WO2019065168A1

WO2019065168A1 - Power supply device

Info

Publication number: WO2019065168A1
Application number: PCT/JP2018/033335
Authority: WO
Inventors: 米田　晴彦; 真己拝野; 岸田　裕司
Original assignee: 三洋電機株式会社
Priority date: 2017-09-29
Filing date: 2018-09-10
Publication date: 2019-04-04
Also published as: CN111149252A; JP7219716B2; PH12020550171A1; CN111149252B; JPWO2019065168A1

Abstract

The purpose of the present invention is to keep the temperature balance between a battery cell and a control element in an optimum range, and to prevent a deterioration of electric characteristics due to a battery cell temperature increase and an operation failure due to a control element temperature increase. This power supply device includes a battery assembly (40) having battery cells (1) and a circuit substrate (80) on which a control element (82) for providing a protection circuit for the battery cells (1) is mounted, the circuit substrate (80) being fixed to a substrate holder (81). A bottom plate (81A) of the substrate holder (81) is disposed between the circuit substrate (80) and the battery assembly (40). The control element (82) is fixed to a surface of the circuit substrate (80) and is closely contacted with a potting resin (7). A heat insulating layer (83) is disposed between a back surface of the circuit substrate (80) and the bottom plate (81A).

Description

Power supply

The present invention relates to a power supply device incorporating a battery cell and an electronic circuit.

In a large-power, large-capacity power supply device, a large number of battery cells are connected in series to increase the output voltage, and in parallel, to increase the output current. In this type of power supply device, a protection circuit is connected to the battery cell, and the charge and discharge current is controlled by the protection circuit to ensure the deterioration and safety of the battery cell. The battery cell protection circuit is realized by a control element mounted on a circuit board. On the circuit board, semiconductor switching elements such as FETs and transistors are mounted as power elements for controlling the current in order to control the current of the battery cell. Since the power element controls a large current, a large current flows and the power loss increases to generate heat. This is because Joule heat increases in proportion to the square of the current. On the other hand, since the battery cell also generates heat due to Joule heat of current, both the battery cell and the power element generate heat. The temperature rise due to the heat generation of the battery cell degrades the electrical characteristics of the battery cell and also reduces the safety. The heat generation of the power element causes the power element to fail. In order to efficiently dissipate the thermal energy of the power element and the battery cell and to prevent an abnormal temperature rise, the conventional power supply device embeds the battery cell and the circuit board in the potting resin and conducts heat to the potting resin. It is radiating heat. (See Patent Document 1)

JP 2012-15121 A

In the power supply device in which both the battery cell and the circuit board are embedded in the potting resin, the thermal energy of the power element mounted on the circuit board and the battery cell is conducted to dissipate both. This power supply device is characterized in that the heat energy of both the power element and the battery cell can be conducted to the potting resin and dissipated. However, this power supply device has a drawback that it can not hold both the power element and the battery cell in the ideal temperature range. This is because the ideal temperature range of the power element and the battery cell is different. Furthermore, since both the power element and the battery cell generate heat together, the temperature rise of the power element and the battery cell is simultaneously caused. The reason is that both generate Joule heat in proportion to the square of the current flowing, and the power element is connected in series to the battery cell, and the current of the battery cell also increases when the current of the power element increases. . Furthermore, the temperature rise of the power element becomes larger than that of the battery cell at the timing when both generate heat simultaneously. This is because the current density of the power element is larger than that of the battery cell, and the power element generates heat in an area smaller than that of the battery cell. Therefore, when the power element and the battery cell are in close contact with each other by the potting resin and both generate heat at the same timing, the thermal energy of the high temperature power element raises the temperature of the battery cell and causes a problem of causing a temperature failure in the battery cell. .

The present invention has been developed for the purpose of solving the above-mentioned drawbacks. One of the objects of the present invention is to keep the temperature balance of the battery cell and the control element in the optimum range by connecting in series and proportionally increasing the current value, and by the temperature rise of both the battery cell and the control element To provide a power supply device that achieves high safety even in a severe use environment by preventing adverse effects and eliminating deterioration of electrical characteristics due to temperature rise of battery cells and malfunction due to temperature rise of control elements. is there.

Means for Solving the Problems and Effects of the Invention

A power supply device according to a first aspect of the present invention includes a battery assembly including a plurality of battery cells, a circuit board on which a control element for realizing a protection circuit of battery cells of the battery assembly is mounted, and the circuit A substrate holder fixed to the substrate and having a bottom plate disposed between the circuit substrate and the battery assembly, the circuit substrate having a surface opposite to the surface facing the bottom plate of the substrate holder The control element is fixed on the surface, the potting resin is in close contact with the surface, and a heat insulating layer is provided between the back surface of the circuit board and the bottom plate.

