Battery pack and battery pack producing method

• US 7,785,729 B2
• Filed: 07/01/2008
• Issued: 08/31/2010
• Est. Priority Date: 07/04/2007
• Status: Active Grant

• Current Assignee: Panasonic EV Energy Company, Limited (Toyota Motor Corporation)
• Original Assignee: Panasonic EV Energy Company, Limited (Toyota Motor Corporation)
• Inventors: Okumura, Motoyoshi, Maegawa, Katsunori
• Primary Examiner(s): Crepeau; Jonathan
• Assistant Examiner(s): DOUYETTE, KENNETH J
• Application Number:
  US12/216,204
• Publication Number:
  US 20090011327A1
• Time in Patent Office: 791 Days
• Field of Search: 429/99, 429/49, 429/52, 296/231, 396/6, 320/122, 320/103, 320/137, 320/112
• US Class Current: 429/49
• 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 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/54 Reclaiming serviceable parts of waste accumulators
• CPC Class Codes: H01M 6/42 Grouping of primary cells into batteries H01M6/40 takes precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02W 30/84 Recycling of batteries or fuel cells
• CPC Class Codes: Y10T 29/49108 Electric battery cell making

Abstract

A battery pack capable of sufficiently exhibiting performance of each secondary battery constituting the battery pack and its producing method are provided. The battery pack producing method of the invention comprises an obtaining process for obtaining a charge amount voltage curve C during charging and a charge amount voltage curve D during discharging, a selecting process for selecting more than one of the used secondary batteries close to each other in curves C and D from a group of the used secondary batteries whose curves C and D have been obtained, and an assembling process for combining the selected used secondary batteries to constitute the battery pack.

Claims

1. A battery pack producing method comprising:

an obtaining process for obtaining, about each of secondary batteries having ever been used, a charge amount-voltage curve during charging representing a relationship between a charge amount and a battery voltage when each used secondary battery is charged under a predetermined charge condition and a charge amount-voltage curve during discharging representing a relationship between a charge amount and a battery voltage when each used secondary battery is discharged under a predetermined discharge condition;

a selecting process for selecting more than one of the used secondary batteries having the charge amount-voltage curves during charging similar to each other and the charge amount-voltage curves during discharging similar to each other from a group of the used secondary batteries whose charge amount-voltage curves during charging and charge amount-voltage curves during discharging have been obtained;

an assembling process for combining and assembling the selected used secondary batteries into a new battery pack,

the selecting process including selecting the used secondary batteries under condition that

when a reference secondary battery exhibiting characteristics corresponding to a new secondary battery or an initial use stage has a charge amount-voltage reference curve during charging representing a relationship between a charge amount and a battery voltage when the reference secondary battery is charged under the predetermined charge condition and a charge amount-voltage reference curve during discharging representing a relationship between a charge amount and a battery voltage when the reference second battery is discharged under the predetermined discharge condition,

when each of the used secondary batteries is defined such that;

of battery voltage differences during charging obtained by comparison in battery voltage at the same charge amount between the charge amount-voltage curve during charging and the charge amount-voltage reference curve during charging, a largest one is a maximum battery voltage difference during charging and a charge amount corresponding to the maximum battery voltage difference during charging is a maximum-difference charge amount during charging; and

of battery voltage differences during discharging obtained by comparison in battery voltage at the same charge amount between the charge amount-voltage curve during discharging and the charge amount-voltage reference curve during discharging, a largest one is a maximum battery voltage difference during discharging and a charge amount corresponding to the maximum battery voltage difference during discharging is a maximum-difference charge amount during discharging, a difference between a largest one and a smallest one of the maximum-difference charge amounts during charging of the selected used secondary batteries falls within 10% of a full charge capacity of the initial reference battery,

a difference between a largest one and a smallest one of the maximum-difference charge amounts during discharging of the selected used secondary batteries falls within 10% of a full charge capacity of the initial reference battery,

a difference in the maximum battery voltage difference during charging between a largest one and a smallest one of the maximum battery voltage differences during charging of the used secondary batteries falls within 50% of the largest maximum battery voltage difference during charging, and

a difference in the maximum battery voltage difference during discharging between a largest one and a smallest one of the maximum battery voltage differences during discharging of the used secondary batteries falls within 50% of the largest maximum battery voltage difference during discharging.

2. A battery pack producing method comprising:

an obtaining process for obtaining, about each of secondary batteries having ever been used, voltage corresponding to a predetermined charge amount during charging which is a battery voltage corresponding to each of a plurality of predetermined charge amounts of each used secondary battery when charged under a predetermined charge condition and voltage corresponding to a predetermined charge amount during discharging which is a battery voltage corresponding to each of a plurality of predetermined charge amounts of each used secondary battery when discharged under a predetermined discharge condition;

a selecting process for selecting more than one of the used secondary batteries having the voltages corresponding to a predetermined charge amount during charging similar to each other and the voltages corresponding to a predetermined charge amount during discharging similar to each other from a group of the used secondary batteries whose voltages corresponding to a predetermined charge amount during charging and voltages corresponding to a predetermined charge amount during discharging have been obtained;

an assembling process for combining and assembling the selected used secondary batteries into a new battery pack,

the selecting process including selecting the used secondary batteries under condition that

when a reference secondary battery exhibiting characteristics corresponding to a new secondary battery or an initial use stage has a reference voltage corresponding to a predetermined charge amount during charging when charged under the predetermined charge condition and a reference voltage corresponding to a predetermined charge amount during discharging when discharged under the predetermined discharge condition,

when each of the used secondary batteries is defined such that;

of battery voltage differences during charging obtained by comparison between each voltage corresponding to the predetermined charge amount during charging and the reference voltage corresponding to the predetermined charge amount during charging at the same predetermined charge amount, a largest one is a maximum battery voltage difference during charging and a charge amount corresponding to the maximum battery voltage difference during charging is a maximum-difference charge amount during charging; and

