Battery charging system for controlling the supply of charging current depending on battery temperature, a battery operated system and a method for state controlled charging

• US 8,368,345 B2
• Filed: 12/23/2009
• Issued: 02/05/2013
• Est. Priority Date: 12/22/2009
• Status: Active Grant

• Current Assignee: CTEK Sweden AB (CTEK Holding AB)
• Original Assignee: CTEK Sweden AB (CTEK Holding AB)
• Inventors: Wahlqvist, Bengt, Maleus, Borje
• Primary Examiner(s): WILLIAMS, ARUN C
• Application Number:
  US12/646,405
• Publication Number:
  US 20110148342A1
• Time in Patent Office: 1,140 Days
• Field of Search: 320/101
• US Class Current: 320/101
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: H02J 7/007192 in response to temperature

Abstract

A battery charging system (15) and method for state controlled charging of a battery (12). The battery charging system comprises two parallel paths (16, 17) for supplying charging current to the battery (12) from two parallel sources of charging current, an energy source (13) and a controlled charging device (14). A control unit (18) is adapted to control the supply of charging current along the two paths in response to a detected state of the battery (12). If a state above a predetermined threshold is detected, the control unit (18) controls the supply of charging current such that the battery (12) receives charging current from the controlled charging device (14), but not directly from the energy source (13). The detected state of the battery may e.g. be a temperature state. The present invention allows for balancing the demands of high charging rate and long expected lifetime of the battery (12).

Claims

1. A battery charging system, comprising:

a first switchable path for supplying charging current from an energy source to a battery;

a second path, in parallel with the first switchable path, for supplying charging current from a controlled charging device to the battery; and

a control unit for controlling the supply of charging current along the first switchable path and the second path in response to a detected temperature of the battery,

wherein the control unit is configured to communicate with a first temperature sensor for receiving information regarding the detected temperature of the battery, and to control the supply of charging current along the second path and to break the first switchable path such that the battery receives charging current from the controlled charging device via the second path, and not from the energy source via the first switchable path, in response to detection of the temperature of the battery above a predetermined first threshold temperature.

2. The battery charging system according to claim 1, wherein the control unit is further configured to control the supply of charging current along the first switchable path and the second path such that no charging current is supplied to the battery from the controlled charging device or from the energy source in response to detection of a temperature of the battery above a predetermined second threshold temperature.

3. The battery charging system according to claim 1, wherein the control unit is further configured to, in response to detection of a temperature of the battery below a predetermined third threshold temperature, connect the first switchable path and the second path such that the battery is supplied with charging current from both the energy source and the controlled charging device.

4. The battery charging system according to claim 3, wherein the control unit is further configured to

communicate with a second temperature sensor for receiving information regarding a detected ambient temperature, and to

control the supply of charging current along the first switchable path and the second path in response to the detected ambient temperature.

5. The battery charging system according to claim 4, wherein said first threshold temperature is dependent on the detected ambient temperature.

6. The battery charging system according to claim 4, wherein said first threshold temperature is specified in terms of a temperature difference between the temperature of the battery and the ambient temperature.

7. The battery charging system according to claim 1, wherein the first switchable path supplies charging current directly from the energy source to the battery.

8. A battery operated system, comprising:

a battery charging system comprising

a first switchable path for supplying charging current from an energy source to a battery,

a second path, in parallel with the first switchable path, for supplying charging current from a controlled charging device to the battery, and

a control unit for controlling the supply of charging current along the first switchable path and the second path in response to a detected temperature of the battery, the control unit being configured to communicate with a first temperature sensor for receiving information regarding the detected temperature of the battery, and to control the supply of charging current along the second path and to break the first switchable path such that the battery receives charging current from the controlled charging device via the second path, and not from the energy source via the first switchable path, in response to detection of the temperature of the battery above a predetermined first threshold temperature;

an energy source connected to the first switchable path of the battery charging system;

a controlled charging device connected to the second path of the battery charging system;

a battery connected to the first switchable path and the second path of the battery charging system; and

a first temperature sensor adapted to detect the temperature of the battery and having a communication connection with the control unit of the battery charging system.

9. The battery operated system according to claim 8, wherein the energy source is an alternator, photovoltaic panel, wind generator or generator.

10. The battery operated system according to claim 8, wherein the battery operated system further comprises a second temperature sensor adapted to detect an ambient temperature and having a communication connection with the control unit of the battery charging system, and wherein the control unit is further configured to control the supply of charging current along the first switchable path and the second path in response to the detected ambient temperature.

11. The battery operated system according to claim 10, wherein the first threshold temperature is dependent on the detected ambient temperature.

12. The battery operated system according to claim 10, wherein the first threshold temperature is specified in terms of a temperature difference between the temperature of the battery and the ambient temperature.

13. The battery operated system according to claim 8, wherein the first switchable path supplies charging current directly from the energy source to the battery.

14. A method for state controlled charging of a battery, the method comprising:

detecting a temperature of the battery; and

supplying charging current to the battery in response to the detected temperature of the battery,

wherein the supply of charging current to the battery is controlled such that the battery receives charging current from an energy source via a first switchable path and from a controlled charging device via a second path, in parallel with the first switchable path, until a temperature above a predetermined first threshold temperature is detected, and when the temperature is detected to be above the predetermined first threshold temperature, the supply of charging current to the battery is controlled such that the battery receives charging current from the controlled charging device but not from the energy source via the first switchable path.

15. The method according to claim 14, wherein the supply of charging current to the battery is controlled such that no charging current is supplied to the battery from the controlled charging device or from the energy source when a temperature above a predetermined second threshold temperature is detected.

16. The method according to claim 14, wherein the method further comprises detecting an ambient temperature, and said first threshold temperature depends on the detected ambient temperature.

17. The method according to claim 14, wherein the battery receives charging current from the energy source directly via the first switchable path.