Title of the invention: Current pattern update device for rapid charging, method, and computer program stored in a storage medium for performing the same
technical field
[One]
Cross Citation with Related Applications
[2]
The present invention claims the benefit of priority based on Korean Patent Application No. 10-2019-0171205 filed on December 19, 2019, and all contents disclosed in the documents of the Korean patent application are incorporated as a part of this specification.
[3]
technical field
[4]
The present invention relates to an apparatus and method for updating a current pattern for fast charging, and a computer program stored in a storage medium for performing the same.
background
[5]
Recently, with the spread of electronic devices such as smart phones and the development of electric vehicles, research on secondary batteries as a power supply source is also being actively conducted. The secondary battery is provided in the form of a battery pack including a battery module in which a plurality of battery cells are connected in series and/or in parallel, and a battery management system (BMS) that manages the operation of the battery module.
[6]
The battery pack performs rapid charging based on a current pattern for rapid charging as necessary. As the number of rapid charging increases, there is a concern that the capacity of the battery pack rapidly decreases.
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[7]
The present invention has been made in view of this situation, and a device and method for updating a current pattern for rapid charging that efficiently perform rapid charging of the battery pack so as not to affect the lifespan of the battery pack, and a computer program stored in a storage medium for performing the same aims to provide
means of solving the problem
[8]
In order to solve the above technical problem, according to one aspect of the embodiments of the present invention, a resistance calculator for calculating the internal resistance of the battery module; a storage unit for storing a current pattern for fast charging for the battery module; and an operation unit that updates the current pattern according to the state of the internal resistance of the battery module, wherein the operation unit calculates a resistance increase rate based on the internal resistance calculated by the resistance calculation unit, and calculates an adjustment coefficient based on the calculated resistance increase rate And, it provides a current pattern update device for fast charging, characterized in that for updating the current pattern using the calculated adjustment coefficient and the current pattern.
[9]
In order to solve the above technical problem, according to another aspect of the embodiments of the present invention, the steps of setting a current pattern for fast charging for the battery module; calculating an internal resistance of the battery module; calculating a resistance increase rate of the battery module; calculating an adjustment coefficient based on the resistance increase rate; and adjusting the current pattern by using the adjustment coefficient to generate an adjusted current pattern.
[10]
In order to solve the above technical problem, according to another aspect of the embodiments of the present invention, there is provided a computer program stored in a computer-readable storage medium that allows a computer to execute the method for updating a current pattern for fast charging as described above. do.
Effects of the Invention
[11]
According to the apparatus and method for updating a current pattern for rapid charging as described above, and a computer program stored in a storage medium for performing the same, when performing rapid charging, it is possible to minimize the effect on the lifespan of the battery module.
Brief description of the drawing
[12]
1 is a diagram illustrating a configuration of a battery pack including a battery management system.
[13]
2 is a block diagram illustrating a function of a battery management system according to an embodiment of the present invention.
[14]
3 is a block diagram illustrating detailed functions of an operation unit according to an embodiment of the present invention.
[15]
4 is a diagram schematically illustrating a method of updating a current pattern for fast charging according to an embodiment of the present invention.
[16]
5 is test data showing a change in capacity of a battery module when a current pattern for fast charging is updated according to an embodiment of the present invention.
[17]
6 is a graph showing an update timing of a current pattern for fast charging according to an embodiment of the present invention.
[18]
7 is test data illustrating a change in capacity of a battery module when a current pattern is updated according to an update timing of a current pattern for fast charging according to an embodiment of the present invention.
[19]
8 is a flowchart illustrating a method of updating a current pattern for fast charging according to an embodiment of the present invention.
[20]
9 is a flowchart illustrating a method of determining an update timing of a current pattern for fast charging according to an embodiment of the present invention.
[21]
10 is a diagram illustrating a modified example of a method of updating a current pattern for fast charging according to the embodiment of FIG. 4 .
[22]
11 is a diagram illustrating another modified example of a method of updating a current pattern for fast charging according to the embodiment of FIG. 4 .
[23]
12 is experimental data obtained by measuring a change in capacity of a battery module using the method of updating a current pattern for fast charging of FIGS. 4, 10 and 11 .
[24]
13 is a diagram illustrating a method of updating a current pattern for fast charging according to another embodiment of the present invention.
[25]
14 is a diagram illustrating a modified example of a method of updating a current pattern for fast charging according to the embodiment of FIG. 13 .
[26]
15 is a diagram illustrating another modified example of a method of updating a current pattern for fast charging according to the embodiment of FIG. 13 .
[27]
16 is a block diagram illustrating detailed functions of an operation unit according to another embodiment of the present invention.
[28]
17 is test data showing a change in capacity of a battery module when a current pattern for fast charging is updated according to another embodiment of the present invention.
[29]
18 is a flowchart illustrating a method of determining when to stop using a battery module according to an embodiment of the present invention.
[30]
19 and 20 are graphs for explaining a use stop point of a battery module according to an embodiment of the present invention.
[31]
21 is a hardware configuration diagram of a battery management system.
Modes for carrying out the invention
[32]
Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this document, the same reference numerals are used for the same components in the drawings, and duplicate descriptions of the same components are omitted.
