Battery pack

• US 20020036481A1
• Filed: 09/21/2001
• Published: 03/28/2002
• Est. Priority Date: 09/25/2000
• Status: Active Grant

• Current Assignee: Envision AESC Energy Devices Ltd.
• Original Assignee: NEC Mobile Energy Corporation (NEC Corporation)
• Inventors: Nagase, Kazuhisa
• Granted Patent: US 6,608,468 B2
• Time in Patent Office: Days
• US Class Current: 320/132
• CPC Class Codes: G01R 31/374 with means for correcting the measurement for temperature or ageing
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• 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: H02J 7/0071 with a programmable schedule
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A battery pack containing a CPU and allowing correction of measured data is provided. The CPU has, at least, a main program for obtaining data concerning the voltage of each cell, charge/discharge current and temperature by measurement to control charging and discharging and to perform cumulative calculation of the remaining battery capacity, a communication program for communicating with an external device, and a correction program for acquiring measured data to obtain a correction factor for calculating a predetermined value from each item of the measured data and for storing the correction factor in a memory. After the state of each cell has been set to a predetermined value, the correction program is started to obtain a correction factor and to store it in the memory. The main program corrects each item of measured data concerning the cell voltage, charge/discharge current and temperature by the correction factor to control charging and discharging and to perform cumulative calculation of the remaining battery capacity. Thus, it is possible to increase the measurement accuracy even if low-cost members are used, and hence possible to reduce the costs.

Claims

1. A battery pack containing a CPU and allowing correction of measured data, wherein said CPU has at least:

a main program for obtaining data concerning a voltage of each cell, charge/discharge current and temperature by measurement to control charging and discharging and to perform cumulative calculation of a remaining battery capacity;

a communication program for communicating with an external device; and

a correction program for acquiring measured data to obtain a correction factor for calculating a predetermined value from each item of said measured data and for storing said correction factor in a memory;

wherein after a state of each cell has been set to a predetermined value, said correction program is started to obtain a correction factor and to store the correction factor in said memory, and said main program corrects each item of measured data concerning the voltage of each cell, charge/discharge current and temperature by the correction factor to control charging and discharging and to perform cumulative calculation of a remaining battery capacity.

2. A battery pack according to claim 1, wherein said correction program judges whether or not the correction factor obtained is within a predetermined range, and stores the correction factor in the memory on condition that the correction factor is within the predetermined range.

3. A battery pack according to claim 1 or 2, wherein said correction program has an initial value for the correction factor and stores said initial value in said memory when a correction factor cannot be obtained by said correction program, or when the correction factor obtained is not within a predetermined range.

4. A battery pack according to claim 2 or 3, wherein said correction program outputs error information to an outside when the correction factor obtained is not within the predetermined range.

5. A battery pack according to claim 1, wherein said correction program is started when the communication program receives a predetermined command issued from the external device.

6. A battery pack according to claim 1, wherein said correction program is started in response to an operation of an idle port of said CPU.