Battery imbalance diagnosis and mitigation

Abstract

Techniques for battery imbalance diagnosis and mitigation are provided. In one embodiment, the technique involves isolating, via a first isolation unit, a first battery cell from a plurality of battery cells, determining, via a complex impedance measurement unit, a state of health of the first battery cell, and controlling, via a controller, the first battery cell based on the state of health of the first battery cell.

Description

Technical Field

[0001] The subject disclosure relates to battery cells, and more particularly, to using impedance estimation to detect unbalanced degradation of individual battery cells in a battery pack or group of battery cells. Background Art

[0002] Conventional battery packs typically include individual battery cells that degrade at different rates. Although some individual battery cells degrade, the battery pack can supply energy to the load. However, using a battery pack including degraded battery cells may reduce performance and reliability and cause damage to the battery pack. Summary of the invention

[0003] In one exemplary embodiment, a method for diagnosing and mitigating battery imbalance is provided. The method includes isolating a first battery cell from a plurality of battery cells via a first isolation unit, determining a state of health of the first battery cell via a complex impedance measurement unit, and controlling the first battery cell based on the state of health of the first battery cell via a controller.

[0004] In addition to one or more features described herein, the first isolation unit includes a first connection point connected to the first end of the switch and a second connection point connected to the second end of the switch.

[0005] In addition to one or more features described herein, the method also includes isolating the second battery cell from the plurality of battery cells via a second isolation unit, determining a state of health of the second battery cell via a complex impedance measurement unit, and determining via a controller that a difference between the state of health of the first battery cell and the state of health of the second battery cell exceeds a state of health threshold, the difference indicating that a remaining useful life of the first battery cell is less than a remaining useful life of the second battery cell, and controlling the first battery cell by disconnecting the first battery cell from the plurality of battery cells via the first isolation unit.

[0006] In addition to one or more features described herein, the first isolation unit includes a first connection point connected to a first end of the switch, a second end of the switch connected to a first electrical path, a third end of the switch connected to a second electrical path; and a second connection point connected to the first electrical path and the second electrical path, the second electrical path including a resistor or an RC filter.

[0007] In addition to one or more features described herein, the method also includes determining, via the controller, a target frequency range for the frequency response, determining, via the complex impedance measurement unit, a frequency response across the target frequency range, determining, via the controller, a state of health of a first battery cell based on the frequency response, and determining, via the controller, that a difference between the state of health of the first battery cell and a state of health estimation map exceeds a battery imbalance threshold, wherein the first battery cell is controlled based on the state of health of the first battery cell.

[0008] In addition to one or more features described herein, the complex impedance measurement unit represents a device configured to apply an input AC signal to a first battery cell, measure an output AC signal of the first battery cell, and determine a real impedance value and an imaginary impedance value based on the input AC signal and the output AC signal.

[0009] In addition to one or more of the features described herein, the state of health of the first battery cell is a graph or profile representing the remaining useful life of the first battery cell relative to at least one metric, the remaining useful life of the first battery cell comprising at least one of an internal impedance value, a number of expected remaining life cycles, or a percentage of remaining charge, and the at least one metric comprising time, cycle count, temperature range, voltage or current usage, or capacity range of the first battery cell.

[0010] In another exemplary embodiment, a vehicle power control system is provided to diagnose and mitigate battery imbalance. The system includes a plurality of battery cells, a first isolation unit, a complex impedance measurement unit, a processor, and a memory or storage device including an algorithm or computer instructions that, when executed by the processor, performs operations including isolating a first battery cell from a plurality of battery cells via the first isolation unit, determining a health state of the first battery cell via the complex impedance measurement unit, and controlling the first battery cell via the processor based on the health state of the first battery cell.

[0011] In addition to one or more features described herein, the first isolation unit includes a first connection point connected to the first end of the switch and a second connection point connected to the second end of the switch.

[0012] In addition to one or more features described herein, the operations also include isolating the second battery cell from the plurality of battery cells via a second isolation unit, determining a state of health of the second battery cell via a complex impedance measurement unit, and determining via a controller that a difference between the state of health of the first battery cell and the state of health of the second battery cell exceeds a state of health threshold, the difference indicating that a remaining useful life of the first battery cell is less than a remaining useful life of the second battery cell, and controlling the first battery cell by disconnecting the first battery cell from the plurality of battery cells via the first isolation unit.

[0013] In addition to one or more features described herein, the first isolation unit includes a first connection point connected to a first end of the switch, a second end of the switch connected to a first electrical path, a third end of the switch connected to a second electrical path; and a second connection point connected to the first electrical path and the second electrical path, the second electrical path including a resistor or an RC filter.

