Electronic circuit for measuring currents during charging and discharging of a secondary battery

• US 10,215,811 B2
• Filed: 01/04/2017
• Issued: 02/26/2019
• Est. Priority Date: 01/07/2016
• Status: Active Grant

• Current Assignee: Braun GmbH (The Procter & Gamble Company)
• Original Assignee: Braun GmbH (The Procter & Gamble Company)
• Inventors: Hermann, Ferdinand, Klemm, Torsten
• Primary Examiner(s): Nguyen, Tung X
• Assistant Examiner(s): Hawkins, Dominic
• Application Number:
  US15/397,866
• Publication Number:
  US 20170199244A1
• Time in Patent Office: 783 Days
• CPC Class Codes: G01R 19/00 Arrangements for measuring currents or voltages or for indicating presence or sign thereof G01R5/00 takes precedence; for measuring bioelectric currents or voltages A61B5/24
• CPC Class Codes: G01R 31/364 Battery terminal connectors with integrated measuring arrangements
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: H02J 7/0045 concerning the insertion or the connection of the batteries
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits
• CPC Class Codes: H02J 7/0068 Battery or charger load switching, e.g. concurrent charging and load supply H02J7/0013 takes precedence

Abstract

An electronic circuit and method for measuring currents during charging and discharging of a secondary battery are disclosed having a secondary battery, at least one shunt for determining the electrical current during charging and/or discharging of the secondary battery by measuring the voltage drop over the shunt, a switchable electrical load, two connectors for connecting a preferably switchable power supply to the electronic circuit for charging the secondary battery and a voltage measuring device. A first shunt is connected in series between the electrical load and the secondary battery, and a second shunt is connected in series between one of the two connectors for connecting the power supply and the secondary battery, wherein the first shunt and the second shunt are connected to the same one of the two battery terminals of the secondary battery, and in that the voltage measuring device comprises only one voltage tapping connected to the electrical conduit between the first shunt and the switchable electrical load and measuring the electrical potential with respect to ground, as defined by the ground potential of the voltage measuring device.

Claims

1. An electronic circuit for measuring currents during charging and discharging of a secondary battery having:

the secondary battery,

a first shunt for determining a first electrical current during discharging of the secondary battery,

a second shunt for determining a second electrical current during charging of the secondary battery,

a switchable electrical load,

two connectors for connecting a switchable power supply to the electronic circuit for charging the secondary battery and

a voltage measuring device,

wherein

the first shunt is connected in series between the switchable electrical load and the secondary battery and

the second shunt is connected in series between one of the two connectors for connecting the switchable power supply and the secondary battery,

wherein the first shunt and the second shunt are connected to the same one of the two battery terminals of the secondary battery, and

wherein the voltage measuring device comprises only one voltage tapping configured to measure a first voltage drop over the first shunt when the secondary battery is discharging and configured to measure a second voltage drop over the second shunt when the secondary battery is charging, the one voltage tapping connected to an electrical conduit between the first shunt and the switchable electrical load and measuring the electrical potential with respect to ground, as defined by the ground potential of the voltage measuring device.

2. The electronic circuit according to claim 1, wherein the first shunt and the second shunt are connected to the battery terminal of the negative pole of the secondary battery.

3. The electronic circuit according to claim 1, wherein the one of the two connectors for connecting the switchable power supply being connected to the second shunt is connectable to the negative pole of the switchable power supply.

4. The electronic circuit according to claim 1, having a control unit adapted to switch off the switchable electrical load during charging.

5. The electronic circuit according to claim 1, wherein the voltage measuring device is a single-ended analog digital converter.

6. Method for measuring the charging and discharging current of a secondary battery with the electronic circuit according to claim 1, wherein

during charging, no current flows through the switchable electrical load such that the voltage measuring device measures with the one voltage tapping the second voltage drop over the second shunt only and

during use of the switchable electrical load no current is delivered by the switchable power supply such that the voltage measuring device measures with the one voltage tapping the first voltage drop over the first shunt only,

wherein the first voltage drop over the first shunt and the second voltage drop over the second shunt show the same polarity.