Current measuring terminal assembly for a battery

• US 6,628,102 B2
• Filed: 12/05/2001
• Issued: 09/30/2003
• Est. Priority Date: 04/06/2001
• Status: Expired due to Term

• Current Assignee: Microchip Technology Incorporated
• Original Assignee: Microchip Technology Incorporated
• Inventors: Batson, David C.
• Primary Examiner(s): Tso, Edward H.
• Assistant Examiner(s): TIBBITS, PIA FLORENCE
• Application Number:
  US10/010,693
• Publication Number:
  US 20020180405A1
• Time in Patent Office: 664 Days
• Field of Search: 320/128, 320/107, 320/136, 324/433, 429/163, 429/178, 429/179
• US Class Current: 320/128
• CPC Class Codes: G01R 31/364 Battery terminal connectors with integrated measuring arrangements
• CPC Class Codes: H01M 10/12 Construction or manufacture
• CPC Class Codes: H01M 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• CPC Class Codes: H01M 10/4257 Smart batteries, e.g. electronic circuits inside the housing of the cells or batteries
• 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: H01M 10/486 for measuring temperature
• CPC Class Codes: H01M 2010/4271 Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
• CPC Class Codes: H01M 50/561 Hollow metallic terminals, e.g. terminal bushings
• CPC Class Codes: H01M 50/569 Constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals battery terminal connectors with integrated measuring arrangements G01R31/364
• CPC Class Codes: H01M 50/581 in response to temperature
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A terminal assembly for measuring electrical current passing to and from a battery post, including an electrically conductive collar for connecting to a post of a battery, and an electrically conductive terminal for receiving a connector of a load. An electrically conductive resistor having a known resistance extends between outer surfaces of the collar and the terminal. The terminal assembly is incorporated into a battery, which also includes a volt meter connected between the outer surfaces of the collar and the terminal for measuring the voltage drop across the resistor, memory for storing the known resistance of the resistor, and a processor programmed to receive the measured voltage drop from the volt meter, retrieve the known resistance from the memory, and calculate current flow through the resistor based on the measured voltage drop and the known resistance, whereby current flow to and from the battery can be measured.

Claims

1. A terminal assembly for measuring electrical current to and from a battery, comprising:

an electrically conductive collar having an inner surface for coupling to a battery post of the battery;

an electrically conductive terminal for coupling to a load;

a resistor having a known resistance, the resistor being connected between the collar and the terminal, wherein current flow from the battery post travels through the resistor in a first direction and current flow to the battery post travels through the resistor in a second direction;

a first lead electrically coupled to a first end of the resistor proximate to the outer surface of the collar, and

a second lead electrically coupled to a second end of the resistor proximate to the outer surface of the terminal.

2. A terminal assembly according to claim 1, further comprising a voltage measuring device coupled to the first and the second leads for measuring a voltage when current flows through the resistor.

3. A terminal assembly according to claim 2, further comprising a computer including:

A. memory storing the known resistance of the resistor; and

B. a processor programmed to,

receive the measured voltage from the voltage measuring device,

retrieve the known resistance from the memory, and

calculate current flowing through the resistor based on the measured voltage and the known resistance.

4. A terminal assembly according to claim 3, further comprising:

A. a thermometer for measuring a temperature of the resistor;

B. the memory of the computer also storing a temperature coefficient of resistivity for the resistor; and

C. the processor of the computer is further programmed to,

receive the temperature from the thermometer,

retrieve the temperature coefficient of resistivity from the memory,

calculate a temperature compensated resistance of the resistor based on the known resistance, the temperature coefficient of resistivity, and the measured temperature, and

calculate current through the resistor based on the measured voltage and the temperature compensated resistance.

5. A terminal assembly according to claim 1, wherein the resistance of the resistor is between about 50 microOhm and about 200 microOhm.

6. A terminal assembly according to claim 1, wherein the resistor material is selected from the group consisting of lead, copper, brass, bronze, manganese and manganin.

7. A terminal assembly according to claim 1, wherein the method of forming the resistor is selected from the group consisting of powdered metal, stamped, machined, cast and forged.

8. A terminal assembly according to claim 1, further comprising:

a battery case;

a storage cell contained within the battery case for receiving and storing an electrical charge; and

an electrically conductive post coupled to the storage cell and extending out of the battery case;

wherein the inner surface of the collar is positioned on a portion of the post extending out of the battery case.

9. A terminal assembly according to claim 8, wherein the storage cell includes lead and lead-oxide plates immersed in an acid electrolyte.