[0014] In addition to one or more features described herein, the operations also include determining, via a controller, a target frequency range for a frequency response, determining, via a complex impedance measurement unit, a frequency response across the target frequency range, determining, via the controller, a state of health of a first battery cell based on the frequency response, and determining, via the controller, that a difference between the state of health of the first battery cell and a state of health estimation map exceeds a battery imbalance threshold, wherein the first battery cell is controlled based on the state of health of the first battery cell.

[0015] In addition to one or more features described herein, the complex impedance measurement unit represents a device configured to apply an input AC signal to a first battery cell, measure an output AC signal of the first battery cell, and determine a real impedance value and an imaginary impedance value based on the input AC signal and the output AC signal.

[0016] In addition to one or more of the features described herein, the state of health of the first battery cell is a graph or distribution representing the remaining useful life of the first battery cell relative to at least one metric, the remaining useful life of the first battery cell comprising at least one of an internal impedance value, a number of expected remaining life cycles, or a percentage of remaining charge, and the at least one metric comprising time, cycle count, temperature range, voltage or current usage, or capacity range of the first battery cell.

[0017] In yet another exemplary embodiment, a computer readable storage medium having computer readable program code implemented therewith is provided to diagnose and mitigate battery imbalance. The computer readable program code is executable by one or more computer processors to perform operations including isolating a first battery cell from a plurality of battery cells via a first isolation unit, determining a health state of the first battery cell via a complex impedance measurement unit, and controlling the first battery cell based on the health state of the first battery cell via a controller.

[0018] In addition to one or more features described herein, the first isolation unit includes a first connection point connected to the first end of the switch and a second connection point connected to the second end of the switch.

[0019] In addition to one or more features described herein, the operations also include isolating the second battery cell from the plurality of battery cells via a second isolation unit, determining a state of health of the second battery cell via a complex impedance measurement unit, and determining via a controller that a difference between the state of health of the first battery cell and the state of health of the second battery cell exceeds a state of health threshold, the difference indicating that a remaining useful life of the first battery cell is less than a remaining useful life of the second battery cell, and controlling the first battery cell by disconnecting the first battery cell from the plurality of battery cells via the first isolation unit.

[0020] In addition to one or more features described herein, the first isolation unit includes a first connection point connected to a first end of the switch, a second end of the switch connected to a first electrical path, a third end of the switch connected to a second electrical path; and a second connection point connected to the first electrical path and the second electrical path, the second electrical path including a resistor or an RC filter.

[0021] In addition to one or more features described herein, the operations also include determining, via a controller, a target frequency range for a frequency response, determining, via a complex impedance measurement unit, a frequency response across the target frequency range, determining, via the controller, a state of health of a first battery cell based on the frequency response, and determining, via the controller, that a difference between the state of health of the first battery cell and a state of health estimation map exceeds a battery imbalance threshold, wherein the first battery cell is controlled based on the state of health of the first battery cell.

[0022] In addition to one or more of the features described herein, the state of health of the first battery cell is a graph or distribution representing the remaining useful life of the first battery cell relative to at least one metric, the remaining useful life of the first battery cell comprising at least one of an internal impedance value, a number of expected remaining life cycles, or a percentage of remaining charge, and the at least one metric comprising time, cycle count, temperature range, voltage or current usage, or capacity range of the first battery cell.

[0023] The above features and advantages and other features and advantages of the present disclosure are apparent from the following detailed description when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Other features, advantages and details appear, by way of example only, in the following detailed description, which refers to the accompanying drawings, in which:

[0025] Figure 1 shows a battery control environment according to one embodiment;

[0026] Figure 2 shows a computing environment according to one embodiment;

[0027] Figures 3A-3CAn isolation unit according to one or more embodiments is shown;

[0028] Figure 4 A flow chart showing a method for diagnosing and mitigating battery imbalance according to one embodiment;

[0029] Figure 5 A flow chart showing a method of diagnosing and mitigating battery imbalance according to another embodiment; and

[0030] Figure 6 A flow chart of a method for diagnosing and mitigating battery imbalance according to yet another embodiment is shown. DETAILED DESCRIPTION

[0031] The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application or use. It should be understood that throughout the drawings, corresponding reference numerals represent identical or corresponding components and features. As used herein, the term "unit" refers to a circuit, which may include an application specific integrated circuit (ASIC), an electronic circuit, a (shared, dedicated or group) processor and memory that executes one or more software or firmware programs, a combinational logic circuit, and / or other suitable components that provide the described functionality.