The above power supply devices can maintain the temperature balance between the battery cell and the control element in the optimum range, in which the current values are proportionally connected in series with each other. Therefore, the adverse effect due to the temperature rise of both the battery cell and the control element is prevented, and the deterioration of the electrical characteristics due to the temperature rise of the battery cell and the operation failure due to the temperature rise of the control element are eliminated. There is a feature that can realize high safety. That is, the above power supply fixes the circuit board to the board holder, arranges the bottom plate of the board holder between the circuit board and the battery assembly, and further fixes the control element on the surface of the circuit board. The potting resin is in close contact, and a heat insulating layer is provided between the back surface of the circuit board and the bottom plate to thermally isolate the circuit board on which the control element is mounted from the battery cell.

The control element that controls the current of the battery cell is connected in series with the battery cell, and thus the current value increases as the current of the battery cell increases. Since the battery cell and the control element generate heat by Joule heat in proportion to the square of the current, the control element also generates heat at the same time as the battery cell generates heat. Therefore, both the battery cell and the control element rise in temperature together. Since the control element is smaller than the battery cell, heat is generated locally and the temperature rise is higher than that of the battery cell. Therefore, in the circuit board on which the control element is mounted, the temperature of the mounting portion of the control element is locally high. Arrow A in FIG. 2 indicates a state where the heat energy of the control element 82 that has generated heat is conducted to the battery cell 1 when the circuit board 80 is in close contact with the battery cell 1. As shown in this figure, when the control element 82 mounted on the circuit board 80 generates heat, the temperature of the circuit board 80 is locally increased, and the specific battery cell 1 in which the circuit board 80 whose temperature is increased is disposed is Heat up. Since the temperature of the control element is higher than that of the battery cell, and the battery cell and the control element generate heat together, the battery cell whose temperature has risen is heated by the control element having a higher temperature, and the battery temperature becomes abnormally high. In addition to raising the specific battery temperature to significantly reduce the electrical characteristics, this state enlarges the temperature difference of each battery cell to unbalance the electrical characteristics. An imbalance in the electrical characteristics causes the specific battery cell to deteriorate rapidly. The power supply device connects the battery cells in series to increase the output voltage without connecting all the battery cells in parallel. With the power supply devices connected in series, the electrical characteristics of any battery cell degrade the overall electrical characteristics. From this, in addition to reducing the temperature rise of the battery cells, the power supply device incorporating a large number of battery cells can reduce the temperature difference between the respective battery cells by reducing the electrical characteristics, that is, the lifetime. It becomes an important parameter to identify.

The power supply device shown in FIG. 2 fixes the circuit board 80 to the board holder 81, arranges the control element 82 on the surface thereof and adheres the potting resin 7 thereto, and the bottom plate of the board holder 81 on the back surface of the circuit board 80. The heat insulating layer 83 is provided between the circuit board 81 and the control element 82 and the heat insulating layer 83 is provided between the circuit board 80 and the control element 82. In the power supply device having this structure, the heat energy of the control element fixed on the surface of the circuit board and generating heat is conducted to the potting resin, and the heat energy of the control element is dissipated and dispersed on the surface of the circuit board. The potting resin efficiently disperses and dissipates the heat energy of the control element. Therefore, the temperature rise of the control element is limited, and the temperature unevenness of the circuit board is reduced. The circuit board with less temperature unevenness has a heat insulating layer between the back surface and the bottom plate. An insulating layer disposed between the circuit board and the bottom plate is between the circuit board and the control element to block heat transfer from the circuit board to the battery assembly. Therefore, in a state where the current flowing to the battery cell increases and the temperature of the battery cell rises due to Joule heat, the control element that generates heat to a higher temperature than the battery cell is not heated. Although the temperature rise of the control element is higher than that of the battery cell, the heat resistance temperature of the control element is higher than that of the battery cell. Moreover, the battery cell which temperature rises is hold | maintained in a preferable setting range, without being heated by the control element of high temperature.

Moreover, according to the power supply device which concerns on a 2nd side surface, in addition to the said structure, the said heat insulation layer can be made into an air layer.

Furthermore, according to the power supply device according to the third aspect, in addition to the above configuration, the air layer can be an air ventilation layer formed by opening the air layer to the outside.

Furthermore, according to the power supply device according to the fourth aspect, in addition to any of the above configurations, the substrate holder provides a peripheral wall around the bottom plate, and arranges the circuit board inside the peripheral wall, The boundary between the peripheral wall and the outer periphery of the circuit board may be a closed gap that prevents the inflow of potting resin.