[33]
For various embodiments of the present invention disclosed in this document, specific structural or functional descriptions are only exemplified for the purpose of describing the embodiments of the present invention, and various embodiments of the present invention may be implemented in various forms. and should not be construed as being limited to the embodiments described in this document.
[34]
Expressions such as "first", "second", "first", or "second" used in various embodiments may modify various components regardless of order and/or importance, do not limit For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, the second component may also be renamed as a first component.
[35]
Terms used in this document are only used to describe specific embodiments, and may not be intended to limit the scope of other embodiments. The singular expression may include the plural expression unless the context clearly dictates otherwise.
[36]
FIG. 1 is a diagram illustrating the configuration of a battery pack 1 including a battery management system 20 .
[37]
Referring to FIG. 1 , a battery pack 1 is made of one or more battery cells, and is connected in series to a chargeable/dischargeable battery module 10 and a + terminal side or a - terminal side of the battery module 10 to the battery module. The switching unit 30 for controlling the charge/discharge current flow of (10) and the voltage, current, temperature, etc. of the battery cell and/or battery module 10 are monitored to prevent overcharging and overdischarging, and and a battery management system 20 (hereinafter referred to as 'BMS') to manage.
[38]
The battery module 10 includes one or more battery cells 11 that can be charged and discharged. The battery cell 11 may be a lithium ion (Li-ion) battery, a lithium ion polymer battery, a nickel cadmium (Ni-Cd) battery, a nickel hydrogen (Ni-MH) battery, etc., but is not limited thereto. does not
[39]
The BMS 20 may control the operation of the switching unit 30 to control charging and discharging of the battery module 10 . In addition, the BMS 20 may monitor the voltage, current, temperature, etc. of the battery module 10 and/or each battery cell 11 included in the battery module 10 . And for monitoring by the BMS 20 , a sensor or various measurement modules not shown may be additionally installed at any location such as the battery module 10 , a charging/discharging path, or the battery pack 1 . The BMS 20 may calculate a parameter indicating the state of the battery module 10 , for example, SOC or SOH, based on the monitored measured values ​​such as voltage, current, and temperature.
[40]
The BMS 20 controls and manages the overall operation of the battery pack 1 . To this end, the BMS 20 may include various components such as a microcomputer as a controller for executing a program and controlling the overall operation of the BMS 20 , input/output devices such as sensors or measuring means, and other peripheral circuits.
[41]
Also, the BMS 20 may perform rapid charging of the battery module 10 according to a preset algorithm. The preset algorithm may be to charge the battery module 10 according to a specific current pattern. In particular, the BMS 20 according to an embodiment of the present invention provides a method of updating a current pattern for fast charging of the battery module 10 and a method of determining an update time. And additionally, the BMS 20 according to an embodiment of the present invention also provides a method for determining when to stop using the battery module 10 . A detailed description of the function of the BMS 20 will be described later.
[42]
The switching unit 30 is a semiconductor switching device for controlling a current flow for charging or discharging of the battery module 10 , and for example, at least one MOSFET may be used. It will be easily understood by those skilled in the art that a relay or a contactor may be used as the switching unit 30 in addition to a semiconductor switching element.
[43]
The battery pack 1 may be further communicatively connected with the external upper controller 2 . That is, the battery pack 1 may transmit various data about the battery pack 1 to the host controller 2 , and may receive a control signal related to the operation of the battery pack 1 from the host controller 2 . The upper controller 2 may be a vehicle controller for controlling the operation of the vehicle when the battery pack 1 is mounted in the electric vehicle. When the battery pack 1 is used in an energy storage device (ESS), the upper controller 2 may be a rack BMS that manages a plurality of battery modules or a BMS that controls the overall operation of the ESS.
[44]
2 is a block diagram illustrating a function of the battery management system 20 according to an embodiment of the present invention.
[45]
Referring to FIG. 2 , the BMS 20 may include a resistance calculation unit 110 , a storage unit 120 , a calculation unit 130 , and a communication unit 140 .
[46]
The resistance calculator 110 calculates the internal resistance of the battery module 10 . The resistance calculator 110 may represent a set of various sensors for calculating the internal resistance of the battery module 10 . For example, the resistance calculator 110 measures the voltage measuring means for measuring the OCV of the battery module 10 , the current measuring means for measuring the current charged and discharged in the battery module 10 , and the temperature of the battery module 10 . It may include at least one of the temperature measuring means for measuring. The resistance calculator 110 may include, in addition to the various measuring means as described above, a calculating means for calculating the internal resistance value of the battery module 10 from a value measured by each measuring means.
[47]
The storage unit 120 may store various programs and data necessary for the operation of the BMS 20 . The storage unit 120 may store an algorithm for rapidly charging the battery module 10 as described above. In addition, the storage unit 20 may store a current pattern for rapid charging for the battery module 10 for use during rapid charging. Algorithms for fast charging may include information on an update method and update timing of a current pattern for fast charging.
[48]
The calculator 130 updates the current pattern according to the state of the internal resistance of the battery module 10 . A detailed operation of the operation unit 130 will be described later with reference to FIG. 3 .
