Sealed nickel-metal hydride storage cells and hybrid electric having the storage cells

• US 7,353,894 B2
• Filed: 03/02/2004
• Issued: 04/08/2008
• Est. Priority Date: 03/10/2003
• Status: Expired due to Fees

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Ikezoe, Michinori
• Primary Examiner(s): PHAN, HAU VAN
• Application Number:
  US10/790,144
• Publication Number:
  US 20040180256A1
• Time in Patent Office: 1,498 Days
• Field of Search: 180/65.1, 180/65.2, 180/65.3, 180/65.8, 180/65.6, 429/223, 429/206, 429/232, 429/9, 701/19, 701/22, 903/908, 903/905
• US Class Current: 180/65.265
• CPC Class Codes: B60K 6/28 characterised by the electric energy storing means, e.g. batteries or capacitors
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60L 2220/12 Induction machines
• CPC Class Codes: B60L 2220/14 Synchronous machines
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 50/64 Constructional details of batteries specially adapted for electric vehicles
• CPC Class Codes: B60L 58/14 Preventing excessive discharging
• CPC Class Codes: H01M 10/345 Gastight metal hydride accumulators
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 2010/4292 Aspects relating to capacity ratio of electrodes/electrolyte or anode/cathode
• 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: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y10S 903/905 : Combustion engine
• CPC Class Codes: Y10S 903/907 : Electricity storage, e.g. battery, capacitor
• CPC Class Codes: Y10S 903/908 : Fuel cell

Abstract

A sealed nickel-metal hydride storage cell includes a positive electrode containing nickel as a positive electrode active material, a negative electrode containing a hydrogen-absorbing alloy as a negative electrode active material, a separator interposed between the positive electrode and the negative electrode and an electrolyte immersing therein the positive electrode and the negative electrode. The negative electrode has a theoretical capacity larger than a theoretical capacity of the positive electrode so as to provide a charge reserve capacity when the positive electrode is in a fully charged state and to provide a discharge reserve capacity when the positive electrode is in a fully discharged state. A ratio of the charge reserve capacity to the discharge reserve capacity ranges from 1:0 to 1:0.5.

Claims

1. A hybrid electric vehicle comprising:

an internal combustion engine;

a plurality of sealed nickel-metal hydride storage cells, each of the storage cells comprising;

a positive electrode comprising nickel as a positive electrode active material;

a negative electrode comprising a hydrogen-absorbing alloy as a negative electrode active material, the negative electrode having a theoretical capacity larger than a theoretical capacity of the positive electrode so as to provide a charge reserve capacity when the positive electrode is in a fully charged state and to provide a discharge reserve capacity when the positive electrode is in a fully discharged state, a ratio of the charge reserve capacity to the discharge reserve capacity ranging from 1;

0 to 1;

0.5;

a separator interposed between the positive electrode and the negative electrode; and

an electrolyte immersing therein the positive electrode and the negative electrode;

a generator driven by the engine to generate electricity for charging the storage cells; and

a controller that controls the engine and the generator to recharge the storage cells.

2. A hybrid electric vehicle according to claim 1, further comprising a charge state detecting unit that detects states of charge of the respective storage cells,

wherein the controller controls the engine and the generator in such a manner as to keep an average value of the states of charge of the storage cells at 55% or higher.

3. A hybrid electric vehicle according to claim 1, further comprising a voltage sensor to detect terminal voltages of the respective storage cells,

wherein the controller controls the engine and the generator in such a manner as to keep the terminal voltages of the storage cells at 1.15 V or larger.

4. A hybrid electric vehicle according to claim 1, wherein the storage cells are overcharged to substantially equal states during initial charge.

5. A hybrid electric vehicle, comprising:

an internal combustion engine;

a battery module comprising a plurality of nickel-metal hydride storage cells, each of the storage cells comprising positive and negative electrodes comprising nickel and hydrogen-absorbing alloy, respectively, as electrochemically active materials, a separator disposed between the positive and negative electrodes and an electrolyte immersing therein the positive and negative electrode, the negative electrode having a theoretical capacity larger than a theoretical capacity of the positive electrode so as to provide a charge reserve capacity when the positive electrode is in a fully charged state and to provide a discharge reserve capacity when the positive electrode is in a fully discharged state, the discharge reserve capacity being smaller than charge reserve capacity;

a generator driven by the engine to recharge the storage cells;

means for detecting states of charge of the respective storage cells; and

means for controlling the engine and the generator to keep an average of the states of charge of the storage cells at a given value or higher.

6. A hybrid electric vehicle according to claim 5, wherein the given value is 55%.

7. A hybrid electric vehicle according to claim 5, further comprising means for detecting voltages of the respective storage cells,

wherein the controller controls the engine and the generator to keep the voltages of the respective storage cells at a discharge voltage limit or higher.

8. A hybrid electric vehicle according to claim 7, wherein the discharge voltage limit is 1.15 V.

9. A hybrid electric vehicle according to claim 5, wherein the storage cells are overcharged during initial charge.

10. A hybrid electric vehicle according to claim 9, further comprising means for approximately equalizing the states of charge of the storage cells during initial charge.