Power supply unit

Abstract

In the present invention, heat generated by individual battery cells in a battery block is efficiently transferred to a cooling plate. This power supply unit comprises: a battery block 3 comprising a plurality of battery cells 2 disposed such that lower-end surfaces thereof are disposed in the same plane to form a cooling surface 3a; an insulating frame 4 located under the cooling surface 3a of the battery block 3 and having through holes 5 open at opposing positions with respect to the lower-end surfaces of the battery cells 2; a heat-dissipating laminate 6 located between the battery block 3 and the insulating frame 4; and a cooling plate 10 disposed under the insulating frame 4. The heat-dissipating laminate 6 comprises: an insulating film 7 layered on the insulating frame 4; and a thermally conductive material 8 filling gaps between the insulating film 7 and the battery block 3 and closely adhered to the insulating film 7 and the lower-end surfaces of the battery cells 2 in a thermally conductive state. In the heat-dissipating laminate 6, a closed area 7a of the insulating film 7, which closes the upper openings of the through holes 5, is disposed in a thermally bonded state opposite the surface of the cooling plate 10 through the through holes 5 of the insulating frame 4.

Description

Power supply unit

[0001] The present disclosure relates to a power supply unit that dissipates thermal energy from each battery cell that generates heat through charging and discharging to the outside.

[0002] In a power supply unit consisting of a battery block consisting of multiple battery cells, the temperature of the battery cells rises due to charging and discharging current. This temperature rise reduces the electrical characteristics and shortens the battery life. Temperature rise is a parameter that affects battery cell degradation, and as the temperature rise increases, the battery cell degradation accelerates. For this reason, it is extremely important for a power supply unit with multiple battery cells to efficiently and evenly cool all battery cells. Furthermore, temperature differences between battery cells can cause unbalanced degradation among the battery cells, leading to the degradation of specific battery cells. Degradation of specific battery cells shortens the life of the entire power supply unit. This is because a power supply unit connects multiple battery cells in series to achieve an output voltage appropriate for the application, and therefore the charge and discharge capacity of a degraded battery cell decreases, limiting the discharge capacity of the power supply unit. Furthermore, degraded battery cells increase their internal resistance and generate more heat, which increases their temperature and further accelerates degradation. For this reason, power supply units with multiple battery cells connected in series can extend the lifespan of each battery cell by causing each cell to deteriorate in a balanced manner, so it is extremely important for power supply units with many battery cells to cool each battery cell efficiently and evenly.

[0003] Patent No. 7186802

[0004] A power supply unit equipped with a structure for cooling multiple battery cells has been developed (Patent Document 1). Patent Document 1 discloses a power supply unit in which multiple battery cells arranged vertically are arranged so that their bottom surfaces are flush with one another to form a battery block, and this battery block is housed in an exterior case. The bottom plate of the exterior case is made of metal, and multiple insulating sheets are laminated on top of the metal bottom plate, with the battery block placed on top of the insulating sheets. Furthermore, a cooling plate is disposed below the metal bottom plate, and the bottom plate is cooled by the cooling plate. In this power supply unit, the cooling plate cools the bottom plate of the exterior case, and the cooled bottom plate cools the bottom surfaces of the battery cells via the multiple insulating sheets, dissipating the thermal energy of the battery cells via the cooling plate.

[0005] The power supply unit described above uses a cooling plate to cool the bottom plate of the exterior case, thereby cooling the internal battery cells. The exterior case has battery cells mounted on the surface of the bottom plate, which is cooled by the cooling plate, with multilayered insulating sheets sandwiched between them. Power supply units with this structure pose a challenge in efficiently cooling each battery cell with the cooling plate. This is because the thermal energy of the battery cells is dissipated by thermal conduction to the cooling plate via the multilayered insulating sheets and the bottom plate of the exterior case. The bottom plate must be thick to support the heavy battery block, and the multilayered insulating sheets must be thick enough to accommodate the vertical misalignment of the bottom edges of the battery cells. This makes it difficult to efficiently conduct the thermal energy of the battery cells to the cooling plate. Furthermore, in the power supply unit described above, the thickness of the multi-layered insulating sheets is changed to accommodate misalignment of the bottom surfaces of the battery cells, and the bottom surface of each battery cell is thermally bonded to the insulating sheet, but it is extremely difficult to thermally bond the bottom surface of each battery cell to the insulating sheet in a desirable thermal bond state. Therefore, it is difficult to conduct the thermal energy of each battery cell evenly to the cooling plate and to equalize the temperature difference when each battery cell generates heat.

