Vehicle battery management system for lithium-based battery pressure determination

Abstract

Some embodiments disclosed herein relate to a vehicle battery management system for determining the pressure of a lithium-based battery. Some embodiments may include generating a pressure measurement of the lithium-based battery based on the normalized pressure and an initial pressure value associated with the lithium-based battery, and adjusting or maintaining a level of compression applied to the lithium-based battery based on the generated pressure measurement. Other embodiments may be disclosed or claimed.

Description

Technical Field

[0001] The present disclosure relates to lithium-based batteries. Specifically, embodiments of the present disclosure relate to a vehicle battery management system for pressure determination of lithium-based batteries. Background Art

[0002] Increasingly, vehicles are produced with propulsion systems utilizing electric motors powered by lithium-based battery systems, such as lithium metal batteries (LMBs). Such battery systems may include multiple battery modules that are pressurized. The pressure of a lithium-based battery can vary significantly during charging and discharging, and can significantly affect the performance of the battery. Some aspects of operating such systems involve monitoring and maintaining the pressure of a lithium-based battery to help optimize the performance of the battery. Among other things, embodiments of the present disclosure provide an enhanced system for determining the pressure of a lithium-based battery in real time or near real time. Summary of the invention

[0003] In one exemplary embodiment, a battery management system is provided. The battery management system includes a processor and a memory connected to the processor. The memory stores instructions that, when executed by the processor, cause the battery management system to receive measurement signals from a lithium-based battery, the measurement signals including voltage measurements, current measurements, and temperature measurements. The memory further stores instructions for determining a normalized pressure of the lithium-based battery based on the received measurement signals and generating a pressure measurement of the lithium-based battery based on the normalized pressure and an initial pressure value associated with the lithium-based battery. The memory also stores instructions for adjusting or maintaining a compression level applied to the lithium-based battery based on the generated pressure measurement.

[0004] In addition to one or more of the features described herein, determining the normalized pressure of the lithium-based battery is performed without a pressure measurement of the lithium-based battery from a pressure sensor.

[0005] In addition to one or more of the features described herein, determining the normalized pressure of the lithium-based battery is further based on a state of charge (SOC) measurement and a lithium density measurement.

[0006] In addition to one or more features described herein, the lithium density measurement is correlated to the lithium surface density at the anode of the lithium-based battery.

[0007] In addition to one or more of the features described herein, the SOC measurement is associated with a change in an estimated pressure of the lithium-based battery over a predetermined period of time.

[0008] In addition to one or more of the features described herein, the measurement signals are received from a plurality of sensors connected to the lithium-based battery.

[0009] In addition to one or more features described herein, the measurement signal reflects measurements of the lithium-based battery taken in real time or near real time.

[0010] In addition to one or more of the features described herein, generating the pressure measurement of the lithium-based battery based on the normalized pressure and the initial pressure value associated with the lithium-based battery is further based on one or more of: the maximum pressure of the lithium-based battery, the minimum pressure of the lithium-based battery, and the pressure of the lithium-based battery associated with a specific SOC value.

[0011] In one exemplary embodiment, a propulsion system for a vehicle is provided. The propulsion system includes an electric motor, a lithium-based battery coupled to the electric motor, and a battery management system coupled to the lithium-based battery. The battery management system includes a processor and a memory coupled to the processor and storing instructions, the instructions, when executed by the processor, causing the battery management system to receive a measurement signal from the lithium-based battery, the measurement signal including a voltage measurement, a current measurement, and a temperature measurement. The memory further stores instructions for causing the battery management system to determine a normalized pressure of the lithium-based battery based on the received measurement signal, and to generate a pressure measurement of the lithium-based battery based on the normalized pressure and an initial pressure value associated with the lithium-based battery. The memory further stores instructions for causing the battery management system to adjust or maintain a compression level applied to the lithium-based battery based on the generated pressure measurement value.

[0012] In addition to one or more of the features described herein, determining the normalized pressure of the lithium-based battery is performed without a pressure measurement of the lithium-based battery from a pressure sensor.

[0013] In addition to one or more of the features described herein, determining the normalized pressure of the lithium-based battery is further based on a state of charge (SOC) measurement and a lithium density measurement.

[0014] In addition to one or more features described herein, the lithium density measurement is correlated to the lithium surface density at the anode of the lithium-based battery.

[0015] In addition to one or more of the features described herein, the SOC measurement is associated with a change in an estimated pressure of the lithium-based battery over a predetermined period of time.

[0016] In addition to one or more of the features described herein, the measurement signal includes one or more of measurements received from a plurality of sensors connected to the lithium-based battery and measurements of the lithium-based battery acquired in real-time or near real-time.