[49]
The communication unit 140 may transmit various types of information on the battery cell 11 , the battery module 10 , and/or the battery pack 1 to the host controller 2 as necessary. Also, the communication unit 140 may receive a control signal for controlling the battery pack 1 from the host controller 2 . When the communication unit 140 determines that the use of the battery module 10 should be stopped, the communication unit 140 may transmit that effect to the host controller 2 .
[50]
3 is a block diagram illustrating detailed functions of the operation unit 130 according to an embodiment of the present invention.
[51]
Referring to FIG. 3 , the calculation unit 130 includes a resistance increase rate calculation unit 131 , an adjustment coefficient calculation unit 132 , a current pattern calculation unit 133 , an update requirement determination unit 134 , a voltage measurement unit 135 , and the like. may include
[52]
The resistance increase rate calculator 131 calculates a resistance increase rate based on the internal resistance calculated by the resistance calculator 110 . The resistance increase rate can be calculated in the following way.
[53]
[Equation 1]
[54]
Resistance increase rate (%)=(Regression resistance/Initial resistance - 1)*100
[55]
[56]
The resistance increase rate calculator 131 may calculate a rate at which the internal resistance of the battery module 10 is changed for a predetermined period. The predetermined period may be any period set periodically. Alternatively, the resistance increase rate calculating unit 131 may calculate the resistance increase rate based on the internal resistance measured just before this fast charging is performed and the previously measured internal resistance. However, the time and period for calculating the internal resistance are only examples and are not limited thereto.
[57]
The adjustment coefficient calculator 132 calculates an adjustment coefficient based on the resistance increase rate calculated by the resistance increase rate calculator 131 . The adjustment coefficient calculator 132 calculates the adjustment coefficient to decrease the adjustment coefficient as the resistance increase rate increases.
[58]
As an example, the resistance increase rate calculator 131 may calculate the adjustment coefficient by Equation 2 below.
[59]
[Equation 2]
[60]
Adjustment factor = (100 - α*(resistance increase rate (%)))/100
[61]
[62]
In this case, the α value may be a value determined according to the type of the battery module 10 . That is, the α value may be a value determined according to chemical components constituting the battery cell, such as whether the battery module 10 is a lithium ion battery or a lithium ion polymer battery. This α value may have a value between 0.5 and 4.
[63]
As another example, the resistance increase rate calculator 132 may calculate the adjustment coefficient according to Equation 3 below.
[64]
[Equation 3]
[65]
Adjustment factor = 1 / (α*(1 + resistance increase rate (%)/100))
[66]
[67]
The α value at this time is also the same value as the α value in Equation 2.
[68]
That is, the resistance increase rate calculator 132 calculates an adjustment coefficient to reduce the current pattern. In other words, the algorithm for updating the current pattern for fast charging according to the embodiments of the present invention reduces the current magnitude of the current pattern.
[69]
The current pattern calculating unit 133 updates the current pattern by using the calculated adjustment coefficient and the current pattern stored in the storage unit 120 . Specifically, the current pattern calculation unit 133 calculates as a new fast charging current pattern for updating a value obtained by multiplying a pre-stored current pattern by the adjustment coefficient calculated by the adjustment coefficient calculation unit 132 .
[70]
4 is a diagram schematically illustrating a method of updating a current pattern for fast charging according to an exemplary embodiment. As described above, it indicates that a new current pattern (b) is calculated by multiplying the existing current pattern for fast charging by the adjustment factor (a). In the case of FIG. 4 , when charging is performed in a capacity-limited method, the current is gradually reduced according to the state of charge (SOC) of the battery module 10 . As shown in Figure 4, the current pattern is set so that the current is charged to i1 until the SOC becomes s1, to i2 from s1 to s2, i3 from s2 to s3, and i4 from s3 to full charge. . And when the current pattern for fast charging needs to be updated, the adjustment factor is multiplied to change the current pattern as shown in the dotted line. The current is changed to i1', i2', i3' and i4', respectively. where i1'=i1*(adjustment coefficient), i2'=i2*(adjustment coefficient), i3'=i3*(adjustment coefficient), and i4'=i4*(adjustment coefficient). That is, an existing current pattern is updated with a current pattern having a new magnitude generated by multiplying the magnitude of the current in the current pattern by an adjustment factor (current derating type update).
[71]
The update requirement determining unit 134 determines when to update the fast charging current pattern. In the present embodiment, as described with reference to FIG. 4 , as for the current pattern for rapid charging, a capacity-limiting type of charging until the battery module 10 reaches a preset charging capacity is applied. In this case, the update requirement determination unit 134 determines that it is time to update the current pattern when the transition curve of the charging termination voltage, which is the voltage at the completion of charging of the fast charging, satisfies a preset criterion. The preset reference for the transition curve of the charging termination voltage may be an inflection point occurring in the transition curve of the charging termination voltage. The occurrence of the inflection point may be a signal indicating that an abnormality has occurred in the battery cell 11 . Therefore, by monitoring the occurrence of such an inflection point, it is possible to determine the update timing of the current pattern for fast charging.
[72]
When it is determined by the update requirement determining unit 134 that the current pattern needs to be updated, the fast charging current pattern is updated with the new current pattern calculated by the current pattern calculating unit 133 . In this case, the updated current pattern may be stored in the storage unit 120 .
