Yazaki Corporation

Youichi Arai

Tsutomu Saigo

Kenichi Shimoyama

Hideaki Kamohara

Yoshihide Takada

Shuji Satake

Tomohiro Kawaguchi

Michito Enomoto

Ryo Kumagai

Hiroshi Ichikawa

Kazuyoshi Ogasawara

Ken Ito

Yoshiyuki Suzuki

Syuji Satake

Yoshiya Miyazaki

Brendan O'Toole

Tsutomo Saigo

Norihito Enomoto

Makoto Ishigami

Kiyoshi Nakajima

A microcomputer monitors, on the basis of outputs from a current sensor and voltage sensor, a voltage drop due to an internal resistance when the drop in the terminal voltage due to polarization occurring during the discharge of a battery is saturated, and a dischargeable capacity of the battery corresponding to the value resulting when the saturated voltage drop of the terminal voltage is subtracted from the chargeable capacity of the battery. Such a configuration provide a battery status monitoring device capable of knowing the battery status correctly, a saturation polarization detecting method which is useful to know the charging state of the battery and a dischargeable capacity detecting method.

Battery status monitoring apparatus which monitors internal battery resistance, saturation polarization detecting method and dischargeable capacity detecting method

A method of estimating a state of charge of a battery, a method of estimating an open circuit voltage of a battery, and a method and device for computing a degradation degree of a battery are provided. As a degradation degree, a ratio of a total electrical quantity chargeable or dischargeable of a battery at any time point to an initial electrical quantity that is a total electrical quantity chargeable or dischargeable of the battery upon non-degradation is computed, and by using the degradation degree, a state of charge or an open circuit voltage of the battery is accurately estimated.

Method of estimating state of charge and open circuit voltage of battery, and method and device for computing degradation degree of battery

A discharge current and terminal voltage of the battery are periodically measured while a rush current flows into a predetermined constant load of the loads. The rush current first monotonically increases from zero to a peak value and subsequently monotonically decreases from the peak value to a steady value. A first approximate expression of a current-voltage characteristic for the increasing discharge current and a second approximate expression of a current-voltage characteristic for the decreasing discharge current are computed. An intermediate value of two values of the terminal voltage change per unit current change at points corresponding to the peak values of the first and second approximate expressions excluding a voltage drop caused by a concentration polarization component is computed when the first and second approximate expressions include the voltage drop. The intermediate value computed is measured as the pure resistance of the battery.

Method and device for measuring pure resistance of on-vehicle battery by periodically measuring a discharge current and terminal voltage while a rush current flows into a constant load

A charging efficiency, which is a ratio of an electrical quantity charged in a battery as an electromotive force to a total electrical quantity supplied to the battery, is computed at a plurality of measuring points between a start and an end of charging of the battery. A resistance difference of the battery between a resistance at the charge start point and a resistance at one of the measuring points is obtained, and a full charged state resistance is obtained at a full charged state of the battery. By using a ratio of the resistance difference to the full charged state resistance, a charging efficiency of the battery is computed at the one of the measuring points. The battery is in an active state where no passivating film is formed on poles of the battery. A charged electrical quantity of the battery is obtained based on the charging efficiencies sequentially obtained during the charging of the battery when the battery is in the active state. In the mean time, a charged electrical quantity of the battery is obtained based on an integration of a charging current multiplied by a corresponding charging time during a transition period in which a passivating film remains on the poles of the battery before the charging current sufficiently breaks the passivating film.

Method and unit for computing charging efficiency and charged electrical quantity of battery

A discharge current and a voltage between a pair of terminals of a battery while a rush current is flowing in a load electrically connected to the pair of the terminals. The rush current simply decreases from a peak to a constant value after the rush current simply increases up to the peak. A first approximate equation is provided for showing a correlation between the current and the voltage in a region where the discharge current is increasing. A second approximate equation is provided for showing a correlation between the current and the voltage in a region where the discharge current is decreasing. A voltage from each of the first and second approximate equations at a point where the discharge current is zero is calculated so that a deference between the two voltages at the current zero point is obtained. The difference is determined to be a total voltage drop due to a concentration polarization of the battery. A voltage drop due to the concentration polarization is calculated from the total voltage drop at any point of the discharge current in use of a relation between the concentration polarization voltage drop and the discharge current with a corresponding discharging time.

Method and unit for computing voltage drop divided along factors for battery

A method and apparatus are provided, by which a state of charge of a battery is accurately computed without being influenced by the polarization effect. An estimated voltage of the battery in a constant load discharge with a predetermined large current value is estimated from a voltage-current characteristic when the discharge current of the constant load discharging process by the battery that is in an equilibrium state is decreasing from the predetermined large current value corresponding to a maximum supplying electric power to the load. A difference between the estimated voltage and an open circuit voltage, which estimates the estimated voltage and is a terminal voltage of the battery that is in an equilibrium state before the start of the constant load discharge by using the predetermined large current value, is calculated. Then, the difference is memorized by first memory means for memorizing a residual voltage drop defining as the residual voltage drop due to a residual polarization at the end of the discharging process of the battery . The residual voltage drop memorized by the first memory means is added to the estimated voltage of the battery , thereby a present charging capacity of the battery is computed.