[0017] In addition to one or more of the features described herein, generating the pressure measurement of the lithium-based battery based on the normalized pressure and the initial pressure value associated with the lithium-based battery is further based on one or more of: the maximum pressure of the lithium-based battery, the minimum pressure of the lithium-based battery, and the pressure of the lithium-based battery associated with a specific SOC value.

[0018] In one exemplary embodiment, a vehicle is provided. The vehicle includes a lithium-based battery and a battery management system coupled to the lithium-based battery. The battery management system includes a processor and a memory coupled to the processor. The memory stores instructions that, when executed by the processor, cause the battery management system to receive measurement signals from the lithium-based battery, the measurement signals including voltage measurements, current measurements, and temperature measurements. The memory further stores instructions for determining a normalized pressure of the lithium-based battery based on the received measurement signals and generating a pressure measurement of the lithium-based battery based on the normalized pressure and an initial pressure value associated with the lithium-based battery. The memory also stores instructions for adjusting or maintaining a level of compression applied to the lithium-based battery based on the generated pressure measurement.

[0019] In addition to one or more of the features described herein, determining the normalized pressure of the lithium-based battery is performed without a pressure measurement of the lithium-based battery from a pressure sensor.

[0020] In addition to one or more of the features described herein, determining the normalized pressure of the lithium-based battery is further based on a state of charge (SOC) measurement associated with a change in the estimated pressure of the lithium-based battery over a predetermined time period, and a lithium density measurement associated with a lithium surface density at an anode of the lithium-based battery.

[0021] In addition to one or more of the features described herein, the measurement signal includes one or more of: measurements received from a plurality of sensors connected to the lithium-based battery and measurements of the lithium-based battery acquired in real-time or near real-time.

[0022] In addition to one or more of the features described herein, generating the pressure measurement of the lithium-based battery based on the normalized pressure and the initial pressure value associated with the lithium-based battery is further based on one or more of: the maximum pressure of the lithium-based battery, the minimum pressure of the lithium-based battery, and the pressure of the lithium-based battery associated with a specific SOC value.

[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, from the following detailed description, which refers to the accompanying drawings, in which:

[0025] Figure 1 is a schematic diagram of a vehicle for use in conjunction with one or more embodiments of the present disclosure;

[0026] Figure 2 is a functional block diagram illustrating aspects of a battery management system according to an embodiment of the present disclosure;

[0027] Figure 3A and Figure 3B is a functional block diagram illustrating a process for determining the pressure of a lithium-based battery according to an embodiment of the present disclosure;

[0028] Figure 3C shows an example of a graph for calibrating normalized pressure of a lithium-based battery according to various embodiments of the present disclosure; and

[0029] Figure 4 is a flow chart illustrating a process in accordance with various aspects of the present disclosure. DETAILED DESCRIPTION

[0030] The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate the same or corresponding parts and features.

[0031] According to an exemplary embodiment, a battery management system for an electric motor is provided. The battery management system can determine pressure measurements of a lithium-based battery based on measurement signals from the battery, such as voltage, current, and temperature. In this way, embodiments of the present disclosure can accurately determine pressure measurements of a lithium-based battery in real time or near real time without the need for a dedicated pressure sensor.

[0032] Reference now Figure 1, a schematic diagram of a vehicle 100 used in conjunction with one or more embodiments of the present disclosure is shown. The vehicle 100 includes a charging port 102, a battery 104, and an electric motor 106. In one embodiment, the vehicle 100 is a hybrid vehicle utilizing both an internal combustion engine and an electric motor. In another embodiment, the vehicle 100 is an electric vehicle utilizing only an electric motor. In an exemplary embodiment, the vehicle 100 is configured to be connected to a high voltage power source (i.e., a voltage source of at least 200 volts (V)) for charging the battery 104 via the charging port 102. The electric motor 106 is configured to receive power from the battery 104 to provide propulsion for the vehicle 100. In an exemplary embodiment, the battery 104 is configured to supply direct current (DC) power to an inverter (not shown), which converts the DC power into three-phase alternating current (AC) power. The three-phase AC power is supplied to the electric motor 106 to propel the vehicle 100.

[0033] Figure 2 1 is an example of a functional block diagram illustrating aspects of a battery management system according to an embodiment of the present disclosure. In this example, the battery 104 includes a plurality of lithium-based battery modules 210, 220, 230. Each respective battery module is connected to a respective battery monitoring unit 215, 225, 235. The battery monitoring units 215, 225, 235 are connected to a battery management system (BMS) 250.

