TW201731193A - Battery management system - Google Patents

Abstract

The application of the present invention discloses a battery management system for a lithium iron phosphate battery cell. The battery management system includes a charging module configured to charge a lithium iron phosphate battery cell, and a logic module configured to control a charging module for phosphoric acid The lithium iron battery cell is charged to a reduced state of charge. The shuttle lowering state of charge is equal to or lower than a predetermined shuttle state, wherein the first derivative of the state of charge of the lithium iron phosphate cell relative to time or charge during charging is at a predetermined number In a critical range of zero of a derivative, and wherein the second derivative of the state of charge of the lithium iron phosphate cell relative to one of time or charge during charging, the first derivative is at the predetermined first derivative The time of the same value in the zero critical range or the critical range of zero of one of the predetermined second derivatives under the charge.

Description

Battery management system

The invention relates to a charging method for a lithium-sulfur battery cell and a battery management system.

Lithium-sulfur battery cells are known in the industry to undergo a shuttling effect during charge and discharge cycles. The dissolved polysulfide formed in the cell is shuttled between the anode and the cathode during the cycle. The dissolved polysulfides react with both the lithium metal anode and the sulfur cathode, causing the two electrodes to passivate, resulting in significant impedance of the cell cells. Moreover, this phenomenon causes the battery cell capacity to rapidly decrease, which in turn makes the cycle life not long. Therefore, the industry has a need to increase the cycle life of lithium-sulfur battery cells.

A battery management system is used to control the battery during at least one of charging and discharging. It is known in the art to charge lithium-sulfur battery cells for a predetermined period of time under a fixed current charging operation. Figure 1 is a graph showing the change in discharge capacity and number of cycles for charging a particular lithium-sulfur battery cell with a fixed current. The discharge capacity is the total amount of electricity that can be drawn from the cell when a fixed current is drawn from the cell until the cell is depleted. After each discharge, the battery cell is again charged for a predetermined period of time in a fixed current charging operation. Thus, after the first few cycles, substantially the same amount of charge is applied to the battery cells during each charge cycle. As will be seen, the cell has a cycle life of about 107 cycles with a capacity efficiency of about 80%. After the 107th cycle, the cell will have a cycle maximum discharge capacity that is less than 80% of the maximum discharge capacity of the cell at any cycle. The maximum discharge capacity of the cell occurs approximately at the 5th cycle. It will be appreciated that the efficiency degradation of the battery cells may depend on the cell chemistry and, in particular, on the electrolyte used in the cell, as well as manufacturing tolerances, even if the cells are intended to be identical.

The present invention seeks to provide at least one alternative to the prior art charging operating conditions.

In the same state of the invention, a battery management system for a lithium-sulfur battery cell is provided. The battery management system includes a charging module configured to charge a lithium-sulfur battery cell, and a logic module configured to control the charging module to facilitate the lithium sulfur during a charging cycle The battery cells are charged to a reduced state of charge. The shuttle reduced state of charge is equal to or lower than a predetermined index value of a shuttle voltage, wherein a first derivative of the voltage of the lithium-sulfur battery cell relative to time or charge during charging is at a predetermined In a critical range of zero of the first derivative, and wherein the second derivative of the voltage of the lithium-sulfur battery cell relative to time or charge during charging, at the first derivative is at the predetermined first derivative The time of the same value in the zero critical range or the critical range of zero of one of the predetermined second derivatives under the charge.

Thus, the predetermined value corresponding to the shuttle voltage (or its indicator) is an index voltage that exhibits a flat state for time or charge system. The predetermined index value of the shuttle voltage can be set by the flatness of the voltage of the lithium-sulfur battery cell during charging. Therefore, the reduced state of charge can be equal to or lower than a predetermined shuttle voltage index, wherein the voltage across the lithium-sulfur battery cell is flattened. Without wishing to be bound by any theory, it is also possible to recognize that the shuttle voltage is the voltage at which the shuttle effect begins significantly. The predetermined index value of the shuttle voltage can be regarded as the shuttle voltage.

