Battery pack

• US 20060158151A1
• Filed: 12/13/2005
• Published: 07/20/2006
• Est. Priority Date: 12/13/2004
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Kimura, Tadao
• Granted Patent: US 8,274,260 B2
• Time in Patent Office: Days
• US Class Current: 320/106
• 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: H01M 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/486 for measuring temperature
• 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: Y02E 60/10 Energy storage using batteries

Abstract

A battery pack is provided which includes: a state detection section which decides whether secondary batteries are in an electricity-charged state or in an electricity-discharging state; a power decision section which decides whether the secondary batteries are in a power-on state or in a power-off state; and a residual-capacity calculation section which, if the state detection section decides that they are in the electricity-charged state, calculates the residual capacity of the secondary batteries by accumulating a current value detected by a current sensor, and if the state detection section decides that they are in the electricity-discharging state, calculates the residual capacity of the secondary batteries by acquiring the voltage of the secondary batteries when the power decision section decides that they are in the power-off state.

Claims

1. A battery pack, comprising:

a secondary battery;

a voltage detecting means for detecting the voltage of the secondary battery;

a current detecting means for detecting an electric current which passes through the secondary battery;

a state detecting means for detecting whether the secondary battery is in an electricity-charged state or an electricity-discharging state;

a receiving means for receiving, from a load apparatus which is connected to the battery pack, a power notification signal for notifying the battery pack whether the power is turned on or off; and

a residual-capacity calculating means for, if the secondary battery is detected being in an electricity-charged state by the state detecting means, then calculating the residual capacity of the secondary battery by accumulating the electric current which is detected by the current detecting means, and if the secondary battery is detected being in an electricity-discharging state by the state detecting means, then calculating the residual capacity of the secondary battery based on the voltage which is detected by the voltage detecting means when the power notification signal indicates that the power is turned off.

2. The battery pack according to claim 1, further comprising:

a temperature detecting means for detecting the temperature of the secondary battery; and

a correcting means for correcting the residual capacity of the secondary battery which is calculated by the residual-capacity calculating means based on the temperature which is detected by the temperature detecting means.

3. The battery pack according to claim 2, wherein the correcting means:

includes a first correction table which indicates the relation between the temperature of the secondary battery and the correction factor of the residual capacity which is created in advance, taking into account the fact that the lower the temperature of the secondary battery becomes, the lower the discharge efficiency of the secondary battery becomes; and

corrects the residual capacity of the secondary battery which is calculated based on the voltage by the residual-capacity calculating means with reference to the first correction table.

4. The battery pack according to claim 2, wherein the correcting means:

includes a second correction table which indicates the relation between the temperature of the secondary battery and the correction factor of the residual capacity which is created in advance, taking into account the fact that as the temperature of the secondary battery changes, the charge efficiency of the secondary battery changes; and

corrects the residual capacity of the secondary battery which is calculated based on the electric current by the residual-capacity calculating means with reference to the second correction table.

5. The battery pack according to claim 1, wherein:

the secondary battery is formed by a plurality of secondary batteries;

the voltage detecting means detects the voltage of each secondary battery; and

if the secondary battery is detected being in an electricity-charged state, the residual-capacity calculating means calculates the residual capacity of the secondary battery by accumulating the electric current which is detected by the current detecting means, and if the secondary battery is detected being in an electricity-discharging state, the residual-capacity calculating means calculates the residual capacity of the secondary battery based on the voltage which is detected by the voltage detecting means when the power notification signal indicates that the power is turned off.

6. The battery pack according to claim 5, wherein the residual-capacity calculating means:

calculates the residual capacity of each secondary battery based on the voltage of each secondary battery which is detected by the voltage detecting means; and

further, calculates the residual capacity of the whole secondary battery based on this residual capacity of each secondary battery.

7. The battery pack according to claim 1, wherein the residual-capacity calculating means:

includes a residual-capacity table which indicates the relation between the voltage and the residual capacity of the secondary battery; and

calculates the residual capacity which corresponds to the voltage which is detected by the voltage detecting means with reference to the residual-capacity table.

8. The battery pack according to claim 1, wherein:

the load apparatus is an electric motor; and

the receiving means receives, as the power notification signal, a drive signal which is sent when the electric motor is driven.

9. A battery pack which is connected to an electricity-charging apparatus that charges a secondary battery or a load apparatus that discharges the secondary battery, wherein:

the electricity-charging apparatus includes a current detecting means for detecting an electric current which passes through the secondary battery, and a transmitting means for transmitting, to the battery pack, the value of the electric current which is detected by the current detecting means; and

the battery pack includes

a voltage detecting means for detecting the voltage of the secondary battery,

a state detecting means for detecting whether the secondary battery is in an electricity-charged state or an electricity-discharging state,

a receiving means for receiving, from the load apparatus, a power notification signal for notifying the battery pack whether the power is turned on or off, and

a residual-capacity calculating means for, if the secondary battery is detected being in an electricity-charged state by the state detecting means, then calculating the residual capacity of the secondary battery by accumulating the value of the electric current which is transmitted by the transmitting means, and if the secondary battery is detected being in an electricity-discharging state by the state detecting means, then calculating the residual capacity of the secondary battery based on the voltage which is detected by the voltage detecting means when the power notification signal indicates that the power is turned off.