KR20170058073A - Apparatus of Measuring Voltage of Battery Pack and Method thereof - Google Patents

Abstract

Disclosed are an apparatus for measuring voltage of a battery pack and a method thereof in the present invention. The apparatus according to the present invention comprises: a resistor circuit unit comprising a first voltage distribution resistor and a second voltage distribution resistor which is serially connected to the first voltage distribution resistor and has a smaller resistor value than the first voltage distribution resistor; a switch unit which parallel-connects the resistor circuit unit to an anode terminal of the battery pack or to a cathode terminal of the battery pack, or disconnects the connection and has a turn-on resistance varying according to temperature; a temperature measuring unit which outputs a temperature measuring signal corresponding to the temperature of the switch unit; a voltage measuring unit which is connected to the second voltage distribution resistor and outputs a voltage measuring signal corresponding to voltage applied to the second voltage distribution resistor; and a control unit. The control unit receives the temperature measuring signal and the voltage measuring signal to determine a temperature measuring value and a voltage measuring value and then, determines a turn-on resistance value corresponding to the temperature measuring value by referring a predefined turn-on resistance data for each temperature of the switch unit, and determines voltage of the battery pack by using the turn-on resistance value, a resistor value of the resistor circuit unit, and the voltage measuring value.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring a voltage of a battery pack,

The present invention relates to an apparatus and a method for accurately measuring the voltage of a battery pack.

Hybrid vehicles, electric vehicles, and energy storage systems include large-capacity battery packs.

The battery pack includes a plurality of unit cells connected in series. The unit cell is a cell capable of repeated charging and discharging. The voltage of the battery pack is equal to the sum of the voltages of the unit cells. Large capacity battery packs typically have voltages in the range of tens to hundreds of volts.

The voltage of the battery pack must be maintained properly within the designed voltage range. When the voltage increases above the design upper limit voltage or decreases below the design lower limit voltage, the battery pack deteriorates and its service life is shortened. Therefore, safety measures must be taken such as stopping charging or discharging when the battery pack voltage exceeds the design voltage range.

It is important to accurately measure the voltage of the battery pack in order to stably manage the voltage of the battery pack.

The voltage of the battery pack is measured using two or more voltage distribution resistors connected in parallel between the positive terminal and the negative terminal. Voltage distribution resistors have a large relative ratio of resistance values. The voltage of the battery pack is measured through a voltage distribution resistor having a relatively small resistance value. The outermost nodes of the voltage distribution resistors are connected to the positive and negative terminals of the battery pack through the switch.

The voltage of the battery pack is measured periodically. When the measurement period comes, the switch is turned on. Then, the voltage of the battery pack is applied to both nodes of the voltage distribution nodes. In this state, a voltage applied to any one of the voltage distribution resistors is input to an analog-to-digital converter (ADC). Then, the voltage of the battery pack is determined from the ratio of the voltage value converted from the ADC to the digital value and the resistance value between the voltage distribution resistors.

Solid State Relay (SSR) switches are typical switches used to connect the voltage distribution resistors to the battery pack when measuring the battery pack voltage.

The SSR switch is an electronic switch that is part of a solid state relay and does not include a mechanical relay and no moving parts. The SSR switch is largely divided into the use of light as a control signal and the use of a voltage as a control signal.

SSR switches have faster response than mechanical relays. In addition, the control logic and the high voltage load can be operated separately, and there is no moving part, so the life span is long.

However, the SSR switch has a turn-on resistance at both ends when closed. Therefore, it is difficult to accurately measure the voltage due to the turn-on resistance of the SSR switch when the voltage distribution resistors are connected to the battery pack using the SSR switch when measuring the voltage of the battery pack. This is because the measured voltage value includes the voltage component derived from the turn-on resistance of the SSR switch. Also, the value of the turn-on resistance when the SSR switch is closed depends on the temperature. Therefore, if the temperature of the SSR switch changes, the measured voltage of the battery pack also changes.

If the voltage of the battery pack is not accurately measured, it is difficult to control the voltage so that the voltage does not deviate from the design voltage range in the latter half of the charging and the latter half of the discharging. For example, when charging or discharging is continued with a constant current, the rate of voltage change increases toward the second half of the charge and the second half of the discharge.

