JPWO2019065168A1 - Power supply - Google Patents

Abstract

The temperature balance between the battery cell and the control element is maintained in the optimum range, and the deterioration of the electrical characteristics due to the temperature rise of the battery cell and the malfunction due to the temperature rise of the control element are eliminated. In the power supply device, the circuit board (80) on which the control element (82) that realizes the protection circuit of the battery cell (1) of the battery assembly (40) is mounted is fixed to the board holder (81), and the board holder (81) is fixed. ) Is arranged between the circuit board (80) and the battery assembly (40), and the control element (82) is fixed to the surface of the circuit board (80) to form a potting resin. (7) is in close contact with each other, and a heat insulating layer (83) is provided between the back surface of the circuit board (80) and the bottom plate (81A).

Description

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

In a high-output, large-capacity power supply device, a large number of battery cells are connected in series to increase the output voltage, and are connected 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 / discharge current is controlled by the protection circuit to ensure deterioration and safety of the battery cell. The battery cell protection circuit is realized by a control element mounted on a circuit board. In order to control the current of the battery cell, a semiconductor switching element such as a FET or a transistor is mounted on the circuit board as a power element for controlling the current. Since the power element controls a large current, a large current flows, the power loss becomes large, and heat is generated. This is because the Joule heat increases in proportion to the square of the current. On the other hand, since the battery cell also generates heat due to the Joule heat of the electric current, both the battery cell and the power element generate heat. The temperature rise due to the heat generated by the battery cell lowers the electrical characteristics of the battery cell and also lowers the safety. The heat generated by the power element causes the power element to fail. In order to efficiently dissipate the heat energy of the power element and the battery cell and 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 dissipates heat. (See Patent Document 1)

Japanese Unexamined Patent Publication No. 2012-15121

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 heat. 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 to dissipate heat. However, this power supply has a drawback that both the power element and the battery cell cannot be maintained in the ideal temperature band. This is because the ideal temperature bands of the power element and the battery cell are different. To make matters worse, both the power element and the battery cell generate heat together, so that the temperature of the power element and the battery cell rises at the same time. This is because the heat generated by Joule heat is proportional to the square of the current flowing through both, and the power element is connected in series with the battery cell, and the current of the battery cell increases as the current of the power element increases. .. Further, the temperature rise of the power element becomes larger than that of the battery cell at the timing when both generate heat at the same time. 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 a region smaller than that of the battery cell. Therefore, when the power element and the battery cell are brought into close contact with each other with 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 temperature hindrance to the battery cell. ..

The present invention has been developed for the purpose of solving the above drawbacks. One of the objects of the present invention is to maintain the temperature balance between the battery cell and the control element in the optimum range, in which the current value increases proportionally by being connected in series with each other, and the temperature rises of both the battery cell and the control element. To provide a power supply device that realizes high safety even in a harsh usage environment by preventing harmful effects and eliminating the deterioration of electrical characteristics due to the temperature rise of the battery cell and the malfunction due to the temperature rise of the control element. is there.

Means for Solving Problems and Effects of Invention

The power supply device according to the 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 for the battery cells of the battery assembly is mounted, and the circuit. A substrate holder for fixing a substrate and arranging a bottom plate between the circuit board and a battery assembly is provided, and the circuit board is a surface opposite to a surface of the substrate holder facing the bottom plate. The control element is fixed to the surface, the potting resin is in close contact with the front 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, which are connected in series with each other and the current value increases proportionally. Therefore, it is possible to prevent the harmful effects caused by the temperature rise of both the battery cell and the control element, eliminate the deterioration of the electrical characteristics due to the temperature rise of the battery cell and the malfunction due to the temperature rise of the control element, and even in a harsh usage environment. It has the feature of being able to achieve high safety. That is, the above power supply device 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. This is because the potting resin is in close contact with the circuit board, and a heat insulating layer is provided between the back surface of the circuit board and the bottom plate to heat-shield the circuit board on which the control element is mounted from the battery cell.