[73]
The voltage measuring unit 135 measures a charging end voltage, which is a voltage at the completion of fast charging, whenever fast charging is performed on the battery module 10 . The voltage measuring unit 135 may be a voltage sensor monitoring the voltage of the battery cell 11 and/or the battery module 10 . In addition, the voltage measuring unit 135 may monitor the voltage of the battery module 10 in real time and derive the charging termination voltage by using the voltage at the required time when determining the update requirement.
[74]
In the present embodiment, the update requirement is determined using the charging termination voltage, but this is exemplary and not limited thereto. For example, if the parameter is correlated with the characteristic of the charging termination voltage, the corresponding parameter may be used as a factor for determining the update requirement. For example, the update requirement may be determined using a resistance value calculated using the charge termination voltage and the OCV value.
[75]
5 is test data showing a change in capacity of the battery module 10 when a current pattern for fast charging is updated according to an embodiment of the present invention.
[76]
As can be seen from the 'Comparative Example' graph in FIG. 5 , when the battery module 10 is rapidly charged repeatedly without changing the current pattern for rapid charging, it is confirmed that the capacity of the battery module 10 is rapidly reduced. can Specifically, when the rapid charging is repeated about 10 times, the capacity of the battery module 10 is rapidly reduced.
[77]
On the other hand, as can be seen from the 'Example' graph, when the battery module 10 is rapidly charged by updating the current pattern for rapid charging according to the present invention, there is little change in the capacity of the battery module 10 . That is, there was hardly any change in the capacity of the battery module 10 according to the number of times of rapid charging.
[78]
When the current pattern stored in advance as the current pattern for rapid charging of the battery module 10 is continuously used without changing, the capacity of the battery module 10 is also affected due to the change in the internal resistance of the battery module 10 . drive crazy
[79]
However, according to the method of updating the current pattern for fast charging according to the embodiment of the present invention as described above, the current pattern is also changed in consideration of the change in the internal resistance of the battery module 10 . Therefore, even when the battery module 10 is rapidly charged, the change in capacity of the battery module 10 can be minimized.
[80]
6 is a graph showing an update timing of a current pattern for fast charging according to an embodiment of the present invention.
[81]
Referring to FIG. 6 , the transition of the charging termination voltage measured when the rapid charging is completed is shown. The update requirement determination unit 134 detects an inflection point in the transition curve of the charging termination voltage, as indicated by an arrow.
[82]
7 is test data illustrating a change in capacity of a battery module when a current pattern is updated according to an update timing of a current pattern for fast charging according to an embodiment of the present invention.
[83]
Referring to FIG. 7 , a graph of 'Comparative Example 1' is a graph showing a change in the charge termination voltage of the battery module 10 when the update algorithm of the current pattern for fast charging is not applied at all. It was confirmed that the charging termination voltage rapidly increased after about 20 rapid charging cycles.
[84]
The graph of 'Comparative Example 2' is a graph in which the update algorithm of the current pattern for fast charging is applied, but the update time is applied after the inflection point occurs. Compared to Comparative Example 1, it was confirmed that the charging termination voltage did not change even after a considerable number of rapid charging repetitions. However, after about 100 times of rapid charging, it was confirmed that the charging termination voltage rapidly increased.
[85]
The 'Example' graph is a graph in which the update algorithm of the current pattern for fast charging is applied immediately after the inflection point occurs. As can be clearly seen from the graph, it was confirmed that the increase in the charge termination voltage of the battery module 10 was significantly suppressed despite repeated rapid charging of 100 times or more.
[86]
If the update timing is delayed even when the current pattern for fast charging of the battery module 10 is not updated, it is unavoidable to reduce the capacity of the battery module 10 .
[87]
However, according to the method for determining the update timing of the current pattern for fast charging according to the embodiment of the present invention as described above, it is possible to accurately and quickly grasp the time when the current pattern for fast charging should be updated, and thus the battery module 10 ) can be minimized.
[88]
8 is a flowchart illustrating a method of updating a current pattern for fast charging according to an embodiment of the present invention.
[89]
Referring to FIG. 8 , a current pattern for fast charging is preset in the storage unit 120 of the BMS 20 ( S10 ). The setting of the current pattern may be set before shipment of the battery pack 1 by the manufacturer. Alternatively, even after shipment of the battery pack 1 , a current pattern for fast charging may be set by a manufacturer or a user.
[90]
Thereafter, while the battery pack 1 is mounted and used in a vehicle, the BMS 20 monitors the internal resistance of the battery module 10 ( S11 ). In other words, the internal resistance of the battery module 10 is calculated. Then, a resistance increase rate of the internal resistance is calculated from the monitored internal resistance (S12). Then, an adjustment coefficient is calculated based on the calculated resistance increase rate (S13). Since the calculation of the resistance increase rate and the calculation of the adjustment coefficient in steps S12 and S13 has been described in detail with reference to FIGS. 2 and 3 , a detailed description thereof will be omitted herein.
[91]
The BMS 20 calls the fast charging current pattern stored in the storage unit 120 (S14), and determines whether the update requirement of the current pattern is satisfied (S15).