The predetermined first derivative threshold may be less than 0.1 volts per ampere hour. The predetermined first derivative threshold may be less than 0.05 volts per ampere. The predetermined first derivative threshold may be less than 0.01 volts per ampere. The predetermined first derivative threshold may be less than 0.1 volts per minute. The predetermined first derivative threshold may be less than 0.05 volts per minute. The predetermined first derivative threshold may be less than 0.01 volts per minute. The predetermined first derivative threshold may be greater than 0.001 volts per ampere. The predetermined first derivative threshold may be greater than 0.005 volts per ampere. The predetermined first derivative threshold may be greater than 0.009 volts per ampere. The predetermined first derivative threshold may be greater than 0.001 volts per minute. The predetermined first derivative threshold may be greater than 0.005 volts/minute. The predetermined first derivative threshold may be greater than 0.009 volts per minute.

The predetermined second derivative threshold may be less than 0.1 volts/(ampere hours) ² . The predetermined second derivative threshold may be less than 0.05 volts per ampere hour ² . The predetermined second derivative threshold may be less than 0.01 volts per ampere hour ² . The predetermined second derivative threshold may be less than 0.1 volts/(minutes) ² . The predetermined second derivative threshold may be less than 0.05 volts/(minutes) ² . The second derivative of the predetermined threshold value may be less than 0.01 volts / (min) ^2. The predetermined second derivative threshold may be greater than 0.001 volts per ampere hour ² . The predetermined second derivative threshold may be greater than 0.005 volts per ampere hour ² . The predetermined second derivative threshold may be greater than 0.009 volts per ampere hour ² . The second derivative of the predetermined threshold may be greater than 0.001 volts / (min) ^2. The predetermined second derivative threshold may be greater than 0.005 volts/(minutes) ² . The second derivative of the predetermined threshold may be greater than 0.009 volts / (min) ^2.

It will be appreciated that where the index value of the shuttle voltage is measured in units other than volts, the predetermined first derivative threshold and the predetermined second derivative threshold will be different.

Other aspects in accordance with the present invention provide a battery management system for a lithium-sulfur battery cell. The battery management system includes a charging module configured to charge a lithium-sulfur battery cell, and a logic module configured to control the charging module to facilitate the lithium during a charging cycle The sulfur battery cells are charged to a reduced state of charge. The shuttle reduced state of charge is equal to or lower than a predetermined value corresponding to a shuttle voltage during which the voltage across the lithium sulfur battery cell is flattened relative to time or charge.

Viewed from other aspects of the invention, the reduced state of charge of the shuttle is equal to or lower than a predetermined index value of a shuttle voltage, wherein the charging voltage or state of the lithium-sulfur battery cell during charging is substantially flattened, or wherein charging The change in voltage or state is reduced.

The charging cycle may be after a previous charging cycle, wherein the logic module is configured to control the charging module to charge the lithium-sulfur battery cell to a first state of charge that is higher than a shuttle-reduced charging state.

Thus, the battery management system is capable of achieving a significant reduction in the shuttle effect over the number of initial charge cycles and is capable of charging the battery cells to a higher state of charge during the initial number of charge cycles.

The logic module can be further configured to set the index value of the predetermined shuttle voltage as a voltage index value, wherein the voltage of the lithium-sulfur battery cell passes during any previous charging cycle prior to the charging cycle, with respect to time or a first derivative of one of the charges, in a critical range of zero of the first derivative; and a second derivative relative to one of time or charge, wherein the first derivative is at zero of the first derivative The time of the same value in the critical range or the critical range of zero of the second derivative under charge.

Any previous charging cycle can be the previous charging cycle. Therefore, it is possible to set a predetermined index value of the shuttle voltage of the battery cell in a charging cycle, wherein the battery cell is charged to a first state of charge higher than the shuttle-reduced charging state.

The logic module is capable of setting a shuttle-reduced charging state based on the predetermined value. The logic module can be further constructed to receive the predetermined value corresponding to the shuttle voltage. A predetermined value corresponding to the shuttle voltage can be received from one of the battery management systems. The predetermined value corresponding to the shuttle voltage can be received from a different module than the logic module of the battery management system. A predetermined value corresponding to the shuttle voltage can be received from an additional device.

