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EP-4741855-A1 - METHOD AND SYSTEM FOR DETERMINING AN FINAL STATE OF HEALTH OF A BATTERY OF AN ELECTRIC OR HYBRID MOTOR VEHICLE

EP4741855A1EP 4741855 A1EP4741855 A1EP 4741855A1EP-4741855-A1

Abstract

- Method and system for determining the final state of health of a battery in an electric or hybrid motor vehicle. - The determination system (1) includes a receiving unit (4) configured to receive discharged energy ( X1 ) during a first cycle and an i-th discharged energy (Xi) during an i-th cycle, a calculation unit (6) configured to determine a final state of health ( SoH1b ) at the end of the first cycle and to determine the final state of health ( SoH1N ) by setting the i-th initial state of health ( SoHia ) equal to the (i-1)-th final state of health (SoH (i-1)b ) at the end of the (i-1)-th cycle and a transmission unit (7) configured to transmit the final state of health ( SoH1N ) of the battery (2) to a user device (8).

Inventors

  • NGUYEN, OLIVIER
  • HADJ-HAMOU, Rayan

Assignees

  • AMPERE s.a.s.

Dates

Publication Date
20260513
Application Date
20251106

Claims (9)

  1. Method for determining the final state of health (SoH 1N ) of a battery (2) of an electric or hybrid motor vehicle (3) capable of being subjected to N successive cycles, N being at least equal to two, each cycle being associated with a degradation curve (C 1 , ..., C N ) indicating the state of health of the battery (2) as a function of energy discharged by the battery (2), the degradation curves of two consecutive cycles being distinct from each other, characterized in that it comprises the following steps: - a first reception stage (E1), implemented by a receiving unit (4), to receive from an energy meter (5) a signal representative of a first energy discharged (X 1 ) during the first cycle; - a first determination step (E2), implemented by a computing unit (6), to determine a first final state of health (SoH 1b ) at the end of a first cycle from a first degradation curve (C 1 ) associated with the first cycle and the first energy discharged (X 1 ) during the first cycle; - the following sequence of steps repeated from i = 2 to i = N: ∘ an i-th reception step (E1 i ), implemented by the receiving unit (4), to receive from the energy meter (5) a signal representative of an i-th energy discharged (X i ) during the i-th cycle, ∘ an i-th determination step (E2 i ), implemented by the calculation unit (6), to determine the final health state (SoH 1N ), an i-th final health state (SoH ib ) at the end of the i-th cycle being determined from an i-th degradation curve (Ci) associated with the i-th cycle and by setting that the i-th initial health state (SoH ia ) is equal to the (i-1)-th final health state (SoH (i-1)b ) at the end of the (i-1)-th cycle; - a transmission step (E3), implemented by a transmission unit (7), to transmit a signal representative of the final state of health (SoH 1N ) of the battery (2) to a user device (8).
  2. Method according to claim 1, characterized in that the i-th determination step (E2 i ) comprises: - a substep of determining (E21 i ) an i-th initial energy (X ia ) at the beginning of the i-th cycle from an i-th initial health state (SoH ia ) and an i-th degradation curve (Ci ), the i-th initial health state (SoH ia ) being equal to the (i-1)-th final health state (SoH (i-1)b ) at the end of the (i-1)-th cycle, - a substep of determining (E22 i ) an i-th final health state (SoH ib ) at the end of the i-th cycle from the i-th degradation curve (Ci) associated with the i-th cycle and a sum of the i-th initial energy (X ia ) and an i-th discharged energy (X i ) during the i-th cycle, - a substep of determining (E23 i ) a state of health of the battery, the state of health of the battery being equal to the difference between the i-th initial state of health (SoH ia ) and the i-th final state of health (SoH ib ).
  3. A method according to any one of claims 1 and 2, characterized in that the first cycle exhibits an initial state of health (SoH 1a ) corresponding to the state of health of a new battery.
  4. A method according to any one of claims 1 to 3, characterized in that the first reception step (E1) is implemented by the reception unit (4) further to receive first operating data characteristic of the first cycling, the first degradation curve ( C1 ) being chosen by the calculation unit (6) according to the operating data; the i-th reception step (E1 i ) being implemented by the reception unit (4) further to receive i-th operating data, the i-th degradation curve (Ci) being chosen by the calculation unit (6) according to the i-th operating data.
  5. System for determining the final state of health (SoH 1N ) of a battery (2) of an electric or hybrid motor vehicle (3) capable of being subjected to N successive cycles, N being at least equal to two, each cycle being associated with a degradation curve (C 1 , ..., C N ) indicating the state of health of the battery (2) as a function of energy discharged by the battery (2), the degradation curves of two consecutive cycles being distinct from each other, characterized in that it comprises: - a receiving unit (4) configured to receive from an energy meter (5) a signal representative of a first energy discharged (X 1 ) during the first cycle, - a computing unit (6) configured to determine a first final state of health (SoH 1b ) at the end of a first cycle from a first degradation curve (C 1 ) associated with the first cycle and the first energy discharged (X 1 ) during the first cycle; for i = 2 to i = N: - the receiving unit (4) being configured to receive from the energy meter (5) a signal representative of an i-th energy discharged (X i ) during the i-th cycle, - the computing unit (6) being configured to determine the final health state (SoH 1N ), an i-th final health state (SoH ib ) at the end of the i-th cycle being determined at each iteration i from an i-th degradation curve (Ci) associated with the i-th cycle and by setting that the i-th initial health state (SoH ia ) is equal to the (i-1)-th final health state (SoH (i-1)b ) at the end of the (i-1)-th cycle; the system further comprising a transmission unit (7) configured to transmit a signal representative of the final state of health (SoH 1N ) of the battery (2) to a user device (8).
  6. System according to claim 5, characterized in that the calculation unit (6) is configured with i = 2 to i = N for: - determine an i-th initial energy (X ia ) at the beginning of the i-th cycle from an i-th initial health state (SoH ia ) and an i-th degradation curve (Ci ), the i-th initial health state (SoH ia ) being equal to the (i-1)-th final health state (SoH (i-1)b ) at the end of the (i-1)-th cycle, - determine an i-th final health state (SoH ib ) at the end of the i-th cycle from the i-th degradation curve (Ci) associated with the i-th cycle and a sum of the i-th initial energy (X ia ) and an i-th discharged energy (X i ) during the i-th cycle, - determine a battery health state, the battery health state being equal to the difference between the i-th initial health state (SoH ia ) and the i-th final health state (SoH ib ).
  7. System according to one of claims 5 and 6, characterized in that the first cycle exhibits an initial state of health (SoH 1a ) corresponding to the state of health of a new battery.
  8. System according to any one of claims 5 to 7, characterized in that the receiving unit (4) is further configured to: - receive initial operating data characteristic of the first cycling, the first degradation curve (C 1 ) being chosen by the calculation unit (6) according to the operating data; - receive i-th operating data with i = 2 to i = N, the i-th degradation curve (Ci) being chosen by the calculation unit (6) as a function of the i-th operating data.
  9. electric or hybrid motor vehicle comprising at least one battery capable of being subjected to N successive cycles, N being at least equal to two, characterized in that it comprises a system for determining (1) a final state of health of a battery (2), as specified under any one of claims 5 to 8.