[92]
When the update requirement of the current pattern is satisfied (YES in S16), the current pattern is updated. The updating of the current pattern may be performed using the adjustment coefficient calculated in step S13 and the current pattern called in step S14. If the update requirement of the current pattern is not satisfied (NO in S16), the process returns to step S11 and the algorithm for updating the current pattern is repeatedly performed.
[93]
9 is a flowchart illustrating a method of determining an update timing of a current pattern for fast charging according to an embodiment of the present invention. 9 shows detailed steps of step S15 of FIG. 8 .
[94]
Referring to FIG. 9 , the BMS 20 determines whether the battery pack 1 starts charging (S20), and when it is determined that the charging has started, determines whether the corresponding charging is rapid charging (S21). If charging is not started or charging is not fast charging, the algorithm according to the embodiments of the present invention is not applied, and thus the process proceeds to step S11.
[95]
On the other hand, when the rapid charging is started (YES in S21), it waits until the corresponding rapid charging is terminated. And when the fast charging is finished, the charging end voltage of the battery module 10 is measured (S23). Then, the transition of the charging termination voltage is determined from the repeatedly measured charging termination voltage (S24).
[96]
If an inflection point is detected in the transition curve of the charging termination voltage as a requirement for updating the current pattern for rapid charging (YES in S25), the process proceeds to step S17 to update the current pattern. On the other hand, if no inflection point is detected in the transition curve of the charging termination voltage (NO in S25), it is determined that rapid charging may be performed using the existing current pattern. Therefore, it proceeds to step S11. That is, step S25 corresponds to step S16 of FIG. 8 .
[97]
Since the operations of measuring the charging end voltage and detecting the inflection point in steps S23 to S25 have been described in detail with reference to FIGS. 2 and 3 , a detailed description thereof will be omitted herein.
[98]
10 is a diagram illustrating a modified example of a method of updating a current pattern for fast charging according to the embodiment of FIG. 4 . In FIG. 10, only the new current pattern obtained by multiplying the current pattern by the adjustment factor is shown. In this example, charging is performed in a capacity-limited method, and the current is gradually reduced according to the SOC of the battery module 10 .
[99]
However, in this example, the current pattern is changed as shown by the dotted line by multiplying the SOC value set at the time of changing the magnitude of the current by the adjustment factor. That is, the point at which the current changes from i1 to i2 is changed from s1 to s1', the point at which the current changes from i2 to i3 is changed from s2 to s2', and the point at which the current changes from i3 to i4 changes from s3 to s3'. . where s1' = s1*(steering factor), s2'=s2*(steering factor), and s3'=s3*(steering factor). That is, the existing current pattern is updated with a current pattern in which the value of the new SOC generated by multiplying the value of the SOC set at the time of changing the size of the current in the current pattern by the adjustment factor is the time of changing the size of the current ( SOC-reduced updates).
[100]
The adjustment coefficient may be a value calculated according to Equation 4 or 5 below. That is, it may be a value different from the adjustment coefficient described in Equations 2 and 3 above.
[101]
[Equation 4]
[102]
Adjustment factor = (100 - β*(resistance increase rate (%)))/100
[103]
[Equation 5]
[104]
Adjustment factor = 1 / (β *(1 + resistance increase rate (%)/100))
[105]
[106]
In this case, the β value may also be a value determined according to the type of the battery module 10 . That is, the β value may be a value determined according to chemical components constituting the battery cell, such as whether the battery module 10 is a lithium ion battery or a lithium ion polymer battery. This β value may have a value between 0.5 and 4.
[107]
11 is a diagram illustrating another modified example of a method of updating a current pattern for fast charging according to the embodiment of FIG. 4 . Also in FIG. 11, only the new current pattern obtained by multiplying the current pattern by the adjustment factor is shown. In this example, charging is performed in a capacity-limited method, and the current is gradually reduced according to the SOC of the battery module 10 .
[108]
In this example, the current pattern is updated using a hybrid update method to which both the current reduction update method described in FIG. 4 and the SOC reduction update method described in FIG. 10 are applied. Accordingly, the magnitude of the current is adjusted according to the adjustment coefficient described with reference to FIG. 4 , and the timing of adjusting the magnitude of the current is adjusted according to the adjustment coefficient described with reference to FIG. 10 .
[109]
12 is experimental data obtained by measuring a change in capacity of a battery module using the method of updating a current pattern for fast charging of FIGS. 4, 10 and 11 . In the experiment of FIG. 12 , the α value and the β value were set to 1. In addition, an experiment was performed using four cells with a resistance increase rate of 12% as measurement targets. In each of the four cells, when there is no current pattern update, a current-reduced update method, a SOC-reduced update method, and a mixed-type update method were applied, and rapid charging was repeatedly performed.
[110]
As shown in FIG. 12 , it can be confirmed that, when rapid charging is continued in the initial current pattern (BOL), the capacity of the battery module is rapidly reduced as the number of rapid charging is repeated, and thus rapid degradation has occurred. On the other hand, in the case of the current reduction update method and the SOC reduction update method, it can be seen that the degradation degree is similarly improved. In addition, in the case of the hybrid update method, it can be seen that the charging time is the longest, but the degree of degradation is the smallest.
