Method and system for battery management including bypassing battery cells in battery pack

Abstract

A system may include a battery pack having battery cell portions connected in series, where each battery cell portion includes a battery cell and a bypass switch. The system may also include a control circuit. The control circuit can determine the capacity of a specific battery cell in the specific battery cell part; determining that the capacity of the particular battery cell is less than a predefined threshold; and responsively performing a bypass sequence on the particular battery cell. The bypass sequence may involve determining a bypass period for bypassing the particular battery cell based on a capacity of the particular battery cell and sending a bypass signal to the driver circuit. The drive circuit may receive a bypass signal and responsively operate a bypass switch of the particular cell portion to bypass the particular cell during a bypass period.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Patent Application No. 18 / 209,279, filed on June 13, 2023, entitled “Methods and Systems for Battery Management of Battery Cells Including Bypass in a Battery Pack,” the disclosure of which is incorporated herein by reference in its entirety for all purposes. Background of the Invention

[0004] The development of rechargeable batteries, such as lithium-ion batteries, has opened up new applications in various industries. Rechargeable batteries offer many advantages in applications due to long operating times and extended battery cycle life. Typically, rechargeable batteries are charged and discharged using specific charging and discharging standards. Therefore, for the health and safe operation of the battery, a battery management system can be used to manage the operation of the battery.

[0005] Despite advances in the field of rechargeable batteries and battery management systems, there remains a need in the art for improved methods and systems relating to rechargeable batteries and battery management systems. Summary of the invention

[0006] The present application generally relates to methods and systems related to battery management systems for managing the charging and discharging of battery packs. More specifically, embodiments of the present invention relate to a battery management system that can be used to monitor a battery pack and automatically and selectively bypass specific battery cells (e.g., defective or defective battery cells) in the battery pack. The present invention is applicable to various high-voltage and low-voltage applications involving multi-cell battery packs used in various applications including automotive and solar energy storage.

[0007] The battery pack may include any number of battery cell sections connected in series, wherein each battery cell section includes a battery cell, a charge (or discharge) switch, and a bypass switch. The control circuit of the battery management system may monitor the voltage across the battery cells in each battery cell section during one or more charging cycles. Based on the rate of change of the voltage across the battery cell (e.g., compared to the current curve of the battery), the control circuit may determine the capacity of the battery cell. If the control circuit determines that the capacity of a particular battery cell is less than a predefined threshold, it may mean that the battery cell is a defective or defective cell that should be bypassed. Therefore, the control circuit may determine a bypass period for bypassing a particular battery cell during a charging (and discharging) cycle. The control circuit may determine the bypass period based on the capacity of the battery cell. The control circuit may then open the charging switch of the corresponding battery cell section and close its bypass switch to bypass the particular battery cell during the bypass period. In this way, the control circuit can automatically monitor the capacity of each battery cell in the battery pack over time and dynamically bypass the defective or defective battery cell during the bypass period to reduce or minimize the negative impact of the defective or defective battery cell on the charging process. Similar principles can be applied during the discharge cycle to reduce or minimize the negative impact of the defective or defective battery cell on the discharge process.

[0008] The battery management system described herein can overcome the problems associated with traditional balancing methods, which are typically lossy, slow, implemented in hardware, and require expensive high-voltage power transistors. For example, the battery management system described herein can selectively bypass defective or defective battery cells at specific time intervals (particularly at each charge / discharge cycle), which means that there is no need to implement traditional balancing methods that use expensive charge equalization circuits. In addition, the battery management system can execute software on the controller to track the capacity of each battery cell, while adaptively deciding which battery cells to bypass, and the time interval for bypassing. By using a software-controlled method to adaptively bypass defective or defective battery cells, rather than using expensive hardware to implement traditional balancing methods, some examples can be cost-effective and have a smaller footprint on a printed circuit board than traditional balancing methods.

[0009] Some examples described herein can further reduce or minimize costs and bypass losses by using a power control switch to isolate the battery pack, and then operating the charging switch and bypass switch to bypass the defective or defective battery. The power control switch can be a high-voltage power transistor, which can have a high resistivity to protect the battery cell from the impact of current surges. More specifically, the battery management system can turn on the power control switch to isolate the battery pack, then operate the charging switch and bypass switch associated with the battery cell to bypass the battery cell, and finally turn off the power control switch to re-establish power flow to the battery pack. Using these techniques, low-voltage transistors can be used as charging switches and bypass switches. This approach can reduce costs compared to traditional balancing methods that use a large number of expensive high-voltage power transistors.

[0010] The battery management system can output the classification and / or capacity of each battery cell to the user using any suitable communication means (such as Modbus, controller area network (CAN), Ethernet or wireless communication), so that the user can further fully understand the status of the battery pack. This can allow the user to take any necessary corrective actions, such as replacing the batteries under warranty if a large number of battery cells are defective. These and other embodiments of the present invention, as well as many of the advantages and features of the present invention, will be described in more detail in conjunction with the following and accompanying drawings.

[0011] According to one embodiment of the present invention, a system may include a battery pack having battery cell sections connected in series. Each battery cell section includes a battery cell and a bypass switch. The bypass switch may be positioned in parallel with the battery cell. The bypass switch may be operated to short-circuit both ends of the battery cell section. The system also includes a control circuit. The control circuit is configured to: determine the capacity of a specific battery cell in a specific battery cell section in the battery cell section; determine whether the capacity of the specific battery cell is less than a predefined threshold; and in response to determining that the capacity of the specific battery cell is less than the predefined threshold, execute a bypass sequence of the specific battery cell. The bypass sequence involves: determining a bypass period for bypassing the specific battery cell based on the capacity of the specific battery cell. The bypass sequence also involves: transmitting a bypass signal to a drive circuit. The drive circuit may be configured to receive the bypass signal and responsively operate the bypass switch of the specific battery cell section to bypass the specific battery cell during the bypass period.

[0012] Another embodiment of the present invention includes a method performed by a control circuit. The method may include: determining the capacity of a specific battery cell in a specific battery cell portion of a battery pack, wherein the specific battery cell portion includes a bypass switch. The method may include: determining whether the capacity of the specific battery cell is less than a predefined threshold. The method may include: in response to determining that the capacity of the specific battery cell is less than the predefined threshold, executing a bypass sequence for the specific battery cell. The bypass sequence involves: determining a bypass period for bypassing the specific battery cell based on the capacity of the specific battery cell. The bypass sequence also involves: transmitting a bypass signal to a drive circuit. The drive circuit may be configured to receive the bypass signal and responsively close the bypass switch of the specific battery cell portion to bypass the specific battery cell during the bypass period.

[0013] Another embodiment of the present invention includes a method performed by a first control circuit associated with a first battery pack. The method may include: determining that a battery cell of the first battery pack will be bypassed within a bypass period based on the capacity of the battery cell. The method may include, in response to determining that the battery cell will be bypassed within the bypass period: executing a first bypass sequence, the first bypass sequence being configured to bypass the battery cell within the bypass period; and transmitting a bypass notification to a second control circuit associated with a second battery pack. The second control circuit is configured to: receive the bypass notification. In response to receiving the bypass notification, the second control circuit may synchronize the second bypass sequence with the first bypass sequence. The second bypass sequence may be configured to: bypass another battery cell in the second battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Various aspects of the present disclosure will be described more fully below with reference to the accompanying drawings, which should be read in conjunction with the present disclosure, the specific embodiments, and any preferred and / or specific embodiments specifically discussed or otherwise disclosed. However, the various aspects may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided by way of illustration only in order to make the present disclosure thorough and complete and to fully convey the full scope to those skilled in the art.

[0015] Figure 1 A block diagram of an example of a battery management system according to some aspects of the present disclosure is shown.

[0016] Figure 2 A flow chart illustrating an example of a process for classifying battery cells as healthy cells, weak cells, or bad cells according to some aspects of the present disclosure.

[0017] Figure 3 A flow chart illustrating an example of a process for bypassing a battery cell during a bypass period according to some aspects of the present disclosure is shown.

[0018] Figure 4A flow chart illustrating an example of a cell bypass sequence according to some aspects of the present disclosure.

[0019] Figure 5 A flow chart illustrating an example of a unit activation sequence according to some aspects of the present disclosure.

[0020] Figure 6 Examples of bypass periods and active periods associated with a battery cell during a charging cycle are shown in accordance with some aspects of the present disclosure.

[0021] Figure 7 A block diagram is shown of an example of a battery management system for multiple battery packs according to some aspects of the present disclosure.

[0022] Figure 8 A flow chart illustrating an example of a process for synchronizing a bypass sequence between multiple battery packs according to some aspects of the present disclosure.