[0006] The present invention was developed with the aim of further resolving the above-mentioned drawbacks, and one of the objects of the present invention is to provide a power supply unit that can efficiently conduct heat from each battery cell that makes up the battery block to a cooling plate, and dissipate the heat from each battery cell evenly through the cooling plate, thereby reducing temperature differences and temperature rises among the battery cells.

[0007] A power supply unit according to one embodiment of the present disclosure has all of the following configurations (a) to (c): (a) The power supply unit includes a battery block formed by arranging the bottom surfaces of multiple battery cells flush with each other to form a cooling surface; an insulating frame positioned below the cooling surface of the battery block and having through holes opening in positions facing the bottom surfaces of the battery cells; a heat dissipation laminate positioned between the battery block and the insulating frame; and a cooling plate positioned below the insulating frame. (b) The heat dissipation laminate includes an insulating film laminated on the insulating frame; and a thermally conductive material filled between the insulating film and the battery block and in close thermal contact with the insulating film and the bottom surfaces of the battery cells. (c) The heat dissipation laminate is positioned such that the closed area of ​​the insulating film, which closes the upper opening of the through hole, faces the surface of the cooling plate via the through hole in the insulating frame in a thermally coupled state.

[0008] The above power supply unit has the advantage that the heat generated by each battery cell that makes up the battery block is efficiently conducted by the cooling plate, and the heat generated by each battery cell is dissipated evenly by the cooling plate, thereby minimizing temperature differences and temperature rises among the battery cells.

[0009] 1 is a perspective view showing a power supply unit according to a first embodiment; FIG. 2 is a perspective view from below of the power supply unit of FIG. 1; FIG. 3 is an exploded perspective view of a battery block; FIG. 4 is an exploded perspective view showing a battery block, an insulating frame, a heat dissipation laminate, and a cooling plate; FIG. 5 is an exploded perspective view from diagonally below showing a battery block, an insulating frame, and a heat dissipation laminate; FIG. 6 is an enlarged cross-sectional view of a main part of the insulating frame and the heat dissipation laminate; FIG. 7 is an enlarged cross-sectional view of a main part of another example of a power supply unit; FIG. 8 is a cross-sectional view showing a step of applying a thermally conductive material to the upper surface of a battery block, and a state in which the insulating frame and the heat dissipation laminate are attached to the battery block; FIG. 9 is a cross-sectional view showing a state in which the insulating frame and the heat dissipation laminate are attached to the battery block; FIG. 10 is a cross-sectional view showing a state in which the battery block is attached to a cooling plate; FIG. 11 is a cross-sectional view showing a state in which the battery block is attached to a cooling plate;

[0010] The present invention will be described in detail below with reference to the drawings. In the following description, terms indicating specific directions or positions (e.g., "upper," "lower," and other terms including these terms) will be used as necessary. However, the use of these terms is intended to facilitate understanding of the invention with reference to the drawings, and the meaning of these terms does not limit the technical scope of the present invention. Furthermore, parts with the same reference numerals appearing in multiple drawings indicate the same or equivalent parts or components. Furthermore, the embodiments described below are illustrative examples of the technical concept of the present invention and do not limit the scope of the present invention. Furthermore, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described below are intended for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, the content described in one embodiment or example can also be applied to other embodiments or examples. Furthermore, the size and positional relationships of components shown in the drawings may be exaggerated for clarity. In this disclosure, the up-down direction is specified based on the drawings. When the device is used upside down, the up-down direction is also reversed.

[0011] The embodiments of the present disclosure may be specified by the following configurations and features. A power supply unit according to one embodiment of the present disclosure includes all of the following configurations (a) to (c): (a) the power supply unit includes a battery block formed by arranging the bottom surfaces of a plurality of battery cells flush with each other to form a cooling surface; an insulating frame positioned below the cooling surface of the battery block and having through holes opening at positions facing the bottom surfaces of the battery cells; a heat dissipation laminate portion positioned between the battery block and the insulating frame; and a cooling plate positioned below the insulating frame. (b) the heat dissipation laminate portion includes an insulating film laminated on the insulating frame; and a thermally conductive material filled between the insulating film and the battery block and in close thermal contact with the insulating film and the bottom surfaces of the battery cells. (c) the heat dissipation laminate portion is positioned such that a blocked region of the insulating film, which blocks the upper openings of the through holes, faces the surface of the cooling plate via the through holes in the insulating frame in a thermally coupled state.