Since the control element that controls the current of the battery cell is connected in series with the battery cell, the current value increases as the current of the battery cell increases. Since the battery cell and the control element generate heat with Joule heat in proportion to the square of the current, the control element also generates heat at the same time when 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, it generates heat 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 becomes locally high. The arrow A in FIG. 2 indicates a state in which the heat energy of the heat-generating control element 82 is conducted to the battery cell 1 when the circuit board 80 is brought into 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 rises locally, and the temperature-raised circuit board 80 causes a specific battery cell 1 arranged in the vicinity. Heat. 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. Therefore, 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 this state, in addition to raising a specific battery temperature and significantly lowering the electrical characteristics, the temperature difference between the respective battery cells is expanded to make the electrical characteristics unbalanced. An imbalance in electrical characteristics causes a rapid deterioration of a particular battery cell. The power supply device does not connect all the battery cells in parallel, but connects the battery cells in series to increase the output voltage. In the power supply devices connected in series, the electrical characteristics of any of the battery cells deteriorate the overall electrical characteristics. From this, in a power supply device having a large number of battery cells built-in, in addition to reducing the temperature rise of the battery cells, how to reduce the temperature difference of each battery cell reduces the electrical characteristics, that is, the life. It is an important parameter to identify.

In the power supply device shown in FIG. 2, the circuit board 80 is fixed to the board holder 81, the control element 82 is arranged on the surface thereof, and the potting resin 7 is brought into close contact with the power supply device. A heat insulating layer 83 is provided between the 81A and the heat insulating layer 83, and the heat insulating layer 83 is arranged between the circuit board 80 and the control element 82. The power supply device having this structure conducts the thermal energy of the control element that is fixed to the surface of the circuit board and generates heat to the potting resin, dissipates the thermal energy of the control element, and disperses it on the surface of the circuit board. The potting resin efficiently disperses the heat energy of the control element and dissipates heat. Therefore, the temperature rise of the control element is limited, and the temperature unevenness of the circuit board is reduced. A circuit board having less temperature unevenness is provided with a heat insulating layer between the back surface and the bottom plate. The heat insulating layer arranged between the circuit board and the bottom plate is located between the circuit board and the control element to block heat conduction from the circuit board to the battery assembly. Therefore, in a state where the current flowing through the battery cell increases and the temperature of the battery cell rises due to Joule heat, the control element that generates heat at a higher temperature than the battery cell does not heat the battery cell. The temperature rise of the control element is higher than that of the battery cell, but the heat resistant temperature of the control element is higher than that of the battery cell. Therefore, heat is dissipated by the potting resin to keep the temperature within a preferable setting range. Further, the battery cell whose temperature rises is held in a preferable setting range without being heated by the control element having a higher temperature.

Further, according to the power supply device according to the second side surface, in addition to the above configuration, the heat insulating layer can be an air layer.

Further, 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 that is open to the outside.

Further, according to the power supply device according to the fourth side surface, in addition to any of the above configurations, the substrate holder is provided with a peripheral wall around the bottom plate, and the circuit board is arranged inside the peripheral wall. The boundary between the peripheral wall and the outer periphery of the circuit board can be a closed gap that prevents the inflow of the potting resin.

Further, according to the power supply device according to the fifth aspect, in addition to the above configuration, a packing for blocking the inflow of the potting resin can be arranged between the peripheral wall and the circuit board.

Further, according to the power supply device according to the sixth side surface, in addition to any of the above configurations, a heat conductive layer is provided on the surface of the circuit board, and the circuit board is made into the potting resin via the heat conductive layer. Can be brought into close contact.

Further, according to the power supply device according to the seventh side surface, in addition to any of the above configurations, the circuit board and the bottom plate are arranged in a horizontal posture, and the potting resin is brought into close contact with the upper surface of the circuit board. The heat insulating layer can be arranged on the lower surface of the circuit board, and the battery assembly can be arranged below the bottom plate.