[0034] exist Figure 2 In the example depicted in , three battery modules are shown as an example, but the actual system may include any suitable number of battery modules. In some embodiments, a single battery monitoring unit may be coupled to multiple battery modules. Additionally or alternatively, BMS250 may be directly coupled to some or all of the battery modules 210, 220, 230 to perform the functions of the battery monitoring units 215, 225, 235.

[0035] In some exemplary embodiments, the BMS 250 includes at least one processor, such as a general purpose processor, a central processing unit, an application specific integrated circuit (ASIC), a digital signal processor, a field programmable gate array (FPGA), a digital circuit, an analog circuit, or a combination thereof. In some embodiments, the BMS 250 includes a memory in communication with the processor to store data and instructions executable by the processor to retrieve measurements from the battery 104 and control features of the battery 104.

[0036] For example, in some embodiments, the BMS 250 manages the charging of the battery 104 of the vehicle (a lithium-ion battery in this example), and monitors and controls the battery 104 as the battery 104 discharges during operation of the vehicle 100. The BMS receives measurement signals from the battery modules 210, 220, 230 (via the battery monitoring units 215, 225, 235 in this example) from sensors connected to the battery modules. The measurement signals may include one or more of voltage measurements, current measurements, and temperature measurements. The BMS 250 may determine other measurements based on the received measurement signals, such as state of charge (SOC) measurements and lithium density measurements. The BMS 250 may receive any other suitable measurements collected from the battery 104.

[0037] Figure 3A and Figure 3B 300 and 350 may be performed by any suitable system or combination of systems, such as by Figure 2 The BMS250 in Figure 3A , the BMS 250 receives measurement signals including a voltage measurement 302 and a current measurement 304 from the battery 104. The BMS 250 also determines a state of charge (SOC) measurement 306 and a lithium density measurement 308.

[0038] At box 310, the BMS 250 uses a data-driven model in a recurrent neural network (RNN) to process the measurement signals (e.g., current, voltage, and temperature) and the determined values ​​of the SOC measurement 306 and the lithium density measurement 308 to generate a normalized pressure value 312 for the battery 104. At 315, the BMS 250 generates a pressure measurement 316 of the lithium-based battery 104 based on the normalized pressure value 312 and the initial pressure value 314 associated with the lithium-based battery.

[0039] Figure 3B An example of a process for generating a normalized pressure 312 using an RNN is shown. In this example, at box 352, the battery management system 250 receives measurements 302, 304, 306, 308, which may be collectively referred to below as input x, where x1=voltage, x2=current, x3=SOC, and x4=Li density. At 354, the BMS250 assigns a first weight U to each discrete measurement (e.g., U1 for voltage, U2 for current, etc.). At box 356, the BMS250 executes a first activation function process h based on the recurrent connection V at 358. At 360, a second weight is assigned to each discrete measurement (e.g., W1 for voltage, W2 for current, etc.). The normalized pressure output 312 is determined based on the second activation function o. The activation processes h and o can be performed according to:

[0040] o t =σ o (W y h t )+b y

[0041] h t =σ h (W h x t )+U h h t-1 +b h

[0042] Where: b y and b h is the bias value.

[0043] like Figure 3A and 3B As shown, the BMS 250 generates a normalized pressure 312 of the battery 104 in real time or near real time based on the measurements 302, 304, 306, 308. The actual pressure of the battery 316 is then determined by multiplying the normalized pressure 312 by the initial pressure of the battery 316. In this example, the initial pressure 316 of the battery 104 (or each individual component battery module 210, 220, 230 of the battery 104) may be determined during manufacturing of the battery 104 or during installation in the vehicle 100.

[0044] In some embodiments, the target pressure value from the pressure sensor can be used to calibrate the model of the RNN used by the BMS 250, on which the BMS 250 can perform cycle tests and measure the voltage, current, temperature, and pressure from the battery or battery module. During or after the test, the system can calculate the normalized pressure by dividing the pressure value by the initial pressure, the maximum pressure, the minimum pressure, or the pressure relative to a specific SOC value. After calibration, the BMS 250 does not need a dedicated pressure sensor to determine the pressure of the battery 104, thereby reducing the cost and complexity of the BMS 250 and the vehicle 100.

