Assembled battery

Patent metadata

Field	Value
Publication number	US-9455480-B2
Application number	US-201414451767-A
Country	US
Kind code	B2
Filing date	Aug 5, 2014
Priority date	Aug 6, 2013
Publication date	Sep 27, 2016
Grant date	Sep 27, 2016

Abstract

An assembled battery includes a plurality of secondary cells, a first arithmetic operator, a second arithmetic operator, and a discharger. The first arithmetic operator calculates a voltage change rate of each of the secondary cells during charging/discharging thereof. The second arithmetic operator determines a discharge condition for each of the secondary cells from the voltage change rate calculated in the first arithmetic operator and a state of charge of each of the secondary cells. The discharger performs discharging of each of the secondary cells on the basis of the discharge condition when the assembled battery is neither being charged nor being discharged. The second arithmetic operator determines the discharge condition of each of the secondary cells such that each of the secondary cells after the discharging has the same state of charge.

First claim

What is claimed is:

1. An assembled battery comprising:
a plurality of secondary cells;
a first arithmetic operator calculating a voltage change rate of each of the secondary cells during charging and discharging thereof;
a second arithmetic operator determining a discharge condition for each of the secondary cells from the voltage change rate calculated by the first arithmetic operator and a state of charge of each of the secondary cells; and
a discharger performing discharging of each of the secondary cells on the basis of the discharge condition when the assembled battery is neither being charged nor being discharged, wherein
the second arithmetic operator determines the discharge condition such that each of the secondary cells after the discharging has the same state of charge,
the second arithmetic operator determines one of the secondary cells having a minimum value of the state of charge among the secondary cells having different voltage change rates calculated in the first arithmetic operator, and determines the discharge condition of another one of the secondary cells on the basis of the minimum value of the state of charge of the one of the secondary cells, and
the second arithmetic operator calculates a difference between the state of charge of one of the secondary cells having a minimum value of the state of charge and the state of charge of another one of the secondary cells, and determines the discharge condition of the another one of the secondary cells so that the discharging of the another one of the secondary cells is performed according to the difference of the state of charge calculated.

2. The assembled battery according to claim 1 , further comprising:
a third arithmetic operator calculating a difference between a maximum value and a minimum value among the states of charge of the secondary cells, wherein,
when the difference between the maximum value and the minimum value of the states of charge calculated in the third arithmetic operator exceeds a threshold value, the discharger is allowed to perform the discharging of each of the secondary cells based on the discharge condition.

3. The assembled battery according to claim 1 , wherein
each of the secondary cells includes a positive electrode material that has two or more plateau regions in which a change in potential is smaller than a predetermined rate in a characteristic between the state of charge and the potential.

4. The assembled battery according to claim 3 , wherein
the positive electrode material has an active material that has a two-phase coexistence type reaction.

5. The assembled battery according to claim 4 , wherein
the active material has an active material having an olivine-type structure.

6. The assembled battery according to claim 5 , wherein
the active material having the olivine-type structure is Li x Mn y M 1-y XO 4 , in which M is one or more transition metals, X is one or more selected from the group consisting of P, As, Si, and Mo, x satisfies a relation of 0≦x<1.0, and y satisfies a relation of 0≦y≦1.0.

7. The assembled battery according to claim 6 , wherein
the active material having the olivine-type structure is Li x Mn y M 1-y XO 4 , in which M is one or more transition metals, X is one or more selected from the group consisting of P, As, Si, and Mo, x satisfies a relation of 0≦x<1.0, and y satisfies a relation of 0.4≦y≦1.0.

8. The assembled battery according to claim 1 , wherein
in the discharging of the another one of the secondary cells performed by the discharger, an electric energy corresponding to the difference of the state of charge calculated is discharged.

Assignees

• Denso Corp

Inventors

• Yoshida Shuhei
• Shibata Daisuke

Classifications

• H02J7/96

  in response to battery voltage · CPC title

• H02J7/92

  with prioritisation of loads or sources · CPC title

• H02J7/82

  Control of state of charge [SOC] · CPC title

• H02J7/54

  Passive balancing, e.g. using resistors or parallel MOSFETs · CPC title

• H01M2010/4271

  Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing · CPC title