Furthermore, according to the power supply device according to the eighth side surface, in addition to the above configuration, an adiabatic air layer can be provided between the bottom plate and the battery assembly.

It is a vertical sectional view which shows the power-source device which concerns on one Embodiment of this invention. FIG. 5 is an enlarged schematic cross-sectional view of a main part of the power supply device of FIG. It is an exploded perspective view of the battery assembly of the power supply device of FIG. It is an exploded perspective view of the blockage cover shown in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiments shown below exemplify a configuration for embodying the technical idea of the present invention, and the present invention is not specified as the following. Moreover, the member shown in the claims is never specified as the member 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 to the specific ones unless otherwise specified. It is just an example of explanation. The size and positional relationship of the members shown in each drawing may be exaggerated to clarify the explanation. Further, in the following description, members having the same or the same quality are shown with the same name and reference numeral, and detailed description thereof will be omitted as appropriate. Further, each element constituting the present invention may be configured such that a plurality of elements are composed of the same member and the plurality of elements are combined with one member, or conversely, the function of one member is performed by the plurality of members. It can also be shared and realized. In addition, the contents described in some examples and embodiments can be used in other embodiments and embodiments.

An example in which the power supply device shown below is mainly applied to a power source for driving an electric vehicle such as an electric vehicle or an electric cart that runs only by a motor will be described. Even if the power supply device of the present invention is used in a hybrid vehicle that runs on both an engine and a motor, or in an application other than an electric vehicle that requires a large output, for example, a power storage device for home or factory use. Good.
(Embodiment 1)

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

The circuit board 80 mounts a control element 82 that realizes a protection circuit for 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 and controls the current to prevent overcharging and overdischarging of the secondary battery cell 1, and further, the secondary battery cell 1 The current in an abnormal state is controlled to prevent deterioration of the secondary battery cell 1 and deterioration of electrical characteristics. The protection circuit that controls the current of the secondary battery cell 1 includes a control element 82 that is connected in series with 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, which is proportional to the product of the square of the current and the equivalent resistance. Since the control element 82 is connected in series with the secondary battery cell 1 to control the current of the secondary battery cell 1, 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 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 heat generation energy also increases in the same manner. Therefore, 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 amount of heat generated by the secondary battery cell 1 and the control element 82 increases at the same rate, but the temperature rise of the control element 82 is larger than that of the secondary battery cell 1. This is because the heat generation region of the control element 82 is an extremely narrow region as compared with the secondary battery cell 1.
(Board holder 81)

The circuit board 80 is arranged at a fixed position of the battery assembly 40 via the board holder 81. In addition to arranging the circuit board 80 in a fixed position, the board holder 81 efficiently diffuses the heat 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. By blocking heat conduction to, the temperature balance of both the control element 82 and the secondary battery cell 1 is optimized, and both the secondary battery cell 1 and the control element 82 are held 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.
(Insulation layer 83)

