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EP-4741852-A1 - ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY SYSTEM AND METHOD

EP4741852A1EP 4741852 A1EP4741852 A1EP 4741852A1EP-4741852-A1

Abstract

An electrochemical impedance system comprising a vehicle battery, a battery management system (BMS), an excitation power module, and a current sensor. The vehicle battery comprises, in turn, one, two or more battery modules. Each battery module includes a plurality of battery cells. The BMS is configured to control the excitation power module to excite at least the one, two or more battery modules. The current sensor is configured to sense at least electric current of the one, two or more battery modules. The BMS is further configured to sense, determine, or receive voltage of the plurality of battery cells of the one, two or more battery modules, and also receive the electric current of the one, two or more battery modules sensed by the current sensor. In this way, the system of the present disclosure is capable of determining the electrochemical impedance of the vehicle battery. It includes two options: the first option, wherein the BMS is configured to determine the impedance of the plurality of battery cells of the one, two or more battery modules based at least on the electric current and the voltage. Alternatively, the second option, wherein the BMS is configured to send the electric current and the voltage to an external controller configured to determine the impedance of the plurality of battery cells of the one, two or more battery modules based at least on the electric current and the voltage. Additionally, the system may be further configured to generate a battery cell degradation output based at least on the determined impedance. The corresponding method is also provided.

Inventors

  • BAUTISTA FLORENSA, Roger
  • GÓMEZ NÚÑEZ, Alberto

Assignees

  • Ficosa Automotive, S.L.U.

Dates

Publication Date
20260513
Application Date
20241106

Claims (15)