Description

technical field The present invention relates to a method and a system for determining the final state of health of a battery of an electric or hybrid motor vehicle subjected to a plurality of successive use cycles, two consecutive cycles having distinct degradation profiles from each other. State of the art During its use, a traction battery in an electric or hybrid vehicle will age. The battery may undergo at least one usage cycle, also known as a cycling cycle. A cycling cycle corresponds to a specific type of battery use involving charging and discharging. The state of health (SoH) of a battery is generally defined at a given time t as the ratio between, on the one hand, the total energy or capacity that can be extracted from the battery at that time t and, on the other hand, the total energy or capacity that can be extracted from the battery before any use, i.e., when the battery is new. The state of health of a battery, often expressed as a percentage, therefore represents an indicator that reflects the percentage of residual energy in a battery, a portion of which is irreversibly lost due to use and associated battery degradation. Understanding the health and aging of a battery is a crucial technical issue for automakers and battery manufacturers. Knowing the State of Health (SoH) allows them to estimate a battery's lifespan. For example, when the SoH indicates that the battery is nearing the end of its life, it may need to be replaced. This knowledge of battery health is also important from an economic perspective. Maximizing the SoH, for instance, makes it possible to consider giving the battery a second life. battery. This knowledge is also an important issue from a regulatory point of view. Indeed, the regulations define the accuracy of the SoH. Several methods already exist for determining the SoH of a battery. The SoH can be determined by direct measurement, either outside the vehicle (battery removed from the vehicle), or during its use requiring a dedicated phase of vehicle use. The state of health (SoH) can also be determined predictively using semi-empirical models. This predictive method can estimate the vehicle's SoH at any given time and inform the customer in real time. However, currently, faced with the increasing number of customer uses, we are witnessing a diversification of battery cycling patterns. Indeed, in addition to traditional driving with conventional charging at charging stations generally limited to low power outputs (between 7 kW and 11 kW, for example), there are now uses involving fast charging (with power levels exceeding 100 kW), or new applications such as Vehicle-to-Grid (V2G) or Vehicle-to-Load (V2L), in which the battery is used to power an electrical grid or an electrical device. This diversity of uses can result in different degradation profiles, that is, varying degradation kinetics or, in other words, rates of degradation depending on the type of cycling. Thus, from a historically simple situation in which only one type of cycling is carried out, we have moved to a more complex situation in which several very different types of cycling and uses are carried out. We can distinguish, in particular, a cycling profile specific to vehicle operation (i.e., at non-zero speed); a profile related to slow vehicle charging; a profile related to fast vehicle charging; a profile related to using the battery to recharge an electrical network external to the vehicle, of the so-called V2G type; etc. However, there are methods for determining the SoH by taking into account the number of different uses or cycles. A process is based on a model that relies on a single degradation law. In other words, if the battery is subjected to at least two types of cycling with different degradation kinetics, then an aging kinetics law The term "averaged" is used to consider a single degradation law in cycling. However, it can prove factually difficult to find an averaged kinetic law, either because it is analytically difficult to construct, or because it would require numerous costly and time-consuming tests. Another method involves summing cycle degradations independently. In other words, it's as if the SoH degradations of a battery subjected to cycle A and cycle B were equal to the SoH degradations calculated independently for cycle A and cycle B, according to an "additivity law" of SoH degradation. However, this law is known to be mathematically incorrect and leads to inaccuracies in SoH estimation. Furthermore, this method doesn't account for battery aging. Indeed, for each cycle, the SoH degradation is determined by taking the SoH of a new battery as the starting point, without considering the battery's aging over the previous cycle(s). The methods for determining the SoH of batteries are therefore not entirely satisfactory. Description of the invention The present invention aims to provide a method for determining the health status of a battery in an electric or hybrid motor vehicle t