The logic module can be further constructed to receive a shuttle voltage index value for another lithium-sulfur battery cell. Therefore, it is possible to receive a voltage index value that significantly starts the shuttle effect in another lithium-sulfur battery cell.

The battery management system can be used with a lithium-sulfur battery cell having a shuttle voltage that is substantially the same as the shuttle voltage of another lithium-sulfur battery cell.

The logic module can be further configured to set a predetermined index value of the shuttle voltage as a shuttle voltage index value of the other lithium-sulfur battery cell received. Thus, the logic module is capable of providing a predetermined threshold value for the shuttle voltage obtained by measuring a similar lithium-sulfur battery cell having a shuttle voltage substantially the same as the shuttle voltage of the lithium-sulfur battery cell.

If the predetermined index value of the shuttle voltage is not predetermined before the predetermined number of cycles, the predetermined index value of the shuttle voltage may be the shuttle voltage index value of the other lithium-sulfur battery cell received.

As previously described, the predetermined number of cycles can be between 70 and 120 charge cycles. The predetermined number of cycles can be greater than 50 charge cycles. The predetermined number of cycles can be greater than 70 charge cycles. The predetermined number of cycles can be greater than 80 charge cycles. The predetermined number of cycles can be less than 120 charge cycles. The predetermined number of cycles can be less than 100 charge cycles.

The logic module can be further configured to control the charging module for charging the lithium-sulfur battery cell to at least one of a shuttle-reduced charging state and a first state of charge in a pulsed charging operation state. In several embodiments, the pulsed charging operating state is a pulse bandwidth modulated charging operating state. Thus, charging of a lithium-sulfur battery cell can use a pulse-width modulated operating state in which the charge is delivered to the cell by a number of pulses having a period of reduced charge between pulses. In some embodiments, the period of reduced charging may be a period without charging.

The duty cycle for the pulse bandwidth modulation operating state can be greater than 30%. The duty cycle for this pulse bandwidth modulation operation can be 70%. The duty cycle for the pulse bandwidth modulation operating state can be approximately 50%. The period of each pulse in the pulse bandwidth modulation operating state may be greater than 5 milliseconds. The period of each pulse in the pulse bandwidth modulation operating state may be less than 40 milliseconds. The period of each pulse in the pulse bandwidth modulation operating state may be approximately 20 milliseconds. In some embodiments, particularly when the battery cell is used to drive a load having a high moment of inertia, the period of each pulse in the pulse bandwidth modulation operating state may be greater than 40 milliseconds.

The battery management system can further include a discharge module constructed to control the discharge of the lithium-sulfur battery cells.

The discharge module can be constructed to control the discharge of the lithium-sulfur battery cells in a pulse discharge operating state. The pulse discharge operating state can be a pulse bandwidth modulation operating state.

The invention extends to a lithium-sulfur battery comprising the battery management system.

From the other aspect of the present invention, it is known to provide a method for managing a lithium-sulfur battery cell. The method includes charging a lithium-sulfur battery cell to a shuttle-reduced state of charge during a charging cycle. The shuttle reduced state of charge is equal to or lower than a predetermined index value of a shuttle voltage, wherein a first derivative of one of the voltages of the lithium-sulfur battery cell relative to time or charge during charging is tied to In a critical range of zero of the first derivative, and wherein a second derivative of one of the voltages of the lithium sulfur battery cell relative to time or charge during charging is at the first derivative is at the first derivative The time of the same value in the zero critical range or the critical range of zero in the second derivative of the charge.

The predetermined first derivative threshold may be less than 0.1 volts per ampere hour. The predetermined first derivative threshold may be less than 0.05 volts per ampere. The predetermined first derivative threshold may be less than 0.01 volts per ampere. The predetermined first derivative threshold may be less than 0.1 volts per minute. The predetermined first derivative threshold may be less than 0.05 volts per minute. The predetermined first derivative threshold may be less than 0.01 volts per minute. The predetermined first derivative threshold may be greater than 0.001 volts per ampere. The predetermined first derivative threshold may be greater than 0.005 volts per ampere. The predetermined first derivative threshold may be greater than 0.009 volts per ampere. The predetermined first derivative threshold may be greater than 0.001 volts per minute. The predetermined first derivative threshold may be greater than 0.005 volts/minute. The predetermined first derivative threshold may be greater than 0.009 volts per minute.

