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Overvoltage detection device, protective device and battery pack

A detection device, overvoltage technology, applied in the direction of measurement device, emergency protection circuit device, measurement power, etc., can solve the problem of inability to subtract the voltage drop of the charging path, etc.

Inactive Publication Date: 2012-08-01
SANYO ELECTRIC CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] However, the above-mentioned protection circuit is usually realized by a general-purpose IC, and the technology of Patent Document 2 cannot subtract the voltage drop generated in the charging path. Therefore, when the charging voltage increases beyond the assumed level, There is a problem that the maximum overcharge state is detected by the protection circuit before being judged as an overvoltage state by the control circuit

Method used

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  • Overvoltage detection device, protective device and battery pack
  • Overvoltage detection device, protective device and battery pack
  • Overvoltage detection device, protective device and battery pack

Examples

Experimental program
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Embodiment approach 1

[0065] figure 1 It is a block diagram showing a configuration example of the battery pack according to Embodiment 1 of the present invention. 10 in the figure is a battery pack, and the battery pack 10 includes: a secondary battery 1 in which battery cells 1a, 1b, and 1c made of lithium-ion batteries are connected in series in this order; and a temperature sensor 2 for detecting the temperature of the secondary battery 1 . The positive terminal of the battery cell 1 a and the negative terminal of the battery cell 1 c correspond to the positive terminal and the negative terminal of the secondary battery 1 , respectively.

[0066] Resistors Ra1 , Ra2 , Rb1 , Rb2 , and Rc1 , Rc2 , which correspond to the resistance generated by the wiring of the charging and discharging path, are connected in equivalent series to each of the battery cells 1 a , 1 b , and 1 c.

[0067] In addition, the secondary battery 1 may be another battery such as a nickel-metal hydride battery or a nickel-...

Embodiment approach 2

[0117] In the first embodiment, when detecting the overvoltage state of the secondary battery 1 based on the battery voltage, the CPU 70 detects the overvoltage state and sets the second detection flag before the protection circuit 5 detects the overvoltage state. On the other hand, in the second embodiment, the difference between the predetermined voltage compared with the battery voltage by the protection circuit 5 and the first voltage determined by the CPU 710 compared with the offset battery voltage is the more negligible the offset voltage is. When the charging current becomes larger, the CPU 70 sets the second detection flag before the protection circuit 5 .

[0118] Figure 6 It is an explanatory diagram showing conditions under which the CPU 70 and the protection circuit 5 detect an overvoltage state according to Embodiment 2 of the present invention. The horizontal axis in the figure represents the overvoltage determination time (seconds) or the number of determinat...

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Abstract

The invention provides an overvoltage detection device, a protective device and a battery pack. The overvoltage state of a secondary battery (1) is detected under the situation that the number of times that a battery voltage including the voltage drop generated in resistors (Resistors Ra1, Ra2, Rb1, Rb2 and Rc1, Rc2) of a charging path having the secondary battery (1) is detected in a period of 250m seconds and the detected voltage is higher than an assigned voltage (4.3V) for a protection circuit (5) to detect the overvoltage state of the secondary battery is less than the second number of times (twice) that the battery voltage is detected by the protection circuit (5) within a period of 1.5 seconds after the detection of the overvoltage. In this way, when the charging current of the secondary battery is increased, the protection circuit, for detecting an overvoltage higher than an overvoltage detected by means of software control, is prevented from firstly detecting the overvoltage state of the secondary battery.

Description

technical field [0001] The present invention relates to an overvoltage detection device for detecting an overvoltage of a secondary battery, a protection device provided with the overvoltage detection device, and a battery pack provided with the protection device. Background technique [0002] In the charging process of secondary batteries represented by lithium-ion batteries, the so-called constant current / constant voltage charging method is mainly used, that is, constant current charging is performed at a specified current, and when the terminal voltage (hereinafter referred to as the battery voltage) reaches the specified After setting a predetermined voltage lower than the maximum allowable voltage (protection voltage for preventing overcharge) of the secondary battery, charging is performed by constant voltage charging. When the battery voltage exceeds the maximum voltage, the life of the battery (the degree of deterioration) and the charge and discharge capacity will b...

Claims

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Application Information

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IPC IPC(8): G01R31/36H02H7/18
CPCY02E60/12Y02E60/10
Inventor 川角笃史冈让治
Owner SANYO ELECTRIC CO LTD