[0032] Embodiments of the present disclosure improve battery cell diagnostic and mitigation systems by providing a battery imbalance mitigation module that is configured to isolate, diagnose, and control battery cells (e.g., individual battery cells connected in series or in parallel) in a battery pack or battery cell group. The battery imbalance mitigation module can isolate each battery cell in a battery pack or battery cell group via an isolation unit associated with the corresponding battery cell. In addition, the battery imbalance mitigation module can diagnose each battery cell based on the frequency response of the corresponding battery cell to the complex impedance measurement battery cell. In addition, the battery imbalance mitigation module can control the isolation unit to mitigate the effects of using a battery pack or battery cell group including battery cells with battery imbalance (e.g., battery degradation due to aging).

[0033] One benefit of the disclosed embodiments is to reduce performance issues using a battery pack or battery cell group that includes degraded battery cells by controlling or disabling the use of degraded battery cells. In addition, the disclosed embodiments can improve the performance, reliability, and life of a battery pack or battery cell group by correcting imbalances in the battery cells of the battery pack or battery cell group.

[0034] Figure 1 A battery control environment 100 is shown according to one embodiment. In the illustrated embodiment, the battery control environment 100 includes a circuit configuration 102 (which includes an isolation unit 104 1-N , battery unit 106 1-Nand power supply 110) and controller 101.

[0035] In one embodiment, the isolation unit 104 1-N Indicates that the battery cell 106 can be operated to 1-N A circuit configuration that is connected and disconnected from the circuit configuration 102. Isolation unit 104 1-N Each of the isolation units 104 may include at least two input or output connection points to the circuit configuration 102. 1-N Connection points to the controller 101 and ground 103 may also be included.

[0036] In the illustrated embodiment, each battery cell 106 1-N The power supply 110 is connected to the ground 103 and is connected to each of the isolation units 104. 1-N A second connection point (eg, connection point 111 ) is connected to the controller 101 .

[0037] In one embodiment, the controller 101 is configured to operate the isolation unit 104 1-N Circuit components to isolate and diagnose battery cells 106 1-N .exist Figure 2 Controller 101 is further discussed in .

[0038] The controller 101 can be based on the isolation unit 104 1-N The isolation unit 104 is configured to select isolation and diagnostic techniques. 1-N An example of a circuit configuration is shown in Figures 3A-3C Isolation and diagnostic techniques are described in Figure 4-6 middle.

[0039] Figure 2 FIG. 2 shows a computing environment 200 according to one embodiment. In the illustrated embodiment, the computing environment 200 includes a controller 101, a network 230, an isolation unit 104, and a 1-N , power source 110 and complex impedance measurement unit 240. In one embodiment, controller 101 is a battery management system of a vehicle, and circuit configuration 102 represents a battery pack of the vehicle.

[0040] In one embodiment, the controller 101 includes a processor 204 that obtains instructions and data from a memory or storage device 206 via a bus 220. Not all components of the controller 101 are shown. The controller 101 is typically under the control of an operating system (OS) suitable for performing or supporting the functions or processes disclosed herein. The processor 204 is a programmable logic device that performs instructions, logic, and mathematical processing, and may represent one or more CPUs. The processor may execute one or more algorithms, instruction sets, or applications in the memory or storage device 206 to perform the functions or processes described herein.

[0041] The memory or storage device 206 may represent a hard drive, a solid state drive, a flash memory device, an optical medium, etc. The memory or storage device 206 may also include a structured storage device (e.g., a database). In addition, the memory or storage device 206 may be considered to include a memory physically located elsewhere. For example, the memory or storage device 206 may be physically located on another computer that is communicatively connected to the controller 101 via the bus 220 or the network 230.

[0042] The controller 101 can be connected to other computers (eg, controllers, distributed databases, servers, or network hosts), isolation units 104, and / or network interfaces 210 and / or networks 230. 1-N , power supply 110 or complex impedance measurement unit 240. Network 230 may include, for example, a local area network, a wide area network or a wireless network. In one embodiment, the network includes a controller area network (CAN) or a transmission control protocol (TCP) bus. Network 230 may also include any combination of a bus, a physical transmission cable, an optical transmission fiber, a wireless transmission, a router, a firewall, a switch, a gateway computer or an edge server. Network interface 210 may be any type of network communication device that allows controller 101 to communicate with other components of computer and computing environment 200 via network 230.

[0043] In the illustrated embodiment, the memory or storage device 206 includes a battery imbalance mitigation (BIM) module 208. In one embodiment, the BIM module 208 represents one or more algorithms, sets of instructions, software applications, or other computer readable program codes that may be executed by the processor 204 to perform the functions, operations, or processes described herein.

