Source: http://www.google.com/patents/US8183836?dq=6,049,612
Timestamp: 2018-01-18 20:19:02
Document Index: 652769213

Matched Legal Cases: ['Application No. 2006', 'art 331', 'art 332', 'art 335', 'art 331', 'art 333', 'art 336', 'art 335', 'art 335', 'Application No. 2006']

Patent US8183836 - Lithium battery pack - Google Patents
In a battery pack which comprises: a battery set composed of two or more lithium battery cells connected in series; a first protection circuit including a first voltage detect part for detecting the voltage(s) of a part of the two or more battery cells, and a first signal output part for issuing an output...http://www.google.com/patents/US8183836?utm_source=gb-gplus-sharePatent US8183836 - Lithium battery pack
Publication number US8183836 B2
Application number US 12/716,953
Also published as CN101047321A, CN101047321B, EP1841039A2, US7723960, US20070273332, US20100159309
Publication number 12716953, 716953, US 8183836 B2, US 8183836B2, US-B2-8183836, US8183836 B2, US8183836B2
Patent Citations (9), Non-Patent Citations (1), Referenced by (3), Classifications (12), Legal Events (3)
US 8183836 B2
In a battery pack which comprises: a battery set composed of two or more lithium battery cells connected in series; a first protection circuit including a first voltage detect part for detecting the voltage(s) of a part of the two or more battery cells, and a first signal output part for issuing an output signal when a detect voltage detected by the first voltage detect part goes below a given over-discharge judgment voltage value; a second protection circuit including a second voltage detect part for detecting the voltage(s) of another part of the two or more battery cells, and a second signal out part for issuing an output signal when the detect voltage of the battery cell detected by the second voltage detect part goes below a given over-discharge judgment voltage value; and, a switch which is connected to the current path of the battery set and can be turned on or off according to the output signals of the first and second signal output parts and, there is further provided dead time means connected between the second signal output part of the second protection circuit for issuing an output not responding to a variation in an input signal occurring within a given time.
1. A lithium battery pack, comprising:
at least five lithium battery cells connected in series;
a first protection circuit, which is connected to at least four lithium battery cells out of the five lithium battery cells to monitor each voltage of the four lithium battery cells respectively, outputting a first signal when the voltage of at least one of the four lithium battery cells is less than a first over-discharge voltage;
a second protection circuit, which is connected to at least one lithium battery cell, which is different from the four lithium battery cells, to monitor the voltage of the lithium battery cell, which is different from the four lithium battery cells, outputting a second signal when the voltage of the lithium battery cell, which is different from the four lithium battery cells, is less than a second over-discharge voltage;
a switch connected to a current path of the plurality of lithium battery cells, the switch turning off and the current path being cut off when the first signal or the second signal is outputted; and
a dead time means, which is connected to the second protection circuit,
wherein said first protection circuit further monitors the current flowing through the current path and outputs a third signal when the current goes over a predetermined current;
wherein the switch turns off and the current path is cut off when the third signal is outputted; and
wherein the second over-discharge voltage is greater than the first over-discharge voltage.
2. The lithium battery pack according to claim 1, the first protection circuit comprising a signal output part outputting the first signal and the third signal.
3. The lithium battery pack according to claim 1, further comprising a first switching element and a second switching element for controlling the switch,
wherein the first switching element is connected to the first protection circuit and receives the first signal and the third signal; and
wherein the second switching element is connected to the second protection circuit and receives the second signal.
4. The lithium battery pack according to claim 1, further comprising a second switch, wherein the first protection circuit monitors each voltage of the four lithium battery cells and outputs a fourth signal to cut off the second switch when at least one of the four lithium battery cells is over charged.
5. The lithium battery pack according to claim 4, wherein the second protection circuit monitors the voltage of the one lithium battery cell, which is different from the four lithium battery cells, and outputs a fifth signal to cut off the second switch when the one lithium battery cell, which is different from the four lithium battery cells, is over charged.
6. The lithium battery pack according to claim 1, wherein the four lithium battery cells connected to the first protection circuit are disposed next to each other respectively.
7. The lithium battery pack according to claim 6, wherein the lithium battery pack has a rated voltage of 18V.
8. The lithium battery pack according to claim 7, the first protection circuit comprising a signal output part outputting the first signal and the third signal.
9. The lithium battery pack according to claim 7, further comprising a first switching element and a second switching element for controlling the switch,
10. The lithium battery pack according to claim 9, wherein the four lithium battery cells connected to the first protection circuit are disposed next to each other respectively.