[0023] Fig. 9 A block diagram is shown of an example of a computing device that may be used to implement some aspects of the present disclosure. DETAILED DESCRIPTION

[0024] The present invention generally relates to methods and systems related to battery management systems for managing the charging and discharging of battery packs. More specifically, embodiments of the present invention provide methods and systems for automatically and selectively bypassing defective or defective battery cells in a battery pack. The present invention is applicable to various high-voltage and low-voltage applications involving multi-cell battery packs, such as automotive and solar energy storage.

[0025] A battery pack, such as a lithium-ion battery pack, will have multiple battery cells connected in series. Over many charge and discharge cycles, some battery cells may become weaker than others. This may be due to manufacturing differences, assembly differences, cell aging, impurities, environmental exposure, etc. These weak cells have a lower ability to hold a charge than normal, healthier cells, so weak cells may charge and discharge faster than healthy cells. Some battery cells may also fail completely. These bad cells are unable to hold any charge at all. Because defective or defective cells, such as weak and bad cells, are in series with other healthy cells, they may prevent the battery pack from fully charging. In some cases, one bad cell can render the entire battery pack inoperable, preventing the battery pack from charging or discharging at all.

[0026] Battery management systems can be used to help account for the fact that some battery cells in a battery pack may be weaker than other battery cells, which may negatively impact the charging and discharging of the battery pack. Conventional battery management systems may employ balancing methods to maintain the same state of charge (SOC) for each battery cell as widely as possible, based on the different capacities of the individual battery cells. However, conventional battery balancing methods have various problems with both their effectiveness and cost. Thus, embodiments of the present invention provide improved methods and systems relating to battery cells in a battery pack and corresponding battery management systems.

[0027] Figure 1 FIG. 1 is a block diagram of an example of a battery management system 100 according to some aspects of the present disclosure. The battery management system 100 includes a battery pack 102 having n battery cells (eg, 128 battery cells), which is represented by U in the figure. 单元 _1 to U 单元 The battery cells are connected in series and arranged within the physical housing of the battery pack 102.

[0028] In the battery pack 102, there are n battery cell sections, such as the battery cell section 104, each of which corresponds to one of the n battery cells. Each battery cell section may include a charging switch, which Figure 1 Designated as S 充电 . Examples of charging switches may include relays or transistors, such as low voltage transistors. The low voltage transistor may be a transistor designed to handle low voltages (e.g., 50 VDC or less). The charging switch is connected in series with the battery cell and is operable between a closed position and an open position. In the closed position, the charging switch may allow current to flow into the battery cell during a charging cycle, or to flow out of the battery cell during a discharge cycle. In the open position, the charging switch may prevent current from flowing into the battery cell during a charging cycle, or prevent current from flowing out of the battery cell during a discharge cycle.

[0029] Each battery cell section may also include a bypass switch that Figure 1 Designated as S 旁路 . Examples of a bypass switch may include a relay or a transistor, such as a low voltage transistor. The bypass switch may be connected in parallel with the battery cell and the charging switch. The bypass switch is operable between a closed position and an open position. In the closed position, the bypass switch may short-circuit the ends of the battery cell portion. This may prevent current from flowing through the remainder of the battery cell portion, which in turn may prevent current from flowing into the battery cell during a charging cycle, or prevent current from flowing out of the battery cell during a discharge cycle. In the open position, the bypass switch may allow current to flow through the remainder of the battery cell portion.

[0030] The bypass switch and the charging switch may be controlled by the control circuit 120 so as to selectively bypass one or more battery cells (e.g., weak battery cells) during a charging cycle or a discharging cycle of the battery pack 102. More specifically, the control circuit 120 may detect the voltage across the battery cell, determine the capacity of the battery cell based on the voltage, and determine whether the battery cell is a defective or defective battery cell based on the capacity. If the battery cell is a defective or defective battery cell, the control circuit 120 may determine a bypass period during which the battery cell is bypassed. The control circuit 120 may then operate the bypass switch and the charging switch of the battery cell to selectively bypass the battery cell during the bypass period. The control circuit 120 may perform this process on some or all of the battery cells so as to selectively and individually bypass defective or defective battery cells during a charging cycle or a discharging cycle of the battery pack 102. In some examples, at least one battery cell is configured to always be enabled as a power supply for the control circuit 120. Alternatively, the control circuit 120 may be powered by the power supply 110.

[0031] To achieve the above functions, the control circuit 120 may include a monitoring circuit 106. The monitoring circuit 106 may be configured to measure the voltage across each battery cell in the battery pack 102. For example, the monitoring circuit 106 includes a voltage sensor electrically connected to the positive and negative terminals of the battery cell for measuring the voltage across the battery cell. The monitoring circuit 106 may be configured to measure the voltage across each battery cell at a predetermined frequency. For example, the monitoring circuit 106 may measure the voltage across each battery cell every 10 milliseconds, 100 milliseconds, 1 second, 3 seconds, etc., depending on the configuration. The monitoring circuit 106 may be electrically connected to the controller 114 and transmit a measurement signal indicating the measured voltage to the controller 114.

[0032] The controller 114 may include a processor and a memory, examples of each of which are described more fully below. The memory may include instructions that the processor may execute to perform operations. The controller 114 may receive measurement signals from the monitoring circuit 106 and store the measured voltages in the memory. The controller 114 may analyze the measured voltages associated with each individual battery cell over time to determine how the voltage of each battery cell changes over time. For example, the controller 114 may monitor the voltage across the battery cells during one or more charging cycles to determine how the voltage across the battery cells changes during one or more charging cycles. Based on the measured voltages, the controller 114 may determine the speed at which each battery cell is charged and / or discharged. For example, the controller 114 may analyze the voltages associated with the U during one or more charging cycles. 单元_3 to determine the speed at which it reaches a fully charged voltage level (e.g., a maximum voltage level). Since the charging speed is related to the capacity of the battery cell, the controller 114 can determine the capacity of each battery cell based on the charging speed. For example, the controller 114 can determine the capacity of each battery cell based on the charging speed of the battery cell. 单元 _3 The charging speed of a battery determines its capacity. A battery cell with a lower capacity (e.g., a weak or defective battery cell) charges significantly faster than a healthy battery cell.

[0033] After determining the capacity of each battery cell, the controller 114 can determine whether the capacity of each battery cell is greater than or equal to a first predefined threshold (e.g., 90% capacity), which can be pre-programmed into the controller 114. If the capacity of a battery cell is greater than or equal to the first predefined threshold, then the battery cell is a healthy battery cell and may not need to be bypassed during the charging cycle. If the capacity of the battery cell is less than the first predefined threshold, it may mean that the battery cell is weak or defective. In other words, the battery cell may be a weak cell or a bad cell. It may be desirable to bypass the weak or defective cells for at least a portion of the charging cycle to mitigate their impact on the charging process.

[0034] If the controller 114 determines that the capacity of the battery cell is less than the first predefined threshold, the controller 114 may next determine whether the battery cell is a defective or defective cell. In doing so, the controller 114 may determine whether the capacity of the battery cell is less than a second predefined threshold (e.g., 60%). The second predefined threshold may also be pre-programmed into the controller 114. If the capacity of the battery cell is greater than or equal to the second predefined threshold, the controller 114 may classify the battery cell as a weak (i.e., insufficient) cell. If the capacity of the battery cell is less than the second predefined threshold, the controller 114 may classify the battery cell as a bad (i.e., defective) cell.

[0035] If the controller 114 determines that the battery cell is a weak cell, the controller 114 may determine the length of time to bypass the battery cell during the charging cycle. This length of time is referred to herein as a bypass period. The controller 114 may determine the bypass period based on the capacity of the battery cell. In some examples, the length of the bypass period may be inversely proportional to the capacity of the battery cell, so as the capacity of the battery cell decreases, the bypass period increases. For example, the length of the bypass period may correspond to the difference between the full cell capacity and the calculated capacity of the battery cell. For example, if the capacity of the battery cell is 75%, then the difference between the two is 100% capacity minus 75% capacity equals 25% capacity. In this case, the bypass period will correspond to 25% of the charging cycle. Therefore, if the charging cycle lasts 100 nanoseconds (100ns), the bypass period will be 25ns, which is only a portion of the entire 100ns charging cycle. On the other hand, if the controller 114 determines that a battery cell is a bad cell, the controller 114 may determine that the battery cell should be bypassed throughout the charging cycle. In this case, the controller 114 may determine that the bypass period corresponds to the length of the entire charging cycle. In this way, the bad cell will not negatively affect the charging of the battery pack 102.