Therefore, there is a need for a technical improvement to reduce the measurement error caused when the voltage of the battery pack is measured by using an electronic switch having a characteristic that the turn-on resistance varies with temperature, such as an SSR switch.

SUMMARY OF THE INVENTION The present invention has been made in view of the above background and it is an object of the present invention to provide an apparatus and method capable of accurately measuring a voltage of a battery pack in consideration of a voltage error derived from a turn on resistance of a switch used for connecting voltage distribution resistors to a battery pack The purpose is to provide.

According to an aspect of the present invention, there is provided an apparatus for measuring a voltage of a battery pack, the apparatus including: a first voltage distribution resistor; and a second voltage distribution resistor connected in series with the first voltage distribution resistor, A resistor circuit portion including a second voltage distribution resistor; A switch unit that connects or disconnects the resistor circuit unit between the positive and negative terminals of the battery pack and changes the turn-on resistance according to the temperature; A temperature measuring unit for outputting a temperature measurement signal corresponding to the temperature of the switch unit; A voltage measuring unit connected to the second voltage distribution resistor and outputting a voltage measurement signal corresponding to a voltage applied to the second voltage distribution resistor; And receiving the temperature measurement signal and the voltage measurement signal to determine a temperature measurement value and a voltage measurement value; Determining a turn-on resistance value corresponding to the temperature measurement value by referring to pre-defined temperature-specific turn-on resistance data of the switch unit; And a control unit configured to determine a voltage of the battery pack using the turn-on resistance value and the resistance value of the resistance circuit unit and the voltage measurement value.

The ratio of the resistance values of the first voltage distribution resistor and the second voltage distribution resistor may be adjusted so that a voltage less than 5V is applied to the second voltage distribution resistor.

According to an aspect of the present invention, the switch unit includes: a first switch that connects or disconnects one end of the resistor circuit unit to the positive terminal of the battery pack; And a second switch for connecting or disconnecting the other end of the resistor circuit to the negative terminal of the battery pack.

Preferably, the first switch and the second switch may be non-contact semiconductor switches. For example, the solid state switch may be a solid state relay (SSR) switch. The temperature measuring unit may include: a first thermistor for measuring a temperature of the first switch; And a second thermistor for measuring the temperature of the second switch.

Preferably, the turn-on resistance data defined for each temperature may be a look-up table capable of mapping the turn-on resistance value by temperature.

Preferably, the control unit may be configured to determine the voltage of the battery pack by the following equation.

(V _pack is the voltage of the battery pack; R ₁ is the first voltage resistance of the distributed resistor; R ₂ is a second resistance value of the voltage distribution resistance; R _on the total switch unit turns on a resistance value; R _known is the voltage of the battery pack, V _measure is the voltage measurement value measured through the second voltage distribution resistor)

According to another aspect of the present invention, one end of the resistance circuit part is connected to a positive terminal or a negative terminal of the battery pack, and the other end of the resistance circuit part is connected to a negative terminal or a positive terminal of the battery pack.

According to another aspect, the control unit may be electrically coupled to the memory unit, and may be configured to store the determined voltage of the battery pack in the memory unit.

According to another aspect, the control unit may be electrically coupled to the communication interface and configured to transmit the voltage of the determined battery pack to another external control device via the communication interface.

According to another aspect, the apparatus according to the present invention may include a PCB substrate on which the switch unit and the temperature measuring unit are installed. A thermally conductive pad may be interposed between the switch unit and the PCB substrate, and the switch unit and the temperature measuring unit may be mounted on the thermally conductive pad.

Preferably, the switch portion includes a first switch and a second switch mounted on the thermally conductive pad, and the temperature measuring portion includes a first switch and a second switch which are mounted on the thermally conductive pad between the first switch and the second switch And may include a thermistor.