In the substrate holder 81 of FIG. 2, the heat insulating layer 83 on the back surface of the circuit board is used as an air layer. The air layer is light and provides excellent insulation properties. Further, the heat insulating layer 83 of FIG. 2 is a ventilation layer 83A of air open to the outside, and the heat insulating characteristics of the air layer are further improved. The ventilation layer 83A is provided with through holes above and below the peripheral wall 81B of the substrate holder 81 to form openings 81a and 81b. In the ventilation layer 83A, the outside air flows in from the lower opening 81a, and the air that has been heated and lightened inside is discharged to the outside from the upper opening 81b to ventilate the internal air and to ventilate the internal air. Reduce the temperature rise. As the heat insulating layer 83, instead of the air layer, a heat insulating material in which innumerable fibers are three-dimensionally assembled or a heat insulating material made of a foam of a plastic or an inorganic material can be used. The substrate holder 81 for filling the heat insulating layer 83 with the heat insulating material has a feature that the potting resin 7 injected on the upper surface can be prevented from flowing into the heat insulating layer 83, so that the potting resin 7 can be easily injected. Further, in the power supply device 100 shown in FIGS. 1 and 2, a heat insulating air layer 84 is also provided between the bottom plate 81A of the substrate holder 81 and the battery assembly 40, and the control element 82 is transferred 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 into the upper surface of the circuit board 80, the substrate holder 81 has a height at which the peripheral wall 81B projects upward from the surface of the circuit board 80. Further, the substrate holder 81 is provided with a peripheral wall 81B around the bottom plate 81A so that the uncured and liquid potting resin 7 injected onto the circuit board 80 does not flow into the back surface of the circuit board 80. Is arranged inside the peripheral wall 81B. The boundary between the peripheral wall 81B and the outer periphery of the circuit board 80 is a closed gap 81C that prevents the inflow of the potting resin 7, and is shaped so that there is no gap between the outer peripheral edge of the circuit board 80 and the inner surface of the peripheral wall. In the substrate holder 81 of FIG. 2, the packing 85 is arranged between the inner surface of the peripheral wall 81B 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 embeds the surface of the circuit board 80 and the entire or lower part of the control element 82, and is brought into close contact with the surface of the circuit board 80 and the control element 82 to transfer the thermal energy of the control element 82 to the surface of the circuit board 80. Disperse and dissipate heat to the outside. In the potting resin 7 shown in the cross-sectional view of FIG. 2, the entire control element 82 is embedded in the potting resin 7, and the peripheral wall 81B is raised so that the entire surface of the control element 82 is in close contact with the potting resin 7. Is thickly filled. The control element 82 embedded in the potting resin 7 conducts thermal energy from the entire surface to the potting resin 7. The potting resin 7 disperses the conducted heat energy on the surface of the circuit board 80, and further dissipates heat from the surface to dissipate the heat energy of the control element 82. Further, the circuit board 80 shown in the cross-sectional view of FIG. 2 is provided with a heat conductive layer 86 on the surface so that the heat energy of the control element 82 can be more efficiently dispersed on the surface, and the heat conductive layer 86 is made of the potting resin 7. It is in close contact. The heat conductive layer 86 is a metal layer having a higher thermal conductivity than the potting resin 7, and disperses the heat energy of the control element 82 on the surface of the circuit board 80 extremely efficiently. Since the circuit board 80 is provided with the heat conductive layer 86 having excellent heat conductive characteristics 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 conductive layer 86. The dispersed heat energy is further dispersed by the potting resin 7 to dissipate heat.

In the power supply device 100 of FIG. 2, the circuit board 80 and the bottom plate 81A are arranged in a horizontal position, the potting resin 7 is brought into close contact with the circuit board 80, and the heat insulating layer 83 is arranged on the lower surface. The body 40 is placed below the bottom plate 81A. The power supply device 100 conducts the heat energy of the heat-generating control element 82 to the potting resin 7 to dissipate heat. The heated potting resin 7 disperses heat energy and dissipates heat from the surface. The potting resin 7 that dissipates heat energy dissipates heat by radiant heat, and also heats air that comes into contact with the surface to dissipate heat. The air heated on the surface of the potting resin 7 becomes lighter and rises. Since the air heated by the potting resin 7 rises, it does not heat the secondary battery cell 1 arranged below. Therefore, in the structure in which the circuit board 80 and the bottom plate 81A are arranged on the battery assembly 40, the heat-generating control element 82 does not heat the secondary battery cell 1 via air, and the control element 82 of the control element 82 It has the feature that the temperature rise of the secondary battery cell 1 due to heat generation can be minimized. The circuit board 80 arranged above the battery assembly 40 is heated by the air whose temperature has risen in the secondary battery cell 1 whose temperature has risen, 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 generated secondary battery cell 1 is not harmful.
(Battery assembly 40)