[0012] The power supply unit described above has the advantage of efficiently conducting heat generated by each battery cell constituting the battery block to the cooling plate, allowing the heat generated by each battery cell to be dissipated evenly by the cooling plate, thereby minimizing temperature differences and temperature rises among the battery cells. The power supply unit has an insulating frame on which the battery block is mounted, with through-holes opened facing the bottom end face of each battery cell, an insulating film placed on the top surface to close these through-holes, a thermally conductive material filled on top of the insulating film, which is in close contact with the cooling surface of the battery block and the insulating film to thermally bond them, and the insulating frame is placed on top of the cooling plate. Therefore, the insulating film with the thermally conductive material in close contact with its top surface is exposed from the through-hole and placed close to the cooling plate, allowing heat generated by the battery cells to be efficiently dissipated to the cooling plate via the thermally conductive material and the insulating film, minimizing temperature differences and temperature rises among the battery cells.

[0013] A power supply unit according to another embodiment of the present disclosure includes a through-hole filler disposed between the cooling plate and the insulating film, the through-hole filler being disposed in the through-hole of the insulating frame, and the blocked area of ​​the insulating film being disposed in thermal conduction with the cooling plate via the through-hole filler. The power supply unit described above has the advantage that the through-hole filler disposed inside the through-hole is in close contact with both the insulating film and the cooling plate, providing a favorable thermal bond, conducting heat generated by the battery cells from the insulating film to the cooling plate, and dissipating the heat generated by each battery cell evenly via the cooling plate, thereby minimizing temperature differences and temperature rises among the battery cells.

[0014] In another embodiment of the power supply unit of the present disclosure, the cooling plate can be a liquid-cooled plate with an internal cooling medium circulation path. The liquid cooling medium can be cooled, for example, by a chiller and circulated to the cooling plate via the circulation path using a circulation pump. This power supply unit has the advantage of being able to efficiently cool the cooling surface of the battery block with a simple structure.

[0015] In another embodiment of the power supply unit of the present disclosure, the battery block includes a battery holder in which each battery cell is positioned in a fixed position, the battery holder includes electrode windows that expose the bottom surfaces of the battery cells, the electrode windows are positioned opposite the through holes in the insulating frame, and a thermally conductive material is filled into the electrode windows so that the electrode windows are in thermally conductive contact with the bottom surfaces of the battery cells.The above power supply unit has the advantage that, because the thermally conductive material is filled into the electrode windows and in thermally conductive contact with the bottom surfaces of the battery cells, the heat generated by each battery cell is efficiently conducted to the cooling plate and dissipated evenly by the cooling plate, thereby reducing temperature differences and temperature rises among the battery cells.

[0016] In another embodiment of the power supply unit of the present disclosure, the battery block includes lead plates electrically connected to the bottom surfaces of the battery cells, and the thermally conductive material filled into the through holes of the insulating frame is thermally coupled to the bottom surfaces of the battery cells by being in close thermally conductive contact with the lead plates. This power supply unit has the advantage that the thermally conductive material filled into the through holes of the insulating frame is thermally coupled to the bottom surfaces of the battery cells by being in close thermally conductive contact with the lead plates, thereby efficiently conducting heat from each battery cell to the cooling plate and dissipating the heat from each battery cell evenly via the cooling plate, thereby reducing temperature differences and temperature rises among the battery cells.

[0017] In another embodiment of the power supply unit of the present disclosure, the insulating frame can be a molded body made of plastic or elastomer.

[0018] In another embodiment of the power supply unit of the present disclosure, either or both of the thermally conductive material and the through-hole filler can be in a paste-like hardened resin in an uncured state. In this power supply unit, the uncured paste fills the irregularities and gaps in the cooling surface of the battery block or the cooling plate, and hardens in a gap-free state, achieving a favorable thermal bond by adhering to the surface of the cooling surface or cooling plate over a wide area. This has the advantage of efficiently conducting heat from each battery cell to the cooling plate and dissipating the heat from each battery cell evenly through the cooling plate, thereby minimizing temperature differences and temperature rises among the battery cells.

[0019] In a power supply unit according to another embodiment of the present disclosure, the thermally conductive material can be a gap filler made of a curable resin that is mixed with two components and cured.

[0020] In another embodiment of the power supply unit of the present disclosure, the gap filler can be a cured resin containing any of urethane resin, silicone resin, and epoxy resin. The above power supply unit has the advantage of being able to efficiently conduct thermal energy from the battery cells to the insulating film by using a cured resin with favorable thermal conductivity.