Furthermore, according to the power supply device according to the fifth aspect, in addition to the above configuration, a packing that prevents the inflow of the potting resin can be disposed between the peripheral wall and the circuit board.

Furthermore, according to the power supply device according to the sixth aspect, in addition to any of the above configurations, a heat conduction layer is provided on the surface of the circuit board, and the circuit board is made into the potting resin via the heat conduction layer. It can be attached closely.

Furthermore, according to the power supply device according to the seventh aspect, in addition to any of the above configurations, the circuit board and the bottom plate are disposed in a horizontal posture, and the potting resin is closely attached to the upper surface of the circuit board The heat insulating layer may be disposed on the lower surface of the circuit board, and the battery assembly may be disposed below the bottom plate.

Furthermore, according to the power supply device of the eighth aspect, in addition to the above configuration, a heat insulating air layer can be provided between the bottom plate and the battery assembly.

It is a vertical sectional view showing a power supply device concerning one embodiment of the present invention. It is a principal part expansion schematic sectional drawing of the power supply device of FIG. It is a disassembled perspective view of the battery assembly of the power supply device of FIG. It is a disassembled perspective view of the closure cover shown in FIG.

Hereinafter, embodiments of the present invention will be described based on the drawings. However, the embodiments shown below exemplify the configuration for embodying the technical concept of the present invention, and the present invention is not specified to the following. Moreover, the members shown in the claims are not limited to the members of the embodiment. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the constituent members described in the embodiments are not intended to limit the scope of the present invention thereto alone, unless specifically described otherwise. It is only an illustrative example. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for the sake of clarity. Further, in the following description, the same names and reference numerals indicate the same or the same members, and the detailed description will be appropriately omitted. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and one member is used in common as a plurality of elements, or conversely the function of one member is realized by a plurality of members It can be shared and realized. In addition, the contents described in some examples and embodiments may be applicable to other examples and embodiments.

The power supply device shown below mainly demonstrates the example applied to the drive power supply of electric vehicles, such as an electric vehicle and an electric cart which drive | works only by a motor. It should be noted that the power supply device of the present invention may be used in a hybrid vehicle traveling with both an engine and a motor, or in applications requiring a large output other than electric vehicles, for example, storage devices for home use and factories Good.
(Embodiment 1)

The power supply device 100 shown in the cross-sectional view of FIG. 1 and the enlarged cross-sectional view of FIG. 2 has the circuit board 80 disposed on the battery assembly 40. As shown in FIG. 3, in the battery assembly 40, the plurality of secondary battery cells 1 are arranged at fixed positions by the battery holder 44. In the illustrated battery assembly 40, the secondary battery cells 1 are arranged in parallel in a horizontal posture, and are arranged in multiple stages.
(Circuit board 80)

The circuit board 80 has mounted thereon a control element 82 for realizing the protection circuit of the secondary battery cell 1 of the battery assembly 40. The protection circuit detects the voltage, remaining capacity, temperature, current, etc. of the secondary battery cell 1 to control the current to prevent overcharging or overdischarging of the secondary battery cell 1, and The current in the abnormal state is controlled to prevent the deterioration of the secondary battery cell 1 and the deterioration of the electrical characteristics. The protection circuit for controlling the current of the secondary battery cell 1 includes a control element 82 connected in series to the secondary battery cell 1 to control the current. The control element 82 is a semiconductor element such as a FET or a transistor. These control elements 82 generate heat with Joule heat that is proportional to the product of the square of the current and the equivalent resistance. The control element 82 is connected in series to the secondary battery cell 1 to control the current of the secondary battery cell 1, so the current of the control element 82, which increases the current of the secondary battery cell 1, also increases. Since the secondary battery cell 1 also generates heat with Joule heat that is proportional to the product of the square of the current and the internal resistance, the control element 82 and the secondary battery cell 1 generate heat at the same timing, and the generated energy also increases. For this reason, for example, when the current is doubled, the heat generation energy of the secondary battery cell 1 and the control element 82 is quadrupled. The calorific value of the secondary battery cell 1 and the control element 82 increase at the same rate, but the temperature rise of the control element 82 becomes larger than that of the secondary battery cell 1. The reason is that the heat generation area of the control element 82 is extremely narrow compared to the secondary battery cell 1.
(Substrate holder 81)