[111]
When the current pattern for rapid charging of the battery module 10 is continuously used without changing the previously stored current pattern, the capacity of the battery module 10 is also affected due to the change in the internal resistance of the battery module 10 . drive crazy
[112]
However, according to the various updating methods of the fast charging current pattern as described above, the current pattern is also changed in consideration of the change in the internal resistance of the battery module 10 . Therefore, even when the battery module 10 is rapidly charged, the change in capacity of the battery module 10 can be minimized.
[113]
13 is a diagram illustrating a method of updating a current pattern for fast charging according to another embodiment of the present invention. Also in FIG. 13, only the new current pattern obtained by multiplying the current pattern by the adjustment factor is shown.
[114]
13 illustrates a case in which charging is performed in a voltage-limited method, in which current is gradually reduced according to a voltage value of the battery module 10 . As shown in FIG. 13, the current pattern is set to charge the magnitude of the current to i1 until the voltage value is v1, to i2 from v1 to v2, i3 from v2 to v3, and i4 from v3 to full charge. has been And when the current pattern for fast charging needs to be updated, the adjustment factor is multiplied to change the current pattern as shown in the dotted line. The current is changed to i1', i2', i3' and i4', respectively. where i1'=i1*(adjustment coefficient), i2'=i2*(adjustment coefficient), i3'=i3*(adjustment coefficient), and i4'=i4*(adjustment coefficient). That is, an existing current pattern is updated with a current pattern having a new magnitude generated by multiplying the magnitude of the current in the current pattern by an adjustment factor (current derating type update).
[115]
14 is a diagram illustrating a modified example of a method of updating a current pattern for fast charging according to the embodiment of FIG. 13 . Also in FIG. 14, only the new current pattern obtained by multiplying the current pattern by the adjustment factor is shown. In this example, charging is performed in a voltage-limited method, and the current is gradually reduced according to the voltage value of the battery module 10 .
[116]
However, in this example, the current pattern is changed as shown by the dotted line by multiplying the voltage value set at the time of changing the magnitude of the current by the adjustment factor. That is, the point at which the current changes from i1 to i2 is from v1 to v1', the point at which the current changes from i2 to i3 is from v2 to v2', and the point at which the current changes from i3 to i4 changes from v3 to v3'. . where v1'= v1*(adjustment factor), v2'= v2*(adjustment factor), and v3'= v3*(adjustment factor). That is, the existing current pattern is updated with a current pattern in which a new voltage value generated by multiplying a voltage value set as the time point for changing the magnitude of the current in the current pattern by an adjustment factor is the time point for changing the magnitude of the current (reducing the voltage). brother update).
[117]
In this example, the adjustment coefficient according to FIG. 13 and the adjustment coefficient according to FIG. 14 may be separately calculated as in FIGS. 4 and 10 .
[118]
15 is a diagram illustrating another modified example of a method of updating a current pattern for fast charging according to the embodiment of FIG. 13 . Also in FIG. 15, only the new current pattern obtained by multiplying the current pattern by the adjustment factor is shown. In this example, charging is performed in a voltage-limited method, and the current is gradually reduced according to the voltage value of the battery module 10 .
[119]
In this example, the current pattern is updated using a hybrid update method to which both the current reduction update method described with reference to FIG. 13 and the voltage reduction update method described with reference to FIG. 14 are applied. Accordingly, the magnitude of the current is adjusted according to the adjustment coefficient described with reference to FIG. 13 , and the timing of adjusting the magnitude of the current is adjusted according to the adjustment coefficient described with reference to FIG. 14 .
[120]
Even when fast charging is performed in the voltage-limited method as described above, if the battery module ( 10) can be minimized.
[121]
16 is a block diagram illustrating detailed functions of an operation unit according to another embodiment of the present invention. Here, differences from FIG. 3 will be mainly described.
[122]
The update requirement determination unit 134 determines when to update the current pattern for fast charging. In the present embodiment, the current pattern for rapid charging is applied to a voltage-limited type of charging until the battery module 10 reaches a preset voltage. In this case, the update requirement determination unit 134 determines that it is time to update the current pattern when the transition curve of the charging end capacity, which is the capacity at the completion of charging of the fast charging, satisfies a preset criterion. The preset reference for the transition curve of the end-of-charge capacity may be an inflection point in the transition curve of the end-of-charge capacity.
[123]
When it is determined by the update requirement determining unit 134 that the current pattern needs to be updated, the fast charging current pattern is updated with the new current pattern calculated by the current pattern calculating unit 133 . In this case, the updated current pattern may be stored in the storage unit 120 .
[124]
The capacity calculating unit 136 calculates the charging end capacity, which is the capacity of the battery module 10 when the fast charging is completed, whenever fast charging is performed on the battery module 10 . The capacity calculator 136 may use a sensor for monitoring voltage, current, etc. of the battery battery cell 11 and/or the battery module 10 . In addition, the capacity calculator 136 may calculate the battery module 10 by a method such as calculating the capacity of the battery module 10 from a value measured using a sensor.
[125]
17 is test data showing a change in capacity of a battery module when a current pattern for fast charging is updated according to another embodiment of the present invention.