[0021] In another embodiment of the power supply unit of the present disclosure, the gap filler can be a synthetic resin containing thermally conductive powder. The above power supply unit has the advantage that thermal conductivity can be improved by filling the gap filler containing thermally conductive powder.

[0022] In another embodiment of the power supply unit of the present disclosure, the thermally conductive powder can be inorganic powder. The above power supply unit has a feature that the thermal conductivity can be improved by filling a gap filler containing inorganic thermally conductive powder.

[0023] In another embodiment of the power supply unit of the present disclosure, the insulating frame can be a plate-shaped honeycomb structure with hexagonal through-holes. This power supply unit has the advantage that the area exposed to the surface of the cooling plate through the through-holes in the insulating frame is increased, allowing heat generated by the battery cells to be efficiently dissipated to the cooling plate. (Embodiment 1)

[0024] The power supply unit 100 according to the first embodiment shown in Figures 1 to 11 includes a battery block 3 consisting of multiple battery cells 2, an insulating frame 4 located below the battery block 3, a heat dissipation laminate 6 laminated between the insulating frame 4 and the battery block 3, and a cooling plate 10 disposed below the insulating frame 4 in a thermally coupled state to cool the battery cells 2 via the insulating frame 4 and the heat dissipation laminate 6. (Battery Block 3)

[0025] The battery block 3 has multiple battery cells 2 arranged in fixed positions and connected in series or parallel by lead plates 3C. Any rechargeable secondary battery can be used for the battery cells 2. For example, non-aqueous secondary batteries such as lithium ion batteries can be used for the battery cells 2, which can increase the charge / discharge capacity relative to the volume and weight. However, this disclosure does not limit the battery cells 2 to lithium ion batteries, and any secondary battery, including currently used or future developed all-solid-state batteries, can be used.

[0026] The battery block 3 holds multiple battery cells 2 in fixed positions via battery holders 3A and 3B. The battery holders 3A and 3B are preferably molded from insulating plastic, allowing adjacent battery cells 2 to be insulated and positioned in fixed positions. The battery holders 3A and 3B have hollow cylinders that allow battery cells 2 to be inserted with almost no gaps. The battery holders 3A and 3B have electrode windows 3b that expose the upper and lower end electrodes of the battery cells 2 positioned in the hollow cylinder. The inner shape of the electrode windows 3b is smaller than the inner shape of the hollow cylinder, and battery cell 2 retention flanges are provided around the electrode windows 3b. The retention flanges prevent the battery cells 2 from slipping out of the hollow cylinder and position them in fixed positions. Battery holders 3A and 3B, which have retention flanges on both ends of the retention cylinder, can be divided into upper and lower halves to hold battery cells 2 in the retention cylinder. The two battery holders 3A and 3B in Figure 3 are connected to each other to hold battery cells 2 in fixed positions.

[0027] The battery block 3 in Figure 3 has lead plates 3C on both the top and bottom surfaces to connect the battery cells 2 in series or parallel. The lead plates 3C have connection arms that are inserted into the electrode windows 3b of the battery holders 3A and 3B and welded to the end electrodes. The connection arms can be connected to the end electrodes of the battery cells 2 by laser welding or other methods.

[0028] The battery block 3 has a thermal interface material (TIM) 8 thermally bonded to its cooling surface 3a on the underside, allowing heat generated by the battery cells 2 to be dissipated by thermal conduction to the insulating film 7 via the thermally conductive material 8. The battery block 3 shown in the exploded perspective view of Figure 3 has multiple rows of parallel lead plates arranged on its bottom surface with insulating gaps. Each parallel lead plate is connected to the end electrodes on the lower end surfaces of multiple battery cells 2, connecting the battery cells 2 in parallel to form parallel units. Adjacent parallel units can be connected in series with series lead plates (not shown), increasing the output voltage of the power supply unit 100. In battery blocks 3 with parallel units connected in series, a potential difference occurs between adjacent parallel lead plates. Parallel lead plates with a potential difference must be insulated from each other.