[0036] After determining the bypass period of the defective or faulty battery cell, the control circuit 120 may execute a bypass sequence to implement the bypass period for the battery cell. 单元 _2 should be bypassed for 30ns, the control circuit 120 can execute a bypass sequence to bypass the battery cell for 30ns. The bypass sequence may involve opening S 充电 _2 and close S 旁路 _2, such as Figure 1 As shown, this can cut off the current flowing to the battery cell during the bypass period. When the bypass period ends, the control circuit 120 can execute an activation sequence to reactivate the battery cell. The activation sequence may involve shutting down S 充电 _2 and open S 旁路 _2, so that the current flow to the battery cell can be re-established.

[0037] In order to operate the bypass switch and the charging switch, the control circuit 120 may include a drive circuit 116. The drive circuit 116 may be electrically connected to the bypass switch and the charging switch. The drive circuit 116 may be configured to apply a drive voltage at appropriate terminals of the bypass switch and the charging switch to operate the switch. For example, if the bypass switch and the charging switch are transistors, the drive circuit 116 may be used as a gate driver configured to apply a drive voltage to the gate (or base) of the transistor to switch between an open state and a closed state. The drive circuit 116 may include a multiplexer or other suitable circuit to selectively and individually control the bypass switch and the charging switch in the battery cell section.

[0038] In order to generate sufficient voltage to control the bypass switch and the charging switch, the drive circuit 116 can be connected to the starter relay and the boost circuit 118. The starter relay can be electrically connected to one or more battery cells in the battery pack 102, such as the battery cell U. 单元 _1 to U 单元 _3. The starter relay may draw power from the connected battery cell to activate the boost circuit. In some examples, the control circuit 120 may always keep the connected battery cell active (not bypassed) to maintain power at the boost circuit 118. The boost circuit may include a boost converter that boosts the voltage from its input. Once activated, the boost circuit can generate a drive voltage greater than its input voltage. The drive circuit 116 can then apply the drive voltage to the bypass switch and the charging switch of the appropriate battery cell to control the switches individually.

[0039] In the control circuit 120, the controller 114 may be electrically coupled to the drive circuit 116. The controller 114 may transmit a control signal to the drive circuit 116, wherein the control signal indicates the battery cell to be bypassed. The drive circuit 116 may receive the control signal and responsively operate the bypass switch and the charging switch of the corresponding battery cell portion to bypass the battery cell. For example, the controller 114 may transmit an opening signal to the drive circuit 116 indicating that the S 充电 _2. The drive circuit 116 may receive the open signal and responsively open S 充电 _2, thereby preventing current from flowing to the battery cell U 单元 _2. The controller 114 may also transmit a bypass signal to the drive circuit 116, indicating that the S 旁路 _2. The driver circuit 116 may receive the bypass signal and responsively turn off S 旁路 _2, thereby short-circuiting the ends of the corresponding battery cell portion and preventing current from flowing to the battery cell U 单元 _2. Therefore, the battery unit U 单元_2 can be bypassed. The driver circuit 116 can maintain the switches in these states until it receives an additional signal from the controller 114 to reactivate the battery cell. For example, the controller 114 can determine that the bypass period of 10ns has ended. In response, the controller 114 can transmit an additional control signal to the driver circuit 116 for shutting down S 充电 _2 and open S 旁路 _2. Close S 充电 _2 can allow current to flow to battery cell U 单元 _2, and open S 旁路 _2 can prevent the battery unit U 单元 _2 is bypassed, thereby reactivating the battery cell.

[0040] In some examples, the battery management system 100 may also include one or more power control switches 108 between the battery pack 102 and a power source 110 for charging the battery pack 102. Examples of the power source 110 may include a solar panel array or an electrical grid. Examples of the power control switch 108 may include a relay or a transistor (e.g., a high voltage transistor). The high voltage transistor may be a transistor designed to handle high voltages (e.g., 60 VDC or higher). As part of the bypass sequence, the control circuit 120 (e.g., the controller 114) may operate one or more power control switches 108 to safely perform the bypass switch operation. For example, in order to bypass the battery cell U 单元 _2, the control circuit 120 may start the bypass sequence by transmitting a first open signal to open the power control switch 108, thereby causing the battery cells in the battery pack 102 to be electrically floating. Next, the control circuit 120 may transmit a second open signal to open the charging switch S 充电 Then, the control circuit 120 may transmit a first shutdown signal to close the bypass switch S 旁路 Finally, the control circuit 120 may transmit a second shutdown signal to close the power control switch 108, thereby reestablishing the current flow from the power source 110 to the battery pack 102. Through this sequence of steps, the control circuit 120 may safely operate the bypass switch and the charging switch without the battery cell being subjected to a current surge from the power source 110.

[0041] As part of the activation sequence, the control circuit 120 may also operate the power control switch 108 so that the activation switch operation can be performed safely. For example, to reactivate the battery unit U 单元 _2, the control circuit 120 may start the bypass sequence by transmitting a first open signal to turn on the power control switch 108, so that the battery cells in the battery pack 102 are in a floating state. Next, the control circuit 120 may transmit a first close signal to turn off the charging switch S 充电Then, the control circuit 120 may transmit a second opening signal to open the bypass switch S 旁路 _2. Finally, the control circuit 120 may transmit a second shutdown signal to close the power control switch 108, thereby reestablishing the current flow from the power source 110 to the battery pack 102. Through this sequence of steps, the control circuit 120 may safely operate the bypass switch and the charging switch.

[0042] Using the above techniques, the control circuit 120 can safely and selectively bypass one or more battery cells of the battery pack 102 during a charging cycle. This can significantly extend the life of the battery pack 102, for example, by reducing the impact of weak and bad cells on the charging and discharging of the battery pack 102.

[0043] Similar principles can also be applied to the discharge of the battery pack 102. For example, the battery pack 102 can be connected to a load 112 (such as a motor or household appliance) to power the load 112. During the discharge cycle, the control circuit 120 can measure the voltage across the battery cell, determine the capacity of the battery cell based on the measured voltage, and determine whether the battery cell is a defective or defective battery cell based on the capacity. If the battery cell is a defective or defective battery cell, the control circuit 120 can determine a bypass period during which the battery cell is bypassed. The control circuit 120 can then operate the bypass switch and the charging switch (and the optional power control switch 108) of the battery cell to selectively bypass the battery cell during the bypass period. The control circuit 120 can perform this process for each battery cell so as to selectively bypass the defective or defective battery cell during the discharge cycle.

[0044] It is understood that, although in the above description, the monitoring circuit 106, the controller 114 and the drive circuit 116 are assigned some functions, these functions are only illustrative and not restrictive. In other examples, the above functions may be allocated in different ways between these components. For example, the controller 114 may be configured to perform one or more functions of the above-mentioned monitoring circuit 106. In some such examples, the controller 114 may include the monitoring circuit 106. Therefore, they may not necessarily be separate components in the control circuit 120. As another example, the monitoring circuit 106 may be configured to perform one or more functions of the above-mentioned controller 114. For example, the monitoring circuit 106 can determine the capacity of each battery cell and transmit a signal indicating the corresponding capacity of each battery cell to the controller 114.

[0045] Now refer to Figures 2 to 4 To further explain the various aspects mentioned above, Figures 2 to 4are illustrative and non-limiting. Other examples may include more operations, fewer operations, different operations, or a different order of operations than those shown in these figures. Figure 1 Components of Figures 2 to 4 For simplicity, these operations are described as being performed by the control circuit 120. However, it should be understood that this means that these operations can be performed by one or more components of the control circuit 120.

[0046] Specifically, Figure 2 1 is a flow chart showing an example of a process for classifying a battery cell as a healthy cell, a weak cell, or a bad cell according to some aspects of the present disclosure. The process begins at block 202. In block 202, the control circuit 120 measures the battery cell U in the battery cell section 104 of the battery pack 102. 单元 For example, the control circuit 120 may include a monitoring circuit 106 configured to periodically measure the voltage across the battery cell. The voltage measurement may be performed at a predetermined frequency during a charging cycle or a discharging cycle, which frequency may be pre-configured in the monitoring circuit 106.

[0047] In block 204, the control circuit 120 stores the voltage measurements in a memory. For example, the controller 114 may store the voltage measurements in an internal memory or in an additional memory. The memory may be a non-volatile memory configured to retain the voltage data after power is removed. In this way, the control circuit 120 may store the voltage data associated with each individual battery cell during one or more charging cycles and / or discharging cycles.