[0044] The BIM module 208 may control the isolation unit 104 1-N The battery cell 106 1-NThe BIM module 208 connects and disconnects the battery cells from the circuit configuration 102. In one embodiment, the BIM module 208 disconnects all but one battery cell (the "isolated" battery cell) from the circuit configuration 102. Thereafter, the BIM module 208 may control the complex impedance measurement unit 240 to determine the frequency response of the isolated battery cell. The BIM module 208 may use the frequency response to determine the state of health (SOH) of the isolated battery cell, and may control the use of the isolated battery cell based on the SOH. The process herein is described in detail in detail in the accompanying drawings. Figure 4-6 Further discussion in.

[0045] Complex impedance measurement unit 240 may represent an electrochemical impedance spectroscopy device, a potentiostat, or another device configured to apply an input alternating current (AC) signal to battery cell 106. 1-N , measuring battery cell 106 1-N The complex impedance measurement unit 240 can determine the real impedance value and the imaginary impedance value based on the input AC signal and the output AC signal. For example, the input AC signal can represent a voltage signal, and the output AC signal can represent a current signal. Therefore, the complex impedance measurement unit 240 can divide the voltage signal by the current signal to determine the real impedance value and the imaginary impedance value of the battery cell 106. 1-N Impedance representation.

[0046] In one embodiment, the impedance representation is modeled as a Bode plot or a Nyquist plot. In one embodiment, the complex impedance measurement unit 240 modulates the AC signal from the power supply 110 to apply the input AC signal to the isolation unit 104. 1-N , which is then applied to the battery cell 106 1-N .

[0047] Figures 3A-3C An isolation unit according to one or more embodiments is shown. Figures 3A-3C In each of the embodiments shown, the isolation unit 1041 represents all isolation units 104 of the embodiment. 1-N Common circuit configuration.

[0048] exist Figure 3A In the illustrated embodiment, the isolation unit 1041 includes a switch 302A connected to the battery unit 1061 via a first connection point 320A of the isolation unit 1041. The switch 302A is also connected to the power source 110 via a second connection point 322A of the isolation unit 1041.

[0049] The controller 101 can operate the switch 302A to connect or disconnect the battery cell 1061 from the circuit configuration 102. In one embodiment, the controller 101 operates the isolation unit 104 1-N The switches in the battery are used to isolate and determine each battery cell 106. 1-N The process is here Figure 5 Detailed discussion in .

[0050] exist Figure 3B In the illustrated embodiment, the isolation unit 1041 includes a switch 302B connected to the battery cell 1061 via a first connection point 320B of the isolation unit 1041. The switch 302B is also connected to the power source 110 via an uppermost electrical path 310B connected to a second connection point 322B of the isolation unit 1041. The switch 302B is also connected to the resistor 304B and the power source 110 via a lowermost electrical path 312B connected to the second connection point 322B of the isolation unit 1041. The isolation unit 1041 may also include an optional additional switch (not shown) connected to the second connection point 322B to connect or disconnect the isolation unit 1041 from the circuit configuration 102.

[0051] The controller 101 can operate the switch 302B to directly connect the battery cell 1061 to the power source 110 via the uppermost electrical path 310B, or to connect the battery cell 1061 to the resistor 304B and the power source 110 via the lowermost electrical path 312B. In one embodiment, the resistor 304B represents the impedance characteristics of the isolation unit 1041 facing the battery cell 1061. 1-N Each of the resistors 304B may have a different impedance characteristic. In one embodiment, the resistor 304B is a variable resistor that can be electromechanically adjusted by the controller 101 to apply different impedance characteristics to the battery cell 1061. This can be specific to the isolation unit 104 1-N Each of the executions is performed as battery cell 106 1-N Each of the isolation units 104 provides a different impedance characteristic. 1-N The diagnostic technology is here Figure 6 Further discussion in.

[0052] exist Figure 3C In the illustrated embodiment, the isolation unit 1041 includes a switch 302C connected to the battery cell 1061 via a first connection point 320C of the isolation unit 1041. The switch 302C is also connected to the power source 110 via an uppermost electrical path 310C connected to a second connection point 322C of the isolation unit 1041. The switch 302C is also connected to an RC filter (which includes a resistor 304C and a capacitor 306C) and the power source 110 via a lowermost electrical path 312C connected to the second connection point 322C of the isolation unit 1041. A first end of the capacitor 306C is connected to the lowermost electrical path 312C between the switch 302C and the resistor 304C, and a second end of the capacitor 306C is connected to the ground 103 via a third connection point 342C of the isolation unit 1041.

[0053] The controller 101 can operate the switch 302C to directly connect the battery cell 1061 to the power source 110 via the uppermost electrical path 310C, or to connect the battery cell 1061 to the RC filter and the power source 110 via the lowermost electrical path 312C. In one embodiment, the resistor 304C represents the impedance characteristic of the isolation unit 1041 facing the battery cell 1061. 1-N Each of the resistors 304C may have a different impedance characteristic. In one embodiment, the resistor 304C is a variable resistor that can be electromechanically adjusted by the controller 101 to apply different impedance characteristics to the battery cell 1061. This can be specific to the isolation unit 104 1-N Each of the executions is performed as battery cell 106 1-N Each of the isolation units 104 provides a different impedance characteristic. 1-N The diagnostic technology is here Figure 6 Further discussion in.

