JP2013021821A - Battery equalization circuit device - Google Patents

Abstract

A battery capable of suppressing a temperature rise of a substrate on which a battery equalizing circuit device is mounted, and thus suppressing deterioration and damage of components constituting the battery equalizing circuit device mounted on the substrate. An equalization circuit device is provided.
In a battery equalization circuit device 10 that manages an assembled battery 22 in which a large number of cells 20 are connected in series, a light emitting element 52 is used in a discharge unit 30 for equalizing the capacity (charge amount) of the cells 20. In addition, a part of the discharge power is converted into light by the light emitting element 52.
[Selection] Figure 1

Description

  The present invention relates to a battery equalization circuit device that equalizes the voltage of each cell of an assembled battery configured by connecting a plurality of cells in series.

  Conventionally, in an assembled battery in which several hundreds of secondary battery cells such as lithium ion batteries and electric double layer capacitors are connected in series, the capacity, internal resistance, and self-discharge rate of each cell are used. Variations occur in the voltage (cell voltage) of each cell due to non-uniformity and the like.

  When the cell voltage varies, the deterioration of the cell progresses at an accelerated rate, or the amount of available energy decreases. Therefore, in order to eliminate variation in cell voltage, a battery equalization circuit device (also referred to as an assembled battery capacity adjusting device or an assembled battery remaining capacity adjusting device) has been proposed (for example, Patent Document 1).

  In the battery equalization circuit device according to Patent Document 1, as shown in FIG. 8, the discharge resistor R <b> 1 constituting the capacity adjustment unit 2 on the substrate 5 for each cell 1 a to 1 c constituting the assembled battery 1. To R3 and switches SW1 to SW3 are provided in parallel, and voltage sensors V1 to V3 are connected to both ends of the switches SW1 to SW3. On the substrate 5, a cell voltage detection unit 3 and a CPU 4 that detect both-end voltages of the cells 1 a to 1 c are provided.

  When equalizing the voltages of the cells 1a to 1c, the cell 1 having a high cell voltage detected by the voltage sensors V1 to V3 or the cell voltage detector 3 when the switches SW1 to SW3 are opened (here, for convenience of understanding) Therefore, the switch SW1 is turned on (conductive state) by the CPU 4 with respect to the cell 1a as an example. As a result, a discharge circuit is formed in a loop passing through the cell 1a having a high cell voltage, the discharge resistor R1, and the switch SW1, and the power of the cell 1a having the high cell voltage is discharged by discharging the power of the cell 1a with this discharge circuit. The voltage is lowered and matched (equalized) with the voltages of the other cells 1b and 1c in the open state of the switches SW2 and SW3.

JP 2006-73364 A ([0051], [0060])

  By the way, in patent document 1, the temperature (substrate temperature) of the board | substrate 5 which mounts a battery equalization circuit apparatus becomes high with the Joule heat which generate | occur | produces in the said resistors R1-R3 at the time of the discharge for capacity equalization, It is disclosed that the substrate 5 may be damaged. In practice, the substrate 5 is often placed in a case having a lid to protect the elements of the discharge circuit and the control circuit, and the temperature rise is correspondingly increased.

  In order to avoid damage to the substrate, in the battery equalization circuit device according to Patent Document 1, the discharge of cells with little variation in charge capacity is stopped to reduce the discharge operation frequency. Further, in order to avoid damage to the substrate, it is conceivable to limit the discharge current, that is, to increase the resistance value of the discharge resistor to increase the discharge time.

  However, reducing the frequency of discharge operation or increasing the discharge time eventually increases the time required for the battery equalization process, and the intended use of the assembled battery, for example, an electric vehicle or a hybrid vehicle There is a risk of limiting the usage time.

  The present invention has been made in consideration of such problems, and it is possible to increase the discharge operation frequency and / or to increase the discharge current, and to achieve a more preferable equalization, the battery equalization circuit Provided is a battery equalization circuit device capable of suppressing a temperature rise of a substrate on which the device is mounted, and thus suppressing deterioration and damage of components constituting the battery equalization circuit device mounted on the substrate. For the purpose.

  The battery equalization circuit device according to the present invention includes a discharge unit connected in parallel to each of a plurality of chargeable / dischargeable cells connected in series, and an imbalance between the charge capacities of the cells. An equalization control unit that reduces imbalance using each discharge unit, a substrate on which each discharge unit is disposed on a surface, and a facing surface unit that faces each discharge unit disposed on the surface of the substrate Each discharge portion is configured by connecting a switch and a light-emitting element that converts current flowing in each discharge portion into light, and the facing surface portion includes the discharge member. A light irradiating part to which light from the light emitting element constituting the part is irradiated, wherein a light non-reflecting part is formed in the light irradiating part.