[0048] In some examples, the control circuit 120 may additionally or alternatively determine the battery cell U 单元_n's state of charge. The state of charge is also referred to herein as SoC (State of Charge), i.e., the charge level of a battery cell relative to its capacity. The state of charge can be expressed as a percentage, for example, 0% for empty and 100% for full. The state of charge of a battery cell can be determined based on a voltage measurement or a current measurement, which can be obtained using a current sensor of the control circuit 120. For example, the state of charge of a battery cell can be determined based on a voltage measurement using a known discharge curve (a curve of the relationship between voltage and state of charge) of the battery cell. After determining the state of charge of the battery cell, the control circuit 120 can store the state of charge in a memory. The control circuit 120 can repeat this process, for example, each time a voltage measurement or a current measurement is performed to generate state of charge data indicating how the state of charge of the battery cell changes over time. Using these techniques, the control circuit 120 can store state of charge data associated with each individual battery cell during one or more charging cycles and / or discharge cycles.

[0049] In block 206, the control circuit 120 determines the voltage of the battery cell U based on the voltage measurement value. 单元 _n capacity. For example, the controller 114 can retrieve the stored voltage measurement from the memory and analyze its rate of change to determine the charging rate of the battery cell. Based on the charging rate and the known charging current (which can also be measured by the battery management system 100 using a current sensor (e.g., a current sensor in the monitoring circuit 106)), the controller 114 can determine the capacity of the battery cell using the following formula:

[0050] Battery capacity = (charging time) * (charging current)

[0051] In some examples, the battery capacity calculation may take into account other factors, such as depth of discharge and charge efficiency, to improve accuracy.

[0052] In some examples, the control circuit 120 can be configured to generate a plurality of battery cells according to the battery cell U. 单元 The charge state data of the battery cell U can additionally or alternatively be used to determine the charge state of the battery cell U. 单元 For example, the controller 114 may retrieve the stored state of charge data from the memory and analyze it to determine the capacity of the battery cell at the current point in time.

[0053] In block 208, the control circuit 120 determines whether the capacity is less than a first predefined threshold. For example, the controller 114 may compare the capacity with the first predefined threshold to determine whether the capacity is less than the first predefined threshold. If not less than the first predefined threshold, the process may proceed to block 216, where the control circuit 120 classifies the battery cell as a healthy cell. Otherwise, the process may proceed to block 210.

[0054] In block 210, the control circuit 120 determines whether the capacity is less than a second predefined threshold. For example, the controller 114 may compare the capacity with the second predefined threshold to determine whether the capacity is less than the second predefined threshold. If not less than the second predefined threshold, the process may proceed to block 212, where the control circuit 120 classifies the battery cell as a weak cell. Otherwise, the process may proceed to block 214, where the control circuit 120 classifies the battery cell as a bad cell.

[0055] In box 218, the control circuit 120 can transmit the capacity and / or classification of the battery cell. For example, the controller 114 can transmit the capacity and classification of the battery cell to a user device external to the control circuit 120. The user device can be associated with a user or maintenance personnel of the battery pack 102. Examples of user devices can include laptops, desktop computers, mobile phones (such as smart phones), wearable devices (such as smart watches), tablets, or e-readers. The controller 114 can transmit the capacity and classification to the user device via a wired or wireless connection. For example, the controller 114 can transmit the capacity and classification to the user device via a Bluetooth connection, a WiFi (such as 802.11g) connection, or a cellular connection. Transmitting the capacity and classification of the battery cell to the user device can allow the user to monitor potential problems with the battery pack 102, for example, for maintenance.

[0056] The above process can be applied repeatedly to each battery cell in the battery pack 102. This can allow the control circuit 120 to monitor the battery cells simultaneously over time to dynamically detect if and when a healthy cell becomes a faulty or defective cell. The faulty or defective cell can then be bypassed for a period of time (bypass period) to improve the operation of the battery pack 102.

[0057] It should be understood that Figure 2 The specific steps shown provide a specific method for classifying battery cells as healthy cells, weak cells, or bad cells according to an embodiment of the present invention. According to other embodiments, other step sequences may also be performed. For example, other embodiments of the present invention may perform the above steps in a different order. In addition, Figure 2 The various steps shown may include multiple sub-steps, which may be performed in various orders suitable for the various steps. In addition, additional steps may be added or deleted according to specific applications. Those of ordinary skill in the art will recognize many variations, modifications, and alternatives.

[0058] Figure 31 is a flow chart showing an example of a process for bypassing a battery cell during a bypass period according to some aspects of the present disclosure. The process begins at block 302. In block 302, the control circuit 120 determines the battery cell U in the battery cell section 104 of the battery pack 102. 单元 _n classification and capacity. The classification indicates whether the battery cell is a healthy cell or a defective or defective cell (e.g., a weak cell or a bad cell). In some examples, the controller 114 may determine the classification based on voltage data associated with the battery cell, where the voltage data is acquired by the monitoring circuit 106 during one or more charging cycles and / or discharging cycles.

[0059] In block 304, the control circuit 120 determines the battery cell U based on the classification. 单元 _n is a bad cell. If so, the process may proceed to block 306, where the control circuit 120 may determine that the bad cell should be bypassed for the remainder of the charge cycle (or, in the case of discharge, the remainder of the discharge cycle). This may involve determining that its bypass period corresponds to the remaining time of the charge cycle or discharge cycle. If the control circuit 120 determines that the bad cell U 单元 _n is not a bad cell, the process can proceed to block 308.

[0060] In block 308, the control circuit 120 determines the battery cell U based on the classification. 单元 _n is a weak cell. If it is not a weak cell, it may mean that the battery cell is a healthy cell, so the process can proceed to box 310. In box 310, the control circuit 120 determines that the battery cell should not be bypassed during the charging cycle (or the discharge cycle in the case of discharge). If the control circuit 120 determines that the battery cell is a weak cell, the process can proceed to box 312.

[0061] In block 312, the control circuit 120 controls the battery cell U based on the 单元 _n capacity determines the bypass period. For example, the control circuit 120 can determine the bypass period based on the inverse relationship between the bypass period and the capacity. In some examples, the control circuit 120 can determine the bypass period using the following formula:

[0062] Bypass period = 100-capacity

[0063] Of course, other formulas may be used in other examples to determine the appropriate bypass period for the battery cell.

[0064] In block 314, the control circuit 120 executes a bypass sequence to bypass the battery cells during the bypass period. An example of a bypass sequence will be described later in conjunction with Figure 4 Give a description.

[0065] In block 316, the control circuit 120 determines whether the bypass period has ended. For example, the control circuit 120 may detect the end of the bypass period by monitoring a clock or other time tracking device. If still in the bypass period, the control circuit 120 may wait until the bypass period ends. In block 318, if the bypass period has ended, the control circuit 120 may execute an activation sequence to activate the battery cell U (e.g., for the remainder of the charge cycle or discharge cycle). 单元 _n. An example of activation sequence will be shown later in conjunction with Figure 5 Give a description.

[0066] In some examples, there may be multiple charging cycles (e.g., operating cycles) during a charging period in which the battery pack 102 is charged. Similarly, there may be multiple discharging cycles (e.g., operating cycles) during a discharging period in which the battery pack 102 is discharged. In either case, the control circuit 120 may repeat some or all of blocks 302 to 318 for each cycle. For example, in each new charging cycle or discharging cycle, the control circuit 120 may repeat blocks 314 to 318 to selectively bypass the battery cell during the bypass period of the cycle.

[0067] It should be understood that Figure 3 The specific steps shown provide a specific method for bypassing a battery cell during a bypass period according to an embodiment of the present invention. According to other embodiments, other step sequences may also be performed. For example, other embodiments of the present invention may perform the above steps in a different order. In addition, Figure 3 The various steps shown may include multiple sub-steps, which may be performed in various orders suitable for the various steps. In addition, additional steps may be added or deleted according to specific applications. Those of ordinary skill in the art will recognize many variations, modifications, and alternatives.

[0068] Reference now Figure 4 , which is a flow chart of an example of a bypass sequence according to some aspects of the present disclosure. The bypass sequence may begin at block 402. In block 402, the control circuit 120 transmits a first opening signal to open the circuit 120 connected to the battery cell U 单元_n, the power control switch 108 associated with the battery pack 102. For example, the controller 114 can transmit a first open signal to the power control switch 108, wherein the first open signal is configured to cause the power control switch 108 to switch from a closed state to an open state. As another example, the controller 114 can transmit a control signal to the drive circuit 116, and the drive circuit 116 can be electrically coupled to the power control switch 108. The drive circuit 116 can respond to the control signal by transmitting the first open signal to the power control switch 108, thereby causing the power control switch 108 to switch from a closed state to an open state. Turning on the power control switch 108 can cause the battery pack 102 to enter an electrically floating state, so that subsequent switching operations can be safely performed.