In the battery assembly 40, a plurality of secondary battery cells 1 are arranged 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 opposite positions (left and right in the figure). In the battery unit 40A, a plurality of secondary battery cells 1 are arranged in a parallel posture, both ends are arranged on the same plane, and the lead plate 45 is connected to the end electrodes 13 at both ends. In the battery assembly 40, a pair of battery units 40A arranged at opposite positions are arranged side by side in the axial direction of the secondary battery cell 1, and an insulating space 6 is provided between the pair of battery units 40A. As shown in the enlarged cross-sectional view of FIG. 2, each battery unit 40A has an end electrode 13 arranged at a position facing the insulating space 6.
(Secondary battery cell 1)

The secondary battery cell 1 is provided with a discharge port (not shown) of a discharge valve that opens at a set pressure on the end face. The secondary battery cell 1 is provided with end electrodes 13 at both ends. In this secondary battery cell 1, the opening of a metal outer can made of aluminum or the like is hermetically sealed with a sealing plate, and a convex electrode is provided on the sealing plate to form a first end electrode 13A, which is the bottom surface of the outer can. Is the 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 lithium ion battery of a cylindrical battery. The lithium ion battery has a large capacity relative to its size and weight, and the total capacity of the power supply device 100 can be increased. However, the power supply device of the present invention does not specify the secondary battery cell as a lithium ion battery. Other rechargeable secondary batteries can be used in the secondary battery cell. Further, in the power supply device 100 shown in the figure, the secondary battery cell 1 is a cylindrical battery, but a square battery can also be used as the secondary battery cell. Each secondary battery cell 1 has a lead plate 45 welded to the end electrodes 13 at both ends thereof, and adjacent secondary battery cells 1 are connected in series or in parallel.
(Battery holder 44)

As shown in FIG. 3, the secondary battery cell 1 is arranged at a fixed position by the battery holder 44. The battery holder 44 is manufactured by molding an insulating material such as plastic. In the battery holder 44 shown in the figure, all the secondary battery cells 1 are arranged in a fixed position in a parallel posture. Since the rechargeable battery cell 1 arranged at a fixed position in the battery holder 44 has lead plates 45 welded to both ends thereof, each of the rechargeable battery cells 45 to be welded to each end is located on the same surface. The secondary battery cell 1 is arranged in the battery holder 44 so that both ends thereof are located on substantially the same surface.

The battery holder 44 is provided with an insertion portion 44A into which the secondary battery cell 1 is inserted and arranged at 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 is cylindrical. The battery holder 44 is formed by molding plastic into a tubular shape and is provided with an insertion portion 44A inside. The insertion portion 44A is provided with openings 44B at both ends that expose the end portions of the battery. 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 an end electrode 13, and a lead plate 45 is welded and fixed thereto.

As shown in FIG. 1, in 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 arranged on both sides of the insulating space 6, the discharge port of the discharge valve is provided. It is arranged in the insulating space 6. When the discharge valve is opened, the high-temperature ejected gas discharged from the discharge port is injected toward the end face of the facing battery unit 40A. The high-temperature ejected gas injected onto the facing surfaces of the secondary battery cells 1 at opposite positions causes thermal runaway of the secondary battery cells 1. In the power supply device 100 of FIG. 1, a heat-resistant sheet 64 is arranged in the middle of the insulating space 6.
(Heat-resistant sheet 64)

The heat-resistant sheet 64 is an insulating sheet having a heat-resistant temperature that is not melted by the ejected gas discharged from the discharge valve, and is, for example, flame-retardant heat-resistant paper. However, as the heat-resistant sheet 64, instead of heat-resistant paper, paper or non-woven fabric in which inorganic fibers that are not melted by ejected gas are assembled in a sheet shape, or an inorganic sheet in which an inorganic material is bonded in a thin sheet shape can be used. Since these heat-resistant sheets 64 can be made thin, the heat-resistant sheet 64 has a feature that the insulating space 6 can be widened and the ejected gas can be smoothly discharged without reducing the substantial volume of the insulating space 6. In the heat-insulating heat-resistant sheet 64, the end faces and lead plates 45 of the secondary battery cells 1 arranged on both sides can be arranged in an insulated state. However, the heat-resistant sheet does not necessarily have to be an insulating material. This is because the surface can be insulated by laminating an insulating sheet on the surface of the heat-resistant sheet. However, a structure in which a heat-resistant sheet is used as an insulating material and an insulating material is laminated on the surface thereof can further improve the insulating property of the heat-resistant sheet.