  1. An electrochemical impedance spectroscopy system comprising: a vehicle battery (10) comprising one, two or more battery modules (M1, M2), wherein each battery module (M1, M2) includes a plurality of battery cells (C1, C2, C3); - a battery management system (20) electrically connected to the vehicle battery (10), wherein the battery management system (20) is configured to sense, determine, or receive voltage (V1, V2, V3) of the plurality of battery cells (C1, C2, C3) of the one, two or more battery modules (M1, M2), wherein the battery management system (20) is configured to control the vehicle battery (10); - an excitation power module (30) electrically connected to the vehicle battery (10) and the battery management system (20), wherein the excitation power module (30) is configured to excite at least the one, two or more battery modules (M1, M2); and - a current sensor (40) configured to sense at least electric current (I) of the one, two or more battery modules (M1, M2) when excited, wherein the battery management system (20) is configured to receive the electric current (I) of the one, two or more battery modules (M1, M2) sensed by the current sensor (40), and wherein the battery management system (20) is configured to determine the impedance (Z1, Z2, Z3) of the plurality of battery cells (C1, C2, C3) of the one, two or more battery modules (M1, M2) based at least on the electric current (I) and the voltage (V1, V2, V3), or wherein the battery management system (20) is configured to send the electric current (I) and the voltage (V1, V2, V3) to an external controller (200) configured to determine the impedance (Z1, Z2, Z3) of the plurality of battery cells (C1, C2, C3) of the one, two or more battery modules (M1, M2) based at least on the electric current (I) and the voltage (V1, V2, V3).
  2. The system of claim 1, wherein the current sensor (40) is a single current sensor electrically connected to two or more battery modules (M1, M2), wherein the current sensor (40) is configured to sense at least electric current of the two or more battery modules (M1, M2).
  3. The system of claim 1 or 2, wherein the excitation power module (30) is a single excitation power module, wherein the excitation power module (30) is configured to excite at least two or more battery modules (M1, M2).
  4. The system of any of claims 1 - 3, wherein the excitation power module (30) is arranged out of the vehicle battery (10) and the battery management system (20).
  5. The system of any of claims 1 - 4, wherein the current sensor (40) is electrically arranged therebetween the excitation power module (30) and the vehicle battery (10) including in the excitation power module (30) or in the vehicle battery (10).
  6. The system of any of claims 1 - 5, wherein the battery management system (20) is configured to receive a vehicle input signal (VIS), wherein the vehicle input signal (VIS) is at least related to vehicle status and the vehicle-battery status, and wherein the battery management system (20) is configured to determine a trigger command of the system based at least on the vehicle input signal (VIS).
  7. The system of claim 6, wherein the vehicle status is at least one of parking mode, ignition off, vehicle not started, and wherein the vehicle-battery status comprises whether the vehicle battery receives and/or supplies electric power or not.
  8. The system of claim 6 or 7, wherein the battery management system (20) is further configured to receive or generate a starting instruction, wherein the trigger command of the system is further based on the starting instruction, preferably, the starting instruction is based at least on one of - a predefined time, - predefined distance, and - an instruction from a user or driver.
  9. The system of any of claims 6 - 8, wherein the trigger command of the system is further based on a temperature of the vehicle battery (10) and/or pre-set time, preferably, the trigger command is delayed by the pre-set time or up to the temperature of the vehicle battery (10) is lower than a pre-established temperature.
  10. The system of any of claims 6 - 9, wherein the vehicle input signal (VIS) is received from a vehicle control unit (VCU) or through a vehicle bus communication channel, wherein the vehicle control unit (VCU) is arranged out of the system.
  11. The system of any of claims 6 - 10, wherein the battery management system (20) or the external controller is configured to receive a change of the vehicle-battery status or the vehicle status, and wherein the battery management system (20) or the external controller is configured to stop determining the impedance (Z1, Z2, Z3) based on the change of the vehicle-battery status or the vehicle status.
  12. The system of any of claims 6 - 11, wherein the trigger command of the system is further based on a cell balancing of the vehicle battery (10), preferably, the trigger command is delayed up to the cell balancing is completed.
  13. A method of operating an electrochemical impedance spectroscopy system comprising: - providing a vehicle battery (10) comprising a first battery module (M1) that includes a plurality of battery cells (C1, C2, C3); - electrically connecting a battery management system (20) to the vehicle battery (10); - forming an electric circuit by electrically connecting at least the first module (M1), and an excitation power module (30); - electrically connecting the excitation power module (30) to the battery management system (20); - electrically connecting a current sensor (40) to the electric circuit; - powering the excitation power module (30) configured to excite the electric circuit; - sensing, by the current sensor (40), electric current (I) of the electric circuit at least when the electric circuit is being excited; - receiving, by the battery management system (20) the electric current (I) of the electric circuit sensed by the current sensor (40); - sensing, determining, or receiving voltage (V1, V2, V3) of the plurality of battery cells (C1, C2, C3) of the first battery module (M1) by the battery management system (20); and - determining the impedance (Z1, Z2, Z3) of the plurality of battery cells (C1, C2, C3) of the first battery module (M1) based at least on the electric current (I) and the voltage (V1, V2, V3), by the battery management system (20), or sending the electric current (I) and the voltage (V1, V2, V3) to an external controller configured to determine the impedance (Z1, Z2, Z3) of the plurality of battery cells (C1, C2, C3) of the one, two or more battery modules (M1, M2) based at least on the electric current (I) and the voltage (V1, V2, V3).
  14. The method of claim 13, further comprising: - providing a second battery module (M2) to the vehicle battery (10) that includes a plurality of battery cells (C1', C2', C3'); - electrically connecting the second module (M2) to the electric circuit; - sensing or determining voltage (V1, V2, V3, V1', V2', V3') of the plurality of battery cells (C1, C2, C3, C1', C2', C3') of the first battery module (M1) and the second battery module (M2) by the battery management system (20); and - determining the impedance (Z1, Z2, Z3, Z1', Z2', Z3') of the plurality of battery cells (C1, C2, C3, C1', C2', C3') of the first battery module (M1) and the second battery module (M2) based at least on the electric current (I) and the voltage (V1, V2, V3, V1', V2', V3') by the battery management system (20).
  15. The method of claim 13 or 14, further comprising: - receiving a vehicle input signal (VIS), wherein the vehicle input signal (VIS) is at least related to vehicle status and the battery pack status; - determining a trigger command of the system based at least on the vehicle input signal (VIS); and - preferably, receiving or generating a starting instruction, wherein the trigger command of the system is further based on the starting instruction, optionally, the starting instruction is based at least on one of ∘ a predefined time, ∘ predefined distance, and ∘ an instruction from a user or driver.

