Secondary-battery system and secondary-battery-failure-detection system

Patent metadata

Field	Value
Publication number	US-9595740-B2
Application number	US-201414564473-A
Country	US
Kind code	B2
Filing date	Dec 9, 2014
Priority date	Jun 15, 2012
Publication date	Mar 14, 2017
Grant date	Mar 14, 2017

Abstract

A secondary battery system and a secondary battery failure detection system includes a monitoring unit, a main gas pipe, a plurality of auxiliary gas pipes, and a plurality of solenoid valves provided in correspondence with the respective auxiliary gas pipes. The monitoring unit includes a pump for sucking a gas supplied into the main gas pipe, an active material detection sensor for detecting active material contained in the gas, a failure module identification unit for identifying a module having a failure based on an output from the active material detection sensor, and a sequence controller for performing opening/closing operation of the solenoid valves in accordance with a predetermined sequence.

First claim

The invention claimed is:

1. A secondary battery system comprising:
two or more modules including a large number of battery cells as secondary batteries and a casing containing the battery cells;
a monitoring unit configured to identify a module having leakage of at least active material, among the two or more modules;
a main gas pipe provided between the two or more modules and the monitoring unit;
a plurality of auxiliary gas pipes provided in correspondence with the modules, at least one of the auxiliary gas pipes being attached to each of the modules;
a plurality of solenoid valves provided in correspondence with the auxiliary gas pipes, the solenoid valves being configured to be opened/closed for connection/disconnection between the corresponding auxiliary gas pipes and the main gas pipe,
wherein the monitoring unit includes:
a pump connected to the main gas pipe and configured to suck a gas supplied into the main gas pipe from the auxiliary gas pipe, into the monitoring unit;
an active material detection sensor configured to detect active material contained in a gas flowing through the main gas pipe;
a failure module identification unit configured to identify a module having leakage of active material based on an output from the active material detection sensor; and
a sequence controller configured to perform opening/closing operation of the plurality of solenoid valves in accordance with a predetermined sequence.

2. The secondary battery system according to claim 1 , wherein the sequence controller opens the plurality of solenoid valves by turns such that each of the solenoid valves is opened for a fixed period for allowing the gas from different auxiliary gas pipes to be supplied into the main gas pipe by turns, respectively; and
the failure module identification unit samples the output from the active material detection sensor to obtain a detection value for each of the auxiliary gas pipes, based on switch timing of opening operation of the solenoid valves.

3. The secondary battery system according to claim 2 , wherein when the failure module identification unit detects that the sampled detection value is equal to or greater than a gas discharge request setting value requiring gas discharge, or when the failure module identification unit determines a mean value sequentially from detection values of historical sampling and detects that the mean value is equal to or greater than +1σ, which is standard deviation, the sequence controller performs the steps of:
(1) suspending operation of opening the solenoid valves by turns and closing all of the solenoid valves;
(2) supplying a reference gas into the main gas pipe to discharge the gas in the main gas pipe; and
(3) resuming operation of opening the solenoid valves by turns.

4. The secondary battery system according to claim 2 , wherein the failure module identification unit identifies a module having attached thereto an auxiliary gas pipe corresponding to a detection value equal to or greater than a predetermined specified value, among detection values corresponding to all of the auxiliary gas pipes, as a module having leakage of active material.

5. The secondary battery system according to claim 2 , wherein the failure module identification unit extracts one detection value from detection values corresponding to all of the auxiliary gas pipes, compares the extracted detection value with the other detection values to calculate deviation, and if the deviation falls out of a predetermined range, identifies modules having attached thereto auxiliary gas pipes corresponding to high detection values, among the compared detection values, as modules having leakage of active material by turns.

6. The secondary battery system according to claim 2 , wherein the fixed period includes a period in which at least two of the solenoid valves are both opened.

7. The secondary battery system according to claim 1 , wherein the monitoring unit includes a drain tank configured to remove at least water content from the gas flowing through the main gas pipe.

8. The secondary battery system according to claim 1 , wherein two or more module strings each formed by connecting a predetermined number of the modules in series are provided, a valve station is provided in correspondence with each of the module strings, and the valve station has a number of the solenoid valves corresponding to the predetermined number, and
the sequence controller includes:
a main control unit provided for the monitoring unit; and
a remote control unit provided in correspondence with each of the module strings and configured to control the solenoid valves of the corresponding valve station, based on an instruction signal from the main control unit.

9. The secondary battery system according to claim 1 , wherein two auxiliary gas pipes are attached to each of the modules.

10. The secondary battery system according to claim 9 , wherein the casing of the module includes a box body containing a large number of the battery cells and a lid body covering an opening on an upper surface of the box body; and
two auxiliary gas pipes run outward from base points provided at bottom of the box body and spaced from each other in the box body, such that the battery structural body made up of a large number of the battery cells placed in the box body is located between the base points.

11. The secondary battery system according to claim 1 , wherein the module is formed by connecting two or more blocks in series;
each of the blocks is formed by connecting two or more circuits in parallel, and each of the circuits is formed by connecting two or more battery cells in series.

12. The secondary battery system according to claim 1 , further comprising a block identification unit provided in correspondence with each of the modules,
wherein the block identification unit detects open circuit voltage values of all of the blocks in the corresponding module at end of electric discharging, and identifies a block having a failure based on the detected open circuit voltage values; and
among the modules, the failure module identification unit identifies a module including the block having the failure, as a module having leakage of active material.

13. The secondary battery system according to claim 12 , wherein the block identification unit identifies a block corresponding to an open circuit voltage value equal to or less than a predetermined specified voltage value, as a block having a failure.

14. The secondary battery system according t claim 12 , wherein the block identification unit extracts one open circuit voltage value from the detected open circuit voltage values, compares the extracted open circuit voltage value with the other open circuit voltage values to calculate deviation, and when the deviation falls out of a predetermined range, identifies blocks corresponding to low voltage values, among the compared voltage values, as blocks having failures by turns.

15. The secondary battery system according to claim 1 , comprising:
two or more module strings each formed by connecting a predetermined number of the modules in series; and
a block identification unit provided in correspondence with each of the module strings,
wherein the block identification unit detects open circuit voltage values of all of the blocks in the corresponding module string at end of electric discharging, and identifies a block having a failure based on the detected open circuit voltage values; and
among the modules, the failure module identification unit identifies a module including the block having the failure, as a module having leakage

Assignees

• Ngk Insulators Ltd

Inventors

• Fukuhara Motohiro

Classifications

• H01M10/4228 Primary

  Leak testing of cells or batteries · CPC title

• H01M10/3909

  Sodium-sulfur cells · CPC title

• H01M10/482 Primary

  for several batteries or cells simultaneously or sequentially · CPC title

• H01M50/204

  Racks, modules or packs for multiple batteries or multiple cells · CPC title

• H01M2/1016

  Electricity · mapped topic