The predetermined second derivative threshold may be less than 0.1 volts/(ampere hours) ² . The predetermined second derivative threshold may be less than 0.05 volts per ampere hour ² . The predetermined second derivative threshold may be less than 0.01 volts per ampere hour ² . The predetermined second derivative threshold may be less than 0.1 volts/(minutes) ² . The predetermined second derivative threshold may be less than 0.05 volts/(minutes) ² . The second derivative of the predetermined threshold value may be less than 0.01 volts / (min) ^2. The predetermined second derivative threshold may be greater than 0.001 volts per ampere hour ² . The predetermined second derivative threshold may be greater than 0.005 volts per ampere hour ² . The predetermined second derivative threshold may be greater than 0.009 volts per ampere hour ² . The second derivative of the predetermined threshold may be greater than 0.001 volts / (min) ^2. The predetermined second derivative threshold may be greater than 0.005 volts/(minutes) ² . The second derivative of the predetermined threshold may be greater than 0.009 volts / (min) ^2.

As previously described, it will be appreciated that in the case where the index value of the shuttle voltage is measured in units other than volts, the predetermined first derivative threshold and the unit of the predetermined second derivative threshold It will be different.

The method of the present invention can further comprise charging the lithium-sulfur battery cell to a first state of charge that is higher than the shuttle-reduced state of charge during a charge cycle prior to the charging cycle.

The method of the present invention can further comprise setting a predetermined index value of the shuttle voltage as an index value of a voltage, wherein the voltage of the lithium-sulfur battery cell passes during any previous charging cycle prior to the charging cycle, with respect to time or One of the charges is one of a first derivative in a critical range of zero of the predetermined first derivative, and one of the time or charge is in a critical range in which the first derivative is zero of the predetermined first derivative a second derivative of the same value of time or a critical range of zero of the predetermined second derivative under charge.

In an embodiment, the method of the present invention can include attempting to set a predetermined index value for the shuttle voltage. The method for setting a predetermined index value of the shuttle voltage can be as described above.

Therefore, when the first derivative and/or the second derivative is never in the critical range of zero, the predetermined index value of the shuttle voltage cannot be determined by the method of the present invention. In this case, the predetermined index value of the shuttle voltage must be set in a different way.

This any previous charging cycle can be the previous charging cycle.

The method of the present invention can include determining a reduced state of charge based on the predetermined value. The method of the present invention can further include receiving a predetermined value corresponding to the shuttle voltage.

The method of the present invention can further comprise receiving an index value of a shuttle voltage of another lithium-sulfur battery cell.

The method of the present invention can be used with a lithium-sulfur battery cell having a shuttle voltage substantially the same as the shuttle voltage of the other lithium-sulfur battery cell.

The predetermined index value of the shuttle voltage may be an index value of the shuttle voltage of the other lithium-sulfur battery cell received.

If the predetermined index value of the shuttle voltage is not predetermined before a predetermined number of previous cycles, the predetermined index value of the shuttle voltage may be an index value of the shuttle voltage of the other lithium-sulfur battery cell received.

Accordingly, in an embodiment of the invention, the method of the present invention includes attempting to set a predetermined index value for the shuttle voltage, the predetermined index value of the voltage being determinable in a variety of manners.

The predetermined number of cycles can be between 70 and 120 charge cycles. The predetermined number of cycles can be greater than 50 charge cycles. The predetermined number of cycles can be greater than 70 charge cycles. The predetermined number of cycles can be greater than 80 charge cycles. The predetermined number of cycles can be less than 120 charge cycles. The predetermined number of cycles can be less than 100 charge cycles.

The method of the present invention can further comprise charging the lithium-sulfur battery cell to at least one of a shuttle-reduced state of charge and a first state of charge in a pulsed charging mode of operation.