The heat-resistant sheet 64 is arranged in a posture parallel to the end surface of the secondary battery cell 1. In the power supply device 100 shown in the figure, a heat-resistant sheet 64 is arranged in the middle of the insulating space 6, and exhaust gas chambers 63 for ejected gas are provided on both sides of the heat-resistant sheet 64. In order to arrange the heat-resistant sheet 63 in the middle of the heat-resistant space 6, the power supply device 100 has closed covers 61 having a shape along the outer peripheral portion of the heat-resistant space 6 on both sides of the heat-resistant sheet 64 as shown in FIGS. The closing cover 61 is arranged and interposed between the heat-resistant sheet 64 and the battery unit 40A. The closing cover 61 in the figure has an outer peripheral frame portion 62 having a shape 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 facing surface 40a of the battery unit 40 by arranging the closing cover 61 having this shape between the facing surface 40a of the battery unit 40 and the heat-resistant sheet 64. The exhaust chamber 63 is provided between the heat-resistant sheet 64 and the facing surface 40a of the battery unit 40 and inside the outer peripheral frame portion 62.

In this way, the insulating space 6 provided with the exhaust chambers 63 on both sides of the heat-resistant sheet 64 can smoothly discharge the exhaust gas to the exhaust chamber 63 without resistance. Further, since the insulating space 6 having this structure diffuses the ejected gas in the exhaust chamber 63 and blows it onto the heat-resistant sheet 64, the thermal damage of the heat-resistant sheet 64 due to the ejected gas is reduced, and the secondary battery cells 1 located at opposite positions are reduced. Can more effectively prevent the induction of thermal runaway. Further, the strength and heat resistance characteristics required for the heat resistant sheet 64 can be lowered, and the cost of the heat resistant sheet 64 can be reduced. Furthermore, since the exhaust gas sprayed on the surface of the heat-resistant sheet 64 is dispersed on both sides by the exhaust chamber 63, the feature that the exhaust gas can be smoothly discharged to the insulating space 6 with a small exhaust resistance is also realized. This makes it possible to quickly reduce the pressure of the secondary battery cell 1 in which the internal pressure has risen abnormally, and effectively prevent adverse effects such as bursting of the outer can due to the rise in the internal pressure.

Further, the heat-resistant sheet 64 is a flexible sheet that is deformed by the discharged gas. Since the heat-resistant sheet 64 can be deformed by the pressure of the ejected gas to be injected to increase the volume of the exhaust chamber 63 on which the ejected gas is discharged, the heat-resistant sheet 64 is ejected from the discharge port of the exhaust valve to the exhaust chamber 63 with less resistance. It has a feature that gas can be smoothly discharged, and destruction due to an increase in internal pressure of the secondary battery cell 1 can be effectively prevented to ensure higher safety.
(Occlusion cover 61)

As shown in FIGS. 1 to 4, the closing covers 61 arranged on both sides of the heat-resistant sheet 64 and arranged between the heat-resistant sheet 64 and the battery unit 40A are outer peripheral frames that close the outer peripheral portion of the insulating space 6. A portion 62 is provided, and an exhaust chamber 63 is provided inside the outer peripheral frame portion 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 surface of the battery unit 40A without a gap to form an exhaust chamber 63 in the insulating space 6. The closing cover 61 having this structure is characterized in that a large-volume exhaust chamber 63 is provided inside the outer peripheral frame portion 62, and the ejected gas can be injected there, so that the ejected gas can be smoothly discharged. This is because the large-volume exhaust chamber 63 has a slow increase in internal pressure due to the exhaust gas injected from the exhaust port of the exhaust valve, and the increase gradient of the exhaust resistance can be made gentle.