  According to this invention, each discharge part has each light emitting element, and the light non-reflecting part is formed on the light irradiation part of the opposing surface part irradiated with light from each light emitting element. A part of energy consumed as heat in the resistor is radiated (released) as light by the current flowing when the (secondary battery) is discharged, and heat generation on the substrate is suppressed correspondingly. In addition, since the light irradiated to the light irradiation unit from the light emitting element according to the current flowing during the discharge is limited by the light non-reflecting unit provided in the light irradiation unit, the reflected light is transmitted to the substrate. It is suppressed that the temperature of the discharge part or the substrate is raised by returning to the surface.

  Thereby, the temperature rise of the board | substrate with which a discharge part is arrange | positioned can be reduced effectively. Therefore, the frequency of discharge operation of the cell can be increased, and the discharge time can be shortened by increasing the discharge current.

  As a result, it is possible to suppress the deterioration and damage of various components such as light emitting elements constituting the substrate and the discharge unit.

  In this case, it is preferable in terms of heat dissipation efficiency that the light non-reflective portion formed in the light irradiation portion of the facing surface portion irradiated with light from the light emitting element is formed of a light absorbing material. Here, it is more preferable that the light absorbing material is a black member. The light absorbing material may be a photovoltaic cell.

  If the light non-reflective portion is made of a light transmitting material that penetrates the facing surface portion, the heat dissipation effect can be further improved.

  In addition, it is preferable to form the light non-reflecting portion as a diffusely reflecting surface treatment portion because the amount of light reflected on the surface of the substrate is suppressed.

  The irregular reflection surface treatment section is manufactured by forming a large number of grooves, for example.

  The light emitting element is preferably a light emitting diode that emits infrared light. An infrared light-emitting diode has a lower forward voltage than a light-emitting diode that emits visible light, so that the voltage range of a cell in which a discharge operation cannot be performed can be reduced. In other words, a discharge operation, that is, a capacity equalization operation can be performed in a wide voltage range.

  In addition, infrared light-emitting diodes have higher electro-optic conversion efficiency than light-emitting diodes that emit visible light, so that heat generated on the substrate surface can be more effectively reduced.

  Furthermore, a photodetector may be disposed on the substrate in order to confirm whether or not the discharge unit is operating normally.

  According to this invention, since each discharge part has each light emitting element and the light non-reflecting part is formed in the light irradiation part of the opposing surface part irradiated with the light from each light emitting element, the cell (secondary battery) By irradiating light from the light emitting element according to the current that flows during the discharge, part of the discharge power is converted to light and emitted to suppress the generation of heat. At the same time, reflection of light emitted from the light emitting element is suppressed by the light non-reflecting part according to the current flowing when the cell (secondary battery) is discharged, so that reflected light is prevented from returning to the surface of the substrate. Is done. Thereby, the temperature rise of the board | substrate with which a discharge part is arrange | positioned can be reduced effectively. Therefore, it is possible to increase the discharge operation frequency of the battery equalization circuit device and / or to increase the discharge current, and the battery equalization circuit device is mounted while achieving more preferable capacity equalization (voltage equalization). It is possible to suppress the temperature rise of the substrate to be performed, and thus to suppress the deterioration and damage of the components constituting the battery equalization circuit device mounted on the substrate.

It is a block diagram which shows a partial structure of a vehicle provided with the board | substrate with which the battery equalization circuit apparatus which concerns on embodiment of this invention is mounted. It is a typical block diagram of the board | substrate with which the battery equalization circuit apparatus shown in FIG. 1 is mounted. It is a typical block diagram which shows the accommodation structure of the board | substrate with which the battery equalization circuit apparatus shown in FIG. 1 is mounted. 4A is a partially omitted schematic diagram illustrating an example (entire coating) of a light non-reflecting portion formed on the lid member, and FIG. 4B is another example (partial coating) of a light non-reflecting portion formed on the lid member. FIG. It is a partial omission schematic diagram which shows the further another example (light transmissive material) of the light non-reflective part formed in a cover member. It is a partial omission schematic diagram which shows the further another example (diffuse reflection surface treatment part) of the light non-reflective part formed in a cover member. It is a partial omission schematic diagram which shows the further another example (photovoltaic cell) of the light non-reflective part formed in a cover member. It is circuit explanatory drawing of the battery equalization circuit apparatus which concerns on a prior art.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows an EV (electric vehicle), HEV (hybrid electric vehicle), PHEV (plug-in hybrid electric vehicle), or FCV (FCV) including a substrate 12 on which a battery equalization circuit device 10 according to an embodiment of the present invention is mounted. 2 shows a partial configuration of a vehicle 14 such as a fuel cell vehicle.