[0054] Figure 4 FIG. 4 is a flow chart showing a method 400 for diagnosing and mitigating battery imbalance according to one embodiment. In one embodiment, the method 400 is performed when the battery cell is not in a high energy consumption state. For example, if the battery cell 106 is used in a vehicle 1-N , the method can be executed when the vehicle is not moving.

[0055] The method begins at block 402. At block 404, the BIM module 208 selects a diagnostic technique based on the circuit configuration of the isolation unit. In one embodiment, when the isolation unit 104 1-N reflect Figure 3A When the circuit configuration shown in FIG. 1 is used, the BIM module 208 performs Figure 5 When the isolation unit 104 1-N reflect Figure 3B-3C When the circuit configuration shown in FIG. 1 is used, the BIM module 208 performs Figure 6 The model described in .

[0056] Boxes 406-412 describe Figure 5 and Figure 6 At block 406, the BIM module 208 isolates the battery cell via the isolation unit. As described above, in one embodiment, when the isolation unit corresponding to the battery cell is used to connect the battery cell (or maintain the connection of the battery cell) to the circuit configuration 102 while other battery cells (e.g., 106 2-N) is disconnected from the circuit configuration 102, the battery cell (e.g., battery cell 1061) is considered isolated. In one embodiment, some or all of the other battery cells are disconnected from the circuit configuration. In one embodiment, battery cell groups can be isolated and used according to method 400 to improve the efficiency of battery imbalance diagnosis and mitigation.

[0057] At block 408, the BIM module 208 determines the state of health of the battery cell via the complex impedance measurement unit 240. The BIM module 208 may use the frequency response of the battery cell to identify the SOH. In one embodiment, the frequency response of the battery cell represents an impedance profile of the battery cell, which includes real impedance values ​​and imaginary impedance values ​​across a frequency range. The BIM module 208 may generate the frequency response by controlling the complex impedance measurement unit 240 to apply an input AC signal to the cell, measure an output AC signal of the battery cell, and determine the real impedance value and the imaginary impedance value based on the input AC signal and the output AC signal.

[0058] In one embodiment, the SOH of a battery cell represents the remaining useful life of the battery cell as a ratio of the current condition of the battery cell to the ideal condition of the battery cell. The SOH can be depicted as a graph or distribution representing the remaining useful life of the battery cell (e.g., internal impedance value, number of expected remaining life cycles, percentage of remaining charge, etc.) relative to at least one metric (e.g., time, cycle count, temperature range, voltage or current usage, capacity range, etc. of the battery cell). The BIM module 208 can determine the SOH of the battery cell based on the impedance (from the frequency response), capacity, and voltage output of the battery cell.

[0059] At block 410, the BIM module 208 controls the battery cell via the controller 101 based on the health status. In one embodiment, upon determining that the battery cell includes a cell imbalance, the BIM module 208 disconnects the battery cell from the circuit configuration 102 using the isolation unit so that the battery pack or battery cell group can supply power without the contribution of the disconnected battery cell. The cell imbalance may represent an increased impedance or energy consumption of one battery cell of the circuit configuration 102 relative to at least one other battery cell of the circuit configuration 102.

[0060] The BIM module 208 may also determine the SOH of other cells of the circuit configuration 102 over time. In one embodiment, upon determining that the difference between the SOH value of the disconnected cell and the SOH value of one or more other cells (or the average of the health state of other cells) exceeds a threshold, the BIM module 208 may reconnect the disconnected battery to the circuit configuration 102 using the isolation unit. In this way, the BIM module 208 may control the energy imbalance of the cells and mitigate the risks caused by using a battery pack or a group of cells that include unbalanced cells. The method 400 ends at block 412.

[0061] Figure 5 FIG. 5 is a flow chart of a method 500 for diagnosing and mitigating battery imbalance according to another embodiment. The method 500 depicts a method for diagnosing and mitigating battery imbalance when the isolation unit 104 1-N reflect Figure 3A The circuit configuration shown in FIG. 5 is one example of battery imbalance diagnosis and mitigation. The method 500 begins at block 502 .

[0062] At block 504, the BIM module 208 isolates the first battery cell from the plurality of battery cells. The BIM module 208 may control a switch (e.g., switch 302A) of the isolation unit to connect or disconnect the battery cell from the circuit configuration 102. As described herein, in one embodiment, when the first battery cell (e.g., battery cell 1061) is connected to the circuit configuration 102 (or remains connected to the circuit configuration 102) and the other battery cells (e.g., battery cell 106 2-N ) is disconnected from the circuit configuration 102, the first battery cell is considered to be isolated.