The block cover 61 is formed of a foam of an insulating material having closed cells that are melted by the ejected gas discharged from the discharge valve. The melting temperature of the block cover 61 melted by the ejected gas is, for example, 100 ° C. or higher and 500 ° C. or lower, preferably 200 ° C. or higher and 400 ° C. or lower. The closing cover 61 having a low melting temperature is rapidly melted by the ejected gas and the ejected gas is discharged to the outside of the insulating space 6, and the closing cover 61 having a high melting temperature can reliably close the insulating space 6 in the used state. If the melting temperature of the block cover 61 is too low, it melts or deforms at the battery temperature, and if it is too high, it cannot be quickly melted by the ejected gas. Therefore, the melting temperature of the closing cover 61 is set in the above-mentioned range in consideration of the temperature characteristics that the blown gas melts quickly and does not deform or melt when the jet gas is not injected.

The closing cover 61, which is melted by the ejected gas, is melted by the high-temperature ejected gas injected from the opened discharge valve. The molten block cover 61 opens the insulating space 6 to the outside, and discharges the inflowing ejected gas from the insulating space 6 as shown by an arrow B in FIG. The closing cover 61 of the insulating material can close the insulating space 6 by being in close contact with the end electrode 13 side of the battery unit 40A. In particular, since the lead plate 45 of the metal plate is arranged on the end electrode 13 side, the closing cover 61 of the insulating material is in close contact with the lead plate 45 and closes the insulating space 6 without short-circuiting the lead plate 45. it can. Further, since the foam closing cover 61 having closed cells has a small weight with respect to a unit volume and can have a low density, it is quickly melted by a high-temperature jet gas, and the blow gas is quickly discharged from the insulating space 6 to the outside. There are features that can be done. Further, since the foam closing cover 61 can control the foaming ratio at the time of molding to lower the specific gravity, the melting time by the ejected gas can be extremely shortened.

The closing cover 61 is made of a rubber-like elastic foam. The rubber-like elastic body closing 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. As the soft plastic foam, for example, a soft urethane foam can be used. The rubber-like elastic body closing cover 61 is arranged between the pair of battery units 40A, pressed by the battery units 40A on both sides, and elastically deformed into a compressed state, so that it adheres to the facing surface 40a of the battery unit 40A. To 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 creates irregularities and gaps in the facing surface 40a, but the closing cover 61 which is elastically deformed and closely adheres to the battery unit 40A. It has the feature of absorbing unevenness and closing the gap. Further, the rubber-like elastic body closing cover 61 made of a foam having closed cells is made more flexible by innumerable bubbles and has a greater degree of freedom to be deformed, and there is no gap on the facing surface 40a of the uneven battery unit 40A. It has the characteristic of being able to adhere closely. Further, the closing cover 61 made of a foam of a rubber-like elastic body can reduce the pressing force of the facing surface 40a of the battery unit 40A in a state of being elastically deformed and in close contact with the facing surface 40a of the battery unit 40A. Therefore, there is a feature that the insulating space 6 can be reliably closed without applying an unreasonable stress to the battery unit 40A while being 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. It is that a packing that elastically deforms is arranged between the closing cover 61 and the facing surface 40a of the battery unit 40A, or a sealing material is applied so that the closing cover 61 is brought into close contact with the facing surface 40a of the battery unit 40A without a gap. Because it can be done.