[0029] To dissipate heat generated by the battery cells 2, the battery block 3 has thermally-bonded thermally-conductive material 8 (described later) in close contact with the underside of the parallel lead plates. The thermally-conductive material 8 is in close contact with the underside of the battery block 3, absorbing and dissipating thermal energy from the battery cells 2. However, a battery block 3 with this structure has insulating thermally-conductive material 8 in close contact with the underside to prevent short-circuiting of the parallel lead plates due to the thermally-conductive material 8. In battery blocks 3 in which the parallel lead plates and the end-face electrodes of the battery cells 2, which have a potential difference, are exposed on the cooling surface 3a, the insulating thermally-conductive material 8 is in close contact with the cooling surface 3a, preventing short-circuiting of the parallel lead plates due to the thermally-conductive material 8. However, in battery blocks 3 in which the lead plates 3C and electrodes, which have a potential difference, are not exposed on the cooling surface 3a, the non-insulating thermally-conductive material 8 is in close contact with the cooling surface 3a, allowing heat generated by the battery cells 2 to be thermally conducted to the insulating film 7. (Insulating frame 4)

[0030] The insulating frame 4 is a plate material on which the battery block 3 is placed, and can be manufactured by molding insulating plastic or elastomer. The insulating frame 4 is plate-shaped, with through-holes 5 formed at positions facing the bottom end surface of each battery cell 2. The insulating frame 4 is formed as a thin plate, allowing for efficient conduction of heat generated by the battery cells 2 to the cooling plate 10, and is therefore molded into a plate shape with a thickness of, for example, 1 mm to 4 mm, preferably 1 mm to 2 mm. The insulating frame 4 has a peripheral wall along its periphery, which leaves a gap of, for example, 2 mm or less between it and the outer contour of the bottom surface of the battery block 3, and the battery block 3 is positioned inside the peripheral wall. The peripheral wall is shaped to extend along the outer contour of the side surface of the battery block 3, allowing the insulating frame 4 to be positioned in a predetermined position and to be fitted, engaged, and connected to the battery block 3.

[0031] The insulating frame 4 shown in Figures 2, 4, and 5 has through holes 5 formed in positions facing the bottom end surfaces of each battery cell 2. The through holes 5 expose the insulating film 7 on the surface facing the cooling plate 10, allowing heat generated by the battery cells 2 to be efficiently dissipated to the cooling plate 10. Although not shown, in an insulating frame 4 without through holes 5, the plate material of the insulating frame 4 sandwiched between the insulating film 7 and the cooling plate 10 suppresses heat conduction between the insulating film 7 and the cooling plate 10. In an insulating frame 4 with through holes 5, the insulating film 7 is exposed to the surface of the cooling plate 10 in the areas where the through holes 5 are formed, improving the thermal coupling characteristics between the insulating film 7 and the cooling plate 10.

[0032] The insulating frame 4 in FIG. 2 is a honeycomb-structured plate with hexagonal through-holes 5. The honeycomb-structured insulating frame 4 can increase the opening area and strength by reducing the amount of plastic or elastomer used to form the honeycomb structure at the connecting portions between adjacent through-holes 5. The honeycomb-structured insulating frame 4, which can increase the opening area of ​​the through-holes 5, increases the area exposed to the surface of the cooling plate 10 through the through-holes 5, allowing for efficient heat dissipation from the battery cells 2 to the cooling plate 10. The insulating frame 4 is placed on the cooling plate 10 and dissipates heat from the battery block 3 placed on top to the cooling plate 10 via the thermally conductive material 8 and insulating film 7. The shape of the through-holes 5 is not limited to hexagonal, and can be polygonal (e.g., triangular, rectangular, pentagonal, octagonal), circular, elliptical, regular, or irregular. The connecting portion has a constant width that keeps the spacing between adjacent through holes 5 constant or within a certain range, and also has a symmetrical shape (line symmetry or point symmetry), which reduces the amount of plastic or elastomer used to mold the connecting portion into a honeycomb structure, and also increases the opening area of ​​the through holes 5, thereby improving the strength of the insulating frame 4 (heat dissipation laminate portion 6).

[0033] The heat dissipation laminate 6 has a two-layer structure in which a thermally conductive material 8 is laminated on top of an insulating film 7. The insulating film 7 is laminated on top of the insulating frame 4, and the thermally conductive material 8 is filled between the insulating film 7 and the cooling surface 3a on the underside of the battery block 3, and is in close contact with the upper surface of the insulating film 7 and the lower end surface of each battery cell 2, thermally bonding the lower end surfaces of the battery cells 2 to the insulating film 7. (Insulating Film 7)

[0034] The insulating film 7 is bonded to the upper surface of the insulating frame 4 and blocks the through-holes 5 in the insulating frame 4, preventing the thermally conductive material 8 from leaking to the underside of the insulating frame 4. The insulating film 7 can be bonded to the upper surface of the insulating frame 4 via an adhesive layer, an adhesive material, or by thermal welding, but it can also be laid on the insulating frame 4 without being bonded and placed in a fixed position. The insulating film 7 shown in the exploded perspective views of Figures 4 and 5 has positioning holes 7b on both ends. This insulating film 7 can be placed in a fixed position on the battery block 3 by guiding the positioning protrusions on the underside of the battery block 3 into the positioning holes 7b. Furthermore, the insulating film 7 can be placed in a fixed position on the insulating frame 4 with its outer shape matching the inner shape of the peripheral wall around the insulating frame 4.