According to an aspect of the present invention, there is provided a method of measuring a voltage of a battery pack, the method comprising: a first voltage distribution resistor; and a second voltage distribution resistor connected in series with the first voltage distribution resistor, And a switch unit having a turn-on resistance varying according to a temperature, wherein the switch circuit is connected between the positive terminal and the negative terminal of the battery pack, Determining a temperature measurement value of the switch unit by receiving a temperature measurement signal corresponding to the temperature of the switch unit from the temperature measurement unit; Connecting the resistor circuit part to the battery pack in parallel by turning on the switch part; Determining a voltage measurement value by receiving a voltage measurement signal corresponding to a voltage applied to the second voltage distribution resistor from a voltage measurement unit connected to the second voltage distribution resistor; Determining a turn-on resistance value corresponding to the temperature measurement value by referring to pre-defined temperature-specific turn-on resistance data of the switch unit; And determining the voltage of the battery pack from the turn-on resistance value and the resistance value of the resistance circuit portion and the voltage measurement value.

According to the present invention, the voltage of the battery pack can be accurately measured even if the switch used when connecting the voltage distribution resistors to the battery pack has a turn-on resistance that varies with temperature.

Particularly, the present invention can effectively prevent overcharge or overdischarge by accurately measuring the voltage during charging or discharging control of a high capacity battery pack.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention and, together with the description given below, serve to further augment the technical spirit of the invention, And shall not be interpreted.
1 is a block diagram of a voltage measuring apparatus for a battery pack according to a preferred embodiment of the present invention.
2 is a view showing an embodiment in which two switch temperatures are commonly measured by one thermistor when two switches used for connecting voltage distribution resistors to a battery pack are used.
3 is a flowchart illustrating a voltage measuring method of a battery pack according to a preferred embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary meanings, and the inventor should appropriately interpret the concept of a term appropriately in order to describe its own application in the best way possible. It should be interpreted in accordance with the meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined. Therefore, the embodiments described in the present specification and the configurations shown in the drawings are only examples of the present invention, and are not intended to represent all of the technical ideas of the present invention. Therefore, various equivalents And variations are possible.

1 is a block diagram illustrating a voltage measuring apparatus for a battery pack according to an embodiment of the present invention.

Referring to FIG. 1, a voltage measuring apparatus 100 according to the present invention can accurately measure a voltage of a battery pack 110, and includes a resistance circuit unit 120; A switch unit 130; A temperature measuring unit 140; A voltage measuring unit 150; And a controller 160.

The battery pack 110 includes a plurality of unit cells connected in series. In one example, the unit cell may be a lithium polymer cell. The battery pack 110 may be a high capacity battery pack mounted on a hybrid vehicle, an electric vehicle, an energy storage system, a drone or the like. The battery pack 110 may have an output voltage of tens to hundreds of volts. However, the present invention is not limited by the type of device or system on which the battery pack 110 is mounted, the type of unit cell included in the battery pack 110, and the output voltage level of the battery pack 110.

The resistance circuit unit 120 includes a first voltage distribution resistor R ₁ and a second voltage distribution resistor R ₂ . The first and second voltage distribution resistors R ₁ and R ₂ are connected in series with each other. The resistance value of the second voltage distribution resistor R ₂ is relatively smaller than the resistance value of the first voltage distribution resistor R ₁ .

The ratio of the resistance values of the first voltage distribution resistor R ₁ and the second voltage distribution resistor R ₂ may be adjusted so that a voltage less than 5 V is applied to the second voltage distribution resistor R ₂ have. For example, the first voltage distribution resistor R ₁ may have a resistance value in megaohms, and the second voltage distribution resistor R ₂ may have a resistance value in units of hundreds of ohms. For reference, 5 V is the operating voltage level of a typical electronic circuit. Of course, the voltage level that is the basis for adjusting the resistance value ratio may vary depending on the electronic circuit. The resistance circuit unit 120 does not limit the resistance to include the first and second voltage distribution resistors R1 and R2.

The switch unit 130 may connect the resistance circuit unit 120 in parallel between the positive terminal and the negative terminal of the battery pack 110 or vice versa. The switch unit 130 may be turned on and turned on by the controller 160. The switch unit 130 has a turn-on resistance whose resistance value varies depending on the temperature.

