Process and device for measuring the state of charge of an electrochemical generator while operating
First Claim
1. A process for measuring the state of charge of an electrochemical generator formed of at least one cell during charging or discharging of the generator, comprising:
- measuring a no-load voltage VM of the generator during an initial connection thereto, said no-load voltage VM corresponding to an electromotive force E(to) at time to of said initial connection;
selectively charging or discharging said generator;
measuring the voltage Vb during selective charging or discharging of the generator at a time t1, and computing a difference Δ
V=E(to)-Vb;
computing a value of the electromotive force E(t1) of the generator representing its state of charge at time t1 as a function of the difference Δ
V and its electromotive force E(to) at time to, wherein E(t1) is computed according to the relation
space="preserve" listing-type="equation">E(t.sub.1)=E(to)-f(Δ
V)·
τ
,in which f(Δ
V) is a predetermined law which, for a given type of generator, is independent of the nominal capacity of the generator and depends on the number of cells which make up the generator and on the sign of the difference Δ
V which is positive at discharge and negative at charge, and τ
is the elapsed time between times to and t1.
0 Assignments
0 Petitions
Accused Products
Abstract
Process and device for measuring the state of charge of an electrochemical generator such as a lead-acid battery, while operating. The device includes means for measuring the voltage of the generator means for storing the no-load voltage (V=E(to)) of the generator during its initial connection, then the last value of the computed electromotive force (V, VM), means for computing the value of the difference ΔV between the measured voltage (Vb) of the generator and the last value of the computed electromotive force (V, VM), means for determining the sign of said difference ΔV, means for measuring the elapsed time (δ) between two successive measurements of the voltage of the generator, means for computing the variation of electromotive force ΔE=f(ΔV)·δ of the generator means for computing the value of the electromotive force from the last computed value and of said variation ΔE, and means for displaying the computed value of the electromotive force.
17 Citations
15 Claims
-
1. A process for measuring the state of charge of an electrochemical generator formed of at least one cell during charging or discharging of the generator, comprising:
-
measuring a no-load voltage VM of the generator during an initial connection thereto, said no-load voltage VM corresponding to an electromotive force E(to) at time to of said initial connection; selectively charging or discharging said generator; measuring the voltage Vb during selective charging or discharging of the generator at a time t1, and computing a difference Δ
V=E(to)-Vb;computing a value of the electromotive force E(t1) of the generator representing its state of charge at time t1 as a function of the difference Δ
V and its electromotive force E(to) at time to, wherein E(t1) is computed according to the relation
space="preserve" listing-type="equation">E(t.sub.1)=E(to)-f(Δ
V)·
τ
,in which f(Δ
V) is a predetermined law which, for a given type of generator, is independent of the nominal capacity of the generator and depends on the number of cells which make up the generator and on the sign of the difference Δ
V which is positive at discharge and negative at charge, and τ
is the elapsed time between times to and t1. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A device for measuring the state of charge of an electrochemical generator during charging or discharging of the generator, comprising:
-
means for measuring and storing the voltage (Vb) of the generator; means for measuring and storing the no-load voltage (VM =E(to)) of the generator during its initial connection; means for computing and storing electromotive force (V, VM) of the generator; means for computing the value of the difference Δ
V between the measured voltage (Vb) of the generator and the last value of the computed electromotive force (V, VM);means for determining the sign of said difference Δ
V;means for measuring the elapsed time (τ
) between two successive measurements of the voltages of the generator;means for computing the variation of the electromotive force Δ
E=f(Δ
V)·
τ
of the generator, where f(Δ
V) is a predetermined law based on Δ
V;means for computing the value of the electromotive force from the last computed value (V, VM) and of said variation Δ
E; andmeans for displaying said computed value of the electromotive force. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15)
-
Specification