Methods at a battery charger

• US 20060132096A1
• Filed: 04/28/2004
• Published: 06/22/2006
• Est. Priority Date: 04/30/2003
• Status: Active Grant

• Current Assignee: CTEK Sweden AB (CTEK Holding AB)
• Original Assignee: Creator Teknisk Utveckling AB
• Inventors: Maleus, Borje
• Granted Patent: US 7,541,778 B2
• Time in Patent Office: Days
• US Class Current: 320/141
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H02J 7/0069 Charging or discharging for charge maintenance, battery initiation or rejuvenation
• CPC Class Codes: H02J 7/00711 with introduction of pulses during the charging process
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A method for charging a battery at a battery charger comprising connection means for connection to the terminals of a battery to be charged, means for detecting a voltage over the terminals of a connected battery, and control means. The method comprises the steps of initiating a burst cycle, wherein a plurality of consecutive voltage burst are applied to a connected battery to be charged, each burst successively lowering the internal resistance of the battery and initiating a charging cycle to charge the connected battery when said burst cycle has been terminated. Furthermore, a method for maintenance charging a battery at a battery charger including detecting a voltage over the connected battery; maintaining the voltage over the battery at a predetermined level for a predetermined period of time; monitoring a battery capacity parameter when said predetermined period of time has elapsed; and applying at least one voltage pulse if said parameter falls below a predetermined threshold level.

Claims

1. Method of charging a battery at a battery charger comprising connection means for connection to the terminals of a battery to be charged, means for detecting a voltage over the terminals of a connected battery, and control means for initiating a burst cycle, characterised in that it comprises the steps of:

applying a voltage at a connected battery;

detecting the voltage over the connected battery to sense an increase of voltage over said battery in order to identify whether the internal resistance of the battery has increased compared to a normal state;

initiating a burst cycle if said internal resistance is identified as increased, wherein a plurality of consecutive voltage bursts are applied to a connected battery to be charged, each burst having a length of at least an order of mS and each burst delivering an amount of charge to the battery and thereby successively lowering the internal resistance of the battery; and

initiating a charging cycle to charge the connected battery when said burst cycle has been terminated.

2. Method according to claim 1, wherein each burst has a length within a range from about 50 mS to several seconds.

3. Method according to claim 1, wherein the step of initiating a burst cycle further comprises the steps of:

applying a voltage burst to the battery when said voltage over the battery has reached a first predetermined level

disconnecting said voltage burst when said voltage over the battery has reached a second predetermined level;

re-applying said voltage burst to the battery when said voltage over the battery has reached the first predetermined level.

4. Method according to claim 1, wherein the step of initiating a burst cycle comprise the step of:

applying said voltage bursts with a predetermined offset time between two consecutive bursts.

9. Computer readable medium comprising instructions for bringing a computer to perform a method according to claim 1.

10. A battery charger comprising connection means connected to the output lines of the charger, connection means for connection to the terminals of a battery to be charged, means for detecting a voltage over a connected battery, and control means, characterized in that said control means is connected to said means for detecting and being arranged to execute the methods according to claim 1.

5. Method of maintenance charging a battery at a battery charger comprising connection means for connection to the terminals of a battery to be charged, means for detecting a voltage over a connected battery, and control means, characterised in that it comprises the steps of:

detecting a voltage over the connected battery;

maintaining the voltage over the battery at a predetermined level for a predetermined period of time;

monitoring a battery capacity parameter when said predetermined period of time has elapsed; and

applying at least one voltage pulse if said parameter falls below a predetermined threshold level.

6. Method according to claim 5, wherein said predetermined capacity parameter is the voltage over the connected battery.

7. Method according to claim 5, wherein the step of applying comprises the step of:

applying voltage pulses until the voltage over the battery has reached at least said predetermined level.

8. Method according to claim 5, wherein the step of applying comprises the step of:

applying voltage pulses during a predetermined period of time.