The switch unit 130 may include a first switch 131 that connects one end of the resistor circuit unit 120 to the positive terminal of the battery pack 110 or vice versa. The switch unit 130 may include a second switch 132 that connects the other end of the resistance circuit unit 120 to the negative terminal of the battery pack 110 or vice versa.

In one example, the first switch 131 and the second switch 132 may be non-contact semiconductor switches. Preferably, the solid state switch is an SSR switch. However, the present invention can be applied to any electronic switch having a characteristic that the value of the turn-on resistance varies with temperature. Therefore, the present invention is not limited by the kind of the first switch 131 and the second switch 132. [

Optionally, either the first switch 131 or the second switch 132 may be omitted. In this case, one end of the resistor circuit part 120 located on the side where the switch is omitted may be directly connected to the positive terminal or the negative terminal of the battery pack 110.

The temperature measuring unit 140 outputs a temperature measurement signal corresponding to the temperature of the switch unit 130 under the control of the controller 160. The temperature measurement signal is input to the control unit 160 side.

The temperature measuring unit 140 may include a thermistor capable of outputting a temperature measurement signal corresponding to the temperature of the switch unit 130. When the switch unit 130 includes two switches 131 and 132, the temperature measuring unit 140 may include two thermistors corresponding to the respective switches. Alternatively, even though the switch 130 includes two switches 131 and 132, the temperature measuring unit 140 may include a single thermistor. The latter case may be preferred in terms of reducing the unit cost of the temperature measuring unit 140. [

FIG. 2 is a view showing an arrangement structure of a thermistor and a switch when a voltage measuring device 100 of the battery pack according to the present invention is manufactured in the form of a PCB substrate.

2 (a) is a top plan view partially enlarging an arrangement part of the thermistor and the switch, and FIG. 2 (b) is a partial cross-sectional view showing a section of the thermistor and the part where the switch is disposed. In FIG. 2, the wiring structure formed on the PCB substrate is not shown.

2, when the switch unit 130 includes the first and second switches 131 and 132, the switches 131 and 132 are connected to the thermal conductive pad 210 formed on the PCB 200, Lt; / RTI > The thermally conductive pad 210 may be a metal or a thermally conductive plastic. The thermistor 141 constituting the temperature measuring unit 140 may be installed to be in contact with the thermally conductive pad 210.

Preferably, the thermistor 141 may be disposed in a space between the first and second switches 131 and 132. In this case, even if there is a temperature difference between the first and second switches 131 and 132, the temperatures of the first and second switches 131 and 132 are made uniform by the thermally conductive pad 210. Therefore, by measuring the temperature of the thermally conductive pad 210 with one thermistor 141, the temperatures of the first and second switches 131 and 132 can be accurately measured.

Unlike the above, when the temperature measuring unit 140 is composed of two thermistors, each thermistor may be installed so as to independently contact the first and second switches 131 and 132 using an adhesive. In this case, the thermally conductive pad 210 may optionally be omitted.

2 (a), line C shows a signal line to which a control signal for controlling the operation of the first switch 131 and the second switch 132 is input. The line B ₁ of the first switch 131 is connected to the node B ₁ 'of FIG. 1, and the line B ₂ of the second switch 132 is connected to the node B ₂ ' of FIG.

The thermistor 141 outputs a temperature measurement signal corresponding to the temperature at the point of contact therewith, and the output temperature measurement signal is input to the control unit 160 side.

1, the voltage measuring unit 150 outputs a voltage measurement signal corresponding to a voltage applied to the second voltage distribution resistor R ₂ included in the resistance circuit unit 120, and the output voltage measurement signal is And is input to the control unit 160 side.

The operation of the voltage measuring unit 150 is controlled by the controller 160. [ That is, the control unit 160 may periodically trigger the voltage measurement operation of the voltage measurement unit 150 by outputting a control signal including a voltage measurement instruction to the voltage measurement unit 150. [

The voltage measuring unit 150 may be an analog-to-digital converter. In this case, when the control signal is inputted from the controller 160, the voltage measuring unit 150 receives a voltage applied to the second voltage distribution resistor R ₂ as an analog voltage signal, converts the voltage into a digital signal, To the control unit 160 side.