[0035] The insulating film 7 is an insulating plastic film, and plastic films such as PET, PP, PVC, etc. are usable. The insulating film 7 is a film strong enough to prevent the thermally conductive material 8 filled on the upper surface from passing through the through holes 5 of the insulating frame 4 during the assembly process and in use, and a plastic film with a thickness of, for example, 30 to 500 μm, preferably 50 to 300 μm, and more preferably 50 to 200 μm can be used. (Thermal Conductive Material 8)

[0036] The thermally conductive material 8 is filled on the insulating film 7 covering the insulating frame 4 and adheres to both the lower end surfaces of the battery cells 2 and the insulating film 7, efficiently absorbing the heat generated by the battery cells 2. The thermally conductive material 8 is filled on the uneven cooling surface 3a of the battery block 3 and adheres to the lower end surfaces of the battery cells 2, effectively absorbing the heat generated by the battery cells 2. A gap filler, which is a hardening resin in a paste form in an uncured state, is suitable for the thermally conductive material 8. This gap filler is filled in an uncured paste form on the uneven cooling surface 3a with gaps, adhering to the cooling surface 3a over a wide area to achieve a favorable thermal coupling state. The gap filler is filled in an uncured paste form on the uneven cooling surface 3a with gaps, and hardens in a gap-free state, maintaining a thermal coupling state between the cooling surface 3a and the insulating film 7. For example, insulating resins such as urethane resin, silicone resin, and epoxy resin can be used as the gap filler. The thermally conductive material 8 can efficiently conduct the thermal energy of the battery cells 2 to the insulating film 7. The insulating thermally conductive material 8 adheres closely to the cooling surface 3a of the battery block 3 where the lead plates 3C and electrodes with a potential difference are exposed, and can absorb heat generated by the battery cells 2 without shorting out the lead plates 3C or electrodes. The thermally conductive material 8 is not limited to gap fillers, but can also be heat dissipation grease or a heat dissipation sheet.

[0037] The lead plates 3C with a potential difference on the cooling surface 3a and the battery blocks 3 with no exposed electrodes can be filled with a non-insulating thermally conductive material 8 to thermally bond the cooling surface 3a of the battery block 3 to the insulating film 7, so the power supply unit 100 with this structure can use a non-insulating thermally conductive material 8.

[0038] Thermally conductive materials 8 such as gap fillers and greases can be filled with thermally conductive powder to improve their thermal conductivity. For example, insulating inorganic powders such as aluminum oxide can be used as the thermally conductive powder, improving thermal conduction efficiency while maintaining insulation. This thermally conductive material 8 is characterized by its ability to efficiently absorb and dissipate heat generated by the battery cells 2 when filled between the insulating film 7 and the battery block 3 with exposed areas that have a potential difference. Since the thermally conductive material 8 filled on the cooling surface 3a of the battery block 3 without exposed areas that have a potential difference does not require insulation, it can be filled with non-insulating thermally conductive powder, such as metal powder of copper or aluminum, to significantly improve thermal conduction efficiency. (Through-Hole Filler 9)

[0039] By filling the gap between the cooling plate 10 and the insulating film 7 with through-hole filler 9, heat generated by the battery cells 2 can be dissipated more efficiently to the cooling plate 10. Like the thermally conductive material 8, the through-hole filler 9 can be a gap filler or grease. The through-hole filler 9 can be made of the same resin as the thermally conductive material 8, but since the top surface is insulated by the insulating film 7, insulating properties are not necessarily required.

[0040] As shown in the enlarged cross-sectional view of Figure 6, the through-hole filler 9 fills the through-hole 5 of the insulating frame 4, achieving an ideal thermal coupling state between the insulating film 7 and the cooling plate 10. The through-hole filler 9 fills the through-hole 5 of the insulating frame 4 from below and adheres closely to the underside of the blocked region 7a of the insulating film 7 that blocks the upper opening of the through-hole 5. In this structure, the through-hole filler 9 filled inside the through-hole 5 adheres closely to both the insulating film 7 and the cooling plate 10, achieving a favorable thermal coupling state, and achieving ideal heat conduction from the insulating film 7 to the cooling plate 10.