[0069] In the case of charging, in the off state, the power control switch 108 may allow power to flow from the power source 110 to the battery pack 102. In the on state, the power control switch 108 may prevent power from flowing from the power source 110 to the battery pack 102. In the case of discharging, in the off state, the power control switch 108 may allow power to flow from the battery pack 102 to the load 112. In the on state, the power control switch 108 may prevent power from flowing from the battery pack 102 to the load 112.

[0070] In block 404, the control circuit 120 transmits a second opening signal to open the connection with the battery unit U. 单元 _nAssociated charging switch S 充电 For example, the controller 114 may transmit a second opening signal to the charging switch S 充电 Alternatively, the controller 114 may transmit a control signal to the drive circuit 116, and the drive circuit 116 may transmit a control signal to the charging switch S 充电 _n transmits a second opening signal in response to the control signal. The second opening signal is configured to enable the charging switch S 充电 _nSwitch from the closed state to the open state.

[0071] In the case of charging, in the closed state, the charging switch S 充电 _n can allow power to flow from the power source 110 to the battery unit U 单元 _n. In the open state, the charging switch S 充电 _n can prevent power from flowing from the power source 110 to the battery unit U 单元 _n. In the discharge state, in the closed state, the charging switch S 充电 _n can allow power to flow from the battery unit U 单元 _n flows to the load 112. In the open state, the charging switch S 充电 _n can prevent power from flowing out of the battery unit U 单元 _n flows to the load 112.

[0072] In block 406, the control circuit 120 transmits a first shutdown signal to shut down the battery unit U. 单元 _n Associated bypass switch S 旁路 For example, the controller 114 may provide a bypass switch S 旁路 Alternatively, the controller 114 may transmit a control signal (eg, a bypass signal) to the drive circuit 116, and the drive circuit 116 may transmit a control signal (eg, a bypass signal) to the bypass switch S 旁路 _n transmits a first shutdown signal in response to the control signal. The first shutdown signal is configured to make the bypass switch S 旁路 _n switches from the open state to the closed state. In the open state, the bypass switch S 旁路 _n allows power to flow through the battery cell portion 104. In the closed state, the bypass switch S 旁路 _n prevents electricity from flowing through the battery cell section.

[0073] In block 408, the control circuit 120 transmits a second shutdown signal to close the power control switch 108. For example, the controller 114 may transmit the second shutdown signal to the power control switch 108, wherein the second shutdown signal is configured to switch the power control switch 108 from an open state to a closed state. Alternatively, the controller 114 may transmit a control signal to the drive circuit 116, and the drive circuit 116 may respond to the control signal by transmitting the second shutdown signal to the power control switch 108.

[0074] It should be understood that Figure 4 The specific steps shown provide a specific method for performing a bypass sequence according to an embodiment of the present invention. According to other embodiments, other step sequences may also be performed. For example, other embodiments of the present invention may perform the above steps in a different order. In addition, Figure 4 The various steps shown may include multiple sub-steps, which may be performed in various orders suitable for the various steps. In addition, additional steps may be added or deleted according to specific applications. Those of ordinary skill in the art will recognize many variations, modifications, and alternatives.

[0075] Figure 5 1 is a flow chart showing an example of an activation sequence according to some aspects of the present disclosure. The activation sequence may begin at block 502. In block 502, the control circuit 120 transmits a first opening signal to open a first activation signal associated with a battery cell U. 单元 _n battery pack 102 associated with the power control switch 108. This operation can be performed using any of the above-mentioned techniques. Opening the power control switch 108 can cause the battery pack 102 to enter an electrically floating state, so that subsequent switching operations can be performed safely.

[0076] In block 504, the control circuit 120 transmits a second opening signal to open the connection with the battery unit U. 单元 _n Associated bypass switch S 旁路 For example, the controller 114 may transmit a second open signal to the bypass switch S 旁路 Alternatively, the controller 114 may transmit a control signal (eg, a bypass signal) to the driver circuit 116, and the driver circuit 116 may transmit a control signal (eg, a bypass signal) to the bypass switch S 旁路 _n transmits a second opening signal in response to the control signal. The second opening signal is configured to enable the bypass switch S 旁路 _nSwitch from the closed state to the open state.

[0077] In block 506, the control circuit 120 transmits a first shutdown signal to shut down the battery unit U. 单元 _nAssociated charging switch S 充电 For example, the controller 114 may transmit a first shutdown signal to the charging switch S 充电 Alternatively, the controller 114 may transmit a control signal to the drive circuit 116, and the drive circuit 116 may transmit a control signal to the charging switch S 充电 _n transmits a first shutdown signal in response to the control signal. The first shutdown signal is configured to enable the charging switch S 充电 _nSwitch from the open state to the closed state.

[0078] In block 508, the control circuit 120 transmits a second shutdown signal to shut down the power control switch 108. This operation may be performed using any of the techniques described above.

[0079] It should be understood that Figure 5 The specific steps shown provide a specific method for executing an activation sequence according to an embodiment of the present invention. According to other embodiments, other step sequences may also be executed. For example, other embodiments of the present invention may execute the above steps in a different order. In addition, Figure 5 The various steps shown may include multiple sub-steps, which may be performed in various orders suitable for the various steps. In addition, additional steps may be added or deleted according to specific applications. Those of ordinary skill in the art will recognize many variations, modifications, and alternatives.

[0080] Figure 6An example of a bypass period 602 and an active period 604 associated with a battery cell during a charging cycle 600 (e.g., a duty cycle) is shown according to some aspects of the present disclosure. The battery cell is bypassed during the bypass period 602 and is active (not bypassed) during the active period 604, which occupies the remainder of the charging cycle 600. This charging cycle can be repeated any number of times, such as 30 to 100 times, to help keep the bypassed cells at the same state of charge as the activated cells.

[0081] In this example, bypass period 602 begins at the beginning of charging cycle 600. However, in other examples, bypass period 602 may begin at any point in charging cycle 600, as long as there is enough time in charging cycle 600 to complete the entire bypass period 602 in charging cycle 600. For example, if the charging cycle is 5 minutes long and bypass period 602 is 1 minute long, then bypass period 602 may begin at any point in time before 4 minutes have passed in the charging cycle. Thus, active period 604 may fork in charging cycle 600 and alternate with bypass period 602.

[0082] In some examples, multiple battery packs may be connected together (e.g., for high power applications). This may require the battery management system to be specially configured to handle the switching operations described above. An example of such a configuration is Figure 7 shown and described below.

[0083] Reference now Figure 7 , a battery management system 700 that can be used to manage multiple battery packs 702a, 702b according to some aspects of the present disclosure is shown. Although this example involves two battery packs 702a, 702b for simplicity, other examples may involve n battery packs and similar principles can be applied.

[0084] In this example, battery pack 702a and battery pack 702b are electrically connected in parallel with each other. Each battery pack can have its own control circuit. For example, the first battery pack 702a can be electrically connected to the first control circuit 704a, and the first control circuit 704a can include some or all components of the control circuit discussed above. The second battery pack 702b can also be electrically connected to the second control circuit 704b, and the second control circuit 704b can include some or all components of the above-mentioned control circuit. One or both of the control circuit 704a and the control circuit 704b can be electrically connected to one or more power control switches 108, and the one or more power control switches 108 can control power to flow from the power supply 110 to the battery pack 702a and the battery pack 702b or flow from the battery pack 702a and the battery pack 702b to the load 112.

[0085] Each of the battery pack 702a and the battery pack 702b may have a corresponding battery cell 708a and a battery cell 708b, which may be monitored by the corresponding control circuit 704a and the control circuit 704b and bypassed using the above-mentioned techniques. In order to bypass one or more battery cells of one or more of the battery packs 702a and 702b, in some examples, the control circuit 704a and the control circuit 704b (e.g., their controllers) may communicate with each other to synchronize their switch operations. For example, the first control circuit 704a may determine that the first battery cell in the first battery pack 702a will be bypassed during the first bypass period. And, the second control circuit 704b may determine that the second battery cell in the second battery pack 702b will be bypassed during the second bypass period, which may be the same or different from the first bypass period. In response to determining that the first battery cell in the first battery group 702a is to be bypassed during the first bypass period, the first control circuit 704a may transmit a bypass notification 706 to the second control circuit 704b via a wired or wireless connection 710. The bypass notification 706 may indicate one or more bypass parameters, such as a start time, an end time, and a length of the first bypass period. The second control circuit 704b may additionally or alternatively transmit a similar bypass notification to the first control circuit 704a, the similar bypass notification indicating one or more bypass parameters, such as a start time, an end time, and a length of the second bypass period.