Description

FIELD OF TECHNOLOGY The present application relates an electrochemical impedance spectroscopy system. The electrochemical impedance spectroscopy system is configured to determine an electrochemical impedance of a vehicle battery. For this, the system is provided with a battery management system that controls an excitation power module configured to excite the vehicle battery. The system may be further configured to generate a battery cell degradation output based at least on the determined impedance. The corresponding method is also provided. BACKGROUND Electric vehicles have at least an electric motor and a vehicle battery. In operation, the electric motor is adapted to provide propulsion to the vehicle, e.g., to drive the transmission connected to the vehicle wheels. Electric vehicles may be pure electric vehicles, only-electric vehicles or all-electric vehicles. Electric vehicles may also include hybrid electric vehicles which combines a conventional internal combustion engine system with an electric propulsion. Different types of batteries are used to power electric motors. Lithium-ion batteries are the most utilized technology in electric vehicles. However, other types of vehicle batteries are known. In any case, it is of vital importance to operate vehicle batteries in pre-defined safety limits to ensure the safety of the user as well as the electric vehicle. In use, vehicle batteries suffer from aging, wearing, or degradation. The monitoring and control of (high-voltage) vehicle batteries in electric vehicles throughout their lifespan aim to maximize efficiency while extending their remaining useful life. The state of health or SOH of a vehicle battery refers to a measure of the current condition or performance of the vehicle battery compared to its ideal or original state when it was new. SOH is typically expressed as a percentage, where 100% indicates a vehicle battery that is in perfect condition, and lower percentages represent aging, wear, or degradation. In fact, SOH helps in assessing the remaining useful life of the vehicle battery and indicates when it may need replacement or maintenance. Improvement and optimization of energy management and the enhancement of battery lifespan are crucial topics in the automotive industry. Recent innovations in computation and electronics present remarkable advances for implementation in battery control. The use of novel artificial intelligence and other predictive models can contribute to improving the precision of battery state estimations. The remaining useful life of the battery is closely related to the SOH. Additionally, battery degradation can result in hazardous events, with thermal runaway being the most well-known. The state of safety or SOS of a vehicle battery refers to the assessment of the battery's safety status, ensuring it operates without posing risks such as fire, explosion, leakage, or other hazardous conditions. SOS evaluates the vehicle battery's ability to function safely under normal and stressful conditions, including temperature extremes, overcharging, physically damage, and other environmental factors. Thus, monitoring the SOS is also a prominent indicator to consider in the technological field of electric vehicles. The state of charge or SOC may be defined as an indication of the current charge level of the vehicle battery, typically as a percentage, showing how much energy is available for use. Existing algorithms yield remarkable results in estimating the SOC; however, the SOH requires more complex algorithms, and the SOS is still challenging to calculate for electric vehicle batteries. In known prior art, algorithms used in battery management systems for SOH and SOS rely on measured signals from the vehicle battery. Particularly, known battery management systems utilize direct measurements, such as voltage, electric current, and temperature, to calculate these indicators. However, the accuracy of these calculations depends on the performance of the underlying algorithms. It would be therefore desirable to provide a system and method for determining an electrochemical impedance of a vehicle battery in order to obviate the above-mentioned drawbacks and to provide advantageous solutions to the shortcomings in the prior art. SUMMARY It is an object of the present invention to provide an electrochemical impedance spectroscopy system configured at least to determine an electrochemical impedance of a vehicle battery. The electrochemical impedance spectroscopy system is referred hereinafter as the system for clarity and conciseness reasons. The system comprises a vehicle battery, a battery management system or BMS. A plurality of voltage sensors may be further provided preferably as part of the battery management system. The system further comprises an excitation power module, and a current sensor. The vehicle battery is arranged within a motor vehicle (for driving the motor(s) configured) to move the wheels thereof as required. The ve