The circuit board 80 is disposed at a predetermined position of the battery assembly 40 via the substrate holder 81. In addition to arranging the circuit board 80 at a fixed position, the substrate holder 81 efficiently diffuses the thermal energy of the control element 82 heated to a high temperature, and further dissipates heat, from the control element 82 to the secondary battery cell 1 The heat conduction to the secondary battery cell is cut off to optimize the temperature balance of both the control element 82 and the secondary battery cell 1, and both the secondary battery cell 1 and the control element 82 are maintained in the optimum temperature range. In order to realize this, the substrate holder 81 is provided with a heat insulating layer 83 between the back surface of the circuit board 80 and the bottom plate 81A, and the potting resin 7 is injected into the upper surface of the circuit board 80.
(Adiabatic layer 83)

The substrate holder 81 of FIG. 2 uses the heat insulating layer 83 on the back surface of the circuit board as an air layer. The air layer is light and achieves excellent thermal insulation properties. Furthermore, the heat insulating layer 83 of FIG. 2 further improves the heat insulating property of the air layer as a ventilation layer 83A of air opened to the outside. The ventilation layer 83A is provided with through holes at the top and bottom of the peripheral wall 81B of the substrate holder 81 to form

openings

81a and 81b. In this ventilation layer 83A, the outside air flows in from the lower opening 81a, and the air heated and lightened inside is discharged from the upper opening 81b to the outside, and the inside air is ventilated to obtain the internal air Reduce temperature rise. Instead of the air layer, the heat insulating layer 83 may be a heat insulating material in which a myriad of fibers are three-dimensionally assembled, or a heat insulating material made of a foam of plastic or inorganic material. The substrate holder 81 for filling the heat insulating layer 83 with a heat insulating material can prevent the potting resin 7 injected on the upper surface from flowing into the heat insulating layer 83, so that the injection of the potting resin 7 can be simplified. Furthermore, the power supply device 100 shown in FIGS. 1 and 2 is provided with a heat insulating air layer 84 also between the bottom plate 81A of the substrate holder 81 and the battery assembly 40, and the control element 82 to the secondary battery cell 1. It blocks heat conduction.
(Potting resin 7)

The substrate holder 81 injects the potting resin 7 onto the circuit board 80 to bring the surface of the circuit board 80 and the control element 82 into close contact with the potting resin 7. In order to inject the potting resin 7 onto the upper surface of the circuit board 80, the substrate holder 81 has a peripheral wall 81B having a height projecting upward from the surface of the circuit board 80. Furthermore, the substrate holder 81 is provided with a peripheral wall 81B around the bottom plate 81A so that the uncured, liquid potting resin 7 injected onto the circuit substrate 80 does not flow into the back surface of the circuit substrate 80. Are disposed inside the peripheral wall 81B. The boundary between the peripheral wall 81B and the outer periphery of the circuit board 80 is formed as a closed gap 81C for blocking the inflow of the potting resin 7 so that no space is formed between the outer peripheral edge of the circuit board 80 and the inner surface of the peripheral wall. The board holder 81 of FIG. 2 has a packing 85 disposed between the inner surface of the peripheral wall 81 B and the outer peripheral edge of the circuit board 80 to prevent the potting resin 7 from flowing into the back surface of the circuit board 80.

The potting resin 7 is embedded in the surface of the circuit board 80 and the whole or the lower part of the control element 82 and is in close contact with the surface of the circuit board 80 and the control element 82 to apply thermal energy of the control element 82 to the surface of the circuit board 80 Disperse and dissipate heat to the outside. The potting resin 7 shown in the cross-sectional view of FIG. 2 embeds the whole of the control element 82 in the potting resin 7 and raises the peripheral wall 81 B to make the potting resin 7 in close contact with the potting resin 7. Is filled thick. The control element 82 embedded in the potting resin 7 conducts thermal energy to the potting resin 7 from the entire surface. The potting resin 7 disperses the conducted thermal energy to the surface of the circuit board 80 and further dissipates heat from the surface to dissipate the thermal energy of the control element 82. Furthermore, the circuit board 80 shown in the cross-sectional view of FIG. 2 is provided with a heat conduction layer 86 on the surface so that the heat energy of the control element 82 can be dispersed to the surface more efficiently. It is in close contact. The heat conduction layer 86 is a metal layer having a thermal conductivity better than that of the potting resin 7 and distributes the heat energy of the control element 82 very efficiently to the surface of the circuit board 80. Since the circuit board 80 is provided with the heat conduction layer 86 excellent in the heat conduction characteristic between the potting resin 7 and the surface of the circuit board 80, the heat energy of the control element 82 is dispersed by the heat conduction layer 86, The dispersed thermal energy is further dispersed by the potting resin 7 and dissipated.