In the power supply device 100 of FIG. 1, as shown in FIGS. 2 to 4, an 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 blocking covers 61 are arranged on both sides of the heat-resistant sheet 64, and the heat-resistant sheet 64 and the blocking covers 61 on both sides are connected in an integral structure to be arranged in the insulating space 6. Insulation spacer 60 is used. The insulating spacer 60 is arranged so as to be sandwiched between the pair of battery units 40A, and the closing cover 61 and the heat-resistant sheet 64 are arranged at a fixed position in the insulating space 6. Therefore, this structure has a feature that the assembly process can be simplified, the heat-resistant sheet 64 and the closing cover 61 can be arranged at accurate positions by efficiently mass-producing.

In the power supply device 100 of FIGS. 1 and 2, the outer peripheral frame portion 62 is provided on the closing cover 61, and the exhaust chamber 63 is provided inside the outer peripheral frame portion 62, but the closing cover 61 is not specified in this shape. .. For example, although not shown, the closing cover is formed into a plate-shaped foam having a recess on the surface facing the discharge port of the discharge valve of the secondary battery cell, or is arranged without a gap in the insulating space. It is also possible to form a plate without an exhaust chamber to close the exhaust port of the exhaust valve. The closed cover 61 having such a shape increases the foaming ratio of the foam to increase the porosity inside the closed cover, and lowers the melting temperature to shorten the melting time by the high-temperature ejected gas, thereby shortening the melting time by the high-temperature ejected gas. The ejected gas injected into the water is quickly discharged to the outside.

The power supply device of the present invention is conveniently used in applications where high safety is required by preventing the induction of thermal runaway of the built-in battery.

100 ... Power supply device 1 ... Secondary battery cell 6 ... Insulation space 7 ... Potting resin 13 ... End electrode 13A ... First end electrode 13B ... Second end electrode 40 ... Battery assembly 40A ... Battery unit 40a ... Facing surface 44 ... Battery holder 44A ... Insertion 44B ... Opening 45 ... Lead plate 60 ... Insulating spacer 61 ... Closing cover 62 ... Outer frame 63 ... Exhaust chamber 64 ... Heat resistant sheet 65 ... Insulating sheet 80 ... Circuit board 81 ... Substrate Holder 81A ... Bottom plate 81B ... Peripheral wall 81C ... Closure gap 81a ... Opening 81b ... Opening 82 ... Control element 83 ... Insulation layer 83A ... Ventilation layer 84 ... Insulation air layer 85 ... Packing 86 ... Heat conductive layer

Claims (8)

A battery assembly with multiple battery cells and
A circuit board on which a control element that realizes a protection circuit for a battery cell of the battery assembly is mounted, and
A board holder for fixing the circuit board and arranging the bottom plate between the circuit board and the battery assembly is provided.
The circuit board has a control element fixed to a surface opposite to the surface of the substrate holder facing the bottom plate.
A potting resin is adhered to the surface of the circuit board.
A power supply device characterized in that 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.
A power supply device characterized in that the heat insulating layer is an air layer. The power supply device according to claim 2.
A power supply device characterized in that the air layer is a ventilation layer of air open to the outside. The power supply device according to any one of claims 1 to 3.
The substrate holder has a peripheral wall around the bottom plate.
The circuit board is arranged inside the peripheral wall,
A power supply device characterized in that the boundary between the peripheral wall and the outer periphery of the circuit board serves as a closing gap that prevents the inflow of the potting resin. The power supply device according to claim 4.
A power supply device characterized in that a packing for blocking the inflow of the potting resin is arranged between the peripheral wall and the circuit board. The power supply device according to any one of claims 1 to 5.
A power supply device characterized in that the circuit board has a heat conductive layer on its surface, and the circuit board is brought into close contact with the potting resin via the heat conductive layer. The power supply device according to any one of claims 1 to 6.
The circuit board and the bottom plate are arranged in a horizontal position.
The circuit board has the upper surface in close contact with the potting resin, and the heat insulating layer is arranged on the lower surface.
Further, the power supply device is characterized in that the battery assembly is arranged below the bottom plate. The power supply device according to claim 7.
A power supply device characterized in that an insulated air layer is provided between the bottom plate and the battery assembly.

Images