the five charging methods' outlines to the total outlines of each radar chart)

[0048]

[0049]

[0050] Based on the data in Table 4, the charging method with the highest area ratio corresponding to a SOH of 100% can be compared as follows: Figure 2 The charging method shown corresponds to the charging method with the highest area ratio when the state of state of equilibrium (SOH) is 95%. Figure 6 The charging method shown corresponds to the charging method with the highest area ratio when the state of state of equilibrium (SOH) is 91%. Figure 6 The charging method shown.

[0051] In step S160, the charging method with the highest area ratio among multiple charging methods is determined as the applicable charging method for a battery health state range. Specifically, a determination unit can determine the charging method with the highest area ratio as the optimal charging method applicable to the battery health state range. The determination unit can be integrated into a controller or a processor. Furthermore, the determination unit can employ a physical circuit formed using at least one semiconductor process, such as a semiconductor wafer or semiconductor package. Based on the comparison of results from the data in Table 4, a determination can be made... Figure 2 The charging method shown is applicable to batteries with a state of health (SOH) between 95% and 100%. Figure 6 The charging method shown is suitable for batteries with a state of health (SOH) between 91% and 95%. Figure 6 The charging method shown is applicable to the battery health state range where the SOH is below 91%.

[0052] As can be seen from the above, the battery health state range can include a range defined by one of multiple battery health states (e.g., SOH of 100%) and another range of battery health states that is lower than and closest to that state (e.g., SOH of 95%), and also includes a range defined by the lowest of multiple battery health states (e.g., SOH of 91%) and a battery health state of zero. In other words, the charging evaluation method based on battery health state of the present invention aims to select the charging method with the largest area proportion on the radar chart as the optimal charging method for the battery, which can effectively improve the temperature rise during battery charging and enhance safety.

[0053] Furthermore, this invention also covers the use of a charging assessment method based on battery health status, wherein a battery in a specific battery health status is charged using a charging method applicable to the battery health status range, wherein the specific battery health status lies within the battery health status range. For example, a battery currently has a specific battery health status of 80%, which falls within the aforementioned battery health status range where SOH is below 91%. By using the charging assessment method based on battery health status of this invention, this battery can be used... Figure 6 The charging method shown is used to charge the battery, thereby reducing the temperature rise during charging and improving safety.

[0054] Based on the above, this paper proposes a charging evaluation method based on battery health status and its application. It performs capacity tests on batteries in various battery health states (e.g., various charging and discharging methods), then extracts various battery parameters during the charging / discharging process, and uses these battery parameters to form a radar chart corresponding to a single battery health state. Then, it calculates and compares the area ratio of various charging methods on the radar chart, and finally determines the charging method with the highest area ratio among the various charging methods as the applicable charging method for a battery health state range.

[0055] In summary, although the present invention has been disclosed above with reference to embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A method for battery state of health based charge assessment, the method comprising: include: Provide one or more batteries in various battery health states; The one or more batteries can be charged using multiple charging methods; Extract various battery parameters of the one or more batteries during the charging process; A radar chart corresponding to the health status of a single battery is formed using the various battery parameters. Calculate and compare the area proportions of the various charging methods on the radar image; as well as The charging method with the highest area ratio among the various charging methods is determined as the applicable charging method for the battery health state range.

2. The charging assessment method based on battery health status as described in claim 1, characterized in that, The battery is provided as a single battery, which is subjected to a battery aging process to achieve a healthy state for the multiple batteries.

3. The charging assessment method based on battery health status as described in claim 1, characterized in that, The present invention provides at least two batteries, wherein the at least two batteries are in different battery health states.

4. The charging assessment method based on battery health status as described in claim 1, characterized in that, The various charging methods mentioned include at least two of the following: a three-constant current constant voltage charging method with different cutoff voltages, a constant power constant voltage charging method, and a constant loss constant voltage charging method.

5. The charging assessment method based on battery health status as described in claim 1, characterized in that, The various battery parameters mentioned include at least three of the following: the reciprocal of the maximum temperature rise, the reciprocal of the average temperature rise, the charging rate, and the charging capacity.

6. The charging assessment method based on battery health status as described in claim 1, characterized in that, After charging one or more batteries using the various charging methods, the one or more batteries are then discharged.

7. The charging assessment method based on battery health status as described in claim 6, characterized in that, This involves extracting various battery parameters of one or more batteries during the discharge process.

8. The charging assessment method based on battery health status as described in claim 7, characterized in that, The various battery parameters mentioned include at least three of the following: the reciprocal of the maximum temperature rise, the reciprocal of the average temperature rise, the charging rate, the charging capacity, the discharging capacity, and the coulombic efficiency.

9. The charging assessment method based on battery health status as described in claim 1, characterized in that, The various battery parameters are further normalized to form a radar chart corresponding to the health status of a single battery.

10. The charging assessment method based on battery health status as described in claim 1, characterized in that, The battery health state range includes a range defined by one of the plurality of battery health states and another of the plurality of battery health states that is lower than and closest to that one.

11. The charging assessment method based on battery health status as described in claim 1, characterized in that, The battery health status interval includes the interval defined by the lowest of the various battery health statuses and the battery health status being zero.

12. The use of the charging assessment method based on battery health status as described in any one of claims 1 to 11, characterized in that, The battery in a specific health state is charged using a charging method applicable to the battery health state range, wherein the specific battery health state is located within the battery health state range.

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