METHOD FOR THE CONTINUOUS MEASUREMENT OF THE EFFICIENCY OF A BATTERY, ESPECIALLY A BATTERY INSTALLED IN MOTOR VEHICLES, AND A DEVICE UTILIZING THIS METHOD

• US 20120265397A1
• Filed: 10/21/2010
• Published: 10/18/2012
• Est. Priority Date: 10/27/2009
• Status: Active Grant

• Current Assignee: Fiamm Energy Technology SpA (Resonac Holdings Corp.)
• Original Assignee: FIAMM S.p.A. (Johnson Controls International plc)
• Inventors: Aliberti, Roberto, Cazzanti, Silvia
• Granted Patent: US 8,788,142 B2
• Time in Patent Office: Days
• US Class Current: 701/34.4
• CPC Class Codes: B60L 58/10 for monitoring or controlling batteries
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/3835 involving only voltage measurements
• CPC Class Codes: G01R 31/388 involving voltage measurements
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: H01M 10/4257 Smart batteries, e.g. electronic circuits inside the housing of the cells or batteries
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H01M 10/486 for measuring temperature
• CPC Class Codes: H01M 10/488 Cells or batteries combined with indicating means for external visualization of the condition, e.g. by change of colour or of light density
• CPC Class Codes: H01M 2010/4271 Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
• CPC Class Codes: H01M 2220/20 Batteries in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A method for the continuous measurement of the efficiency of a battery, especially a battery installed in motor vehicles, comprising the following phases: —determination of the state of charge SOC % of the battery installed in the vehicle, both during key-off phase and key-on phase, without the direct measurement of current through progressive readings of battery voltage, both in the absence and in the presence of electrical load and considering the time elapsed since the beginning of each discharge phase; —determination of the state of health SOH of the same battery through the application of a controlled current load and the comparison of the resulting voltage drop compared to predetermined parameters; —determination of the state of function SOF of said battery through an estimation of its residual autonomy in function of the discharge rate or current rate and of the evolution of SOC %; —correlation and normalization of the above described parameters (SOC, SOH, and SOF) depending on the battery operating temperature; —memorization of at least the values of initial SOC % and SOH detected during the key—off phase.

Claims

1. ) A method for the continuous measurement of the efficiency of a battery, especially a battery installed in motor vehicles, including the following phases:

determination of the state of charge SOC % of the battery installed in the vehicle, both during key-off phase and key-on phase, without the direct measurement of current through progressive readings of battery voltage, both in the absence and in the presence of electrical load and considering the time elapsed since the beginning of each discharge phase;

determination of the state of health SOH of the same battery through the application of a controlled current load and the comparison of the resulting voltage drop compared to predetermined parameters;

determination of the state of function SOF of said battery through an estimation of its residual autonomy in function of the discharge rate or current rate and of the evolution of SOC %;

correlation and normalization of the above described parameters (SOC, SOH, and SOF) depending on the battery operating temperature;

memorization of at least the values of initial SOC % and SOH detected during the key—

off phase.

2. ) The method for the continuous measurement of the efficiency of a battery as in claim 1, including the additional monitoring phase or repetition of the periodic detection of the SOC %, SOH and SOF and memorization of the respective data.

3. ) The method for the continuous measurement of the efficiency of a battery as in claim 1, in which the progressive reading of the battery voltage is used to determine when said battery is in a state of discharge.

4. ) The method for the continuous measurement of the efficiency of a battery as in claims 1 and 2, in which the current rate or current discharge rate is determined by means of the parameters:

initial SOC %, V_n and t_n which respectively indicate the initial state of charge of the battery, the battery voltage at time t_n and the time in seconds counted from the beginning of a discharge phase.

5. ) The method for the continuous measurement of the efficiency of a battery as in claim 1, in which the variation of SOC % is evaluated by the determination of the discharge rate.

6. ) The method for the continuous measurement of the efficiency of a battery as in claim 5, in which the determination of SOH at the n-th time is correlated to the SOC % at the n-th time and is evaluated by means of a voltage drop Δ

V determined by applying a controlled and constant current load of 15÷

50 A for a predetermined period of time of 0.1÷

30 seconds.

7. ) The method for the continuous measurement of the efficiency of a battery as in claim 6, in which the initial SOH value is converted into a numerical value of between zero and 1 through the relation:

(B−

Δ

V)/(b−

a)

in which “

b”

indicates the voltage drop that occurs at a given SOC % value by application of the controlled current load, while “

a”

indicates the minimum voltage drop that occurs by application of the controlled current load at a given SOC % value.

8. ) The method for the continuous measurement of the efficiency of a battery as in claim 1, in which the state of function, SOF, is related, on the one hand, to the residual autonomy of the battery at all times, determined by evaluation of the discharge rate and, on the other hand, to the SOC % at the same time, and finally to a SOC % limit which defines the guarantee of engine restart.

9. ) A device for the continuous measurement of the efficiency of a battery, according to the methods described in the previous claims, said device being installed in the vehicle and in electrical contact with the battery, by which it is powered, including at least one temperature sensor and one voltage sensor, with connecting wires to the battery terminals, a predetermined and controlled resistive load, an electronic monitoring, recording, processing and data storage card, said device must be able to transmit in output the processed information (encoded or not), with the possible transmission of an audible and/or visible signal to the driver of the vehicle.