,

of battery voltage differences during discharging obtained by comparison between each voltage corresponding to the predetermined charge amount during discharging and the reference voltage corresponding to the predetermined charge amount during discharging at the same predetermined charge amount, a largest one is a maximum battery voltage difference during discharging and a charge amount corresponding to the maximum battery voltage difference during discharging is a maximum-difference charge amount during discharging,

a difference in maximum-difference charge amounts during charging between a largest one and a smallest one of the maximum-difference charge amounts during charging of the selected used secondary batteries falls within 10% of a full charge capacity of the initial reference battery,

a difference in maximum-difference charge amounts during discharging between a largest one and a smallest one of the maximum-difference charge amounts during discharging of the selected used secondary batteries falls within 10% of a full charge capacity of the initial reference battery,

a difference in the maximum battery voltage difference during charging between a largest one and a smallest one of the maximum battery voltage differences during charging of the used secondary batteries falls within 50% of the largest maximum battery voltage difference during charging, and

a difference in the maximum battery voltage difference during discharging between a largest one and a smallest one of the maximum battery voltage differences during discharging of the used secondary batteries falls within 50% of the largest maximum battery voltage difference during discharging.

3. A battery pack including secondary batteries that have ever been used and are newly combined,

wherein

when each of the used secondary batteries is defined such that:

between a charge amount-voltage curve during charging representing a relationship between a charge amount and a battery voltage when each battery is charged under a predetermined charge condition and a charge amount-voltage reference curve during charging representing a relationship between a charge amount and a battery voltage when an initial reference secondary battery having characteristics corresponding to a new secondary battery or an initial use stage is charged under the predetermined charge condition,

of battery voltage differences during charging obtained by comparison between the battery voltages at the same charge amount, a largest one is a maximum battery voltage difference during charging and a charge amount corresponding to the maximum battery voltage difference during charging is a maximum-difference charge amount during charging; and

,

between a charge amount-voltage curve during discharging representing a relationship between a charge amount and a battery voltage when each battery is discharged under a predetermined discharge condition and a charge amount-voltage reference curve during discharging representing a relationship between a charge amount and a battery voltage when the initial reference secondary battery is discharged under the predetermined discharge condition,

of battery voltage differences during discharging obtained by comparison between the battery voltages at the same charge amount, a largest one is a maximum battery voltage difference during discharging and a charge amount corresponding to the maximum battery voltage difference during discharging is a maximum-difference charge amount during discharging,

a difference in maximum-difference charge amount during charging between a largest one and a smallest one of the maximum-difference charge amounts during charging of the selected used secondary batteries falls within 10% of a full charge capacity of the initial reference battery,

a difference in maximum-difference charge amount during discharging between a largest one and a smallest one of the maximum-difference charge amounts during discharging of the selected used secondary batteries falls within 10% of a full charge capacity of the initial reference battery, and

of the used secondary batteries constituting the battery pack,

a difference in the maximum battery voltage difference during charging between a largest one and a smallest one of the maximum battery voltage differences during charging falls within 50% of the largest maximum battery voltage difference during charging, and

a difference in the maximum battery voltage difference during discharging between a largest one and a smallest one of the maximum battery voltage differences during discharging falls within 50% of the largest maximum battery voltage difference during discharging.

4. A battery pack including secondary batteries that have ever been used and are newly combined,

wherein

when each of the used secondary batteries is defined such that:

between a voltage corresponding to a predetermined charge amount during charging which is a battery voltage corresponding to each of predetermined charge amounts of each used secondary battery when charged under a predetermined charge condition and a reference voltage corresponding to a predetermined charge amount during charging which is a battery voltage corresponding to a predetermined charge amount of an initial reference secondary battery having characteristics corresponding to a new secondary battery or an initial use stage when it is charged under the predetermined charge condition,

of battery voltage differences during charging obtained by comparison between the battery voltages at the same charge amount, a largest one is a maximum battery voltage difference during charging and a charge amount corresponding to the maximum battery voltage difference during charging is a maximum-difference charge amount during charging; and

between voltage corresponding to a predetermined charge amount during discharging which is a battery voltage corresponding to each of predetermined charge amounts of each used secondary battery when discharged under a predetermined discharge condition and a reference voltage corresponding to a predetermined charge amount during discharging which is a battery voltage corresponding to each predetermined charge amount of the initial reference secondary battery when discharged under the predetermined charge condition,

of battery voltage differences during discharging obtained by comparison between the battery voltages at the same charge amount, a largest one is a maximum battery voltage difference during discharging and a charge amount corresponding to the maximum battery voltage difference during discharging is a maximum-difference charge amount during discharging;

a difference in a maximum-difference charge amount during charging between a largest one and a smallest one of the maximum-difference charge amounts during charging of the selected used secondary batteries falls within 10% of a full charge capacity of the initial reference battery,

a difference in maximum-difference charge amount during discharging between a largest one and a smallest one of the maximum-difference charge amounts during discharging of the selected used secondary batteries falls within 10% of a full charge capacity of the initial reference battery.

a difference in the maximum battery voltage difference during charging between a largest one and a smallest one of the maximum battery voltage differences during charging of the used secondary batteries falls within 50% of the largest maximum battery voltage difference during charging, and

a difference in the maximum battery voltage difference during discharging between a largest one and a smallest one of the maximum battery voltage differences during discharging of the used secondary batteries falls within 50% of the largest maximum battery voltage difference during discharging.