Electricity: measuring and testing – Electrolyte properties – Using a battery testing device
Reexamination Certificate
1999-01-15
2001-05-22
Metjahic, Safet (Department: 2858)
Electricity: measuring and testing
Electrolyte properties
Using a battery testing device
C320S144000
Reexamination Certificate
active
06236216
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to a temperature/voltage detecting unit for detecting a temperature and a terminal voltage of each of batteries of a heavy electric system for supplying a voltage to a motor for operating an electric car.
Further, the present invention relates to a battery element unit having a battery element and a temperature/voltage detecting unit corresponding to this battery element.
2. Description of Prior Art
Conventionally, electric cars are run by rotationally driving a motor which is supplied with a voltage from a battery of a heavy electric system. Recently, along with the progress of development of batteries with high performance of charge and discharge functions, there has been an increasingly strong demand for voltage management and temperature management of these batteries. For example, a heavy electric system battery for a driving system is structured by about twenty to thirty battery elements connected in series, and it has become necessary to manage both voltage and temperature of each of these battery elements. Therefore, a voltage detector and a temperature detector are necessary by the number of these battery elements.
As a conventional voltage detector, there has been used a voltage detector to which a zero magnetic flux method is applied as shown in
FIG. 1. A
voltage detector
101
shown in
FIG. 1
has a magnetic core
103
which is wound up with a primary winding
105
and a secondary winding
107
. The primary winding
105
is connected with a heavy electric system battery
111
structured by a plurality of power supplies
111
a,
111
b,
. . . , and
111
n
connected in series, through a resistor
109
. A Hall element
115
is provided in a gap
113
formed on a magnetic core
103
.
In this case, a magnetic flux&PHgr;
1
is generated within the magnetic core
103
by the primary current I
1
flowing through the primary winding
105
, and the Hall element
115
for detecting this magnetic field generates a voltage corresponding to a direction of the magnetic field and a size of the magnetic field, and outputs this voltage to a current amplifier
117
. The current amplifier
117
amplifies a current based on the voltage from the Hall element
115
and flows an output current I
2
to the secondary winding
107
. When the output current I
2
flows to the secondary winding
107
, a magnetic flux&PHgr;
2
is generated. In this case, the magnetic flux&PHgr;
2
works to cancel the magnetic flux&PHgr;
1
.
When the magnetic flux&PHgr;
2
becomes equal to the magnetic flux&PHgr;
1
, the magnetic flux&PHgr;
1
within the magnetic core
103
becomes zero. Accordingly, the Hall element
115
makes the output zero, and the magnetic flux&PHgr;
2
also becomes zero. In this state, the magnetic flux&PHgr;
1
is generated again within the magnetic core
103
and an output is generated in the Hall element
115
as well, so that the magnetic flux&PHgr;
2
becomes larger than the magnetic flux&PHgr;
1
within the magnetic core
103
. This operation is repeated in high frequency, and the output current I
2
is made as an effective value. At this time, the following law of equal ampere-turns is established.
N
1
·I
1
=N
2
·I
2.
When the output current I
2
from the current amplifier
117
is measured by using this expression, the primary current I
1
can be obtained. A detection voltage across both ends of the resistor
119
becomes a voltage proportional to the output current I
2
.
However, according to the prior-art technique, a unit having a voltage detector and a unit having a temperature detector are provided separately for each battery element, and therefore, a battery unit as a whole has a large size for these detectors and a considerably large space has been necessary for these detectors.
Further, although the prior-art voltage detector has high precision, this has required a large size for the. magnetic core
103
, the primary winding
105
and the secondary winding
107
, resulting in a high cost as well.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a compact and low-cost temperature/voltage detecting unit having a temperature detector and a voltage detector accommodated together therein, with insulation property.
Further, it is another object of the present invention to provide a battery element unit for accommodating the above temperature/voltage detecting unit in a groove portion on an external wall of the battery element unit.
In order to achieve the above objects, there is provided a temperature/voltage detecting unit corresponding to each of a plurality of battery elements connected in series that constitute a heavy electric system power supply for an electric car, the temperature/voltage detecting unit comprising: a temperature detector for detecting a temperature of a corresponding battery element when a light electric system power supply voltage is being applied; and a voltage detector for inputting a signal to show whether or not the light electric system power supply voltage is being applied to the temperature detector, and, when this voltage is being supplied, for detecting a terminal voltage of the corresponding battery element in a state electrically insulated from the signal.
In a preferred embodiment of the present invention, the temperature detector comprises: a light electric system stabilized power supply for stabilizing the light electric system power supply voltage: a temperature resistance element provided close to a corresponding battery element, for changing a resistance value thereof based on a change in the temperature of the battery element; and a resistance terminal voltage detector operating based on a voltage from the light electric system stabilized power supply, for detecting a terminal voltage of the temperature resistance element to which a constant current flows from the light electric system stabilized power supply.
In another preferred embodiment of the present invention, the temperature detector further comprises a voltage-to-frequency converter for converting a value of the terminal voltage detected by the resistance terminal voltage detector into frequency information and outputting the frequency information.
In still another preferred embodiment of the present invention, the voltage detector comprises: a heavy electric system stabilized power supply for stabilizing a voltage supplied from a corresponding battery element; a voltage supply control section for inputting a signal to show whether or not the light electric system power supply voltage is being applied to the temperature detector, and, when the light electric system power supply voltage is being supplied, for applying the voltage from the corresponding battery element to the heavy electric system stabilized power supply; and a battery element terminal voltage detector operating based on a voltage from the light electric system stabilized power supply, for detecting the terminal voltage of the corresponding battery element.
In yet still another preferred embodiment of the present invention, the voltage detector further comprises a voltage-to-frequency converter for converting a value of the terminal voltage detected by the battery element terminal voltage detector into frequency information and outputting the frequency information.
In a further preferred embodiment of the present invention, the voltage supply control section comprises: a light-emitting diode for inputting a signal to show whether or not the light electric system power supply voltage is being applied to the temperature detector, and for emitting light or non-emitting light depending on whether or not the light electric system power supply voltage is being applied; a photo-transistor for being turned on/off according to light emission
on-light emission of the light-emitting diode; and a transistor for applying the voltage from the corresponding battery element to the heavy electric system stabilized power supply according to on/off of the photo-transistor.
Further, in order to achieve
Arai Yoichi
Maemoto Toshifumi
Shimoyama Kenichi
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Kerveros J.
Metjahic Safet
Yazaki -Corporation
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