The control unit 160 controls the temperature measuring unit 140 and the voltage measuring unit 150 each time a voltage measuring period of the battery pack 110 arrives so that the temperature measuring unit 140 and the voltage measuring unit 150 And receives a temperature measurement signal and a voltage measurement signal. The controller 160 determines a temperature measurement value and a voltage measurement value from the input temperature measurement signal and the input voltage measurement signal.

When the switch 130 includes the first switch 131 and the second switch 132, the temperature measurement signal includes two temperature measurement signals corresponding to the temperatures of the switches 131 and 132 . When the temperature measurement signal includes two signals, the temperature measurement value is also two. Alternatively, the temperature measurement signal may comprise one temperature measurement signal corresponding to a common temperature of each switch 131, 132. In this case, the temperature measurement value is one. The common temperature may be, for example, the temperature of the thermally conductive pad 210 of FIG.

The control unit 160 also determines a turn-on resistance value corresponding to the temperature measurement value of the switch unit 130 by referring to the pre-defined turn-on resistance data for each temperature. When the temperature measurement value is two, the controller 160 may determine a turn-on resistance value for the first switch 131 and the second switch 132, respectively. Also, when the temperature measurement value is one, the controller 160 may determine a turn-on resistance value common to the first switch 131 and the second switch 132. [

The predefined temperature-specific turn-on resistance data may be a look-up table capable of mapping the turn-on resistance value by temperature. This look-up table can be stored in advance in the memory unit 170 described later. The temperature-specific turn-on resistance data can be measured through experiments.

When the turn-on resistance value of each switch constituting the switch unit 130 is determined, the controller 160 uses the determined turn-on resistance value and the resistance value of each resistor constituting the resistance circuit unit 120 and the voltage measurement value The voltage of the battery pack 110 can be determined.

Preferably, the controller 160 may determine the voltage of the battery pack 110 using Equation (1).

≪ Formula 1 >

In Equation 1, V _pack is the voltage of the battery pack. R ₁ is a resistance value of the first voltage distribution resistor R ₁ . And R ₂ is the resistance value of the second voltage distribution resistor R ₂ . R _on is the total turn-on resistance value of the switch (s) included in the switch portion 130. R _known is a resistance value of another resistance component existing in the voltage measurement path of the battery pack 110 and is a constant that can be predetermined according to the design condition of the voltage measurement path. R _known has a value of zero or more. V _measure is the voltage measurement measured through the second voltage distribution resistor (R ₂ ).

The derivation process of Equation (1) is as follows. The voltage V _pack of the battery pack 110 is the same as the voltage applied between nodes N ₁ and N ₂ in FIG. Further, the relative ratio of the resistance value of the voltage V _measure, the total resistance value than the second voltage distribution resistor (R ₂₎ that exists between the nodes N ₁ and N ₂ is applied to the second voltage distribution resistor (R ₂₎ battery Lt; RTI ID = 0.0 > _Vpack < / RTI > Therefore, the following equation 2 is established, and the voltage equation of equation 1 can be obtained by summarizing equation (2) for V _pack .

&Quot; (2) "

The voltage measuring apparatus 100 of the battery pack 110 according to the present invention may further include a memory unit 170. [ The memory unit 170 is not particularly limited as long as it is a storage medium capable of recording, erasing and maintaining information.

As one example, the memory section 170 may be a RAM, a ROM, or a register. The memory unit 170 may also be electrically connected to the controller 160 through a data bus or the like so that the controller 160 can access the memory unit 170.

The memory unit 170 also stores and / or updates and / or erases and / or transmits data, which is generated when the control logic is executed, and / or a program including various control logic performed by the control unit 160. [

The memory unit 170 may be logically divided into two or more, and the memory unit 170 is not limited to being included in the controller 160.

The control unit 160 may store the determined voltage value in the memory unit 170 whenever the voltage of the battery pack 160 is determined. At this time, it is preferable to store the voltage determination time point together.

The voltage measuring apparatus 100 of the battery pack 110 according to the present invention may further include a communication interface 180. [ The communication interface 180 is a component necessary for the controller 160 to communicate with another external control device 300.

The communication interface 180 may be any known communication interface that supports two different devices to communicate with each other. The communication interface may support wired or wireless communication. Preferably, the communication interface may be CAN (CANN) communication or Daisy Chain communication support.