11. The lithium battery pack according to claim 10, wherein the lithium battery pack has a rated voltage of 18V.
wherein said first protection circuit further monitors the current flowing through the current path and outputs a third signal when the current is greater than a predetermined current;
13. A lithium battery pack, comprising:
a first protection circuit, which is connected to at least one lithium battery cell to monitor voltage of the at least one lithium battery cell respectively, outputting a first signal when the voltage of at least one of the lithium battery cells is less than a first over-discharge voltage;
a second protection circuit, which is connected to at least one lithium battery cell, which is different from the lithium battery cells connected to the first protection circuit, to monitor voltage of the at least one lithium battery cell, which is different from the lithium battery cells connected to the first protection circuit, outputting a second signal when at least one of the voltages of the lithium battery cell, which is different from the lithium battery cells connected to the first protection circuit, is less than a second over-discharge voltage which is smaller than the first over-discharge voltage;
a dead time means, which is connected to the first protection circuit in order to delay the timing that the first signal reaches the switch, when the voltage of the at least one lithium battery cell connected to the first protection circuit is lower than the first over-discharge voltage.
14. The lithium battery pack according to claim 13,
wherein one of the first protection circuit and the second protection circuit further monitors the current flowing through the current path and outputs a third signal when the current goes over a predetermined current.
15. The lithium battery pack according to claim 14, further comprising a first switching element and a second switching element for controlling the switch,
wherein the first switching element is connected to one of the first protection circuit and the second protection circuit and able to receive the first signal and the third signal; and
wherein the second switching element is connected to another one of the first protection circuit and the second protection circuit and able to receive the second signal.
16. The lithium battery pack according to claim 13,
wherein the plurality of lithium battery cells have five battery cells connected in series,
one of the first protection circuit and second protection circuit is connected to four lithium battery cells, and
another one of the first protection circuit and second protection is connected to one lithium battery cell which is different from the four lithium battery cells.
17. The lithium battery pack according to claim 13, further comprising a second switch, wherein at least one of the first protection circuit and the second protection circuit monitors voltage of at least one of the plurality of lithium battery cells and outputs a fourth signal to cut off the second switch when at least one of the plurality lithium battery cells is over charged.
18. The lithium battery pack according to claim 13, wherein the dead time means comprises a capacitor.
19. The power tool according to the claim 18,
20. The power tool according to the claim 18,
one of the first protection circuit and the second protection circuit is connected to four lithium battery cells, and
another one of the first protection circuit and the second protection circuit is connected to one lithium battery cell which is different from the four lithium battery cells.
21. The power tool according to the claim 18, the power tool further comprising a second switch, wherein at least one of the first protection circuit and the second protection circuit monitors voltage of at least one of the plurality of lithium battery cells and outputs a fourth signal to cut off the second switch when at least one of the plurality lithium battery cells is over charged.
a first protection circuit, which is connected to at least one lithium battery cell to monitor the voltage of the at least one lithium battery cell respectively, outputting a first signal when the voltage of at least one of the lithium battery cells is less than a first over-discharge voltage;
a second protection circuit, which is connected to at least one lithium battery cell, which is different from the lithium battery cells connected to the first protection circuit, to monitor voltage of the lithium battery cell, which is different from the lithium battery cells connected to the first protection circuit, outputting a second signal when at least one of the voltage of the lithium battery cell, which is different from the lithium battery cells connected to the first protection circuit, is less than a second over-discharge voltage which is smaller than the first over-discharge voltage;
a dead time means, which is connected to the first protection circuit in order to delay the timing that the first signal reaches the switch, after the voltage of the at least one lithium battery cell connected to the first protection circuit is lower than the first over-discharge voltage.
23. The power tool according to the claim 22, further comprising a first switching element and a second switching element for controlling the switch,
24. The lithium battery pack according to claim 22, wherein the dead time means comprises a capacitor.
This application is a Continuation of U.S. application Ser. No. 11/710,482, filed on Feb. 26, 2007, now U.S. Pat. No. 7,723,960, claiming priority of Japanese Patent Application No. 2006-097090, filed on Mar. 31, 2006, the entire contents of each of which are hereby incorporated by reference.
As the power supply of the cordless power tool, conventionally, there are often used a nickel-cadmium (N—Cd) battery, a nickel hydrogen (Ni-MH) battery and the like. However, recently, with the increasing need for the enhanced capacity and reduced weight of the power supply, there has been used the lithium battery.