[0063] At block 506, the BIM module 208 determines the state of health of the first battery cell. As described herein, the BIM module 208 may control the complex impedance measurement unit 240 to generate a frequency response of the first battery cell. The BIM module 208 may then determine the SOH based on the capacity, voltage, and frequency response of the first battery cell. In one embodiment, the SOH of the first battery cell represents a characteristic of the remaining useful life of the first battery cell (e.g., an internal impedance value, a number of expected remaining life cycles, a percentage of remaining charge, etc.).

[0064] At block 508 , the BIM module 208 isolates the second battery cell from the plurality of battery cells. At block 510 , the BIM module 208 determines the SOH of the second battery cell. The method 500 may perform these processes in a similar manner to the processes performed at blocks 504 and 506 .

[0065] At block 512, the BIM module 208 determines whether the difference between the state of health of the first battery cell and the state of health of the second battery cell exceeds a state of health threshold. Upon determining that the SOH threshold has not been exceeded, the BIM module 208 determines that the first battery cell and the second battery cell are not unbalanced. Therefore, the method 500 proceeds to block 504, where it is performed as described above. However, upon determining that the SOH threshold has been exceeded, the BIM module 208 determines that an imbalance exists between the first battery cell and the second battery cell. The method 500 then proceeds to block 514.

[0066] At block 514, the BIM module 208 controls the first battery cell or the second battery cell. In one embodiment, the BIM module 208 uses the isolation unit to disconnect the first battery cell or the second battery cell from the circuit configuration 102 based on the SOH value corresponding to the battery cell (e.g., the BIM module 208 may disconnect the battery cell with a lower remaining useful life). The method 500 ends at block 516.

[0067] Figure 6 FIG. 6 is a flowchart of a method 600 for diagnosing and mitigating battery imbalance according to another embodiment. The method 600 describes a method for diagnosing and mitigating battery imbalance when the isolation unit 104 1-N reflect Figure 3B-3C The circuit configuration shown in FIG. 6 is one example of battery imbalance diagnosis and mitigation. The method 600 begins at block 602 .

[0068] At block 604, the BIM module 208 isolates the battery cell from the plurality of battery cells. 1-N The circuit configuration reflects Figure 3B When the circuit configuration is shown, the BIM module 208 can control a switch (e.g., switch 302B) of the isolation unit (e.g., isolation unit 1041) to directly connect the battery unit (e.g., battery unit 1061) to the power source 110 via the first electrical path of the isolation unit 1041. The BIM module 208 can also control the switch 302B to connect to the power source 110 via the resistor 304B in the second electrical path of the isolation unit 1041.

[0069] In one embodiment, the battery cell 1061 is considered isolated when connected to the power source 110 via the first electrical path, while other battery cells (e.g., the battery cell 106 2-N ) via a corresponding isolation unit (eg, isolation unit 104 2-N ) is connected to the power source 110. In this way, the BIM module 208 can be based on the isolation unit 104 1-N The original impedance distribution of the circuit configuration is used to evaluate the frequency response of the isolation unit.

[0070] In another embodiment, the battery cell 1061 is considered isolated when it is connected to the power source 110 via the second electrical path. 1-N Allows isolation of unit 104 1-N The circuit components are used as facing the battery cell 106 1-N In one embodiment, the BIM module 208 can change the impedance characteristics of the isolation unit 104 1-N For example, the BIM module 208 may apply different electromechanical adjustments to the variable resistors of different isolation cells. Thus, the impedance signature may be used to isolate the battery cells 106 by shifting the impedance signature facing one battery cell to a different impedance range that does not overlap with the impedance signature of another battery cell. 1-N The frequency response of each.

[0071] When the isolation unit 104 1-N The circuit configuration reflects Figure 3C When the circuit configuration is shown, the BIM module 208 can control the switches (e.g., switches 302C and 308C) of the isolation unit to connect or disconnect the battery unit (e.g., battery unit 1061) from the circuit configuration 102. When the battery unit 1061 is connected to the circuit configuration 102, the BIM module 208 can directly connect the battery unit to the power source 110 via the first electrical path of the isolation unit 1041. The BIM module 208 can also control the switch 302C to connect to the power source 110 via the RC filter (which includes the resistor 304C and the capacitor 306C) in the second electrical path of the isolation unit 1041.

