Patent ID: 7486079

Claim:
An available input-output power estimating device for a secondary battery, comprising: a current detector measuring a value I of a current of the secondary battery; a voltage detector measuring a value V of a terminal voltage of the secondary battery; a parameter estimating section substituting the measured current value I and the measured voltage value V into an adaptive digital filter using a battery model represented by an equation (a) for thereby collectively estimating a value of a parameter vector, as a parameter vector estimate value, in the equation (a); an open circuit voltage calculator substituting the measured current value I, the measured voltage value V, and the parameter estimate value into the equation (a) for thereby calculating a value {circumflex over (V)} 0 , as an open circuit voltage estimate value, of an open circuit voltage V 0 ; an available input power estimating section substituting a set of components (â n ,{circumflex over (b)} n ), which is associated with a direct term in the equation (a) through an equation (d) where components (â n ,{circumflex over (b)} n ), are estimate values of parameters (â n ,{circumflex over (b)} n ), of the parameter vector estimate value, the open circuit voltage estimate value {circumflex over (V)} 0 , and an upper limit voltage V max , which is predetermined, of the terminal voltage V into an equation (b) for thereby estimating an available input power P in of the secondary battery; and an available output power estimating section substituting the one set of components (â n ,{circumflex over (b)} n ), which is associated with the direct term in the equation (a), of the parameter vector estimate value, the open circuit voltage estimate value {circumflex over (V)} 0 , and a lower limit voltage V min , which is predetermined, of the terminal voltage V into an equation (c) for thereby estimating an available output power P out of the secondary battery; wherein the equations (a), (b), and (c) are described, respectively, as V = B ⁡ ( s ) A ⁡ ( s ) ⁢ I + 1 C ⁡ ( s ) ⁢ V 0 , ( a ) P ^ in = V max - V ^ 0 b ^ n ⁢ ⁢ a ^ n ⁢ V max , ( b ) and P ^ out = V ^ 0 - V min b ^ n ⁢ ⁢ a ^ n ⁢ V min ( c ) where A(s), B(s), and C(s) represent polynomials of a Laplace operator s, respectively, as follows: A ⁡ ( s ) = ∑ k = 0 n ⁢ a k ⁢ s k , B ⁡ ( s ) = ∑ k = 0 n ⁢ b k ⁢ s k , and ⁢ ⁢ C ⁡ ( s ) = ∑ k = 0 n ⁢ c k ⁢ s k ( d ) where the first order coefficients a 1 , b 1 , and c 1 of the polynomials take non-zero values, respectively, wherein: the set of components (â n ,{circumflex over (b)} n ) includes time constants of the parameter vector estimate value and is filtered with a lowpass function.