The power supply device 100 of FIG. 2 arranges the circuit board 80 and the bottom plate 81A in a horizontal posture, adheres closely to the potting resin 7 on the circuit board 80, and arranges the heat insulating layer 83 on the lower surface. The body 40 is disposed below the bottom plate 81A. The power supply device 100 conducts the heat energy of the control element 82 that generates heat to the potting resin 7 to radiate the heat. The heated potting resin 7 disperses thermal energy and radiates heat from the surface. The potting resin 7 which dissipates heat energy dissipates heat by radiant heat, and also heats and dissipates air contacting the surface. The air warmed on the surface of the potting resin 7 is lightened and rises. Since the air heated by the potting resin 7 rises, it does not heat the secondary battery cell 1 disposed below. Therefore, in the structure in which the circuit board 80 and the bottom plate 81A are disposed on the battery assembly 40, the control element 82 that generates heat does not heat the secondary battery cell 1 via air. There is a feature that the temperature rise of the secondary battery cell 1 due to heat generation can be minimized. The circuit board 80 disposed above the battery assembly 40 is heated by the air whose temperature has risen in the temperature rising secondary battery cell 1, but the temperature rise of the secondary battery cell 1 is smaller than that of the control element 82 Moreover, since the temperature rise of the control element 82 is higher than that of the secondary battery cell 1, the heating of the control element 82 by the secondary battery cell 1 that generates heat does not have a problem.
(Battery assembly 40)

The battery assembly 40 arranges the plurality of secondary battery cells 1 at fixed positions by the battery holder 44. In the battery assembly 40 shown in FIGS. 1 to 3, a pair of battery units 40A are arranged and connected at opposing positions (left and right in the drawing). In the battery unit 40A, the plurality of secondary battery cells 1 are arranged in a parallel posture, both ends thereof are arranged on the same plane, and the lead plate 45 is connected to the end electrodes 13 at both ends. The battery assembly 40 arranges a pair of battery units 40A arranged at opposing positions in the axial direction of the secondary battery cell 1, and also provides an insulating space 6 between the pair of battery units 40A. Each battery unit 40A arrange | positions the edge part electrode 13 in the opposing position of the insulation space 6, as shown to the enlarged sectional view of FIG.
(Secondary battery cell 1)

The secondary battery cell 1 is provided at its end face with a discharge port (not shown) of a discharge valve that opens at a set pressure. The secondary battery cell 1 is provided with end electrodes 13 at both ends. In the secondary battery cell 1, the opening of a metal outer can such as aluminum is hermetically sealed with a sealing plate, and a convex electrode is provided on the sealing plate to form a first end electrode 13A, and the bottom of the outer can As a second end electrode 13B. The discharge port of the discharge valve is provided on the convex electrode side or on the bottom surface of the outer can.

The secondary battery cell 1 is a cylindrical lithium ion battery. The lithium ion battery has a large capacity with respect to size and weight, and can increase the total capacity of the power supply device 100. However, the power supply device of the present invention does not specify the secondary battery cell as a lithium ion battery. Other secondary batteries that can be charged can be used for the secondary battery cell. Moreover, although the power supply device 100 of a figure makes the secondary battery cell 1 a cylindrical battery, a square battery can also be used for a secondary battery cell. In each of the secondary battery cells 1, a lead plate 45 is welded to the end electrodes 13 at both ends thereof, and the adjacent secondary battery cells 1 are connected in series or in parallel.
(Battery holder 44)

The secondary battery cell 1 is disposed at a fixed position by the battery holder 44 as shown in FIG. The battery holder 44 is manufactured by molding an insulating material such as plastic. The illustrated battery holder 44 arranges all the secondary battery cells 1 at a fixed position in a parallel posture. Since the secondary battery cells 1 arranged at a fixed position by the battery holder 44 have the lead plates 45 welded to both ends, each lead plate 45 to be welded to each end is positioned in the same plane. The secondary battery cell 1 is disposed in the battery holder 44 so that both ends thereof are positioned substantially in the same plane.

The battery holder 44 is provided with the insertion part 44A which inserts the secondary battery cell 1 and arrange | positions in a fixed position. In the power supply device 100 shown in the figure, since the secondary battery cell 1 is a cylindrical battery, the insertion portion 44A has a cylindrical shape. The battery holder 44 has a cylindrical plastic shape and is provided with the insertion portion 44A inside. The insertion portion 44A is provided at both ends with openings 44B for exposing the battery end. The opening 44B exposes the end of the secondary battery cell 1 inserted into the insertion portion 44A to the outside from the insertion portion 44A. The end face of the secondary battery cell 1 exposed to the opening 44B becomes the end electrode 13 and the lead plate 45 is welded and fixed here.