[0041] The insulating frame 4 can also thermally couple the insulating film 7 and the cooling plate 10 by using an air layer inside the through holes 5 without filling the through hole filler 9 inside the through holes 5. The air layer inside the through holes 5 creates a narrow air layer inside the through holes 5 in a thermally conductive state via radiant heat radiated from the insulating film 7 to the cooling plate 10. The enlarged cross-sectional view of Figure 7 shows that the through hole filler 9 is not filled between the insulating film 7 and the cooling plate 10, and the narrow gap inside the through holes 5 is an air layer. Although the insulating film 7 facing the surface of the cooling plate 10 is thermally coupled via the narrow air layer, thermal energy is not transferred from the insulating film 7 to the cooling plate 10 via thermal conduction through the through hole filler 9. Instead, thermal energy is transferred from the insulating film 7 to the cooling plate 10 via radiant heat, transferring heat generated by the battery cells 2 to the cooling plate 10. Therefore, the gap formed between the closed area 7a of the insulating film 7 and the surface of the cooling plate 10 does not necessarily need to be filled with through-hole filler 9, and thermal energy can be transferred from the insulating film 7 to the cooling plate 10 as a narrow air layer. Furthermore, the closed area 7a of the insulating film 7 can be pressed downward by the thermally conductive material 8 filled on the top surface, causing it to protrude into the through-hole 5 and come into close contact with the surface of the cooling plate 10, thereby bringing the insulating film 7 into direct contact with and thermally coupled to the surface of the cooling plate 10. This structure does not require filling with through-hole filler 9, and the closed area 7a of the insulating film 7 comes into close contact with the surface of the cooling plate 10, allowing thermal conduction from the insulating film 7 to the cooling plate 10, allowing the thermal energy of the battery cells 2 to be dissipated by the cooling plate 10. This structure reduces the thickness of the insulating frame 4, which is formed into a plate shape, enlarges the through-holes 5, and uses a thinner, more flexible insulating film 7, thereby increasing the area in which the blocked region 7a of the insulating film 7 adheres to and is close to the surface of the cooling plate 10, thereby efficiently conducting heat from the insulating film 7 to the cooling plate 10. Furthermore, by filling the gap created when part of the blocked region 7a of the insulating film 7 adheres to and is close to the surface of the cooling plate 10 with through-hole filler 9, the area of ​​heat conduction between the insulating film 7 and the cooling plate 10 can be increased, allowing for efficient conduction of thermal energy from the insulating film 7 to the cooling plate 10. (Cooling plate 10)

[0042] The cooling plate 10 dissipates the thermal energy of the battery cells 2 to the outside. The cooling plate 10 in FIG. 4 is a metal plate with a circulation path 11 inside that circulates a cooling medium. Chilled water is preferably used as the cooling medium, but freon gas, carbon dioxide gas, etc. can also be used. The chilled water can be cooled in a water chiller and circulated to the cooling plate 10 using a circulation pump, allowing for efficient cooling of the cooling plate 10 with a simple structure. Refrigerants such as freon gas and carbon dioxide gas have the advantage of being able to cool the cooling plate 10 to low temperatures because the liquefied cooling medium cools the cooling plate 10 by vaporizing it inside the cooling plate 10. The cooling medium that vaporizes inside the cooling plate 10 is compressed by a compressor, and the pressurized gaseous cooling medium is cooled and liquefied in a condenser. The liquefied cooling medium is then circulated through the cooling plate 10 to cool the cooling plate 10.

[0043] Furthermore, although not shown, the cooling plate 10 may be an air-cooled cooling plate 10, which has multiple cooling fins arranged in parallel on its surface and dissipates thermal energy to the outside using the cooling fins. The air-cooled cooling plate 10 can be cooled efficiently by forcing air onto the cooling fins with a fan. However, the air-cooled cooling plate 10 can also be cooled by air flowing over the surface of the cooling fins without providing a fan. (Assembly of the Power Supply Unit)