[0045] Figure 3C An example of a graph of normalized pressure for calibrating a lithium-based battery according to various embodiments of the present disclosure is shown. In this example, graph 370 represents the actual pressure Pr(k) measured from the pressure sensor during calibration. Graph 375 represents the normalized pressure determined based on the initial pressure according to the following formula:

[0046] Pr norm =Pr(k) / Pr(0)

[0047] Graph 380 shows the normalized pressure determined based on the minimum pressure of the battery according to the following equation:

[0048] Pr norm =Pr(k) / Pr min

[0049] Graph 385 shows the normalized pressure determined based on the maximum pressure of the battery according to the following equation:

[0050] Pr norm =Pr(k) / Pr max

[0051] Figure 4 Examples of processes that may be performed according to various embodiments are shown. Figure 4 The process 400 in FIG. 4 may be performed by any suitable device or combination of devices, such as by a processor of the battery management system 250 executing computer-readable instructions stored in a memory of the battery management system 250 .

[0052] In this example, process 400 includes receiving a measurement signal of a lithium-based battery at 410. In some embodiments, the measurement signal may include one or more of: a voltage measurement, a current measurement, and a temperature measurement. System 250 may further determine or estimate a state of charge (SOC) measurement and a lithium density measurement.

[0053] Process 400 also includes, at 420, determining a normalized pressure of the lithium-based battery based on the received and determined measurements. Process 400 further includes, at 430, generating a pressure measurement of the lithium-based battery. In some embodiments, the pressure measurement is generated based on the normalized pressure and an initial pressure value associated with the lithium-based battery. In an alternative embodiment, as described above in Figure 3C As described in , the pressure measurement can be generated based on the normalized pressure measurement in combination with one or more of the following: the maximum pressure of the lithium-based battery, the minimum pressure of the lithium-based battery, and the pressure of the lithium-based battery associated with a specific SOC value.

[0054] Process 400 also includes adjusting or maintaining the level of compression applied to the lithium-based battery based on the generated pressure measurement at 440. In some embodiments, BMS 250 may generate and transmit an alert to a user of vehicle 100 or other entity in response to the generated pressure measurement exceeding a predetermined threshold.

[0055] The terms "one" 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.

[0056] 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.

[0057] Unless otherwise indicated 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.

[0058] 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.

[0059] 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 battery management system, comprising: processor; as well as a memory connected to the processor and storing instructions that, when executed by the processor, cause the battery management system to: receiving a measurement signal from a lithium-based battery, the measurement signal comprising: a voltage measurement, a current measurement, and a temperature measurement; determining a normalized pressure of the lithium-based battery based on the received measurement signal; generating a pressure measurement of the lithium-based battery based on the normalized pressure and an initial pressure value associated with the lithium-based battery; and The level of compression applied to the lithium-based battery is adjusted or maintained based on the resulting pressure measurements.

2. The battery management system according to claim 1, wherein: Determining the normalized pressure of the lithium-based battery is performed without a pressure measurement of the lithium-based battery from a pressure sensor. 3 . The battery management system of claim 1 , wherein determining the normalized pressure of the lithium-based battery is further based on a state of charge (SOC) measurement and a lithium density measurement. 4 . The battery management system of claim 3 , wherein the lithium density measurement is correlated to a lithium surface density at an anode of the lithium-based battery.

5. The battery management system according to claim 3, wherein: The SOC measurement is correlated to a change in an estimated pressure of the lithium-based battery over a predetermined period of time. 6 . The battery management system of claim 1 , wherein the measurement signal is received from a plurality of sensors connected to the lithium-based battery.

7. The battery management system of claim 1, wherein the measurement signal reflects measurements of the lithium-based battery taken in real time or near real time.

8. The battery management system of claim 1 , wherein generating the pressure measurement of the lithium-based battery based on the normalized pressure and the initial pressure value associated with the lithium-based battery is further based on one or more of: a maximum pressure of the lithium-based battery, a minimum pressure of the lithium-based battery, and a pressure of the lithium-based battery associated with a specific SOC value.

9. A propulsion system for a vehicle, comprising: Electric motor; a lithium-based battery connected to the electric motor; as well as A battery management system connected to the lithium-based battery and comprising: Processor; and a memory connected to the processor and storing instructions that, when executed by the processor, cause the battery management system to: receiving a measurement signal from a lithium-based battery, the measurement signal comprising: a voltage measurement, a current measurement, and a temperature measurement; determining a normalized pressure of the lithium-based battery based on the received measurement signal; generating a pressure measurement of the lithium-based battery based on the normalized pressure and an initial pressure value associated with the lithium-based battery; and The level of compression applied to the lithium-based battery is adjusted or maintained based on the resulting pressure measurements.

10. The propulsion system of claim 9, wherein determining the normalized pressure of the lithium-based battery is performed without a pressure measurement of the lithium-based battery from a pressure sensor.

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