The control unit 160 reads the current voltage value of the battery pack 110 stored in the memory unit 170 when there is a request from the control device 300 located outside and transmits the current voltage value of the battery pack 110 via the communication interface 180 to the control device 300 ).

The control device 300 can control charging or discharging of the battery pack 110 by using the voltage value of the battery pack 110 transmitted. Particularly, when the voltage value of the battery pack 110 is out of the design voltage range of the battery pack 110, the charging or discharging of the battery pack 110 can be blocked. To this end, the control device 300 may turn off a switch installed in a line through which a charging or discharging current flows.

The controller 160 may optionally include a processor, an application-specific integrated circuit (ASIC), another chipset, a logic circuit, a register, a communication modem, a data processing device, etc., as is known in the art for executing the various control logic . Further, when the control logic is implemented in software, the control unit 160 may be implemented as a set of program modules. At this time, the program module is stored in the memory and can be executed by the processor. The memory may be internal or external to the processor and may be coupled to the processor by various well known computer components. Also, the memory may be included in the memory unit 170 of the present invention. Further, the memory collectively refers to a device in which information is stored regardless of the type of the device, and does not refer to a specific memory device.

At least one of the various control logic of the controller 160 may be combined, and the combined control logic may be written in a computer-readable code system and recorded in a computer-readable recording medium. The type of the recording medium is not particularly limited as long as it can be accessed by a processor included in the computer. As one example, the recording medium includes at least one selected from the group including a ROM, a RAM, a register, a CD-ROM, a magnetic tape, a hard disk, a floppy disk and an optical data recording apparatus. In addition, the code system can be distributed and stored in a network-connected computer. Also, functional programs, code, and code segments for implementing the combined control logic can be easily inferred by programmers skilled in the art to which the present invention pertains.

Hereinafter, a method of measuring the voltage of the battery pack 110 performed by the controller according to an embodiment of the present invention will be described in detail with reference to FIG.

3 is a flowchart sequentially illustrating a flow of a method of measuring a voltage of the battery pack 110 according to an embodiment of the present invention.

First, in step S10, the controller 160 determines whether a voltage measurement period has elapsed. If the voltage measurement period has elapsed, the controller 160 moves the process to step S20. On the contrary, if the voltage measurement period has not elapsed, the controller 160 holds the progress of the process.

The control unit 160 controls the temperature measuring unit 140 to receive the temperature measurement signal from the temperature measuring unit 140 and determine a temperature measurement value of each switch included in the switch unit 130. In step S20, When the switch unit 130 is composed of two switches 131 and 132, the temperature measurement value may be two. In this case, the temperature measuring unit 140 may include a thermistor corresponding to the number of switches. When the switch 130 is composed of one switch, the temperature measurement value may be one. In this case, the temperature measuring unit 140 may include one thermistor. If the two switches 131 and 132 are mounted on a thermally conductive pad as shown in FIG. 2, the temperature measurement may be one. In this case, the temperature measuring unit 140 may include one thermistor. Step S20 is followed by step S30.

In step S30, the controller 160 turns on the switch included in the switch unit 130 to connect the resistor circuit unit 120 to the battery pack 110 in parallel. When the switch unit 130 includes two switches, the control unit 160 turns on the respective switches. On the other hand, when the switch unit 130 includes one switch, the controller 160 turns on one switch. Step S40 is followed by step S30.

In step S40, the control unit 160 controls the voltage measuring unit 150 to receive a voltage measurement signal corresponding to the voltage applied to the second voltage distribution resistor R ₂ from the voltage measuring unit 150, . Step S40 is followed by step S50.

In step S50, the control unit 160 accesses the memory unit 170 to refer to predefined temperature-specific on-resistance data for each temperature, and uses the temperature measurement values of the respective switches included in the switch unit 130 to determine the on- ≪ / RTI > When the number of switches is one, the number of turn-on resistance values to be determined is one. On the other hand, when the number of switches is two, the number of turn-on resistance values determined is two.