  The vehicle 14 includes an assembled battery 22 or the like on which a plurality of cells 20 that are chargeable / dischargeable secondary batteries are connected in series on a chassis (not shown). A traveling motor or the like (not shown) is driven by the assembled battery 22.

  FIG. 2 shows a schematic configuration of the substrate 12 on which the battery equalization circuit device 10 shown in FIG. 1 is mounted.

  In FIG. 1, the assembled battery 22 is actually configured such that a large number of cells 20 are connected in series. However, in this embodiment, only four cells are drawn for convenience of understanding.

  Each positive terminal and each negative terminal of each cell 20 of the assembled battery 22 are connected to the substrate 12 through wiring and connectors 24 (see also FIG. 2), and further mounted on the surface side of the substrate 12 through a wiring pattern on the substrate 12. The discharge unit 30 (discharge circuit) and the control circuit 26 are connected.

  The control circuit 26 includes a microcomputer, a plurality of ICs (integrated circuits), and the microcomputer realizes various functions by the CPU executing programs stored in a memory such as a ROM based on various inputs. It operates as a function realization unit (function realization means). These functions can also be realized by hardware.

  In this embodiment, as shown in FIG. 1, the control circuit 26 detects each cell voltage of the cell 20 and calculates a series composite voltage (a voltage across the assembled battery 22) and an average voltage of each cell. In order to equalize each cell voltage detected in the voltage detection part 34 and the cell voltage detection part 34, the equalization control part 32 which can discharge-discharge each discharge part 30 separately is provided.

  The control circuit 26 is connected to a vehicle control device 40 that controls the entire vehicle 14 such as a traveling motor through various states in the control circuit 26 through a communication circuit 36 and a connector 38 (see also FIG. 2). The control circuit 26 is connected to the light receiving element 42.

  The discharge units 30 are connected to the cells 20 in parallel. The discharge unit 30 is formed by a series circuit of a resistor 51, a light emitting element 52, and a switch 53. On / off control of the switch 53 formed of a semiconductor element or the like is performed by the equalization control unit 32 configuring the control circuit 26. During the equalization process, the switch 53 of the discharge unit 30 connected in parallel to the cells 20 that need equalization is turned on.

  When the switch 53 is turned on, a current flows from the positive electrode terminal of the cell 20 in the closed loop to the negative electrode terminal side of the cell 20 through the resistor 51, the light emitting element 52, and the switch 53 constituting the discharge unit 30 and discharges. When a discharge current is flowing, heat is radiated (heat is released or radiated) through the resistor 51 and the light emitting element 52. The resistor 51 is set to an appropriate resistance value so that the current flowing through the light emitting element 52 can be limited to a value corresponding to the rated current of the light emitting element 52 and the like.

  The state of the vehicle 14 (power running state etc.) can be known from the vehicle control device 40 through the communication circuit 36 by the control circuit 26 from time to time.

  As the light emitting element 52, a light emitting element such as an LED (Light Emitting Diode) is used. In this embodiment, the light emitting element 52 is an infrared LED (infrared light emitting diode). Infrared LEDs have the characteristics of high luminous efficiency (light quantity / current) and low forward voltage drop compared to LEDs in the visible light band.

  Since the forward voltage drop is low, it is suitable not only for a secondary battery cell having a high cell voltage, but also for a discharge part 30 of a cell such as a storage element having a low cell voltage, for example, a lithium ion capacitor.

  The circuit component including the circuit element shown in FIG. 2 is mounted on the substrate 12 by soldering or the like, but the substrate 12 on which the component is mounted (referred to as a circuit substrate or a control substrate) is placed on the vehicle 14. As schematically shown in FIG. 3, the case 60 is housed and fixed in the case 60, and the opening of the case 60 is a lid member 62 as a facing member having a facing surface portion 62 s facing each discharge portion 30. It will be blocked.

  4A and 4B are schematic views of the main part in a state where the substrate 12 is stored in the case 60 (see FIG. 3) and the lid member 62 is fixed to the case 60 (the case 60 is closed by the lid member 62). The cross section is shown.

  As shown in FIG. 4A, the light emitting element 52 is formed in the shape of a surface mount package, a main body portion 52a in which the element main body is accommodated, leads 52b for soldering to the surface 12s of the substrate 12, and light L as a substrate. The lens part 52c radiates | emits from the surface 12s side of 12.