As shown in FIG. 1, the battery assembly 40 in which the insulating space 6 is provided between the pair of battery units 40A and the end faces of the secondary battery cells 1 are disposed on both sides of the insulating space 6 has a discharge port of the discharge valve. It is arranged in the insulating space 6. When the discharge valve is opened, the high-temperature jetted gas discharged from the discharge port is injected toward the end face of the opposing battery unit 40A. The high-temperature jetted gas injected to the facing surface of the secondary battery cell 1 at the facing position causes the thermal runaway of the secondary battery cell 1 to be induced. In the power supply device 100 of FIG. 1, a heat-resistant sheet 64 is disposed in the middle of the insulating space 6.
(Heat resistant sheet 64)

The heat-resistant sheet 64 is an insulation sheet having a heat-resistant temperature which is not melted by the jetted gas discharged from the discharge valve, and is, for example, a heat-resistant paper subjected to a flame retardant treatment. However, instead of heat-resistant paper, paper or non-woven fabric in which inorganic fibers which are not melted by jet gas are gathered in sheet form, or inorganic sheet in which inorganic material is bound in thin sheet form can be used. Since these heat-resistant sheets 64 can be made thin, the heat-resistant sheets 64 can widen the insulating space 6 without reducing the substantial volume of the insulating space 6 and can discharge the jetted gas smoothly. The insulating heat-resistant sheet 64 can arrange the end face of the secondary battery cell 1 arranged on both sides and the lead plate 45 in an insulating state. However, the heat-resistant sheet does not necessarily have to be an insulating material. That is because the insulating sheet can be laminated on the surface of the heat resistant sheet to insulate the surface. However, the structure which laminates an insulating material on the surface by using a heat-resistant sheet as the insulating material can further improve the insulation by the heat-resistant sheet.

The heat-resistant sheet 64 is disposed in a posture parallel to the end face of the secondary battery cell 1. The power supply apparatus 100 of the figure arrange | positions the heat-resistant sheet | seat 64 in the middle of the insulation space 6, and provides the exhaust chamber 63 of blowing gas on both surfaces of the heat-resistant sheet 64. FIG. In order to place the heat-resistant sheet 63 in the middle of the insulating space 6, as shown in FIGS. 1 to 4, the power supply apparatus 100 has a closing cover 61 shaped along the outer periphery of the insulating space 6 on both sides of the heat-resistant sheet 64. It arrange | positions and this occlusion cover 61 is interposed between the heat-resistant sheet | seat 64 and the battery unit 40A. The closing cover 61 in the figure has an outer peripheral frame portion 62 shaped along the outer peripheral portion of the insulating space 6. The power supply device 100 arranges the heat-resistant sheet 64 in a state of being separated from the opposing surface 40 a of the battery unit 40 by arranging the blocking cover 61 of this shape between the opposing surface 40 a of the battery unit 40 and the heat-resistant sheet 64. An exhaust chamber 63 is provided between the heat-resistant sheet 64 and the opposing surface 40 a of the battery unit 40 and inside the outer peripheral frame portion 62.

As described above, the insulating space 6 in which the exhaust chamber 63 is provided on both sides of the heat-resistant sheet 64 can discharge the jetted gas smoothly to the exhaust chamber 63 without resistance. Further, since the insulating space 6 of this structure diffuses the jetted gas in the exhaust chamber 63 and blows it to the heat-resistant sheet 64, the heat damage of the heat-resistant sheet 64 due to the jetted gas is reduced, and the secondary battery cell 1 located at the opposing position Can prevent the thermal runaway more effectively. Furthermore, the strength and heat resistance required for the heat resistant sheet 64 can be reduced, and the cost of the heat resistant sheet 64 can be reduced. Furthermore, since the jetted gas sprayed on the surface of the heat-resistant sheet 64 is dispersed on both sides by the exhaust chamber 63, a feature is also realized in which the jetted gas can be smoothly discharged to the insulating space 6 with a small exhaust resistance. This can quickly reduce the pressure of the secondary battery cell 1 in which the internal pressure has abnormally increased, thereby effectively preventing negative effects such as the rupture of the outer can caused by the increase in internal pressure.