In step S60, the control unit 160 uses the determined turn-on resistance value for each switch constituting the switch unit 130, the resistance value of the resistors constituting the resistance circuit unit 120, and the voltage measurement value determined in step S40 The voltage of the battery pack 110 is determined. At this time, the controller 160 can determine the voltage of the battery pack 110 using the calculation formula according to Equation (1). After step S60, step S70 or step S80 may be selectively performed.

In step S70, the control unit 160 may store the voltage value of the battery pack 110 determined in step S60 in the memory unit 170. [

The control unit 160 reads the voltage value of the battery pack 110 stored in the memory unit 170 and transmits the voltage value to the control device 300 via the communication interface 180 in step S80 . The external control device 300 can control charging or discharging of the battery pack 110 based on the voltage value of the battery pack 110 transmitted from the controller 160. [ Step S90 follows step S70 or step S80.

In step S90, the controller 160 determines whether the battery pack 110 is in the key off state. Here, the key-off state refers to a case where the battery pack 110 stops charging or discharging and is in a no-load state. The key off state can be determined by the magnitude of the charge or discharge current.

To determine whether or not the key is turned off, a current measurement sensor not shown in Fig. 2 may be utilized. That is, the controller 160 controls the current measuring sensor to receive the current measurement signal indicating the magnitude of the charging or discharging current from the current measuring sensor and determine the current measuring value. In addition, the controller 160 may determine that the battery pack 110 is in the key-off state when the current measurement value is substantially zero. On the other hand, the controller 160 can determine that the battery pack 110 is not in the key off state if the current measurement value is not substantially zero.

If the controller 160 determines that the battery pack 110 is in the key off state, the control unit 160 terminates the voltage measurement process of the battery pack 110. On the other hand, if it is determined that the battery pack 110 is not in the key off state, the control unit 160 determines the voltage value of the battery pack 110 by executing the steps described above by moving the process to step S10. This voltage value determination process can be repeatedly performed every time the voltage measurement period elapses unless the battery pack 110 is in the key off state.

According to the embodiment of the present invention described above, the voltage of the battery pack can be accurately measured even if the switch used when connecting the voltage distribution resistors to the battery pack has a turn-on resistance that varies with temperature.

Particularly, the present invention can effectively prevent overcharge or overdischarge by accurately measuring the voltage during charging or discharging control of a high capacity battery pack.

In describing the various embodiments of the present invention, the components labeled 'to' should be understood to be functionally distinct elements rather than physically distinct elements. Thus, each component may be selectively integrated with another component, or each component may be divided into sub-components for efficient execution of the control logic (s). It will be apparent to those skilled in the art, however, that, even if components are integrated or partitioned, the integrity of the functionality can be recognized, it is understood that the integrated or segmented components are also within the scope of the present invention.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not to be limited to the details thereof and that various changes and modifications will be apparent to those skilled in the art. And various modifications and variations are possible within the scope of the appended claims.

Claims (19)

A resistance circuit portion including a first voltage distribution resistor and a second voltage distribution resistor connected in series with the first voltage distribution resistor and having a resistance value relatively lower than the first voltage distribution resistor;
A switch unit which connects or disconnects the resistor circuit unit between the positive and negative terminals of the battery pack and changes the turn-on resistance according to the temperature;
A temperature measuring unit for outputting a temperature measurement signal corresponding to the temperature of the switch unit;
A voltage measuring unit connected to the second voltage distribution resistor and outputting a voltage measurement signal corresponding to a voltage applied to the second voltage distribution resistor; And
Receiving the temperature measurement signal and the voltage measurement signal and determining a temperature measurement value and a voltage measurement value; Determining a turn-on resistance value corresponding to the temperature measurement value by referring to pre-defined temperature-specific turn-on resistance data of the switch unit; And a controller configured to determine a voltage of the battery pack using the turn-on resistance value, the resistance value of the resistance circuit section, and the voltage measurement value.
The method according to claim 1,
Wherein a ratio of resistance values of the first voltage distribution resistor and the second voltage distribution resistor is adjusted so that a voltage less than 5V is applied to the second voltage distribution resistor.
The apparatus according to claim 1,
A first switch for connecting or disconnecting one end of the resistance circuit portion to the positive terminal of the battery pack; And
And a second switch for connecting or disconnecting the other end of the resistor circuit to a negative terminal of the battery pack.
The method of claim 3,
Wherein the first switch and the second switch are non-contact semiconductor switches.
5. The method of claim 4,
Wherein the solid state relay (SSR) switch is a solid state relay (SSR) switch.
The apparatus according to claim 3,
A first thermistor for measuring a temperature of the first switch; And
And a second thermistor for measuring a temperature of the second switch.
The method according to claim 1,
Wherein the turn-on resistance data defined for each temperature is a look-up table capable of mapping a turn-on resistance value by temperature.
The method according to claim 1,
Wherein the control unit is configured to determine the voltage of the battery pack by the following equation.

