Apparatus and method for measuring the amount of the current in battery cells using a plurality of sensing resistors

• US 7,696,727 B2
• Filed: 03/31/2006
• Issued: 04/13/2010
• Est. Priority Date: 03/31/2005
• Status: Active Grant

• Current Assignee: LG Energy Solution Limited (LG Corporation)
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: Choi, Jin Ho
• Primary Examiner(s): Tso; Edward
• Assistant Examiner(s): OMAR, AHMED H
• Application Number:
  US11/394,907
• Publication Number:
  US 20060267592A1
• Time in Patent Office: 1,474 Days
• Field of Search: 320/127, 320/132, 320/134, 320/136, 320/149, 324425-427, 324/434
• US Class Current: 320/149
• CPC Class Codes: G01R 1/203 Resistors used for electric measuring, e.g. decade resistors standards, resistors for comparators, series resistors, shunts resistors in general H01C; microwave or radiowave terminations H01P1/26; coupling devices H01R
• CPC Class Codes: G01R 15/002 Switches for altering the measuring range or for multitesters
• CPC Class Codes: G01R 19/16542 for batteries charge condition monitoring in G01R31/36
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• CPC Class Codes: G01R 31/386 using test-loads

Abstract

Disclosed is an apparatus for measuring an amount of current in battery cells. The apparatus includes: a plurality of resistors (R1, R2, and R3) connected in parallel; a main chip connected to both ends of one (R1) of the plurality of resistors, detecting voltage across the connected resistor, and adding up the amount of current on the basis of the detected voltage; a multiplexer selecting one of the other resistors (R2 and R3) when the amount of current added up at the main chip exceeds a predetermined threshold value; and a plurality of switches connected to the plurality of resistors respectively, and switched on/off by an output signal of the multiplexer. Thereby, it is possible to prevent damage to the surrounding components caused by the generation of heat from the single detection resistor, and detect a more precise amount of current in the battery cells.

Claims

1. An apparatus for measuring an amount of current in battery cells, the apparatus comprising:

a plurality of resistors connected in parallel and installed on a current flow line connected to the battery cells;

a plurality of switches connected to the plurality of resistors respectively, and switching on/off the current from the battery cells to each of the plurality of switches;

a multiplexer outputting a switching signal to each of the plurality of switches;

a main chip controlling the operation of the multiplexer, the main chip being connected to both ends of each resistor of the plurality of resistors, and integrating current flowing in switched-on resistor (s) over time and calculating a total current from the integrated current and increasing a number of resistors of the plurality of resistors having current flowing therethrough by controlling the multiplexer according to a level increase of the current.

2. The apparatus according to claim 1, wherein the plurality of resistors each have a different value of resistance.

3. The apparatus according to claim 1, wherein the switches each include Field Effect Transistor (FET) or Bipolar Junction Transistor (BJT).

4. The apparatus according to claim 1, wherein the multiplexer includes a selection circuit.

5. A method for measuring an amount of current in battery cells, the method comprising the steps of:

detecting a current flowing in one or more switched-on resistors among a plurality of resistors connected in parallel and installed on a current flow line connected to the battery cells;

integrating the detected current in switched-on resistor(s) over time and calculating a total current from the integrated current; and

increasing a number of the switched on resistors by switching on additional resistors of the plurality of resistors according to a level increase of the total current.

6. The method according to claim 5, wherein the increasing step includes returning to the detecting step when the added-up amount of current in the battery cells does not exceed a predetermined threshold value.

7. An apparatus for measuring an amount of current in battery cells, comprising:

first, second, and third resistors connected in parallel to one another and electrically coupled to a current flow line connected to the battery cells;

first, second, and third switches connected in series to the first, second, and third resistors, respectively, the first switch having a closed operational position to allow current from the battery cells to flow through the first resistor in response to a first switching signal, the second switch having a closed operational position to allow current from the battery cells to flow through the second resistor in response to a second switching signal, the third switch having a closed operational position to allow current from the battery cells to flow through the third resistor in response to a third switching signal;

a multiplexer electrically coupled to the first, second, and third switches, respectively;

a main chip operably coupled to the multiplexer, the main chip being further connected to both ends of the first, second, and third resistors;

the main chip configured to induce the multiplexer to output the first switching signal to induce the first switch to have the closed operational position;

the main chip further configured to integrate a first current flowing through the first resistor over time and calculate a first total current from the integrated first current;

the main chip further configured to induce the multiplexer to output the second switching signal to induce the second switch to have the closed operational position when the first total current exceeds a predetermined threshold value;

the main chip further configured to maintain integration of the first current flowing through the first resistor over time and staff to integrate a current flowing through the second resistor over time and calculate a second total current from the integrated first and second current; and

the main chip further configured to induce the multiplexer to output the third switching signal to induce the third switch to have the closed operational position when the second total current exceeds the predetermined threshold value.