The method of the present invention can further comprise controlling the discharge of the lithium sulfur battery cell.

The discharge of the lithium-sulfur battery cell can be performed under one pulse operation.

During the development of battery management systems for lithium-sulfur battery cells, the industry understands that the significant beginning of the shuttle effect occurs only when the voltage of the cell reaches a certain voltage during charging, the term for that particular voltage. It is called the shuttle voltage. The shuttle voltage is roughly corresponding to the state of charge of one of the battery cells. It is known that after a significant start of the shuttle effect, although an additional charge can be applied to the battery cells, the amount of increase is extremely small even if the voltage across the cells increases. In some cases, such as where the temperature exceeds 45 degrees Celsius, further charging actually reduces the voltage. It is also understood that during the initial number of charging cycles, the significant start of the shuttle effect does not occur at all.

Figure 2 shows a graph showing the shuttle effect of a typical lithium-sulfur battery cell beginning during charging. In the diagram, the "shuttle voltage" line indicates the set shuttle voltage, which corresponds to a state of charge, and further charging beyond the voltage will cause significant deactivation of the two electrodes, reducing the coulomb of the cell. effectiveness. The shuttle voltage in this particular case was set at approximately 2.41 volts. It can be seen that the first cycle exhibits a voltage charging characteristic that exceeds the voltage of the shuttle voltage to approximately 2.45 volts at a charge capacity of approximately 2.4 ampere-hours. As previously stated, the maximum capacity of the battery cells will occur after the first charge cycle, as seen in the cell cells. Although not shown in the chart, the maximum capacity of this cell will occur between the 50th and 100th charge cycles. It can be appreciated that during the 100th charge cycle, the voltage does not significantly exceed the shuttle voltage of 2.41 volts during charging. In addition, although the total charge amount introduced into the battery is extended to 4 ampere hours for the 100th, 150th, and 200th charge cycles, it is recognized that as the number of cycles increases, the voltage increases. Trends can cause significant delays at earlier points in time. At the 100th charge cycle, the voltage characteristics will generally flatten towards the shuttle voltage at a capacitance of approximately 3.2 ampere-hours. At the 150th charge cycle, the voltage characteristics will generally flatten towards the shuttle voltage at a capacitance of approximately 2.7 ampere-hours. At the 200th charge cycle, the voltage characteristics will generally flatten towards the shuttle voltage at a capacitance of approximately 2.3 ampere-hours. Assuming that an additional amount of charge is input to the cell after the shuttle voltage is reached, the shuttle effect is substantially initiated and driven, resulting in passivation of the electrode and reducing the coulombic efficiency of the cell.

Although the shuttle voltage for this particular cell is set at 2.41 volts, it has been found that such cell cells having the same cell cell composition (eg, the same electrolyte, the same sulfur loading) are at the shuttle voltage. Aspects show small changes due to manufacturing quality and internal impedance. Similar to the shuttle voltage in the cell, a minimum of 2.4 volts has been found. It will be appreciated that this voltage will also vary due to different cell cell composition (eg, different electrolytes, different sulfur loadings).

Figure 3 shows a graph showing the shuttle effect of another typical lithium sulfur battery cell beginning during charging. Similar to the manner of Figure 2, the line labeled "No Shuttle" indicates the initial charging cycle of the battery cells. The line labeled "shuttle" shows that an essential shuttle effect begins at about 2.35 volts during this later charge cycle.

Based on the above observations, it has been found that by controlling the charging of the battery cells, the electrodes of the battery cells are prevented from being significantly passivated due to the shuttle effect, so that the state of charge of the battery cells does not reach or exceed a shuttle. The state of charge. The reduced state of charge of the shuttle corresponds to a voltage at which the shuttle start effect occurs. Essentially, it has been found that if the voltage across the cell during charging does not reach or exceed the shuttle voltage, significant lithium passivation can be avoided by a lithium-sulfur battery cell.