[0086] Based on one or both of the above communications, the control circuit 704a and the control circuit 704b can synchronize their bypass sequences so that the first bypass sequence performed by the first control circuit 704a overlaps at least partially with the second bypass sequence performed by the second control circuit 704b. For example, the control circuit 704a and the control circuit 704b can coordinate their bypass sequences so that the power control switch 108 only operates (e.g., opens and closes) once for the two bypass sequences. Additionally or alternatively, the control circuit 704a and the control circuit 704b can also synchronize their activation sequences so that the first activation sequence performed by the first control circuit 704a overlaps at least partially with the second activation sequence performed by the second control circuit 704b. For example, the control circuit 704a and the control circuit 704b can coordinate their activation sequences so that the power control switch 108 only operates once for the two activation sequences. This can reduce the number of operations of the power control switch 108, thereby increasing speed and preventing conflicting operations of the power control switch 108.

[0087] As a specific example, the first control circuit 704a may determine that the first battery cell in the first battery group 702a is to be bypassed within a bypass period of 10ns based on the first capacity of the first battery cell. The second control circuit 704b may determine that the second battery cell in the second battery group 702b is to be bypassed within a bypass period of 8ns based on the second capacity of the second battery cell. The first control circuit 704a may transmit a bypass notification 706 to the second control circuit 704b indicating a bypass period of 10ns. The first control circuit 704a may then initiate a first bypass sequence to implement a bypass period of 10ns (e.g., in response to receiving a confirmation communication from the second control circuit 704b). The second control circuit 704b may receive the bypass notification 706 and determine that it will be subordinate to the first control circuit 704a in the bypass process based on one or more factors (e.g., the second bypass period is less than the first bypass period). Therefore, the second control circuit 704b can allow the first control circuit 704a to operate the power control switch 108 to implement the first bypass sequence, during which the second control circuit 704b can also perform the second bypass sequence (e.g., not attempt to operate the power control switch 108, so that the control circuit 704a and the control circuit 704b do not attempt to operate the power control switch 108 at the same time). In this way, the control circuit 704a and the control circuit 704b can synchronize their bypass sequences.

[0088] In order to synchronize their activation sequence, in some examples, the second control circuit 704b can cover the second bypass period with the first bypass period, so that the two bypass periods are the same. For example, the second control circuit 704b can determine that the bypass period of 8ns of the second battery cell is shorter than the bypass period of 10ns of the first battery cell. Based on the fact that the second bypass period is shorter than the first bypass period, the second control circuit 704b can cover the bypass period of 8ns with the bypass period of 10ns, so that the two bypass periods are the same. Therefore, the first bypass period and the second bypass period should end at approximately the same time. When the first control circuit 704a determines that the first bypass period ends, the first control circuit 704a can operate the power control switch 108 to implement the first activation sequence. Within the same time range, the second control circuit 704b can also execute the second activation sequence (for example, without attempting to operate the power control switch 108). In this way, the control circuit 704a and the control circuit 704b can synchronize their activation sequences.

[0089] The above example involves bypassing two battery cells in battery pack 702a and battery pack 702b, and for the purpose of illustration, the example is relatively simple. However, it is understood that any number of battery cells with the same or different capacities in one or both of battery pack 702a and battery pack 702b can be selectively bypassed for the same bypass period or different bypass periods. Control circuit 704a and control circuit 704b can communicate with each other bidirectionally via wired or wireless connection 710 to coordinate (e.g., synchronize) bypass parameters of the bypass period, thereby preventing conflicting operations of one or more power control switches 108 or other problems.

[0090] Figure 8 A flowchart illustrating an example of a process for synchronizing a bypass sequence between multiple battery packs according to some aspects of the present disclosure. Other examples may include: Figure 8 More operations, fewer operations, different operations, or a different order of operations as shown. Figure 7 For simplicity, the operations are described as being performed by the control circuit 704a and the control circuit 704b. However, it should be understood that this means that the operations can be performed by one or more components of the control circuit 704a and the control circuit 704b.

[0091] In block 802, a first control circuit 704a associated with a first battery pack 702a determines that a first battery cell of the first battery pack 702a is to be bypassed for a first bypass period. The first control circuit 704a may be electrically coupled to the first battery pack 702a to manage charging and discharging of the first battery pack 702. The first control circuit 704a may make this determination using any of the techniques described above.

[0092] In block 804, the first control circuit 704a transmits a bypass notification 706 to a second control circuit 704b associated with the second battery pack 702b. The second control circuit 704b may be electrically coupled to the second battery pack 702b to manage the charging and discharging of the second battery pack 702b. The bypass notification 706 may include one or more bypass parameters associated with the first bypass period. For example, the bypass notification 706 may include a start time and a length associated with the first bypass period. The first control circuit 704a may transmit the bypass notification 706 to the second control circuit 704b via an electrical connection (e.g., a bus).

[0093] In block 806, the first control circuit 704a executes a first bypass sequence to bypass the first battery cell during a first bypass period. An example of a first bypass sequence may be as described above with respect to Figure 4 The process described.

[0094] In block 808, the second control circuit 704b receives the bypass notification 706 from the first control circuit 704. The second control circuit 704b may extract from the bypass notification 706 the bypass parameters associated with the first bypass order.

[0095] In block 810, the second control circuit 704b determines that the second battery cell of the second battery pack 702b is to be bypassed for a second bypass period, which may be the same as or different from the first bypass period. The second control circuit 704b may make this determination using any of the techniques described above.

[0096] In block 812, the second control circuit 704b synchronizes execution of a second bypass sequence with execution of the first bypass sequence, wherein the second bypass sequence is configured to bypass the second battery cell during a second bypass period. This may involve synchronizing a first set of bypass parameters associated with the first bypass period and a second set of bypass parameters associated with the second bypass period. For example, the second control circuit 704b may adjust (e.g., override) at least one bypass parameter in the second set of bypass parameters based on at least one bypass parameter in the first set of bypass parameters. Such an adjustment may cause at least a portion of the second bypass sequence to overlap (in time) with the first bypass sequence.

[0097] In block 814, the second control circuit 704b synchronizes execution of a second activation sequence with execution of a first activation sequence, wherein the second activation sequence is configured to activate the second battery cell after the second bypass period, and wherein the first activation sequence is configured to activate the first battery cell after the first bypass period. For example, the second control circuit 704b may adjust at least one bypass parameter in the second set of bypass parameters based on at least one bypass parameter in the first set of bypass parameters. Such adjustment may cause at least a portion of the second activation sequence to overlap (in time) with the first activation sequence.

[0098] It should be understood that Figure 8 The specific steps shown provide a specific method for synchronizing the bypass sequence between multiple battery packs according to an embodiment of the present invention. According to other embodiments, other step sequences may also be performed. For example, other embodiments of the present invention may perform the above steps in a different order. In addition, Figure 8 The various steps shown may include multiple sub-steps, which may be performed in various orders suitable for the various steps. In addition, additional steps may be added or deleted according to specific applications. Those of ordinary skill in the art will recognize many variations, modifications, and alternatives.

[0099] As previously described, control circuit 704a and control circuit 704b may each include a controller and other computing devices. Fig. 9, a block diagram of an example of a computing device 900 that can be used to implement some aspects of the present disclosure is shown. In some examples, the computing device 900 may correspond to Figure 1 Controller 114 in.

[0100] The computing device 900 includes a processor 902 that communicates with a memory 904 and other components of the computing device 900 using one or more communication buses 906. The processor 902 is hardware that may include one processing device or multiple processing devices. Examples of the processor 902 may include a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), or a microprocessor. The processor 902 is configured to execute processor executable instructions 914 stored in the memory 904 to perform one or more processes described herein. The instructions 914 may include processor-specific instructions generated by a compiler or interpreter from a code written in any suitable computer programming language (such as C, C++, C#, Java, or Python).

[0101] Memory 904 is hardware that may include one storage device or multiple storage devices. Memory 904 may be volatile or non-volatile (it may retain stored information when power is turned off). Examples of memory 904 include electrically erasable and programmable read-only memory (EEPROM), flash memory, or cache memory. At least some of memory 904 includes non-transitory computer-readable media from which processor 902 can read instructions 914. Computer-readable media may include electronic, optical, magnetic, or other storage devices that can provide instructions 914 or other program code to processor 902. Examples of computer-readable media include disks, memory chips, ROM, random access memory (RAM), ASICs, configured processors, and optical storage.

[0102] The computing device 900 may include one or more user input devices 908 (eg, keyboard, mouse, touch screen, video capture device, microphone, etc.) to accept user input. The computing device 900 also includes a display 910 to provide visual output to the user.