  A light receiving element 42 is disposed in the vicinity of the light emitting element 52. In this embodiment, the light receiving element 42 can detect reflected light or scattered light that is emitted from the light emitting element 52 and cannot be absorbed by the light non-reflecting portion 64 described later when any one of the light emitting elements 52 is lit. The arrangement is as follows.

  A light non-reflecting portion 64 including a portion irradiated with the light L from the light emitting element 52 is formed on the facing surface portion 62 s of the lid member 62 facing the lens portion 52 c of the light emitting element 52 of the substrate 12. The formation area of the light non-reflecting portion 64 may be the entire facing surface portion 62s as shown in FIG. 4A, or may be formed only in the portion irradiated with the light L as shown in FIG. 4B. The light non-reflecting unit 64 prevents the light L emitted from the light emitting element 52 from being reflected as much as possible on the surface 12 s side of the substrate 12 to prevent the temperature of the substrate 12 from rising.

  The light non-reflecting portion 64 has a structure in which a black body (black member) made of carbon that absorbs infrared light, or a light absorbing material of a mixture of the black body and a resin is applied as shown in FIGS. 4A and 4B. It is good.

  In the vehicle 14 including the substrate 12 on which the battery equalization circuit device 10 configured as described above is mounted, the voltage (= capacity) of each cell 20 is set to the cell voltage when the switch 53 is in the off state (open state). Detected by the detection unit 34, and by the equalization control unit 32, for example, the switch 53 of the discharge unit 30 of the cell 20 having a voltage exceeding the upper limit of the allowable cell voltage variation is turned on (closed state), and the voltage variation By discharging until the cell voltage is within the allowable range, the capacity of the cells 20 is equalized.

  In this way, since the light non-reflecting portion 64 is formed in the light irradiation portion of the facing surface portion 62s irradiated with the light L from the light emitting element 52 of the discharge portion 30, the cell (secondary battery) as in the prior art. A part of the energy consumed as heat by the current flowing at the time of discharge 20 is emitted as light L, and heat generation on the substrate 12 is suppressed accordingly. In addition, the light irradiated from the light emitting element 52 to the light irradiation unit according to the current flowing during the discharge is limited in reflection by the light non-reflecting unit 64 provided in the light irradiation unit, and the reflected light is reflected on the substrate 12. Return to the surface 12s is suppressed.

  Thereby, the temperature rise of the board | substrate 12 with which the discharge part 30 is arrange | positioned can be reduced effectively. Therefore, the discharge operation frequency of the battery equalization circuit device 10 can be increased, and the discharge time can be shortened by increasing the discharge current.

  As a result, while achieving more preferable equalization, the temperature rise of the substrate 12 on which the battery equalization circuit device 10 is mounted is suppressed, and as a result, the deterioration or damage of components constituting the battery equalization circuit device 10 mounted on the substrate 12 is achieved. Can be suppressed.

  A modification of the light non-reflecting portion 64 formed on the lid member 62 will be described below.

  As a first modification, as shown in FIG. 5, the light non-reflective portion 64 may be formed of a light transmissive material 66. The light transmissive material 66 may be a transparent member formed of a transparent resin. When the light L is infrared light, white polyethylene is preferable. For example, the light transmissive material 66 may be embedded in the opening of the lid member 62.

  As a second modification, as shown in FIG. 6, the light non-reflecting part 64 may be a V groove part group 68 as an irregular reflection surface treatment part formed in a part irradiated with the light L. In this case, the light non-reflecting portion 64 is more accurately referred to as the light non-regular reflecting portion 64.

  In the case of the light non-reflecting portion 64 in the example of FIG. 6, if the groove angle is an acute angle as small as possible, the number of reflections in the groove portion increases, and as a result, the reflected light toward the surface 12s side of the substrate 12 is reduced. In addition, since the base material of the lid member 62 is generally made of a metal such as aluminum having a good thermal conductivity, the metal can be roughened by surface treatment to form the irregular reflection surface treatment portion.

  As a third modification, as shown in FIG. 7, the light non-reflecting portion 64 may be configured by a photovoltaic cell 70 such as a solar cell. In this case, the electric power generated by converting the light L emitted from the light emitting element 52 into electric power by the photovoltaic cell 70 can be used as the operating electric power of the circuit of the substrate 12, and also for supplementary charging of a cell with a small amount of charge. It can also be used as electric power.