(V _pack is the voltage of the battery pack; R ₁ is the first voltage resistance of the distributed resistor; R ₂ is a second resistance value of the voltage distribution resistance; R _on the total switch unit turns on a resistance value; R _known is the voltage of the battery pack, V _measure is the voltage measurement value measured through the second voltage distribution resistor)
The method according to claim 1,
Wherein one end of the resistance circuit part is connected to a positive terminal or a negative terminal of the battery pack and the other end of the resistance circuit part is connected to a negative terminal or a positive terminal of the battery pack.
The method according to claim 1,
And a memory unit electrically coupled to the control unit,
Wherein the control unit is configured to store the determined voltage of the battery pack in the memory unit.
The method according to claim 1,
Further comprising a communication interface electrically coupled to the control unit,
And the control unit is configured to transmit the determined voltage of the battery pack to another external control device through the communication interface.
The method according to claim 1,
And a PCB substrate on which the switch unit and the temperature measuring unit are mounted,
A thermally conductive pad interposed between the switch unit and the PCB substrate,
Wherein the switch unit and the temperature measuring unit are mounted on the thermally conductive pad.
13. The method of claim 12,
Wherein the switch portion includes a first switch and a second switch mounted on the thermally conductive pad,
Wherein the temperature measuring unit includes a thermistor mounted on the thermally conductive pad between the first switch and the second switch.
A resistance circuit portion including a first voltage distribution resistor and a second voltage distribution resistor connected in series with the first voltage distribution resistor and having a resistance value relatively lower than that of the first voltage distribution resistor; A method for measuring a voltage of a battery pack using a switch unit connected or disconnected in parallel between a positive terminal and a negative terminal and a turn-on resistance varying with temperature,
(a) receiving a temperature measurement signal corresponding to a temperature of the switch unit from a temperature measurement unit and determining a temperature measurement value of the switch unit;
(b) turning on the switch unit to connect the resistor circuit unit in parallel with the battery pack;
(c) receiving a voltage measurement signal corresponding to a voltage applied to the second voltage distribution resistor from a voltage measurement unit connected to the second voltage distribution resistor, and determining a voltage measurement value;
(d) determining a turn-on resistance value corresponding to the temperature measurement value by referring to pre-defined temperature-specific turn-on resistance data of the switch unit;
(e) determining a voltage of the battery pack from the turn-on resistance value and the resistance value of the resistance circuit portion and the voltage measurement value.
15. The method of claim 14,
Wherein a ratio of resistance values of the first voltage distribution resistor and the second voltage distribution resistor is adjusted so that a voltage less than 5V is applied to the second voltage distribution resistor.
15. The method of claim 14,
Wherein the step (d) is a step of determining a turn-on resistance value corresponding to the temperature measurement value by referring to a look-up table capable of mapping a turn-on resistance value according to a temperature.
15. The method of claim 14,
The step (e)

(V _pack is the voltage of the battery pack; R ₁ is the first resistance of the voltage distribution resistance; R ₂ is the resistance value of the second voltage distribution resistor; R _on the switch unit turns on a resistance value; R _known to the voltage measurement of the battery pack, V _measure is a voltage measurement value measured through the second voltage distribution resistor)
And determining the voltage of the battery pack using the formula.
15. The method of claim 14,
And storing the determined voltage of the battery pack in a memory unit.
15. The method of claim 14,
And transmitting the determined voltage of the battery pack to another external device through a communication interface.

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