Battery capacity calculating method and device therefor

A base resistance of the battery is obtained by cyclically measuring a discharge current and a voltage between a pair of terminals of the battery, while a rush current is flowing in an electric load electrically connected to the pair of the terminals. The rush current monotonically decreases from a peak to a constant value after the rush current monotonically increases from zero to the peak. A concentration polarization resistance and an activation polarization resistance of the battery are also obtained from the discharge current and the terminal voltage. A degradation degree of the battery is obtained by multiplying the degradation degrees of the base resistance and the polarization resistances together.

Degradation degree computing method and unit for battery

A method and an apparatus for computing a charging state of a battery without being affected by an influence of polarization are provided. First computing means computes a voltage-current characteristic including the influence of the polarization during an decrease of a discharge current of the battery on the basis of a terminal voltage and discharge current measured while the battery carries out a constant load discharge with a current value large enough to cancel a charge-side polarization arisen in the battery at least just before the discharge. A second computing means shifts the voltage-current characteristic to a specific extent in the direction of a voltage coordinate axis. A residual voltage drop value in advance stored by storing means is added to a present estimated voltage value estimated by estimating means on the basis of the shifted voltage-current characteristic, thereby a present open circuit voltage of the battery is computed.

Method and apparatus for estimating terminal voltage of battery, method and apparatus for computing open circuit voltage of battery, and method and apparatus for computing battery capacity

In an apparatus for measuring a pure resistance of an in-vehicle battery, a terminal voltage and a discharging current of the battery are measured when the discharging current flows from the battery. A first approximate equation of a voltage-current characteristic curve is acquired for an increasing discharging current, and a second approximate equation is the voltage-current characteristic curve is acquired for a decreasing discharging current. Two points providing equal synthesized resistances each composed of the pure resistance and polarization resistance component are set on the voltage-current characteristic curves represented by the first and the second approximate equations, respectively. The gradients between the two points in each of the voltage-current characteristic curves are corrected to provide two corrected gradients each exclusive of a voltage drop due to the polarization resistance component. The two corrected gradients are averaged to provide an average value which is measured as a pure resistance of the battery.

Method and apparatus for measuring pure resistance of in-vehicle battery

After an initial capacity setter (,) sets the initial residual capacity immediately after the application of power as 100%, a full-charge voltage corrector (,) sets the full-charge voltage as the estimation voltage Vn,of a battery (,) immediately after a load change, this full-charge voltage Vno being used to determine the residual capacity SOC immediately after the change. After charging is interrupted midway, if the load is changed, a full-charge voltage estimator estimates the full-charge voltage responsive to the estimation voltage immediately after the load change, this estimated full-charge voltage being used to determine the residual capacity.

Residual capacity measurement system for battery

A battery capacity detection system according to the invention is provided with: a temperature sensor for sensing a temperature of the battery; a full-charge voltage calculation section for calculating a voltage of the battery in a full charge state by using the temperature sensed by the temperature sensor; and an SOC calculation section for calculating an SOC of the battery by using the voltage of the battery in the full charge state calculated by using the temperature in the full-charge voltage calculation processing section.

Battery capacity detection system with temperature correction

A method and apparatus capable of detecting a considerably high voltage of a power supply while preventing an increase in the size and cost of circuitry, an increase in the amount of heat being generated, and a reduction in the detection accuracy of the circuitry. The voltage of a power supply to be detected is divided by way of a voltage-dividing resistor array. An voltage-to-current converter converts a potential difference appearing across the second voltage-dividing resistor in the array into a primary current so as to correspond to the potential difference. The converted primary current flows through a primary winding and an energization resistor. A second magnetic flux develops in a magnetic core from a secondary current, which flows through the secondary winding from a current buffer on the basis of the voltage output from a hole element according to the primary current. This second magnetic flux cancels the primary magnetic flux developed in the magnetic core from the primary current flowing through the primary winding and an energization load. As a result, a potential difference, which can be used for detecting the voltage of the power supply, develops across a detection load connected to the secondary winding.

Method and apparatus for detecting supply voltage

A battery remaining capacity measuring apparatus comprises a temperature sensor 5 and a remaining capacity operation portion 19. A temperature sensor 5 detects a temperature of a battery 3. A remaining capacity operation portion 19, wherein when a detected temperature of a battery 3 from a temperature sensor 5 is not within the range of a predetermined temperature in the state of an open circuit, a load 1 and a battery 3 which are previously obtained according to a detected temperature correct a line pattern in the state of an open circuit and when a load is connected to a battery, a remaining capacity can be obtained on the corrected line. Accordingly, it is possible to obtain a remaining capacity according to this temperature, even if a temperature of a battery 3 is not within the range of a predetermined temperature.

Battery remaining capacity measuring apparatus

As a simulation load is driven with an object cell, a cell discharge stop voltage is estimated by collecting data of a discharge current and a terminal voltage, processing the collected data to obtain an approximate linear function between the discharge current and the terminal voltage, substituting a first reference value into the linear function to estimate a first voltage, making a decision for the first voltage having reached a second reference value, responding to the decision for substituting a third reference value into the linear function to estimate a second voltage, and outputting the second voltage as a representative value of the discharge stop voltage.

Method and system for estimation of cell discharge stop voltage

A battery remaining capacity measuring apparatus including a remaining capacity operation portion 3 for collecting a voltage of a battery 3 and a current passing through a load until an accelerator is on when turning an accelerator on and once turning an accelerator off after starting an ignition, obtaining a line from 2 points having a strongest relationship between the voltage and the current, and displaying an initial remaining capacity according to this line and a reference value.

Growing community of inventors

Shizuoka, Japan

Youichi Arai