Power supply apparatus

• US 20050231169A1
• Filed: 03/11/2005
• Published: 10/20/2005
• Est. Priority Date: 03/30/2004
• Status: Active Grant

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Furukawa, Kimihiko, Seo, Kazuhiro
• Granted Patent: US 7,262,605 B2
• Time in Patent Office: Days
• US Class Current: 320/150
• CPC Class Codes: G01K 7/24 in a specially-adapted circuit, e.g. bridge circuit
• CPC Class Codes: H01M 10/486 for measuring temperature
• CPC Class Codes: H01M 50/581 in response to temperature
• CPC Class Codes: H01M 6/42 Grouping of primary cells into batteries H01M6/40 takes precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A power supply apparatus has a battery apparatus that is composed of a battery, a temperature sensor that is thermally coupled to the battery and whose electrical resistance changes with the temperature of the battery to which it is thermally coupled, a temperature detection circuit that detects the temperature of the battery by detecting the electrical resistance of the temperature sensor, and a power supply circuit that feeds electrical power to the temperature detection circuit. The temperature sensor is connected via an overcurrent protection circuit to the power supply circuit.

Claims

1. A power supply apparatus comprising:

a battery apparatus that is composed of a battery;

a temperature sensor that is thermally coupled to the battery and whose electrical resistance changes with a temperature of the battery to which the temperature sensor is thermally coupled;

a temperature detection circuit that detects the temperature of the battery by detecting the electrical resistance of the temperature sensor; and

a power supply circuit that feeds electrical power to the temperature detection circuit,

wherein the temperature sensor is connected via an overcurrent protection circuit to the power supply circuit.

2. The power supply apparatus of claim 1,

wherein the power supply circuit feeds a temperature detection current for producing a voltage across the temperature sensor to the temperature sensor via the overcurrent protection circuit, and

wherein, when an abnormal voltage is externally applied to the temperature sensor, the overcurrent protection circuit limits, within a predetermined limit current level, magnitude of an abnormal current that is caused by the abnormal voltage to flow into or out of the power supply circuit.

3. The power supply apparatus of claim 2,

wherein the overcurrent protection circuit includes:

a diode that is connected to one end of the temperature sensor so that a forward direction of the diode coincides with a direction in which the temperature detection current flows; and

a current controller that is connected to another end of the temperature sensor and that, when the abnormal voltage is applied to the temperature sensor, limits the magnitude of the abnormal current within the predetermined limit current level.

4. The power supply apparatus of claim 2,

wherein the overcurrent protection circuit includes two sets, respectively connected to each end of the temperature sensor, of:

a diode whose forward direction coincides with a direction in which the temperature detection current flows; and

a current controller that, when the abnormal voltage is applied to the temperature sensor, limits the magnitude of the abnormal current within the predetermined limit current level.

5. The power supply apparatus of claim 3,

wherein the current controller includes:

a bipolar transistor that receives a predetermined potential at a base thereof, that has a collector thereof connected to the temperature sensor, and that has an emitter thereof connected to a bias resistor.

6. The power supply apparatus of claim 4,

wherein the current controller includes:

a bipolar transistor that receives a predetermined potential at a base thereof, that has a collector thereof connected to the temperature sensor, and that has an emitter thereof connected to a bias resistor.

7. The power supply apparatus of claim 2,

wherein the temperature detection circuit comprises a voltage detection circuit that detects the voltage produced across the temperature sensor by the temperature detection current so that the temperature detection circuit detects the electrical resistance of the temperature sensor based on the voltage across the temperature sensor as detected by the voltage detection circuit, and

wherein a protection resistor is provided between the voltage detection circuit and the temperature sensor.

8. The power supply apparatus of claim 7,

wherein a protection power supply circuit is provided on a voltage detection circuit side of the protection resistor, and

wherein the protection power supply circuit keeps, within a predetermined limit voltage range, a voltage applied to the voltage detection circuit side of the protection resistor.

9. The power supply apparatus of claim 1,

wherein both ends of the temperature sensor are connected to the overcurrent protection circuit.

10. A power supply apparatus comprising:

a battery apparatus that is composed of a plurality of batteries;

a plurality of temperature sensors of which each is thermally coupled to at least one of the batteries and whose electrical resistances change with temperatures of the batteries to which the temperature sensors are thermally coupled;

a temperature detection circuit that has, on an input side thereof, a multiplexer for switching among the temperature sensors for individual detection of the electrical resistances thereof and that detects the electrical resistances of the temperature sensors individually; and

a power supply circuit that feeds electrical power to the temperature detection circuit,

wherein the temperature sensors are each connected via an overcurrent protection circuit to the power supply circuit.