[0072] In one embodiment, battery cell 1061 is considered isolated when connected to power source 110 via a first electrical path, while other battery cells (e.g., battery cell 106 2-N ) via a corresponding isolation unit (eg, isolation unit 104 2-N ) is connected to the power source 110. In this way, the impedance response of the battery cell isolated via the first electrical path can be easily distinguished from the impedance response of the battery cell connected to the second electrical path (whose signal is filtered out by the RC filter in the common frequency range).

[0073] At block 606, the BIM module 208 determines a target frequency range for the frequency response. In one embodiment, the target frequency range represents a minimum frequency range that captures the expected impedance response range of the battery cell and the isolation unit corresponding to the battery cell. Figure 3B The isolation unit 104 of the circuit configuration shown 1-N , the target frequency range can be determined based on the impedance of the battery cell and the impedance characteristics of the isolation unit facing the battery cell. Figure 3C The isolation unit 104 of the circuit configuration shown 1-N , the target frequency range can be determined based on the impedance of the isolated battery cells.

[0074] At block 608, the BIM module 208 determines a frequency response across the target frequency range. In one embodiment, the frequency response of the battery cell represents an impedance profile of the battery cell, which includes real impedance values ​​and imaginary impedance values ​​within the target frequency range. The BIM module 208 can generate the frequency response by controlling the complex impedance measurement unit 240 to apply an input AC signal to the cell, measure an output AC signal of the battery cell, and determine real impedance values ​​and imaginary impedance values ​​based on the input AC signal and the output AC signal.

[0075] During this process, the BIM module 208 may also isolate the unit 140 1-N The BIM module 208 may use the isolation unit 104 to test whether there is an error in the switching mechanism. 1-N The predetermined impedance of the isolation unit 104 is generated 1-N When the isolation unit 140 1-N When the measured impedance of the isolation unit 104 is outside the expected impedance range, the BIM module 208 may determine that the measured impedance reflects an error in the switching mechanism, which may cause the isolation unit 104 whose impedance is measured to be 1-N The unintended aggregation of or removal from the circuit configuration 102 .

[0076] At box 610, the BIM module 208 determines the state of health of the battery cell based on the frequency response. In one embodiment, the SOH of the battery cell represents the remaining useful life of the battery cell as a ratio of the current condition of the battery cell to the ideal condition of the battery cell. The SOH can be depicted as a graph or distribution representing the current remaining useful life of the battery cell (e.g., internal impedance value, number of expected remaining life cycles, percentage of charge remaining, etc.) relative to at least one metric (e.g., time, cycle count, temperature range, voltage or current usage, capacity range, etc. of the battery cell). The BIM module 208 can determine the SOH of the battery cell based on the impedance (from the frequency response), capacity, and voltage output of the battery cell.

[0077] At block 612, the BIM module 208 determines whether the difference between the state of health of the battery cell and the state of health estimation map exceeds a battery imbalance threshold. In one embodiment, the SOH estimation map represents the expected remaining useful life of the battery cell when the battery cell begins to be used in the circuit configuration 102. In another embodiment, the SOH map represents the expected life distribution of the battery cell generated when the battery cell is created.

[0078] Upon determining that the difference does not exceed the cell imbalance threshold, the BIM module 208 determines that the remaining useful life of the cell does not deviate from expectations and that there is no imbalance in the battery cells (e.g., elevated internal impedance). Therefore, the method 600 proceeds to block 604, where it is performed as described above. However, upon determining that the difference does exceed the cell imbalance threshold, the BIM module 208 determines that the remaining useful life of the battery cell deviates from expectations and that there is an imbalance in the battery cells. The method 600 then proceeds to block 614.

[0079] At block 614, the BIM module 208 controls the battery cells based on the health status of the battery cells. In one embodiment, when the battery cells include an imbalance, the BIM module 208 disconnects the battery cells from the circuit configuration 102 using the isolation unit so that the battery pack or battery cell group can supply power without the contribution of the disconnected battery.

[0080] The BIM module 208 may also determine the SOH of other cells of the circuit configuration 102 over time. In one embodiment, upon determining that the difference between the SOH of the disconnected cell and the SOH of one or more other cells (or the average of the health status of other cells) exceeds a threshold, the BIM module 208 may reconnect the disconnected cell to the circuit configuration 102 using the isolation unit. In this way, the BIM module 208 may control the energy imbalance of the cells and mitigate the risks of using a battery pack or a group of cells that includes unbalanced cells. The method 600 ends at block 616.

[0081] The terms "a" and "an" do not indicate a limitation of quantity, but rather indicate the presence of at least one of the referenced item. Unless the context clearly indicates otherwise, the term "or" means "and / or". References to "aspects" throughout the specification mean that a particular element (e.g., a feature, structure, step, or characteristic) described in conjunction with that aspect is included in at least one aspect described herein, and may or may not be present in other aspects. In addition, it should be understood that the described elements may be combined in any suitable manner in the various aspects.

