Secondary cell state detector

• US 10,249,914 B2
• Filed: 07/26/2016
• Issued: 04/02/2019
• Est. Priority Date: 07/30/2015
• Status: Active Grant

• Current Assignee: Yazaki Corporation
• Original Assignee: Yazaki Corporation
• Inventors: Takahashi, Yuichi, Syouda, Takahiro, Takahashi, Nobuyuki, Saito, Ayako, Saigo, Tsutomu, Fujii, Hironao, Wang, Jian
• Primary Examiner(s): McAndrew, Christopher P
• Application Number:
  US15/219,750
• Publication Number:
  US 20170033415A1
• Time in Patent Office: 980 Days
• Field of Search: 324426
• CPC Class Codes: B60K 6/22 characterised by apparatus, components or means specially adapted for HEVs
• CPC Class Codes: B60L 58/10 for monitoring or controlling batteries
• CPC Class Codes: B60Y 2200/91 Electric vehicles
• CPC Class Codes: B60Y 2200/92 Hybrid vehicles
• CPC Class Codes: B60Y 2400/308 Electric sensors
• CPC Class Codes: H01M 10/4285 Testing apparatus
• 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 2220/20 Batteries in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y10S 903/904 Component specially adapted for hev

Abstract

One-side plates of first and second condensers are connected to a one-side electrode of one of a plurality of secondary cells. First switches connect the other-side electrode of the secondary cell to the other-side plate of one of the first condenser and the second condenser. An MCU controls the first switches to connect the other-side electrode of the secondary cell to the other-side plate of the first condenser when the plurality of secondary cells is in a first state, and then connect the other-side electrode of the secondary cell to the other-side plate of the second condenser when the plurality of secondary cells is in a second state. A differential amplifier circuit outputs a differential voltage of voltages of the other-side plates of the first condenser and the second condenser. A cell monitoring IC detects states of the secondary cells based on the differential voltage.

Claims

1. A secondary cell state detector comprising:

a plurality of secondary cells connected to one another in series, each of the secondary cells includes a one-side electrode and an other-side electrode;

a first condenser and a second condenser, each of which has a one-side plate and an other-side plate, each of the one-side plates is connected to the one-side electrode of each of the plurality of secondary cells;

a first switch selectively connecting the other-side electrode of each of the secondary cells to the other-side plate each of the first condenser and the second condenser;

a first switch control unit controlling the first switch to connect the other-side electrode of each of the secondary cells to the other-side plate of the first condenser when the plurality of secondary cells is in a first state, and then connect the other-side electrode of each of the secondary cells to the other-side plate of the second condenser when the plurality of secondary cells is in a second state;

a differential amplifier circuit outputting a differential voltage of voltages of the other-side plates of the first condenser and the second condenser; and

a cell state detecting unit detecting a state of each of the secondary cells based on the differential voltage.

2. The secondary cell state detector according to claim 1, further comprising:

second switches selecting one of the plurality of secondary cells; and

a second switch control unit controlling the second switches to connect the one-side electrode of the one selected secondary cell to the one-side plates of both the first condenser and the second condenser,

wherein the first switch control unit connects the other-side electrode of the one secondary cell selected by the second switches to the other-side plate of the first condenser when the plurality of secondary cells is in the first state, and then connects the other-side electrode of the one secondary cell selected by the second switches to the other-side plate of the second condenser when the plurality of secondary cells is in the second state.

3. The secondary cell state detector according to claim 2, further comprising:

an equalization unit equalizing electrode-to-electrode voltages of the plurality of secondary cells by controlling the first switch and the second switches to allow an electric charge to transfer among the plurality of secondary cells using the first condenser or the second condenser.

4. The secondary cell state detector according to claim 2, wherein one side end of the second switch is connected to the other-side electrodes of the plurality of secondary cells, respectively, and the other-side end of the second switch is connected in common to the first switch, and wherein the secondary cell state detector further includes:

resistors connected between the second switches and the secondary cells, respectively; and

an equalization unit performing equalization by controlling the second switches such that both electrodes of the secondary cells having a high voltage are connected to both ends of the second switches.

6. The secondary cell state detector according to claim 1, further comprising:

third switches provided between the first condenser and the second condenser, and the differential amplifier circuit,

wherein the first switch control unit controls the third switches to control the first switch with the first condenser and the second condenser circuit being disconnected from the differential amplifier, and controls the third switches to connect the differential amplifier circuit to the first condenser and the second condenser with the both plates of the first condenser and the second condenser being disconnected from the secondary cell.

5. A secondary cell state detector comprising:

a plurality of secondary cells connected to one another in series, each of the secondary cells includes a one-side electrode and an other-side electrode;

a plurality of first condensers corresponding to the plurality of secondary cells and a plurality of second condensers corresponding to the plurality of secondary cells, each of the first and second condensers includes a one-side plate and an other-side plate, the one-side plate of each of the first condensers is connected to the one-side electrode of the corresponding secondary cell, and the one-side plate of each of the second condensers is connected to the one-side electrode of the corresponding secondary cell;

a plurality of first switches corresponding to the plurality of secondary cells to connect the other-side electrode of a corresponding secondary cell among the plurality of secondary cells to the other-side plates of the first condenser and the second condenser;

a first switch control unit controlling each of the first switches to connect the other-side electrode of the corresponding secondary cell to the other-side plate of a corresponding one of the first condensers when the plurality of secondary cells is in a first state, and then connect the other-side electrode of the corresponding secondary cell to the other-side plate of a corresponding one of the second condensers when the plurality of secondary cells is in a second state;

a differential amplifier circuit outputting a differential voltage of voltages of the other-side plates of each of the first condensers and each of the second condensers; and

a cell state detecting unit detecting a state of each of the secondary cells based on the differential voltage.