Battery system

Patent metadata

Field	Value
Publication number	US-10189366-B2
Application number	US-201314783268-A
Country	US
Kind code	B2
Filing date	Apr 11, 2013
Priority date	Apr 11, 2013
Publication date	Jan 29, 2019
Grant date	Jan 29, 2019

Abstract

[Task] To accurately estimate a distribution of concentration of lithium in an active material.
[Means for Solution] A battery system has a lithium-ion secondary battery ( 1 ) and a controller ( 300 ). The lithium-ion secondary battery ( 1 ) employs a two-phase coexistence type positive electrode active material ( 141 b ). The controller ( 300 ) calculates a distribution of concentration of lithium in an active material ( 141 b, 142 b ) of the lithium-ion secondary battery, through the use of a diffusion equation in which a boundary condition is set. The controller corrects a diffusion coefficient that is used in the diffusion equation, in accordance with history data indicating a charge/discharge state of the lithium-ion secondary battery to the present time.

First claim

The invention claimed is:

1. A battery system comprising:
a lithium-ion secondary battery that employs a two-phase coexistence type positive electrode active material; and
a controller that:
calculates a distribution of concentration of lithium in an active material in the lithium-ion secondary battery based on a diffusion coefficient and a boundary condition,
calculates an average concentration of lithium in the active material based on the calculated distribution of concentration of lithium, and
calculates a state of charge (SOC) corresponding to the calculated average concentration based on a corresponding relationship between the average concentration and an SOC of the lithium-ion secondary battery, wherein

the controller corrects the diffusion coefficient in accordance with history data indicating a charge/discharge state of the lithium-ion secondary battery in a predetermined period to a present time, by multiplying a reference value of the diffusion coefficient by a correction coefficient corresponding to the history data, and
wherein the history data is updated every time the lithium-ion secondary battery is charged or discharged.

2. The battery system according to claim 1 , wherein
the controller calculates the correction coefficient corresponding to the present history data in the lithium-ion secondary battery based on a corresponding relationship between the history data and the correction coefficient.

3. The battery system according to claim 1 , further comprising:
a memory in which the history data are stored.

4. The battery system according to claim 1 , wherein
the history data include at least one of a variation in a state of charge (SOC) of the lithium-ion secondary battery in the predetermined period to a present time, and an average current value of the lithium-ion secondary battery in the predetermined period.

5. The battery system according to claim 4 , wherein
the variation in the SOC is a difference between a maximum value of the SOC in the predetermined period and a minimum value of the SOC in the predetermined period.

6. The battery system according to claim 1 , further comprising:
a temperature sensor that detects a temperature of the lithium-ion secondary battery, wherein
the controller calculates the reference value corresponding to the detected temperature of the temperature sensor based on a corresponding relationship between the temperature of the lithium-ion secondary battery and the reference value.

7. The battery system according to claim 1 , wherein
the controller calculates the reference value corresponding to a present state of charge (SOC) of the lithium-ion secondary battery based on a corresponding relationship between the SOC of the lithium-ion secondary battery and the reference value.

8. The battery system according to claim 1 , further comprising:
a plurality of discharge circuits being connected in series to one another, and a plurality of the lithium-ion secondary batteries being connected in series to one another, wherein
the plurality of discharge circuits are connected in parallel to the plurality of lithium-ion secondary batteries, respectively, to discharge the respective lithium-ion secondary batteries, and
the history data include voltage variations at a time when the lithium-ion secondary batteries are discharged by the discharge circuits respectively.

9. The battery system according to claim 1 , wherein
the lithium-ion secondary battery outputs an electric power that is converted into kinetic energy to cause a vehicle to run.

Assignees

• Toyota Motor Co Ltd

Inventors

• Takahashi Kenji
• Kaiya Hiroyuki
• Todoroki Chihaya

Classifications

• H01M10/48 Primary

  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 title

• H02J7/00

  Circuit arrangements for charging or discharging batteries or for supplying loads from batteries · CPC title

• H01M10/425

  Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing (printed circuits H05K1/00) · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M10/052

  Li-accumulators · CPC title