It has also been found that this shuttle effect is not significantly produced in an initial cycle range. In an exemplary lithium-sulfur battery cell, its charging voltage diagram is shown in Figure 2, which does not become significant until about 100 charge cycles have elapsed. Therefore, the lithium-sulfur battery cell can be subjected to the first 100 charge cycles in a first operating state (or until it is determined that a shuttle effect is significantly caused). In the first operating state, the maximum charging voltage through the battery cell (or the state of charge of the battery cell) may be left uncontrolled or limited. The first charging operation state is followed by a second charging operation state, wherein the maximum charging state of the battery cell is controlled during charging to not exceed a predetermined shuttle voltage or a reduced charging state, thereby reducing A significant beginning of the shuttle effect.

4 shows a graph showing the charging characteristics of a lithium-sulfur battery cell using one of the battery management systems in accordance with an embodiment of the present invention. The left axis of this chart represents the capacity measurement in amp hours. The charging capacity indicator line (the "chrg cap" line in the figure) and the discharge capacity indicator line (the "discharge cap" line in the figure) are plotted against the capacity measurement of the left axis. The initial life discharge depth (abbreviated as "BOL DOD" line in the drawing) is plotted against the right axis, which represents the discharge amount of a lithium-sulfur battery cell containing one of the electrolytes containing dioxalate as a solvent. Measure depth. It can be seen that as the number of cycles increases, the charging capacity of the battery cells decreases. In other words, the amount of charge applied to the lithium-sulfur battery cell tends to gradually decrease as the number of cycles increases. It can be expected that the discharge capacity of the lithium-sulfur battery cell will also decrease as the number of cycles increases. For each cycle, the maximum state of charge of one of the lithium-sulfur battery cells is controlled so as not to exceed a state of charge corresponding to a voltage of 2.41 volts through the cell, which is determined to exceed Significantly start the voltage with a shuttle effect. Although the efficiency of the lithium-sulfur battery cells is slowly attenuated (as measured by the initial life discharge depth line), this can be achieved more gently than allowing a significant start of the shuttle effect (as shown in Figure 1). Attenuation mode.

It has also been found that charging only the cell cells to 2.41 volts causes the cell to produce a lower discharge capacity, which itself also causes the cell to degrade to a depth relative to the initial lifetime of the cell. . For example, it can be seen that 70% of the depth of discharge is shown between Figure 1 and Figure 4 between 100 and 110 cycles. However, 60% of the depth of discharge occurred in about 150 cycles in Figure 1, and in Figure 4 it occurred in about 200 cycles, showing improved cycle life of the cell.

It has also been found that adaptive charging offers more benefits. In an adaptive charging operation state, a charging cycle of a first subset is constructed, and a charging cycle of a second subset performed after the first subset is continued. During the charging cycle of the first subset, there may be no need to limit the state of charge during charging or the maximum voltage through the cell. During the charging cycle of the second subset, the battery cell can only be charged to the limit of a shuttle to lower the state of charge. In this way, it was found that adaptive charging can further improve the cycle life of the battery cells. The second subset can be implemented at the beginning of the first cycle in which the shuttle effect is expected to occur.

FIG. 5 shows a graph illustrating charge and discharge characteristics of a battery management system in accordance with an embodiment of the present invention. The charging characteristics of Figure 5 show the application of a pulsed charging operating state to the battery cells. The amount of charge can be pulsed into the battery such that the voltage across the cell during charging also has a pulse characteristic. This charging characteristic operates from a cell capacity of 0 amp hours to approximately 10 amp hours. Above this capacity, the battery cells are discharged. In this particular embodiment, both the charging and discharging of the battery cells operate in a pulsed operating state. During discharge, current is drawn from the cell cells in a pulsed manner. The period of each pulse is approximately 20 milliseconds. It has been found that for lithium-sulfur battery cells, charging and/or discharging using a pulsed operating state can further reduce the shuttling effect and thereby increase cycle life.