[126]
Referring to FIG. 17 , a graph of 'Comparative Example 1' is a graph showing a change in the charging end capacity of the battery module 10 when the update algorithm of the current pattern for fast charging is not applied at all. It was confirmed that the charging end capacity rapidly increased after about 20 rapid charging cycles.
[127]
The graph of 'Comparative Example 2' is a graph in which the update algorithm of the current pattern for fast charging is applied, but the update time is applied after the inflection point occurs. Compared to Comparative Example 1, it was confirmed that the charging end capacity did not change even after a considerable number of rapid charging repetitions. However, it was confirmed that the charging end capacity rapidly increased after about 60 times of rapid charging.
[128]
The 'Example' graph is a graph in which the update algorithm of the current pattern for fast charging is applied immediately after the inflection point occurs. As can be clearly seen from the graph, it was confirmed that there is little increase in the charging end capacity of the battery module 10 despite repeated rapid charging of 100 times or more.
[129]
If the update timing is delayed even when the current pattern for fast charging of the battery module 10 is not updated, it is unavoidable to reduce the capacity of the battery module 10 .
[130]
However, according to the method for determining the update timing of the current pattern for fast charging according to the embodiment of the present invention as described above, it is possible to accurately and quickly grasp the time when the current pattern for fast charging should be updated, and thus the battery module 10 ) can be minimized.
[131]
Alternatively, other methods may be used in addition to determining the timing of updating the current pattern for fast charging based on the inflection point of the transition curve of the charging termination voltage or the transition curve of the charging termination capacity as described above. For example, it may be set to update the current pattern when the previously calculated increase rate of the resistance becomes greater than or equal to a preset reference value.
[132]
18 is a flowchart illustrating a method of determining when to stop using a battery module according to an embodiment of the present invention.
[133]
Referring to FIG. 18 , the algorithm for determining when to stop using the battery module determines whether rapid charging is performed ( S30 ). In this embodiment, it is assumed that the current pattern for fast charging is already applied to the update algorithm according to the embodiment of the present invention. When it is determined that rapid charging is performed, a charging end voltage or a charging end capacity is detected (S31). Then, it is determined whether the detected charging termination voltage or charging termination capacity has fluctuated by more than a reference value (S32). The determination of whether or not the reference value has changed may include determining whether the charging end voltage has become greater than or equal to the reference value. In addition, the determination of whether the change by more than the reference value may include determining whether the charging end capacity is less than the reference value.
[134]
When the charging end voltage or the charging end capacity fluctuates more than the reference value, it is determined that the use limit of the battery module 10 is reached and the use of the battery module 10 is stopped (S33). In addition, the purpose of discontinuing use of the battery module 10 may be notified to the host controller 2 or the like. On the other hand, when the charging end voltage or the charging end capacity does not fluctuate more than the reference value, it is determined that the battery module 10 can be used continuously.
[135]
19 and 20 are graphs for explaining a use stop point of a battery module according to an embodiment of the present invention.
[136]
As shown in FIGS. 19 and 20 , when the rapid charging is repeated, the charging termination voltage or the charging termination capacity rapidly fluctuates, and in this case, the battery module 10 cannot supply the required output. Therefore, a serious safety situation may occur in a vehicle in which the battery pack 1 is mounted. Therefore, when the charging termination voltage or charging termination capacity is changed by more than the reference value, the use of the battery module 10 is stopped.
[137]
Alternatively, the determination of when to stop using the battery module 10 may use another method. For example, it may be set to stop using the battery module 10 when the number of times that an inflection point is detected in the transition curve of the previously detected charging termination voltage or charging termination capacity becomes a preset reference number.
[138]
21 is a hardware configuration diagram of a battery management system.
[139]
Referring to FIG. 21 , the BMS 20 may include a controller (MCU) 210 , a memory 220 , an input/output interface 230 , and a communication interface 240 .
[140]
The MCU 210 processes various operations and calculations in the BMS 20 and controls each configuration.
[141]
In the memory 220 , an operating system program and a program for performing a function of the BMS 20 are recorded. That is, in the memory 220, an algorithm for updating a current pattern for fast charging according to embodiments of the present invention, an update time of the current pattern, an algorithm for determining when to stop using the battery module 10, etc. are described in a computer A program may be stored. The memory 220 may include a volatile memory and a non-volatile memory. For example, the memory 220 may be at least one of various storage media such as a semiconductor memory such as a RAM, a ROM, and a flash memory, a magnetic disk, and an optical disk. The memory 220 may be a memory built into the MCU 210 , or may be an additional memory installed separately from the MCU 210 .
[142]
The input/output interface 230 performs input/output of various input signals and output signals. For example, the MCU 210 included in the BMS 20 may receive signals from various sensors through the input/output interface 230 .
[143]
The communication interface 240 is configured to communicate with the outside by wire and/or wirelessly.
[144]
By executing the program stored in the memory 220 by the MCU 210, the resistance calculation unit 110, the calculation unit 130, the resistance increase rate calculation unit 9131, the adjustment coefficient calculation unit 132, the current pattern calculation unit 133, A module that performs the functions of the update requirement determining unit 134 and the capacity calculating unit 136 may be implemented. The memory 220 may function as the storage unit 120 . The MCU 210 may operate together with the input/output interface 230 to perform functions as the resistance calculating unit 110 and the voltage measuring unit 135 . Also, the MCU 210 may operate together with the communication interface 240 to perform a function as the communication unit 140 .