Furthermore, the heat-resistant sheet 64 is a flexible sheet that is deformed by the ejected gas. The heat resistant sheet 64 is deformed by the pressure of the jetted gas to be jetted, and the volume of the exhaust chamber 63 from which the jetted gas is discharged can be increased. There is a feature that the gas can be smoothly discharged to effectively prevent the destruction due to the increase of the internal pressure of the secondary battery cell 1 and ensure higher safety.
(Occlusion cover 61)

A cover 61 disposed on both sides of the heat-resistant sheet 64 and disposed between the heat-resistant sheet 64 and the battery unit 40A is an outer peripheral frame that closes the outer peripheral portion of the insulating space 6, as shown in FIGS. The exhaust chamber 63 is provided inside the outer peripheral frame 62 to expose the exhaust port of the exhaust valve to the exhaust chamber 63. The outer peripheral frame portion 62 has a shape extending along the outer peripheral edge portion of the insulating space 6 and is in close contact with the end face of the battery unit 40A without a gap to form an exhaust chamber 63 in the insulating space 6. The closed cover 61 having this structure is characterized in that a large volume exhaust chamber 63 is provided inside the outer peripheral frame 62 and the jetted gas can be jetted here, so that the jetted gas can be smoothly discharged. The reason is that the large-volume exhaust chamber 63 has a slow rise in internal pressure due to the gas jetted from the discharge port of the discharge valve, and can make the rise gradient of the exhaust resistance gentle.

The closing cover 61 is formed of a foam of an insulating material having closed cells which are melted by the gas discharged from the discharge valve. The melting temperature of the blocking cover 61 melted by the jet gas is, for example, 100 ° C. or more and 500 ° C. or less, preferably 200 ° C. or more and 400 ° C. or less. The closing cover 61 having a low melting temperature can be quickly melted by the jetted gas to discharge the jetted gas to the outside of the insulating space 6, and the closing cover 61 having a high melting temperature can block the insulating space 6 reliably in use. If the melting temperature of the blocking cover 61 is too low, it will melt or deform at the battery temperature, and if too high, it will not be possible to quickly melt it with the jet gas. Therefore, the melting temperature of the closing cover 61 is set in the above-mentioned range in consideration of the temperature characteristic which is promptly melted in the jetted gas and does not deform or melt in the state where the jetted gas is not jetted.

The closing cover 61 melted by the jetted gas is melted by the high-temperature jetted gas injected from the opened discharge valve. The melted closing cover 61 opens the insulating space 6 to the outside and discharges the inflowing jetted gas from the insulating space 6 as shown by the arrow B in FIG. The closing cover 61 made of an insulating material is in close contact with the end portion electrode 13 side of the battery unit 40A, so that the insulating space 6 can be closed. In particular, since the lead plate 45 of a metal plate is disposed on the side of the end electrode 13, the closing cover 61 of the insulating material is in close contact with the lead plate 45, and the insulating space 6 is closed without shorting the lead plate 45. it can. Furthermore, since the closed cover 61 of the foam having the closed cells has a small weight per unit volume and can have a low density, it is rapidly melted by the high-temperature jetted gas, and the jetted gas is rapidly discharged to the outside from the insulating space 6 There is a feature that can be done. Furthermore, since the closed cover 61 of the foam can be made to have a lower specific gravity by controlling the foaming ratio at the time of molding, the melting time by the jet gas can be extremely shortened.

The closing cover 61 is formed of a rubber-like elastic foam. The rubber-like elastic closure cover 61 is formed of, for example, a synthetic rubber foam or a soft plastic foam. Propylene rubber can be used as the synthetic rubber foam. For example, a soft urethane foam can be used for the soft plastic foam. The closing cover 61 made of a rubber-like elastic body is disposed between the pair of battery units 40A, pressed by the battery units 40A on both sides, and elastically deformed in a compressed state to be in close contact with the opposing surface 40a of the battery unit 40A. Do. In particular, in the battery unit 40A in which the lead plate 45 is fixed to the facing surface 40a with the insulating space 6, the lead plate 45 forms asperities and gaps on the facing surface 40a. There is a feature that can absorb unevenness and close the gap. Furthermore, the closed cover 61 of the rubber-like elastic body made of the foam having the closed cells has a greater degree of freedom to be softened and deformed by the innumerable air bubbles, and there is no gap on the facing surface 40a of the battery unit 40A having unevenness. There is a feature that can be closely attached. Further, the closing cover 61 made of a rubber elastic body can be elastically deformed to be in close contact with the facing surface 40a of the battery unit 40A, thereby reducing the pressing force of the facing surface 40a of the battery unit 40A. Therefore, there is a feature that the insulating space 6 can be reliably closed without causing an excessive stress on the battery unit 40A while in close contact with the facing surface 40a of the battery unit 40A.