In attaining the above object, according to the invention, there is provided a lithium battery pack, comprising: a battery set composed of two or more lithium battery cells connected in series; a first protection circuit including a first voltage detect part for detecting the voltage (s) of a part of the two or more battery cells, and a first signal output part for issuing an output signal when a detect voltage detected by the first voltage detect part goes below a given over-discharge judgment voltage value; a second protection circuit including a second voltage detect part for detecting the voltage (s) of another part of the two or more battery cells, and a second signal output part for issuing an output signal when the detect voltage of the battery cell detected by the second voltage detect part goes below a given over-discharge judgment voltage value; characterized by dead time means connected between the second signal output part of the second protection circuit for issuing an output not responding to a variation in an input signal occurring within a given time.
According to a third aspect of the invention, the dead time means is composed of a time constant circuit made of a resistor and a capacitor; and a diode connected between the two terminals of the resistor.
According to a sixth aspect of the invention, there is provided a power tool, comprising: a battery set including two or more lithium battery cells connected in series; a first protection circuit for detecting the cell voltage (s) of a part of the two or more lithium battery cells and, when the thus detected voltage goes below a given over-discharge judgment voltage value, for issuing an output signal; a second protection circuit for detecting the cell voltage(s) of another part of the two or more lithium battery cells and, when the thus detected voltage goes below a given over-discharge judgment voltage value, for issuing an output signal; switch means connected to the current path of the battery set such that it can be turned on or off according to the outputs of the first and second protection circuit; dead time means connected between the second protection circuit and the switch means for issuing an output not responding to a variation in an input signal within a given time; and, a motor to which a voltage from the battery set can be supplied through the switch means.
FIG. 3 is a waveform view for explanation of the operation of the battery pack according to the invention.
The voltage across the battery cell 21 (which is designated as 21E) disposed on the lower-most stage of the battery set 2 is detected by the battery voltage detect part 331. The thus detected voltage is compared with a first given voltage V1 set in the over-discharge judgment part 332 of the second protection circuit 33 and, when the detected voltage goes below the first given voltage V1, there is issued an H signal from the over-discharge signal output part 335. Also, the voltage detected by the battery voltage detect part 331 is compared with a second given voltage V2 set in the overcharge judgment part 333 and, when the detected voltage goes beyond the second given voltage V2, there is issued an H signal from the overcharge, signal output part 336.
When the operations of the above-mentioned respective switching elements 51˜54 and 31A, 31B are put in order, they can be displayed as shown in FIG. 5.
An A1 portion contained in the waveform a which shows the detect voltage of the battery cell 21 shows a voltage in a state where the switch 72 of the tool 7 is off and, specifically, the A1 portion shows that it is a voltage in the vicinity of 3.6 V which is the rated voltage of the lithium battery cell 21. Next, when the switch 72 of the tool 7 is turned on, the detect voltage lowers according to the load of the motor 71, thereby providing the waveform of an A2 portion. After then, when the switch 72 is turned off, the detect voltage rises and recovers up to the vicinity of 3.6 V, thereby providing a waveform shown by an A3 portion. Further, when a large load is applied and the switch 72 is turned on, the detect voltage lowers further to thereby cause a state in which the detect voltage goes below the over-discharge voltage judgment value L2 of the second protection circuit 33. During this period, the output b of the over-discharge signal output part 335 of the second protection circuit 33, as shown by B1 in FIG. 3, turns from an L output to an H output. However, according to the invention, since the output of the over-discharge signal output part 335 is applied through the dead time means 6 to the gate of the switching element 52, the applied voltage of the switching element 52 varies as shown by c. That is, the applied voltage varies an in a Cl portion according to a time constant which has been previously set by the dead time means 6. Thanks to this, the switching element 52 is allowed to maintain an off state, while the switch circuit 31 is allowed to maintain an on state.
US6396246 * Mar 26, 2001 May 28, 2002 Fujitsu Limited Charge/discharge control circuit and secondary battery
US20040178768 * Mar 29, 2004 Sep 16, 2004 Hideki Miyazaki Battery apparatus for controlling plural batteries and control method of plural batteries
JP2002223063A Title not available
JPS6369415A Title not available
1 Japanese Office Action, and English translation thereof, issued in Japanese Patent Application No. 2006-097090 dated Jan. 5, 2012.
U.S. Classification 320/134, 320/136, 340/636.21, 324/426, 340/636.1, 320/155, 320/149