[0103] The computing device 900 may also include a communication interface 912. In some examples, the communication interface 912 may use one or more networks (including a local area network ("LAN"); a wide area network ("WAN"), such as the Internet; a metropolitan area network ("MAN"); a point-to-point or end-to-end connection, etc.) to achieve communication. Any suitable network protocol may be used to achieve communication with other devices. For example, a suitable network protocol may include the Internet Protocol ("IP"), the Transmission Control Protocol ("TCP"), the User Datagram Protocol ("UDP"), or a combination thereof, such as TCP / IP or UDP / IP.

[0104] Various examples of the present disclosure are provided below. As described below, any reference to a series of examples should be understood as a separate reference to each of these examples (e.g., "Examples 1 to 4" should be understood as "Example 1, Example 2, Example 3, or Example 4").

[0105] Example 1 is a system comprising: a battery pack and a control circuit, wherein the battery pack has a battery cell section connected in series, wherein each of the battery cell sections comprises: a battery cell and a bypass switch, wherein the bypass switch is positioned in parallel with the battery cell, wherein the bypass switch is operable to short-circuit both ends of the battery cell section; the control circuit is configured to: determine the capacity of a specific battery cell of a specific battery cell section in the battery cell section; determine whether the capacity of the specific battery cell is less than a predefined threshold; and in response to determining that the capacity of the specific battery cell is less than the predefined threshold, execute a bypass sequence for the specific battery cell, wherein the bypass sequence involves: determining a bypass period for bypassing the specific battery cell based on the capacity of the specific battery cell; and transmitting a bypass signal to a drive circuit, wherein the drive circuit is configured to receive the bypass signal and responsively operate the bypass switch of the specific battery cell section to bypass the specific battery cell during the bypass period.

[0106] Example 2 is a system according to Example 1, which also includes: a power control switch connected between the battery pack and the power supply, for controlling the current flowing from the power supply to the battery pack, wherein the bypass sequence also includes: before transmitting the bypass signal, transmitting an open signal for opening the power control switch to prevent current from flowing from the power supply to the battery pack during the remainder of the bypass sequence.

[0107] Example 3 is a system according to Examples 1 to 2, wherein the open signal is a first open signal, and wherein the bypass sequence includes: after transmitting the first open signal, transmitting a second open signal for opening a charging switch of the specific battery cell portion to prevent current from flowing through the specific battery cell, the charging switch being positioned in series with the specific battery cell; after transmitting the second open signal, transmitting the bypass signal; and after transmitting the bypass signal, completing the bypass sequence by transmitting a close signal to close the power control switch to allow current to flow from the power source to the battery pack.

[0108] Example 4 is the system of Examples 1 to 3, wherein the bypass period is part of a duty cycle for charging the battery pack.

[0109] Example 5 is a system according to Examples 1 to 4, wherein the control circuit is further configured to: determine that the bypass period of the specific battery cell has ended; and in response to determining that the bypass period of the specific battery cell has ended, execute an activation sequence of the specific battery cell, wherein the activation sequence is configured to allow current to flow to the specific battery cell.

[0110] Example 6 is a system according to Examples 1 to 5, wherein the activation sequence includes: transmitting a first turn-on signal for turning on a power control switch to prevent current from flowing from a power source to the battery pack during the remainder of the activation sequence; after transmitting the first turn-on signal, transmitting a second turn-on signal for turning on the bypass switch to prevent current from bypassing the specific battery cell; after transmitting the second turn-on signal, transmitting a first turn-off signal for turning off a charging switch of the specific battery cell portion to allow current to flow through the specific battery cell, the charging switch being positioned in series with the specific battery cell; and after transmitting the first turn-off signal, completing the activation sequence by transmitting a second turn-off signal to turn off the power control switch to allow current to flow from the power source to the battery pack.

[0111] Example 7 is a system according to Examples 1 to 6, which also includes a starting relay configured to draw power from one or more battery cells in the battery pack to activate a boost circuit; the boost circuit configured to generate a drive voltage greater than an input voltage of the boost circuit; and the drive circuit configured to apply the drive voltage generated by the boost circuit to the bypass switch of the specific battery cell to close the bypass switch.

[0112] Example 8 is a system according to Examples 1 to 7, which also includes a monitoring circuit, which is configured to measure the voltage across the specific battery cell and transmit a measurement signal indicative of the voltage to the control circuit, wherein the control circuit is configured to determine the capacity of the specific battery cell based on the voltage.

[0113] Example 9 is a system according to Examples 1 to 8, wherein the control circuit is configured to: store a voltage or a charging state associated with the specific battery cell portion during multiple charging cycles; and determine the bypass period based on the stored voltage or the charging state.

[0114] Example 10 is a method, comprising: determining the capacity of a specific battery cell in a specific battery cell portion of a battery pack through a control circuit; wherein the specific battery cell portion includes a bypass switch; determining through the control circuit whether the capacity of the specific battery cell is less than a predefined threshold; and in response to determining that the capacity of the specific battery cell is less than the predefined threshold, executing a bypass sequence of the specific battery cell through the control circuit, wherein the bypass sequence involves: determining a bypass period for bypassing the specific battery cell based on the capacity of the specific battery cell; and transmitting a bypass signal to a drive circuit, the drive circuit being configured to receive the bypass signal and responsively close the bypass switch of the specific battery cell portion to bypass the specific battery cell during the bypass period.

[0115] Example 11 is a method according to Example 10, wherein the bypass sequence further includes: before transmitting the bypass signal, transmitting an open signal for turning on a power control switch to prevent current from flowing from the power source to the battery pack during the remainder of the bypass sequence, and the power control switch is connected between the battery pack and the power source.

[0116] Example 12 is a method according to Examples 10 to 11, wherein the open signal is a first open signal, and wherein the bypass sequence includes: after transmitting the first open signal, transmitting a second open signal for opening the charging switch of the specific battery cell portion to prevent current from flowing through the specific battery cell, the charging switch being positioned in series with the specific battery cell; after transmitting the second open signal, transmitting the bypass signal; and after transmitting the bypass signal, completing the bypass sequence by transmitting a close signal to close the power control switch to allow current to flow from the power source to the battery pack.

[0117] Example 13 is the method of Examples 10 to 12, wherein the bypass period is part of a duty cycle for charging the battery pack.

[0118] Example 14 is a method according to Examples 10 to 13, which also includes determining that the bypass period of the specific battery cell has ended; and in response to determining that the bypass period of the specific battery cell has ended, executing an activation sequence of the specific battery cell, wherein the activation sequence is configured to allow current to flow to the specific battery cell.

[0119] Example 15 is a method according to Examples 10 to 14, wherein the activation sequence includes: transmitting a first turn-on signal to turn on a power control switch to prevent current from flowing from the power source to the battery pack during the remainder of the activation sequence; after transmitting the first turn-on signal, transmitting a second turn-on signal to turn on the bypass switch to prevent current from bypassing the specific battery cell; after transmitting the second turn-on signal, transmitting a first turn-off signal to turn off a charging switch of the specific battery cell portion to allow current to flow through the specific battery cell; and after transmitting the first turn-off signal, completing the activation sequence by transmitting a second turn-off signal to turn off the power control switch to allow current to flow from the power source to the battery pack.

[0120] Example 16 is a method according to Examples 10 to 15, which also includes, during the startup phase of the battery pack, operating a starting relay to draw power from one or more battery cells of the battery pack to activate a boost circuit; operating the boost circuit to generate a drive voltage greater than an input voltage of the boost circuit; and operating the drive circuit to apply the drive voltage generated by the boost circuit to the bypass switch of the specific battery cell, thereby closing the bypass switch.

[0121] Example 17 is a method according to Examples 10 to 16, which also includes measuring the voltage across the specific battery cell; and transmitting a measurement signal indicating the voltage to the control circuit, wherein the control circuit is configured to determine the capacity of the specific battery cell based on the voltage.

[0122] Example 18 is a method according to Examples 10 to 17, which also includes storing a voltage or a charge state associated with the specific battery cell during multiple charging cycles; and determining the bypass period based on the stored voltage or the charge state.

[0123] Example 19 is a method, comprising: determining, through a first control circuit associated with a first battery pack, that a battery cell of the first battery pack will be bypassed within a bypass period based on the capacity of the battery cell; and in response to determining that the battery cell will be bypassed within the bypass period: executing a first bypass sequence through the first control circuit, the first bypass sequence being configured to bypass the battery cell within the bypass period; and transmitting a bypass notification to a second control circuit associated with a second battery pack through the first control circuit, wherein the second control circuit is configured to: receive the bypass notification; and in response to receiving the bypass notification, synchronizing a second bypass sequence with the first bypass sequence, the second bypass sequence being configured to bypass another battery cell in the second battery pack.

