VOLTAGE MONITOR CIRCUIT

• US 20080157718A1
• Filed: 12/19/2007
• Published: 07/03/2008
• Est. Priority Date: 12/19/2006
• Status: Abandoned Application

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: OHNUKI, Yasumichi
• Application Number:
  US11/960,328
• Publication Number:
  US 20080157718A1
• Time in Patent Office: Days
• US Class Current: 320/134
• CPC Class Codes: H02J 7/0024 Parallel/serial switching of connection of batteries to charge or load circuit
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A voltage monitor circuit, wherein a high voltage is not applied to a monitor circuit even if a series circuit of plural batteries connecting a battery pack is cut off, is provided. When a current breaking switch is turned off, a high series voltage with reversed polarity of plural batteries is generated across the current breaking switch. Subsequently, a solid state switch with a negative voltage is turned off. Further, as a wire on the side of a battery pack monitor circuit also has a negative voltage, another solid state switch biased by a voltage of the wire is turned off likewise. Consequently, a high voltage is not generated between the wires on the side of the battery pack monitor circuit even if the current breaking switch is turned off.

Claims

1. A voltage monitoring circuit for a storage unit including:

N electric storage cells connected in series, each including a given number of electric storage elements; and

a current breaking switch interposed between at least a pair of adjacent electric storage cells of the N electric storage cells, the voltage monitoring circuit comprising;

a monitor circuit comprising (N+1) wires connected to terminals of the N electric storage cells for detecting a voltage of each of the N electric storage cells; and

N switching elements provided to the N wires out of the (N+1) wires, each of the N switching elements switching between electrically connecting and disconnecting a one of the N wires in response to a signal from a one of the (N+1) wires which is adjacent to the one of the N wires, in which the N wires exclude a one of the (N+1) wires which is connected to a maximum or a minimum potential of the storage unit.

2. The voltage monitor circuit according to claim 1, wherein a resistance element is connected between the wires, and wherein an electric load is connected across both terminals of the storage unit.

3. The voltage monitor circuit according to claim 2, wherein a resistance element is connected in parallel with a diode in which an anode is placed on a side of a low electric potential and a cathode is placed on a side of a high electric potential.

4. The voltage monitor circuit according to claim 1, wherein the switching element is a solid state switch which is turned on in response to a positive voltage, and wherein the solid state switch is interposed in the wire except for a wire with a maximum electric potential and is turned on in response to an electric potential of a wire adjoining on a side of a high electric potential.

5. The voltage monitor circuit according to claim 1, wherein the switch element is a solid state switch which is turned on in response to a negative voltage, and wherein the solid state switch is interposed in series in the wire except for a wire with a minimum electric potential and is turned on in response to an electric potential of a wire adjoining on a side of a low electric potential.