[0044] The power supply unit 100 is assembled through steps (1) to (4), as illustrated in Figures 8 to 11 . (1) In the step of applying the thermally conductive material 8, as shown in Figure 8 , the battery block 3 is turned upside down and a uniform thickness of the thermally conductive material 8 is applied to the upper surface. (2) As shown in Figures 8 and 9 , the insulating frame 4, which has an insulating film 7 bonded to its surface, is turned upside down and placed on top of the battery block 3 to which the thermally conductive material 8 has been applied. (3) As shown in Figures 9 and 10 , the battery block 3, which has the insulating frame 4 on its upper surface with the thermally conductive material 8 interposed therebetween, is turned upside down and the battery block 3 is placed on top of the insulating frame 4, and the battery block 3 presses against the thermally conductive material 8. The thermally conductive material 8 is pressed by the battery block 3, filling the electrode windows 3b of the battery holders 3A and 3B and coming into close contact with the lower end surfaces of the battery cells 2. (4) As shown in Figures 10 and 11, battery blocks 3 are assembled on a cooling plate 10 that has been coated with a uniform thickness of through-hole filler 9, and an insulating frame 4 is placed on top of the cooling plate 10 with the battery blocks 3 arranged on the upper surface via thermally conductive material 8. In this state, the weight of the battery blocks 3 presses down on the insulating frame 4, and the through-hole filler 9 coated on the upper surface of the cooling plate 10 fills the through-holes 5 in the insulating frame 4.

[0045] The present invention can be effectively used in a power supply unit in which heat generated by each battery cell in a battery block made up of multiple battery cells is dissipated by a cooling plate.

[0046] DESCRIPTION OF SYMBOLS 100... Power supply unit 2... Battery cell 3... Battery block 3a... Cooling surface 3b... Electrode window 3A, 3B... Battery holder 3C... Lead plate 4... Insulating frame 5... Through hole 6... Heat dissipation laminated portion 7... Insulating film 7a... Blocked area 7b... Positioning hole 8... Thermally conductive material 9... Through hole filler 10... Cooling plate 11... Circulation path

Claims

1. A power supply unit has all of the following components (a) to (c): (a) a battery block formed by arranging the bottom surfaces of multiple battery cells in the same plane to form a cooling surface; an insulating frame positioned below the cooling surface of the battery block and having through holes opening in positions facing the bottom surfaces of the battery cells; a heat dissipation laminate positioned between the battery block and the insulating frame; and a cooling plate positioned below the insulating frame. (b) The heat dissipation laminate includes an insulating film laminated on the insulating frame; and a thermally conductive material filled between the insulating film and the battery block and in close thermal contact with the insulating film and the bottom surfaces of the battery cells. (c) The heat dissipation laminate is positioned such that the blocked area of ​​the insulating film, which blocks the upper openings of the through holes, faces the surface of the cooling plate via the through holes in the insulating frame in a thermally coupled state.

2. A power supply unit as claimed in claim 1, comprising a through-hole filler filled between the cooling plate and the insulating film, the through-hole filler being filled into the through-hole of the insulating frame, and the closed area of ​​the insulating film being arranged in a state of thermal conduction to the cooling plate via the through-hole filler.

3. A power supply unit according to claim 2, wherein the cooling plate is a liquid-cooled cooling plate having a cooling medium circulation path provided therein.

4. A power supply unit as claimed in claim 1, wherein the battery block comprises a battery holder in which each of the battery cells is arranged in a fixed position, the battery holder comprises an electrode window that exposes the lower end face of the battery cell, the electrode window is arranged in a position opposite the through hole of the insulating frame, and the thermally conductive material is filled into the electrode window and is in close thermally conductive contact with the lower end face of the battery cell.

5. A power supply unit as claimed in claim 4, wherein the battery block is provided with lead plates electrically connected to the lower end surfaces of the battery cells, and the thermally conductive material filled in the through holes of the insulating frame is in close thermal contact with the lead plates and thermally bonded to the lower end surfaces of the battery cells.

6. A power supply unit according to claim 1, wherein the insulating frame is a molded body made of plastic or elastomer.

7. A power supply unit according to claim 2, wherein either or both of the thermally conductive material and the through-hole filler are pasty cured resins in an uncured state.

8. A power supply unit according to claim 7, wherein the thermally conductive material is a gap filler made of a curable resin that is mixed with two liquids and cured.

9. A power supply unit according to claim 8, wherein the gap filler is a cured resin containing any one of urethane resin, silicone resin, and epoxy resin.

10. A power supply unit according to claim 8, wherein the gap filler is a synthetic resin containing a thermally conductive powder.

11. A power supply unit according to claim 10, wherein the thermally conductive powder is an inorganic powder.

12. A power supply unit according to any one of claims 1 to 11, wherein the insulating frame is a plate-like honeycomb structure in which the through holes are hexagonal.

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