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EP-4741853-A1 - ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY SYSTEM AND METHOD

EP4741853A1EP 4741853 A1EP4741853 A1EP 4741853A1EP-4741853-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. 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
20251105

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 excitation power module (30) comprises an energy accumulator (31), and an energy modulator (32), wherein the energy accumulator (31) is configured to store electric power to be provided to the energy modulator (32), and wherein the energy modulator (32) is configured to generate a variable excitation current signal to the vehicle battery (10), preferably the energy accumulator (31) is or comprises a DC-link capacitor (412), a low-voltage converter (312), a DC/DC converter, or an on-board charger system (440).
  3. The system of claim 2, wherein it further comprises a first switching device (51) connected to the vehicle battery (10), the first switching device (51) being configured to switch between an open position to a close position, wherein the energy modulator (32) is associated with the first switching device (51), and wherein the first switching device (51) is in the open position during operation of the excitation power module (30).
  4. The system of claim 3, wherein it further comprises a second switching device (52) connected to the vehicle battery (10), the second switching device (52) being configured to switch between an open position to a close position, wherein the energy modulator (32) is associated with the first switching device (51) and the second switching device (52), and wherein the first switching device (51) is in the open position and the second switching device (52) is in the closed position during operation of the excitation power module (30).
  5. The system of claim 4, wherein when both the first switching device (51) and the second switching device (52) are open, the vehicle battery (10) is electrically isolated, wherein when both the first switching device (51) and the second switching device (52) are closed, the vehicle battery (10) supplies electric power, and during operation of the excitation power module, the first switching device (51) is in the open position, and the second switching device (52) is in the closed position.
  6. The system of any of claims 3-5, wherein the excitation power module (30) and the vehicle battery (10) are electrically connected to each other through a first conductor (11) and a second conductor (12), in use, the first switching device (51) is connected to the first conductor (11), and preferably the second switching device (52) is connected to the second conductor (12).
  7. The system of any of claims 3-6, wherein it further comprises a switching device controller configured to control the open and closed positions of the first switching device (51) and preferably the second switching device (52), optionally the switching device controller is arranged in the junction box (300), preferably the energy modulator (32) is arranged in the junction box (300), and wherein the energy accumulator (31) is preferably out of the junction box (300).
  8. The system of any of claims 3-7, wherein the first switching devices (51) and/or the second switching device (52) is an electronic switching device or an electromechanical switching device such as a contactor or a relay.
  9. The system of any of claims 3-8, wherein the first switching device (51) defines a first side (511) and a second side (512), the first side (511) being arranged between the energy accumulator (31) and the first switching device (51), and the second side (512) being arranged between the first switching device (51) and the vehicle battery (10), wherein the energy modulator (32) comprises a first branch (321), and a second branch (322), wherein the first branch (321) is electrically connected to the second branch (322), and wherein the first branch (321) is electrically connected to the first side (511) of the first switching device (51), and the second branch (322) is electrically connected to the second side (512) of the first switching device (51), preferably the energy modulator (32) comprises an inductor (329) associated with the second branch (322), and more preferably the energy modulator (32) comprises a first semiconductor switch (325) associated with the first branch (321).
  10. The system of claim 9, wherein the energy modulator (32) further comprises a third branch (323), the third branch (323) being electrically connected to the first and second branches (321, 322), and wherein the third branch (323) is electrically connected to either side (521, 522) of the second switching device (52), preferably the energy modulator (32) comprises a second semiconductor switch (326) associated with the third branch (323).
  11. The system of any of claims 9-10, wherein the energy modulator (32) comprises a first anti-series semiconductor switch (325') associated with the first branch (321), being connected in series with the first semiconductor switch (325), with its conduction path arranged in an opposite direction to the conduction path of the first semiconductor switch (325). .
  12. The system of any of claims 10-11, wherein the energy modulator (32) comprises a second anti-series semiconductor switch (326') associated with the third branch (323), being connected in series with the second semiconductor switch (326), with its conduction path arranged in an opposite direction to the conduction path of the second semiconductor switch (326).
  13. The system of any of claims 2-12, wherein the energy modulator (32) comprises at least a two-quadrant topology that includes the first and the second semiconductor switches (325, 326), in use, enabling at least bidirectional current flow so as to modulate the excitation current signal.
  14. The system of any of claims 9-13, wherein it further comprises a semiconductor switch controller configured to control the open and closed positions of each semiconductor switch (325, 326, 327, 328, 325', 326'), preferably the semiconductor switch controller is arranged in the junction box (300), and optionally the semiconductor switch controller and the switching device controller are integrated into an electronic control unit, preferably arranged in the junction box (300).
  15. 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). preferably the method further comprises: - opening a first switching device (51), and preferably closing a second switching device (52), optionally the first switching device (51) is open at least in an instant when the second switching device (52) is closed; - closing a first semiconductor switch (325) in a first stage, wherein energy of an energy accumulator (31) of the excitation power module (30) passes through an inductor (329) and is received by the vehicle battery (10), returning to the energy accumulator (31) preferably through the second switching device (52); and - opening the first semiconductor switch (325) in a second stage, wherein energy of the energy accumulator (31) does not pass through the first semiconductor switch (325), wherein the inductor (329) provides energy to the vehicle battery (10), for example, through a second semiconductor switch (326) or a diode.

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