Battery voltage monitoring device

• US 10,033,201 B2
• Filed: 05/19/2010
• Issued: 07/24/2018
• Est. Priority Date: 05/20/2009
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Kaneko, Kazumi, Iguchi, Hirofumi, Takanezawa, Yuki
• Primary Examiner(s): QUIGLEY, KYLE ROBERT
• Application Number:
  US13/265,990
• Publication Number:
  US 20120046893A1
• Time in Patent Office: 2,988 Days
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2250/10 by alarm
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 58/14 Preventing excessive discharging
• CPC Class Codes: B60L 58/18 of two or more battery modules
• CPC Class Codes: B60L 58/21 having the same nominal voltage
• CPC Class Codes: B60L 58/24 for controlling the temperature of batteries
• CPC Class Codes: G01R 31/396 Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
• CPC Class Codes: H01M 10/441 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/005 Detection of state of health [SOH]
• CPC Class Codes: H04Q 2209/30 using a wired architecture
• CPC Class Codes: H04Q 2209/823 where the data is sent when the measured values exceed a threshold, e.g. sending an alarm
• CPC Class Codes: H04Q 9/00 Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 90/16 Information or communication technologies improving the operation of electric vehicles

Abstract

A battery controller 10 outputs a voltage sampling and holding command signal to an integrated circuit CCn located at an upstream end of cascade connection of integrated circuits CC1-CCn such that integrated circuits CC1-CCn sample and hold output voltages of unit cells 1 grouped into battery modules M1-Mn. The battery controller 10, after transmission of the voltage sampling and holding command signal, outputs a transmission command signal to the integrated circuit CCn at the upstream end of the cascade circuit to transmit output voltages of the unit cells 1 held in the integrated circuits CC1-CCn to the battery controller 10. As a result, a time lag in the detection timings of output voltages of the unit cells 1 of the battery modules M1-Mn can be decreased.

Claims

1. A battery voltage monitoring device for monitoring an output voltage of a unit cell or unit cells in each of battery modules that are connected in series, comprising:

integrated circuits, each of which samples and holds the output voltage of the unit cell or unit cells in each of the battery modules;

a cascade communication circuit that connects the integrated circuits in series to transmit signals to the integrated circuits according to a connection order of the integrated circuits; and

a programmable controller connected to an integrated circuit located at an upstream end of the cascade communication circuit and an integrated circuit located at a downstream end of the cascade communication circuit with respect to signal transmission;

wherein the controller is programmed to;

output a voltage sampling and holding command signal to the integrated circuit at the upstream end such that the voltage sampling and holding command signal be transmitted to each of the integrated circuits via the cascade communication circuit, the voltage sampling and holding command signal commanding each of the integrated circuits to sample and hold the output voltage of the unit cell or unit cells in each of the battery modules; and

output a transmission command signal to the integrated circuit at the upstream end such that the transmission command signal be transmitted via the cascade communication circuit to each of the integrated circuits after transmission of the voltage sampling and holding command signal, the transmission command signal commanding each of the integrated circuits to transmit the output voltage held by each of the integrated circuits to the controller via the cascade communication circuit,

wherein the device further comprises an entire output voltage detection circuit that detects an entire output voltage of the battery modules, and the controller is further programmed to calculate, assuming that a period required to transmit the output voltage of the unit cell or unit cells held by the integrated circuits to the controller is a second cycle period, the output voltage of the unit cell or unit cells at intervals corresponding to a first cycle period that is shorter than the second cycle period on the basis of the output voltages transmitted from the integrated circuits at intervals corresponding to the second cycle period and the entire output voltage of the battery modules that is detected by the entire output voltage detection circuit at intervals corresponding to the first cycle period, and

wherein the controller is further programmed to calculate the output voltage of each of the unit cells at intervals corresponding to the first cycle period on the basis of a maximum value and a minimum value of the output voltages transmitted from the integrated circuits to the controller in a last interval corresponding to the second cycle period and an entire output voltage of the battery modules that is detected by the entire output voltage detection circuit at the intervals corresponding to the first cycle period.

2. The battery voltage monitoring device as defined in claim 1, wherein the controller is further programmed to calculate a difference between a value obtained by multiplying the maximum value of the output voltages transmitted from the integrated circuits to the controller during the previous interval corresponding to the second cycle period by a number of the unit cells of the battery modules and an entire output voltage of the battery modules that is detected by the entire output voltage detection circuit at a timing when the controller outputs the voltage sampling and holding command signal to the integrated circuit at the upstream end as a maximum battery voltage deviation, calculate a difference between a value obtained by multiplying the minimum value of the output voltages transmitted from the integrated circuits to the controller during the previous interval corresponding to the second cycle period by a number of the unit cells of the battery modules and an entire output voltage of the battery modules that is detected by the entire output voltage detection circuit at a timing when the controller outputs the voltage sampling and holding command signal to the integrated circuit at the upstream end as a minimum battery voltage deviation, calculate a maximum cell output voltage at the intervals corresponding to the first cycle period using an entire output voltage of the battery modules detected by the entire output voltage detection circuit at the intervals corresponding to the first cycle period and the maximum battery voltage deviation, and calculate a minimum cell output voltage at the intervals corresponding to the first cycle period using the entire output voltage of the battery modules detected by the entire output voltage detection circuit at the intervals corresponding to the first cycle period and the minimum battery voltage deviation.

3. The battery voltage monitoring device as defined in claim 2, further comprising a current sensor that detects an entire output current of the battery modules, wherein the controller is further programmed to calculate an internal resistance deviation corresponding to the maximum battery voltage at the intervals corresponding to the first cycle period from an entire output voltage of the battery modules detected in a state where the entire output voltage of the battery modules was not zero, the maximum value of the output voltages transmitted from the integrated circuits to the controller during the last interval corresponding to the second cycle period, and the maximum battery voltage deviation, calculate an internal resistance deviation corresponding to the minimum battery voltage at the intervals corresponding to the first cycle period from the entire output voltage of the battery modules detected in a state where the entire output voltage of the battery modules was not zero, the minimum value of the output voltages transmitted from the integrated circuits to the controller during the last interval corresponding to the second cycle period, and the minimum battery voltage deviation, and calculate the maximum cell output voltage and the minimum cell output voltage at the intervals corresponding to the first cycle period according to the following equations (A) and (B):

VHb=(Vsb+VdH1+RdH2×

Ib)/n 

 

(A)

VLb=(Vsb−

VdL1−

RdL2×

Ib)/n 

 

(B)

where, VHb=maximum cell voltage calculated at intervals corresponding to first cycle period;

VLb=minimum cell voltage calculated at intervals corresponding to first cycle period;

Vsb=entire output voltage of battery modules detected at intervals corresponding to first cycle time;

VdH1=maximum battery voltage deviation;

RdH2=internal resistance deviation corresponding to the maximum battery voltage;

Ib=entire output current of battery modules if detected at intervals corresponding to first cycle period;

n=number of unit cells of battery modules; and

RdL2=internal resistance deviation corresponding to the minimum battery voltage.