[145]
In addition, terms such as "include", "compose", or "have" described above mean that the corresponding component may be inherent unless otherwise stated, so other components are excluded. Rather, it should be construed as being able to further include other components. All terms, including technical or scientific terms, may be interpreted as having the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs, unless otherwise defined. Terms commonly used, such as those defined in the dictionary, should be interpreted as being consistent with the contextual meaning of the related art, and are not interpreted in an ideal or excessively formal meaning unless explicitly defined in the present invention.
[146]
The above description is merely illustrative of the technical spirit of the present invention, and various modifications and variations will be possible without departing from the essential characteristics of the present invention by those skilled in the art to which the present invention pertains. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.
Claims
[Claim 1]
a resistance calculator for calculating the internal resistance of the battery module; a storage unit for storing a current pattern for fast charging for the battery module; and a calculating unit that updates the current pattern according to the state of the internal resistance of the battery module, wherein the calculating unit calculates a resistance increase rate based on the internal resistance calculated by the resistance calculation unit, and receives the calculated resistance increase rate. An adjustment coefficient is calculated based on the adjustment coefficient, and the current pattern update device for fast charging, characterized in that the current pattern is updated using the calculated adjustment coefficient and the current pattern.
[Claim 2]
The apparatus of claim 1 , wherein the calculation unit uses a current pattern to update a value obtained by multiplying the current pattern by the adjustment coefficient.
[Claim 3]
The apparatus of claim 1 , wherein the calculating unit decreases the adjustment coefficient as the resistance increase rate increases.
[Claim 4]
The apparatus according to claim 1, wherein the rapid charging of the battery module is a capacity-limited method that is performed until a preset charging capacity is reached.
[Claim 5]
The method according to claim 4, wherein the operation unit for fast charging current pattern update characterized in that for updating the existing current pattern with a current pattern having a new size of the current generated by multiplying the size of the current in the current pattern by the adjustment factor Device.
[Claim 6]
The method according to claim 4 or 5, wherein the operation unit sets the value of the new SOC generated by multiplying the adjustment factor by the value of the SOC set as the time point at which the magnitude of the current in the current pattern is changed as the time point at which the magnitude of the current is changed. A current pattern update device for fast charging, characterized in that for updating the existing current pattern with a current pattern.
[Claim 7]
The method according to claim 4, wherein the calculation unit further comprises a voltage measuring unit for measuring a charging end voltage that is the voltage at the completion of the fast charging each time the fast charging is performed on the battery module, the transition curve of the charging end voltage When a preset criterion is satisfied, the current pattern update device for fast charging, characterized in that the calculation unit updates the current pattern.
[Claim 8]
The apparatus of claim 7, wherein the preset criterion is a case in which an inflection point is detected in the transition curve of the charging termination voltage.
[Claim 9]
The apparatus according to claim 1, wherein the rapid charging of the battery module is a voltage-limited method performed until a preset voltage is reached.
[Claim 10]
10. The method of claim 9, wherein the operation unit for fast charging current pattern update characterized in that for updating the existing current pattern with a current pattern having a new size of the current generated by multiplying the magnitude of the current in the current pattern by the adjustment factor Device.
[Claim 11]
11. The current according to claim 9 or 10, wherein the operation unit sets a new voltage value generated by multiplying a voltage value set as a time point for changing the magnitude of the current in the current pattern by the adjustment factor as a time point for changing the magnitude of the current. A current pattern update device for fast charging, characterized in that it updates an existing current pattern with a pattern.
[Claim 12]
The method according to claim 9, further comprising a capacity calculation unit for calculating a charging end capacity that is the capacity of the battery module when the rapid charging of the battery module is completed, and when the transition curve of the charging end capacity satisfies a preset criterion, A current pattern update device for rapid charging, characterized in that the calculating unit updates the current pattern.
[Claim 13]
The apparatus of claim 12 , wherein the preset criterion is a case in which an inflection point is detected in the transition curve of the charging end capacity.
[Claim 14]
setting a current pattern for fast charging for the battery module; calculating an internal resistance of the battery module; calculating a resistance increase rate of the battery module; calculating an adjustment coefficient based on the resistance increase rate; and adjusting the current pattern using the adjustment coefficient to generate an adjustment current pattern.
[Claim 15]
A computer program stored in a computer-readable storage medium, the method comprising: calculating an internal resistance of a battery module; calculating a resistance increase rate based on the calculated internal resistance; calculating an adjustment coefficient based on the calculated resistance increase rate; and updating the current pattern using the calculated adjustment coefficient and a preset current pattern for fast charging.
[Claim 16]
The method according to claim 15, further comprising the step of detecting a charging end voltage that is a voltage at the completion of fast charging for the battery module or a charging end capacity that is a capacity at the completion of fast charging, the transition curve of the charging end voltage or the charging end capacity A computer program stored in a computer-readable storage medium, characterized in that performing the step of updating the current pattern when it is detected that an inflection point has occurred.