[0124] Example 20 is the method according to Example 19, wherein the bypass notification indicates the bypass period, and wherein the second bypass order is configured to bypass the other battery unit within the bypass period based on the bypass notification.

[0125] Although examples and features of the disclosed principles are described herein, they may be modified, adapted, and otherwise implemented without departing from the spirit and scope of the disclosed embodiments. In addition, the words "including," "having," "containing," and "comprising," and other similar forms are intended to represent equivalent meanings and are open-ended, i.e., one or more items following any of these words are not intended to be an exhaustive enumeration of the one or more items, nor are they intended to be limited to the one or more items listed. It must also be noted that the singular forms "a," "an," and "the" used herein include the plural forms unless the context clearly dictates otherwise.

[0126] It should also be understood that the examples and embodiments described herein are for illustrative purposes only, and that those skilled in the art may make various modifications or changes based on these examples and embodiments, and these modifications or changes should be included in the spirit and scope of this application and the scope of the appended claims.

Claims

1. A system comprising: A battery pack having battery cell sections connected in series, wherein each of said battery cell sections comprises: battery cells; and a bypass switch positioned in parallel with the battery cell, wherein the bypass switch is operable to short-circuit both ends of the battery cell section; and A control circuit configured to: determining a capacity of a specific battery cell of a specific battery cell section in the battery cell section; determining whether the capacity of the particular battery cell is less than a predefined threshold; and In response to determining that the capacity of the particular battery cell is less than the predefined threshold, performing a bypass sequence for the particular battery cell, wherein the bypass sequence involves: determining a bypass period for bypassing the specific battery cell based on the capacity of the specific battery cell; and A bypass signal is transmitted to a drive circuit, the drive circuit being configured to receive the bypass signal and responsively operate the bypass switch of the specific battery cell portion to bypass the specific battery cell during the bypass period.

2. The system according to claim 1, further comprising a power control switch, the power control switch being coupled between the battery pack and a power source for controlling a current flowing from the power source to the battery pack, wherein the bypass sequence further comprises: Prior to transmitting the bypass signal, an open signal is transmitted for opening the power control switch to prevent current from flowing from the power source to the battery pack during a remainder of the bypass sequence.

3. The system of claim 2, wherein the open signal is a first open signal, and wherein the bypass sequence comprises: After transmitting the first opening signal, transmitting a second opening signal for opening a charging switch of the specific battery cell portion to prevent current from flowing through the specific battery cell, the charging switch being positioned in series with the specific battery cell; After transmitting the second opening signal, transmitting the bypass signal; as well as After transmitting the bypass signal, the bypass sequence is completed by transmitting a shutdown signal to close the power control switch to allow current to flow from the power source to the battery pack.

4. The system of claim 1, wherein the bypass period is part of a duty cycle for charging the battery pack.

5. The system of claim 1 , wherein the control circuit is further configured to: determining that the bypass period for the particular battery cell has ended; and In response to determining that the bypass period of the particular battery cell has ended, an activation sequence of the particular battery cell is performed, the activation sequence configured to allow current to flow to the particular battery cell.

6. The system of claim 5, wherein the activation sequence comprises: transmitting a first opening signal for opening a power control switch to prevent current from flowing from a power source to the battery pack during a remainder of the activation sequence; After transmitting the first opening signal, transmitting a second opening signal for opening the bypass switch to prevent current from bypassing the specific battery cell; After transmitting the second opening signal, transmitting a first closing signal for closing a charging switch of the specific battery cell portion to allow current to flow through the specific battery cell, the charging switch being positioned in series with the specific battery cell; as well as After transmitting the first shutdown signal, the activation sequence is completed by transmitting a second shutdown signal to close the power control switch to allow current to flow from the power source to the battery pack.

7. The system of claim 1, further comprising: a starter relay configured to draw power from one or more battery cells in the battery pack to activate a boost circuit; The boost circuit is configured to generate a driving voltage greater than an input voltage of the boost circuit; as well as The driving circuit is configured to apply the driving voltage generated by the boosting circuit to the bypass switch of the specific battery cell to close the bypass switch.

8. The system according to claim 1 further includes a monitoring circuit, which is configured to measure the voltage across the specific battery cell and transmit a measurement signal indicative of the voltage to the control circuit, wherein the control circuit is configured to determine the capacity of the specific battery cell based on the voltage.

9. The system of claim 1, wherein the control circuit is configured to: storing a voltage or state of charge associated with the particular battery cell portion over a plurality of charging cycles; and The bypass period is determined based on the stored voltage or the state of charge.

10. A method comprising: determining, by the control circuit, a capacity of a specific battery cell in a specific battery cell section of the battery pack; wherein the particular battery cell portion includes a bypass switch; determining, by the control circuit, whether the capacity of the specific battery cell is less than a predefined threshold; as well as In response to determining that the capacity of the specific battery cell is less than the predefined threshold, executing, by the control circuit, a bypass sequence for the specific battery cell, wherein the bypass sequence involves: determining a bypass period for bypassing the specific battery cell based on the capacity of the specific battery cell; as well as A bypass signal is transmitted to a drive circuit, the drive circuit being configured to receive the bypass signal and responsively close the bypass switch of the specific battery cell section to bypass the specific battery cell during the bypass period.

11. The method of claim 10, wherein the bypass sequence further comprises: Prior to transmitting the bypass signal, an open signal is transmitted for opening a power control switch coupled between the battery pack and the power source to prevent current from flowing from the power source to the battery pack during a remainder of the bypass sequence.

12. The method of claim 11, wherein the turn-on signal is a first turn-on signal, and wherein the bypass sequence comprises: After transmitting the first opening signal, transmitting a second opening signal for opening a charging switch of the specific battery cell portion to prevent current from flowing through the specific battery cell, the charging switch being positioned in series with the specific battery cell; After transmitting the second opening signal, transmitting the bypass signal; as well as After transmitting the bypass signal, the bypass sequence is completed by transmitting a shutdown signal to close the power control switch to allow current to flow from the power source to the battery pack.

13. The method of claim 10, wherein the bypass period is part of a duty cycle for charging the battery pack.

14. The method according to claim 10, further comprising: determining that the bypass period of the particular battery cell has ended; as well as In response to determining that the bypass period of the particular battery cell has ended, an activation sequence of the particular battery cell is performed, the activation sequence configured to allow current to flow to the particular battery cell.

15. The method of claim 14, wherein the activation sequence comprises: transmitting a first opening signal for opening a power control switch to prevent current from flowing from a power source to the battery pack during a remainder of the activation sequence; After transmitting the first opening signal, transmitting a second opening signal for opening the bypass switch to prevent current from bypassing the specific battery cell; After transmitting the second opening signal, transmitting a first closing signal for closing the charging switch of the specific battery cell portion to allow current to flow through the specific battery cell; as well as After transmitting the first shutdown signal, the activation sequence is completed by transmitting a second shutdown signal to close the power control switch to allow current to flow from the power source to the battery pack.

16. The method according to claim 10, further comprising: During a startup phase of the battery pack, operating a starter relay to draw power from one or more battery cells of the battery pack to activate a boost circuit; operating the boost circuit to generate a drive voltage greater than an input voltage of the boost circuit; as well as The driving circuit is operated to apply the driving voltage generated by the boosting circuit to the bypass switch of the specific battery cell, thereby closing the bypass switch.

17. The method according to claim 10, further comprising: measuring a voltage across the specific battery cell; as well as A measurement signal indicative of the voltage is transmitted to the control circuit, wherein the control circuit is configured to determine the capacity of the particular battery cell based on the voltage.

18. The method according to claim 10, further comprising: storing a voltage or state of charge associated with the particular battery cell over a plurality of charging cycles; as well as The bypass period is determined based on the stored voltage or the state of charge.

19. A method comprising: determining, by a first control circuit associated with a first battery pack, based on the capacity of a battery cell of the first battery pack, that the battery cell is to be bypassed during a bypass period; as well as In response to determining that the battery cell is to be bypassed during the bypass period: executing a first bypass sequence by the first control circuit, the first bypass sequence being configured to bypass the battery cell during the bypass period; as well as transmitting, by the first control circuit, a bypass notification to a second control circuit associated with a second battery pack, wherein the second control circuit is configured to: receiving the bypass notification; as well as In response to receiving the bypass notification, a second bypass sequence is synchronized with the first bypass sequence, the second bypass sequence being configured to bypass another battery cell in the second battery group. 20 . The method of claim 19 , wherein the bypass notification indicates the bypass period, and wherein the second bypass order is configured to bypass the another battery unit within the bypass period based on the bypass notification.

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