초록 ▼

The present invention relates to a method and an apparatus for estimating discharge and charge power of battery applications, including battery packs used in Hybrid Electric Vehicles (HEV) and Electric Vehicles (EV). One charge/discharge power estimating method incorporates voltage, state-of-charge

The present invention relates to a method and an apparatus for estimating discharge and charge power of battery applications, including battery packs used in Hybrid Electric Vehicles (HEV) and Electric Vehicles (EV). One charge/discharge power estimating method incorporates voltage, state-of-charge (SOC), power, and current design constraints and works for a user-specified prediction time horizon Δt. At least two cell models are used in calculating maximum charge/discharge power based on voltage limits. The first is a simple cell model that uses a Taylor-series expansion to linearize the equation involved. The second is a more complex and accurate model that models cell dynamics in discrete-time state-space form. The cell model can incorporate a inputs such as temperature, resistance, capacity, etc. One advantage of using model-based approach is that the same model may be used in both Kalman-filtering to produce the SOC and the estimation of maximum charge/discharge current based on voltage limits.

대표청구항 ▼

I claim: 1. A method for estimating a maximum discharge power of a battery, comprising: generating a signal indicative of a present state-of-charge of said battery, utilizing a sensor; calculating said present state-of-charge of said battery based on said signal, utilizing an arithmetic circuit ope

I claim: 1. A method for estimating a maximum discharge power of a battery, comprising: generating a signal indicative of a present state-of-charge of said battery, utilizing a sensor; calculating said present state-of-charge of said battery based on said signal, utilizing an arithmetic circuit operably coupled to said sensor; calculating a maximum discharge current of said battery utilizing said arithmetic circuit based on at least a minimum state of charge limit associated with said battery, said present state of charge of said battery a minimum voltage limit associated with said battery, and of a cell model that is solved by a Taylor series expansion of an open cell voltage of the battery to determine a future output voltage at the battery, such that the future output voltage of said battery does not fall below said minimum voltage limit and a future state-of-charge of said battery does not fall below said minimum state-of-charge limit associated with said battery; and, calculating said maximum discharge power based on said maximum discharge current value, utilizing said arithmetic circuit. 2. The method of claim 1 wherein said cell model is solved by using a discrete time-state space model. 3. The method of claim 1 wherein said battery is a battery pack comprising at least one cell. 4. The method of claim 3 wherein said cell model is description="In-line Formulae" end="lead"vk(t+Δt)=OCV(zk (t+Δt))-R��ik(t)description="In-line Formulae" end="tail" wherein vk(t+Δt) denotes the cell voltage for cell k for the time period Δt units into the future, OCV(zk(t+Δt)) denotes the open cell voltage as a function of the state-of-charge zk for cell k for the time period Δt units into the future, R is a constant that denotes an internal resistance of said cell k, and ik(t) denotes a cell current for cell k. 5. The method of claim 4 wherein said cell model is solved by using a discrete time-state space model. 6. The method of claim 5 wherein said discrete time-state space model is description="In-line Formulae" end="lead"xk[m+1]=f(xk[m],u k[m])description="In-line Formulae" end="tail" description="In-line Formulae" end="lead"vk[m]=g(xk[m],u k[m])description="In-line Formulae" end="tail" wherein m denotes the discrete time sample index, xk[m] denotes the vector function of time and the state of the battery, uk[m] denotes the input to the battery and includes cell current ik[m] as a component, and f(•) and g(•) are functions chosen to model the cell dynamics. 7. The method of claim 6 wherein is found by looking for ik that causes equality in description="In-line Formulae" end="lead"vmm=g(xk[m+T],u k[m+T])description="In-line Formulae" end="tail" wherein g(xk[m+T], uk[m+T]) is utilized to determine the cell voltage for the cell k at a predetermined time in the future.