Adaptive battery charger with universal interface plate

• US 5,818,197 A
• Filed: 10/30/1996
• Issued: 10/06/1998
• Est. Priority Date: 10/30/1996
• Status: Expired due to Fees

• Current Assignee: Alexander Technologies Europe Ltd.
• Original Assignee: Alexander Manufacturing Co.
• Inventors: Miller, Jay S., Mumm, Bret Evan, Bollman, Trent Lee
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): Toatley, Jr., Gregory J.
• Application Number:
  US08/739,914
• Time in Patent Office: 706 Days
• Field of Search: 320/2, 320/21, 320/22, 320/23, 320/24, 320/107, 320/160, D13/107
• US Class Current: 320/107
• CPC Class Codes: H02J 7/00047 with provisions for charging different types of batteries
• CPC Class Codes: H02J 7/0045 concerning the insertion or the connection of the batteries
• CPC Class Codes: H02J 7/00712 the cycle being controlled or terminated in response to electric parameters

Abstract

A universal interface plate has a predetermined and universal configuration suitable for connecting any one of a plurality of types of rechargeable batteries to the circuitry of a charging device. The universal plate is adapted to any type of rechargeable battery using an appropriate bay adapter, the bay adapter including a first interface for mounting the bay adapter to the universal interface plate and a second interface for accommodating a particular type of battery. The charging device utilizes a ramping charge method whereby batteries are initially charged at a low charging rate, thereby allowing safe charging of low and high capacity batteries utilizing a single charging algorithm. The charging rate is increased incrementally after determining whether the incremental current increase would cause the power to the battery to exceed the maximum power that can be handled by the bay. If the maximum charging rate is reached, charging is continued at the previous rate, otherwise the charging current is increased by the incremental amount thereby providing for rapid ramp-up of charging current for high capacity batteries while providing a low charging current for low capacity batteries, thus preventing overcurrent charging of low capacity batteries. During charging, the battery is monitored to determine whether a termination criterion is met.

Claims

1. A battery charger interface, comprising:

a plate having a plurality of openings disposed therethrough, the plate being releasably engagable with a respective one of a plurality of battery adapters via a predetermined number of the plurality of openings, each of the plurality of battery adapters also being releasably engagable with a respective one of a plurality of different types of rechargeable batteries; and

a plurality of first contacts disposed in the predetermined number of the plurality of openings, the plurality of first contacts being electrically connectable to a plurality of second contacts of the respective one of the plurality of the battery adapters, wherein the plurality of first contacts connect each of the plurality of battery adapters to a charging circuit of a battery charger.

2. The battery charger interface according to claim 1, wherein the plate is mounted to the battery charger.

3. The battery charger interface according to claim 1, wherein the plurality of first contacts include a battery positive contact, a battery negative contact, an identification circuit contact and a thermistor circuit contact.

4. The battery charger interface according to claim 3, wherein the plurality of second contacts include a battery positive contact, a battery negative contact, an identification circuit contact and a thermistor circuit contact.

5. The battery charger interface according to claim 1, wherein the plurality of different types of rechargeable batteries includes a nickel cadmium battery, a nickel metal hydride battery, a lead acid battery and a lithium ion battery.

6. The battery charger interface according to claim 1, wherein the charging circuit is coupled to a control circuit, the control circuit terminating a charging of at least one of the plurality of different types of rechargeable batteries as a function of a termination criterion.

7. A charging device comprising:

a power supply;

at least one charging circuit coupled to the power supply;

a control circuit coupled to the at least one charging circuit; and

at least one universal charger interface plate coupled to the at least one charging circuit, the universal charger interface plate including

a plate having a plurality of openings disposed therethrough, the plate being releasably engagable with a respective one of a plurality of battery adapters via a predetermined number of the plurality of openings, each of the plurality of battery adapters also being releasably engagable with a respective one of a plurality of different types of rechargeable batteries, and

a plurality of first contacts disposed in the predetermined number of the plurality of openings, the plurality of first contacts being electrically connectable to a plurality of second contacts of the respective one of the plurality of the battery adapters, wherein the plurality of first contacts connect each of the plurality of battery adapters to a charging circuit of a battery charger.

8. The charging device according to claim 7, wherein the control unit includes a microprocessor, the microprocessor instructing the charging circuit to provide a ramping charge, via the universal interface plate, to the battery.

9. The charging device according to claim 8, wherein the microprocessor instructs the charging circuit to provide the ramping charge by

a) charging the battery at an initial charging rate for a first predetermined period of time,

b) increasing the initial charging rate by a predetermined increment to provide a next charging rate,

c) determining whether the next charging rate exceeds a maximum charging rate,

d) if the next charging rate is no greater than the maximum charging rate, charging the battery at the next charging rate for a second predetermined period of time, and

e) repeating steps b) and c) until one of the next charging rate exceeds the maximum charging rate and the battery charging is complete.

10. The charging device according to claim 7, wherein the control circuit terminates a charging of at least one of the plurality of different types of rechargeable batteries as a function of a termination criterion.

11. A method of charging a rechargeable battery, comprising the steps of:

a) charging the battery at an initial charging rate for a first predetermined period of time;

b) increasing the initial charging rate by a predetermined increment to provide a next charging rate;

c) determining whether the next charging rate exceeds a maximum charging rate, the determining step including the steps of

determining a maximum charging power for the battery as a function of a chemistry and a cell count of the battery,

determining a charging power for the battery as a function of a voltage of the battery and the next charging rate, and

comparing the maximum charging power and the charging power;

d) if the next charging rate is no greater than the maximum charging rate, charging the battery at the next charging rate for a second predetermined period of time; and

e) repeating steps b) and c) until one of the next charging rate exceeds the maximum charging rate and the battery charging is complete.

12. A method of charging a rechargeable battery, comprising the steps of:

a) charging the battery at an initial charging rate for a first predetermined period of time,

b) increasing the initial charging rate by a predetermined increment to provide a next charging rate;

c) determining whether the next charging rate exceeds a maximum charging rate;

d) if the next charging rate is no greater than the maximum charging rate, charging the battery at the next charging rate for a second predetermined period of time;

e) repeating steps b) and c) until one of the next charging rate exceeds the maximum charging rate and the battery charging is complete; and

f) terminating charging of the battery as a function of a termination criterion.

13. The method according to claim 12, wherein the termination criterion includes a predetermined temperature of the battery.

14. The method according to claim 12, wherein the termination criterion includes a negative-delta termination criterion.

15. The method according to claim 12, wherein the termination criterion includes a maximum voltage termination criterion.