6 is a graph showing the charging characteristics of a lithium-sulfur battery cell using one of the battery management systems in accordance with an embodiment of the present invention. Compared to a pulsed charge/discharge operating state with a maximum state of charge set to reduce the shuttle effect, this graph shows the charge and discharge capacity for a fixed current charging operating state (without the state of charge capacity to reduce the shuttle effect) ). The efficiency of these two charging methods is also shown in the pulse width modulation (PWM) efficiency vs. initial life (BOL) line, and the fixed current efficiency in the BOL line. It can be seen that although the fixed current charging method shows an efficiency of 80% after just more than 100 charging cycles, the PWM charging operating state with the shuttle effect reducing the charging state exhibits an efficiency of 80% after more than 180 cycles. , indicating a significant increase in the efficiency of the battery cell.

In the context of the description of the specification and the scope of the invention, the words "including" and "comprising", and variations thereof mean "including but not limited to" and the words are not used (and cannot be used) Exclude other components, wholes or steps. Throughout the description of the invention and the scope of the invention, the single-word number includes the plural numeral. In particular, the indefinite articles used herein are to be understood as being

In addition to being incompatible, the features, integers, or characteristics described in connection with a particular aspect, embodiment, or example of the invention can be applied to any other aspect, embodiment, or example herein. All of the features disclosed in this specification (including any accompanying claims, abstracts and drawings), and/or the steps of any method or procedure disclosed may be combined in any combination, unless at least some of the combinations Features and/or steps are mutually exclusive. The invention is not limited to any of the embodiments described in detail above. The present invention extends to any innovation or any combination of features (including any accompanying claims, abstracts and drawings) of the features disclosed in this specification, or any of the steps of any method or procedure as disclosed herein. An innovation or any combination of innovations.

The embodiments of the present invention are further described below with reference to the accompanying drawings in which: Figure 1 shows a graph showing the change in discharge capacity of a typical lithium-sulfur battery cell for a cycle number at a fixed current; Figure 2 shows A graph showing the shuttle effect of a typical lithium-sulfur battery cell during charging; Figure 3 shows a graph showing the shuttle effect of another typical lithium-sulfur battery cell during charging; Figure 4 shows A graph showing the charging characteristics of a lithium-sulfur battery cell using one of the battery management systems according to an embodiment of the present invention; FIG. 5 is a diagram showing the charge and discharge characteristics of the battery management system according to an embodiment of the present invention. The graph; and FIG. 6 shows a graph showing the charging characteristics of a lithium-sulfur battery cell using one of the battery management systems in accordance with an embodiment of the present invention.

Claims (25)