[0082] When an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present.

[0083] Unless stated to the contrary herein, all test standards are the most current standards in effect as of the filing date of this application or, if priority is claimed, the filing date of the earliest priority application in which the test standards appear.

[0084] Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0085] Although the above disclosure has been described with reference to exemplary embodiments, it will be appreciated by those skilled in the art that various changes may be made and equivalents may be substituted for its elements without departing from its scope. In addition, many modifications may be made to adapt specific circumstances or materials to the teachings of the disclosure without departing from the basic scope of the disclosure. Therefore, it is intended that the disclosure is not limited to the specific embodiments disclosed, but will include all embodiments falling within its scope.

Claims

1. A vehicle power control system, comprising: a first battery unit; a plurality of battery cells; a first isolation unit; Complex impedance measurement unit; processor; as well as A memory or storage device including an algorithm or computer instructions that, when executed by the processor, performs operations comprising: isolating the first battery cell from the plurality of battery cells via a first isolation unit; determining a state of health of a first battery cell via the complex impedance measurement unit; and The first battery cell is controlled, via the processor, based on a state of health of the first battery cell.

2. The vehicle power control system according to claim 1, wherein the first isolation unit comprises: a first connection point connected to a first end of the switch; as well as A second connection point is connected to a second end of the switch.

3. The vehicle power control system of claim 2, said operation further comprising: isolating the second battery cell from the plurality of battery cells via a second isolation unit; determining a state of health of a second battery cell via the complex impedance measurement unit; as well as The processor determines that a difference between a state of health of a first battery cell and a state of health of a second battery cell exceeds a state of health threshold, wherein the difference indicates that a remaining useful life of the first battery cell is less than a remaining useful life of the second battery cell, and wherein the first battery cell is controlled by disconnecting the first battery cell from a plurality of battery cells via a first isolation unit.

4. The vehicle power control system according to claim 1, wherein the first isolation unit comprises: a first connection point connected to a first end of the switch, wherein a second end of the switch is connected to the first electrical path, and wherein a third end of the switch is connected to the second electrical path; as well as A second connection point is connected to the first electrical path and a second electrical path, wherein the second electrical path includes a resistor or an RC filter.

5. The vehicle power control system of claim 4, said operations further comprising: determining, via the processor, a target frequency range for a frequency response; determining, via the complex impedance measurement unit, a frequency response across the target frequency range; determining, via the processor, a state of health of a first battery cell based on the frequency response; as well as A determination is made, via the processor, that a difference between a state of health of a first battery cell and a state of health estimate map exceeds a battery imbalance threshold, wherein the first battery cell is controlled based on the state of health of the first battery cell.

6. The vehicle power control system of claim 1 , wherein the complex impedance measurement unit represents a device configured to apply an input AC signal to a first battery cell, measure an output AC signal of the first battery cell, and determine a real impedance value and an imaginary impedance value based on the input AC signal and the output AC signal.

7. The vehicle power control system of claim 1 , wherein the state of health of the first battery cell is a graph or distribution representing a remaining useful life of the first battery cell relative to at least one metric, wherein the remaining useful life of the first battery cell comprises at least one of: an internal impedance value, a number of expected remaining life cycles, or a percentage of charge remaining, and wherein the at least one metric comprises: Time, cycle count, temperature range, voltage or current usage, or capacity range of the first battery cell.

8. A computer readable storage medium having computer readable program code embodied therewith, the computer readable program code being executable by one or more computer processors to perform operations comprising: isolating the first battery cell from the plurality of battery cells via a first isolation unit; determining a state of health of a first battery cell via a complex impedance measurement unit; as well as The first battery cell is controlled via the controller based on the state of health of the first battery cell.

9. The computer-readable storage medium of claim 8, the operations further comprising: The second battery cell is isolated from the plurality of battery cells via the second isolation unit. determining a state of health of a second battery cell via the complex impedance measurement unit; as well as The controller determines that a difference between a state of health of a first battery cell and a state of health of a second battery cell exceeds a state of health threshold, wherein the difference indicates that a remaining useful life of the first battery cell is less than a remaining useful life of the second battery cell, and wherein the first battery cell is controlled by disconnecting the first battery cell from a plurality of battery cells via a first isolation unit.

10. The computer-readable storage medium of claim 8, the operations further comprising: determining, via the controller, a target frequency range for a frequency response; determining, via the complex impedance measurement unit, a frequency response across the target frequency range; determining, via the controller, a state of health of a first battery cell based on the frequency response A determination is made, via the controller, that a difference between a state of health of a first battery cell and a state of health estimation map exceeds a battery imbalance threshold, wherein the first battery cell is controlled based on the state of health of the first battery cell.

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