However, in the power supply device of the present invention, the closing cover 61 does not necessarily have to be formed of a rubber-like elastic body. In this method, a packing that elastically deforms is disposed between the closing cover 61 and the facing surface 40a of the battery unit 40A, or a sealing material is applied to closely attach the closing cover 61 to the facing surface 40a of the battery unit 40A. It is because

In the power supply device 100 of FIG. 1, as shown in FIGS. 2 to 4, the insulating sheet 65 is laminated on the surface of the outer peripheral frame portion 62 of the closing cover 61 and the surface of the heat resistant sheet 64. The insulating sheet 65 is made of plastic, and the closing covers 61 are disposed on both sides of the heat resistant sheet 64, and the heat resistant sheet 64 and the closing covers 61 on both sides are integrally connected to each other. As the insulating spacer 60 of FIG. The insulating spacer 60 is disposed in a state of being sandwiched between the pair of battery units 40A, and places the closing cover 61 and the heat-resistant sheet 64 at a predetermined position of the insulating space 6. Therefore, this structure is characterized in that the assembly process is simplified and mass production is efficiently performed, and the heat-resistant sheet 64 and the closing cover 61 can be disposed at the correct positions.

The power supply device 100 of FIGS. 1 and 2 is provided with the outer peripheral frame portion 62 in the closing cover 61 and the exhaust chamber 63 inside the outer peripheral frame portion 62, but the closing cover 61 is not limited to this shape . For example, although not shown, the closing cover is formed into a plate-like foam in which a recess is provided on the surface facing the discharge port of the discharge valve of the secondary battery cell, or it is disposed without gaps in the insulating space, It is also possible to form a plate without the exhaust chamber to close the outlet of the outlet valve. The closure cover 61 having these shapes increases the expansion ratio of the foam to increase the porosity inside the closure cover, and lowers the melting temperature to shorten the melting time by the high temperature gas, thereby making the insulation space Immediately discharge the gas jetted to the outside to the outside.

The power supply device of the present invention can be used conveniently for applications requiring high safety by preventing the thermal runaway of the built-in battery.

100 Power supply device 1 Secondary battery cell 6 Insulating space 7 Potting resin 13 End electrode 13A First end electrode 13B Second end electrode 40 Battery assembly 40A Battery unit 40a Opposite surface 44: battery holder 44A: insertion portion 44B: opening 45: lead plate 60: insulating spacer 61: closing cover 62: outer peripheral frame 63: exhaust chamber 64: heat resistant sheet 65: insulating sheet 80: circuit board 81: board Holder 81A: Bottom plate 81B: Peripheral wall 81C: Closed gap 81a: Opening 81b: Opening 82: Control element 83: Heat insulation layer 83A: Ventilation layer 84: Heat insulation air layer 85: Packing 86: Heat conduction layer

Claims

A battery assembly comprising a plurality of battery cells;
A circuit board on which a control element for realizing a protection circuit of a battery cell of the battery assembly is mounted;
A substrate holder having the circuit board fixed and a bottom plate disposed between the circuit board and the battery assembly;
The circuit board fixes a control element on a surface opposite to the surface facing the bottom plate of the substrate holder.
In the circuit board, potting resin is in close contact with the surface,
A heat insulating layer is provided between the back surface of the circuit board and the bottom plate.
The power supply device according to claim 1, wherein
The power supply apparatus characterized in that the heat insulation layer is an air layer.
The power supply device according to claim 2, wherein
The power supply apparatus characterized in that the air layer is a ventilating layer of air opened to the outside.
The power supply device according to any one of claims 1 to 3, wherein
The substrate holder comprises a circumferential wall around the bottom plate,
The circuit board is disposed inside the peripheral wall,
A power supply device characterized in that a boundary between the peripheral wall and an outer periphery of the circuit board is a closed gap that prevents the inflow of the potting resin.
The power supply device according to claim 4, wherein
A power supply device characterized in that a packing for blocking the inflow of the potting resin is disposed between the peripheral wall and the circuit board.
The power supply device according to any one of claims 1 to 5, wherein
The power supply device, wherein the circuit board has a heat conduction layer on the surface, and the circuit board is in close contact with the potting resin through the heat conduction layer.
The power supply device according to any one of claims 1 to 6, wherein
The circuit board and the bottom plate are disposed in a horizontal attitude;
The circuit board has the upper surface in close contact with the potting resin, and the heat insulating layer is disposed on the lower surface,
Furthermore, the battery assembly is disposed below the bottom plate.
The power supply device according to claim 7, wherein
A power supply apparatus characterized by providing a heat insulation air layer between the bottom plate and the battery assembly.