A battery management system for a lithium-sulfur battery cell, the battery management system comprising: a charging module configured to charge a lithium-sulfur battery cell; and a logic module configured to control the Charging module for charging the lithium-sulfur battery cell to a shuttle-reduced charging state during a charging cycle; wherein the shuttle-reduced charging state is equal to or lower than a predetermined index value of a shuttle voltage, wherein charging Passing a first derivative of the voltage of the lithium-sulfur battery cell relative to one of time or charge during a critical range of zero of a predetermined first derivative, and wherein the lithium-sulfur battery is passed during charging a second derivative of the voltage of the cell relative to one of time or charge, at a time or charge of the same value in the critical range of zero of the predetermined first derivative In the critical range of zero of the second derivative. The battery management system of claim 1, wherein the charging cycle is continued after a previous charging cycle, wherein the logic module is configured to control the charging module to charge the lithium sulfur battery cell to be higher than the A first state of charge of the reduced state of charge is shuttled. The battery management system of claim 2, wherein the logic module is further configured to set the predetermined index value of the shuttle voltage as a voltage index value, wherein during any previous charging cycle prior to the charging cycle, One of the voltages of the lithium-sulfur battery cell has a first derivative in a critical range of zero of the predetermined first derivative with respect to one of time or charge, and one of the time or charge A derivative is one of a second derivative of the same value of the critical range of zero of the predetermined first derivative or a critical range of zero of the predetermined second derivative under the charge. The battery management system of claim 3, wherein the any previous charging cycle is a previous charging cycle. The battery management system of any one of claims 1 to 4, wherein the logic module is further configured to receive an index value of a shuttle voltage of one of the lithium-sulfur battery cells. A battery management system according to claim 5, wherein the battery management system is for a lithium-sulfur battery cell having a shuttle voltage substantially the same as a shuttle voltage of the other lithium-sulfur battery cell. The battery management system of claim 5 or 6, wherein the logic module is further configured to set the predetermined index value of the shuttle voltage as a shuttle voltage index value of the received other lithium-sulfur battery cell. The battery management system of claim 7, wherein if the predetermined index value of the shuttle voltage is not determined before a predetermined number of cycles, the predetermined index value of the shuttle voltage is the received other lithium sulfur The index value of the shuttle voltage of the battery cell. The battery management system of claim 8, wherein the predetermined number of cycles is between 70 and 120 charge cycles. The battery management system of any one of claims 1 to 9, wherein the logic module is further configured to control the charging module to charge the lithium sulfur battery cell to the shuttle in a pulsed charging operation state. At least one of a reduced state of charge and the first state of charge. The battery management system of any one of claims 1 to 10, further comprising a discharge module constructed to control discharge of the lithium-sulfur battery cell. The battery management system of claim 11, wherein the discharge module is configured to control discharge of the lithium sulfur battery cell in a pulsed operating state. A lithium-sulfur battery comprising the battery management system of any one of claims 1 to 12. A method for managing a lithium-sulfur battery cell, the method comprising: charging a lithium-sulfur battery cell to a shuttle-reduced charging state during a charging cycle; wherein the shuttle-reduced charging state is equal to or lower than one a predetermined index value of the shuttle voltage, wherein a first derivative of the voltage of the lithium-sulfur battery cell relative to time or charge during charging is in a critical range of zero of a predetermined first derivative And wherein a second derivative of one of a voltage of the lithium-sulfur battery cell relative to time or charge during charging is in a threshold value of zero of the predetermined first derivative The time of the same value or the critical range of zero of a predetermined second derivative under charge. The method of claim 14, wherein the method further comprises: charging the lithium-sulfur battery cell to be higher than the shuttle in a previous charging cycle before the charging cycle A first state of charge of the state of charge. The method of claim 15 for managing a lithium-sulfur battery cell, wherein the method further comprises: setting the predetermined index value of the shuttle voltage as an index value of a voltage, wherein any previous charging before the charging cycle a voltage passing through the lithium-sulfur battery cell during the cycle, having one of a first derivative in a critical range of zero of the predetermined first derivative with respect to time or charge, and one of time or charge A second derivative of the critical range of zero of the predetermined second derivative at a time when the first derivative is at the same value in the critical range of zero of the predetermined first derivative or at a charge. The method of claim 16, wherein the any previous charging cycle is the previous charging cycle. A method for managing a lithium-sulfur battery cell according to any one of claims 14 to 17, wherein the method further comprises receiving an index value of a shuttle voltage of one of the lithium-sulfur battery cells. A method for managing a lithium-sulfur battery cell according to claim 18, wherein the method is for a lithium-sulfur battery cell having a shuttle voltage substantially the same as a shuttle voltage of the other lithium-sulfur battery cell. The method of claim 18 or 19 for managing a lithium-sulfur battery cell, wherein the predetermined index value of the shuttle voltage is an index value of the shuttle voltage of the other lithium-sulfur battery cell received. The method for managing a lithium-sulfur battery cell according to claim 18 or 19, wherein if the predetermined index value of the shuttle voltage is not determined before a predetermined number of cycles, the predetermined index value of the shuttle voltage is The index value of the shuttle voltage of the other lithium-sulfur battery cell received. The method of claim 21 for managing a lithium-sulfur battery cell, wherein the predetermined number of cycles is between 70 and 120 charge cycles. The method for managing a lithium-sulfur battery cell according to any one of claims 14 to 22, wherein the method further comprises charging the lithium-sulfur battery cell to the shuttle-reduced charging state in a pulsed charging operation state. And at least one of the first state of charge. A method for managing a lithium-sulfur battery cell according to any one of claims 14 to 23, wherein the method further comprises controlling the discharge of the lithium-sulfur battery cell. A method for managing a lithium-sulfur battery cell according to claim 24, wherein the discharge of the lithium-sulfur battery cell is in a pulsed operation state.