Battery module system, method of charging battery module and charging type vacuum cleaner

• US 7,723,956 B2
• Filed: 03/20/2007
• Issued: 05/25/2010
• Est. Priority Date: 03/30/2006
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Harada, Yasuhiro, Takami, Norio, Tatebayashi, Yoshinao, Inagaki, Hiroki
• Primary Examiner(s): Tso; Edward
• Assistant Examiner(s): Berhanu; Samuel
• Application Number:
  US11/688,461
• Publication Number:
  US 20070229034A1
• Time in Patent Office: 1,162 Days
• Field of Search: 320/119, 320/132
• US Class Current: 320/119
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/441 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 2004/021 Physical characteristics, e.g. porosity, surface area
• CPC Class Codes: H01M 4/131 Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/485 of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy H01M4/505, H01M4/525 take precedence
• CPC Class Codes: H01M 4/661 Metal or alloys, e.g. alloy coatings H01M4/669 take precedence
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A battery module system includes a battery module and a control member. The battery module comprises battery units are connected in series. Each of the battery units comprises a unit cell having a voltage variation rate A (mV/% SOC) at a full charge voltage V_H1 (V) is larger than 20 (mV/% SOC), which is a value obtained when the unit cell is charged at a current of 1 C at 25° C. The control member controls current to a current I₁ until a maximum value V_max (V) among the voltage of each unit cell reaches the full charge voltage V_H1 (V) and then controls a voltage of the battery module to a voltage V2 (V) given by the following equation (1):
V2=V_H2×n  (1).

Claims

1. A battery module system comprising:

a battery module comprising battery units which are connected in series, each of the battery units comprising a unit cell having a voltage variation rate A mV/% SOC at a full charge voltage V_H1 (V) larger than 20 mV/% SOC, which is a value obtained when the unit cell is charged at a current of 1 C at 25°

C.

a current supply member which supplies current to the battery module;

a voltage detecting member which detects a voltage of the unit cells; and

a control member which controls the current to a current I₁ until at least one unit cell reaches the full charge voltage V_H1 (V) and then controls a voltage of the battery module to a voltage V2 (V) given by the following equation (1);

V2=V_H2×

n 

 

(1)

where V_H2 is a voltage lower than a voltage V_MI of the unit cell, where V_M1 is a rate of variation point where rate of variation is 20 mV/% SOC, when the voltage variation rate A mV/% SOC reaches 20 mV/% SOC from less than 20 mV/% SOC and n denotes the number of battery units connected in series.

2. The system according to claim 1, wherein the control member controls the current to a current I₂ smaller than the current I₁ after controlling the current to the current I₁ and before controlling the voltage of the battery module to the voltage V2.

3. The system according to claim 1, wherein the control member controls the current to a constant current of 3 C or less and controls the voltage of the battery module to a constant voltage not higher than a voltage V_H3 (V) given by the following equation (2), after controlling the voltage of the battery module to the voltage V2:

V_H3=V_H1×

n 

 

(2)

where V_H1 is the full charge voltage and n denotes the number of the battery units connected in series.

4. The system according to claim 1, wherein the control member controls the current I₁ such that a time taken until the SOC of the battery module reaches 80% from 0% is within 20 minutes.

5. The system according to claim 4, wherein the current I₁ is 5 C or more.

6. The system according to claim 1, wherein the control member controls the voltage V2 such that the SOC of the battery module reaches 70 to 98%.

7. The system according to claim 1, wherein each of the battery units comprises a plurality of the unit cell.

8. The system according to claim 1, wherein the unit cell is a nonaqueous electrolyte secondary battery comprising a positive electrode, a separator and a negative electrode containing lithium-titanium oxide.

9. The system according to claim 7, wherein the lithium-titanium oxide has a spinel structure.

10. The system according to claim 7, wherein the negative electrode comprises a negative electrode current collector formed from aluminum having an average crystal grain size of 50 μ

m or less or from an aluminum alloy having an average crystal grain size of 50 μ

m or less.

11. The system according to claim 7, wherein the nonaqueous electrolyte secondary battery has a laminate structure in which the positive electrode and the negative electrode are alternately laminated while sandwiching the separator therebetween.

12. The system according to claim 7, wherein the separator has a band shape and is folded in a zigzag shape and the positive electrode and the negative electrode are alternately inserted into the folded parts of the separator.

13. A charging type vacuum cleaner comprising the battery module system according to claim 1.

14. A method of charging a battery module comprising battery units which are connected in series, each of the battery units comprising a unit cell having a voltage variation rate A mV/% SOC at a full charge voltage V_H1 (V) larger than 20 mV/% SOC, which is a value obtained when the unit cell is charged at a current of 1 C at 25°

C., the method comprising;

a first constant-current charging at a current I₁ until at least one unit cell reaches the full charge voltage V_H1 (V); and

a first constant-voltage charging which controls a voltage of the battery module to a voltage V2 given by the following equation (1)

V2=V_H2×

n 

 

(1)

where V_H2 is a voltage lower than a voltage V_MI of the unit cell, where V_M1 is a rate of variation point where rate of variation is 20 mV/% SOC, when the voltage variation rate A mV/% SOC reaches 20 mV/% SOC from less than 20 mV/% SOC and n denotes the number of battery units connected in series.

15. The method according to claim 14, further comprising a second constant-current charging at a current I₂ smaller than the current I₁ between the first constant-current charging and the first constant-voltage charging.

16. The method according to claim 14, further comprising a third constant-current charging at a current of 3 C or less after the first constant-voltage charging, and a second constant-voltage charging wherein the voltage of the battery module is controlled to a voltage not higher than a voltage V_H3 (V) given by the following equation (2), after the third constant-current charging:

V_H3=V_H1×

n 

 

(2)

where V_H1 is the full charge voltage and n denotes the number of the battery units connected in series.

17. The method according to claim 14, wherein the current I₁ is set such that a charging time taken until the SOC of the battery module reaches 80% from 0% is within 20 minutes.

18. The method according to claim 14, wherein the voltage V2 is set such that the SOC of the battery module after the first constant-voltage charging reaches 70 to 98%.

19. The method according to claim 14, wherein the unit cell is a nonaqueous electrolyte secondary battery comprising a positive electrode, a separator and a negative electrode containing lithium-titanium oxide.

20. The method according to claim 19, wherein the lithium-titanium oxide has a spinel structure.