  As described above, according to the embodiment described above, in the battery equalization circuit device 10 that manages the assembled battery 22 in which a large number of cells 20 are connected in series, the capacity (charge amount) of the cells 20 is equalized. The light emitting element 52 is used in the discharge unit 30 (discharge circuit), and a part of the discharge power is converted into the light L by the light emitting element 52. Further, the light L is applied to the substrate 12 on which the discharge unit 30 is mounted. Since the light is not reflected, heat generated on the substrate 12 can be reduced. Therefore, it is possible to increase the discharge operation frequency by the equalization control unit 32 of the battery equalization circuit device 10 and / or to increase the discharge current, while achieving more preferable capacity equalization (voltage equalization), It is possible to suppress the temperature rise of the substrate 12 on which the battery equalization circuit device 10 is mounted, and thus to suppress the deterioration and damage of components such as the control circuit 26 constituting the battery equalization circuit device 10 mounted on the substrate 12. .

  In particular, when an infrared LED is used as the light emitting element 52 as in the above-described embodiment, the infrared LED has a low forward voltage drop and a high conversion efficiency to the light L. This is suitable because it is possible to widen the range of heat and generate less heat. Infrared LEDs currently in circulation have a conversion efficiency of about 30%, so that the Joule heat generated in the discharge circuit can be reduced by approximately 30%. The use of a light-emitting element with higher conversion efficiency is also included in the present invention.

  Further, by providing a light non-reflecting portion 64 that has been subjected to a surface treatment that easily absorbs light L on the facing surface portion 62s on the lid member 62 facing the substrate 12, the light L emitted from the light emitting element 52 is reflected. Thus, it is possible to prevent heat from returning to the substrate 12. The lid member 62 can effectively diffuse heat by using a material having high thermal conductivity (metal such as aluminum). The light non-reflecting part 64 formed in the light irradiating part irradiated with the light L of the light emitting element 52 includes a light transmitting material 66, a V groove part group 68 (uneven reflection surface treating part), a photovoltaic cell 70, and the like. can do.

  Further, a light receiving element 42 as a photodetector is placed on the substrate 12, and the control circuit 26 (a discharge unit operation confirmation unit (not shown)) determines whether or not the light L is detected in synchronization with the operation of the discharge unit 30. If it cannot be confirmed, it can be determined that the discharge unit 30 is faulty or the wiring between the substrate 12 and the assembled battery 22 is faulty. When the photocell 70 is provided, the light receiving element 42 can be omitted.

  Note that the present invention is not limited to the above-described embodiment, and it is needless to say that various configurations can be adopted based on the contents described in this specification.

DESCRIPTION OF SYMBOLS 10 ... Battery equalization circuit apparatus 12 ... Board | substrate 12s ... Surface 14 ... Vehicle 20 ... Cell (secondary battery) 22 ... Battery assembly 26 ... Control circuit 30 ... Discharge part 32 ... Equalization control part 34 ... Cell voltage detection part 51 ... Resistor 52 ... Light emitting element 53 ... Switch 60 ... Case 62 ... Cover member 62s ... Opposing surface part 64 ... Light non-reflective part 66 ... Light transmitting material 68 ... V groove part group 70 ... Photocell

Claims (8)

A discharge unit connected in parallel to each of a plurality of chargeable / dischargeable cells connected in series;
When an imbalance occurs in the charge capacity of each cell, an equalization control unit that reduces the imbalance using each discharge unit;
A substrate on which the discharge parts are disposed on the surface;
A facing member having an opposing surface portion facing the discharge portions disposed on the surface of the substrate,
Each of the discharge units is configured by connecting a switch and a light emitting element that converts the current flowing through each of the discharge units into light, and is connected in series.
The battery equalization circuit device, wherein the facing surface portion is a light irradiation portion to which light from the light emitting element constituting the discharge portion is irradiated, and a light non-reflecting portion is formed in the light irradiation portion. . The battery equalization circuit device according to claim 1,
The light non-reflecting part is formed of a light absorbing material. The battery equalization circuit device according to claim 2,
The said light absorption material is a black member. The battery equalization circuit apparatus characterized by the above-mentioned. The battery equalization circuit device according to claim 2,
The said light absorption material is a photovoltaic cell. The battery equalization circuit apparatus characterized by the above-mentioned. The battery equalization circuit device according to claim 1,
The light non-reflective portion is made of a light transmissive material that penetrates the facing surface portion. The battery equalization circuit device according to claim 1,
The battery equalization circuit device, wherein the light non-reflecting part formed in the light irradiating part irradiated with light from the light emitting element on the facing surface part is formed as an irregular reflection surface treating part. In the battery equalization circuit device according to any one of claims 1 to 6,
The light-emitting element is a light-emitting diode that emits infrared light. In the battery equalization circuit device according to any one of claims 1 to 7,
A battery equalization circuit device, wherein a photodetector is disposed on the substrate.

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