MXPA00002488A - Battery pack and power tool - Google Patents

Abstract

A battery pack having a plurality of battery cells 1 stored side by side in a case 2. The case, in particular, includes a bottomed trough and a lid, the trough having a space as a cell storage portion defined between inner wall portions 21 and outer wall portions 22 paired to form a loop and a space as a hollow 6 surrounded by the inner wall portion and penetrating the trough from top to bottom, the lid closing a top opening of the cell storage portion. The battery cells are arranged in a loop along the inner and outer wall portions, whereby a rise and variation in their temperature can be restrained.

Description

BATTERY PACK AND ENERGIZED TOOL BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The present invention relates to a battery pack that includes a plurality of battery cells stored in a box, and more specifically, to a battery pack capable of restricting an elevation and variation in the temperature of the battery cells, ensuring with this the uniform charge and the reliable performance of the cell.

DESCRIPTION OF THE PREVIOUS TECHNIQUE The nickel-metal hydride secondary battery cells are used as power sources for modern electric vehicles, energized bicycles, energized tools, etc. Conventionally, cells of this type are provided in the form of a battery pack wherein a plurality of battery cells which are connected in series or in parallel with each other, are stored in a box which is formed of ABS resin or of polycarbonate, for example. In order to enjoy a compact overall configuration, the conventional battery pack is designed so that the battery cells are stored in very close contact with each other in the P1173 / 0OMX box, which improves the efficiency of its capacity. In the case of columnar cells, twelve battery cells 1 are arranged alternately in three rows with their respective peripheral surfaces in reciprocal contact to minimize the storage capacity for them, and are stored in a rectangular box 2, as is shown in Figure 19, for example. In the battery pack of this conventional construction, variation in temperature is easily caused between the battery cells 1 which are arranged along the wall surface of the box 2 and those which are located in the central portion. Although the heat generated in the cells 1 which are arranged along the wall surface of the box can be easily released through the wall surface, the heat produced in the central cells is prone to accumulate therein. The variation in the temperature of the cells causes dispersion of the properties (capacities, in particular) of the individual battery cells 1. If the battery pack is used with the battery cells 1 subject to the dispersion of properties, the respective capacities of the cells 1 are gradually dissipated, the smaller ones first. The dissipated battery cells 1 may suffer some P1173 / 00MX problems, for example: pole inversion, increase in internal resistance that can be attributed to the dissipation of the electrolytic solution, etc. The dissipation of the electrolytic solution is attributed solely to the discharge of gas from a relief valve that occurs as the internal pressure of the battery cells 1 increases. As a result, problems may occur, including decreased cell properties, failure to recharge, etc. In this way, the battery pack decreases in performance, and its life is shortened. In the case where the battery cells 1 are nickel-metal hydride secondary battery cells, these generate a great heat while being charged. The battery cells 1 generate, in particular, intense heat when they are charged with a high current in a short period of time. In addition, the charging efficiency and cell capacity of the nickel-metal hydride secondary battery cells decreases as the cell temperature increases. As the cell temperature increases, a hydrogen-trapping alloy that forms a negative electrode easily corrodes in the electrolyte solution, so that its occlusion / hydrogen release capacity decreases. It is essential, therefore, to avoid the increase in P1173 / 00MX temperature of battery cells 1 (nickel-metal hydride secondary battery cells) in box 2, especially when cells are charged. Since energized tools are roughly handled in general, it is expected that the battery pack used as their energy source will be structurally resistant to external impacts, for example to the impact of falling.

SUMMARY OF THE INVENTION An object of the present invention is to provide a battery pack capable of preventing or restricting an elevation and a variation in the temperature of the battery cells stored in a box, thus fulfilling its cell performance. Another object of the invention is to provide a battery pack capable of being safely loaded in such a way that a rise in the temperature of the cells is effectively restricted during charging. Still another object of the invention is to provide an energized tool that is capable of effectively cooling a battery case. According to the present invention, there is provided a battery pack having a plurality of battery cells stored side by side in the box, the box includes a trough bottom and a lid, the trough has a space as a portion P1173 / 00MX cell storage defined between the inner and outer wall portions paired to form a circuit and a central space such as a recess enclosed by the inner wall portion and penetrating the trough from the top to the bottom, the lid closes an upper opening of the cell storage portion. The heat generated in the battery cells is released through the gap from the inner wall portion of the tundish as well as from the outer wall portion. In this way, the elevation and temperature variation of the battery cells can be restricted. Preferably, the tundish is designed so that the pillar-shaped battery cells stored in the cell storage portion are arranged side by side in a circuit with their respective outer peripheral surfaces in reciprocal contact, such that the heat in the battery cells it can be released through the inner and outer wall portions. The generation of heat during charging can be effectively restricted even in the case where a secondary nickel-metal hydride battery cell is used as each battery cell. The battery pack according to the invention can also comprise a terminal block P1173 / 00MX which overlies the battery cells stored in the cell storage portion of the tundish and which has electrode leads from the group of battery cells conducted outside thereof, and may be designed so that the cover has openings in the cells. those regions thereof which are oriented towards the electrode conductors, through which the electrode conductors are exposed for external connection. Preferably, the electrode leads of the terminal block are arranged in a region opposite the gap. The openings through which the electrode conductors are exposed for external connection are arranged along the inner peripheral portion of the cap opposite the recess. In particular, the terminal block is provided with a pair of terminals of electrode leads, positive and negative, individually connected to the conductive electrodes of the group of cells and a terminal or a plurality of auxiliary terminals for the group of cells. Auxiliary terminals are used when the group of cells is loaded. More specifically, these include a charging terminal connected in series with the group of cells through elements for temperature protection to cut a load path to the group of P1173 / 00 X cells, in response to the temperature of the cells, a terminal for temperature detection connected to a temperature transducer to detect the temperature of the cells, and a terminal for the identification of the cell type, which is connected to a resistor that has a resistance value corresponding to the specifications of the cells. The elements for temperature protection are provided individually at a plurality of points in the array direction of the battery cells stored in a circuit in the cell storage portion of the tundish. These are interposed in series between the group of cells and the loading terminal. The inner wall portion of the tundish is tilted outward from the base portion thereof to the upper opening, whereby the sectional area of the upper opening of the recess encircled by the inner wall portion is gradually reduced. By reducing the sectional area in this way, a current of air circulating in the gap can be dispersed on the upper end side, whereby the cooling efficiency can be increased. In this case, the inner wall portion must be inclined at an angle of 0.5 ° to 5 ° towards the vertical direction. In addition, the interior and exterior wall portions of the trough P1173 / 00MX should only be as high as the cylindrical battery cells. The battery pack constructed in this way can be integrally connected to, for example, the lower portion of a handle or handle portion of an energized tool to be used as a power source thereof. It is desired that the cooling efficiency for the group of cells should be increased by the circulation of air in the hollow of the battery pack, using the rotation of a motor. In accordance with the present invention, a battery pack can be provided which can store a plurality of battery cells with structural stability and which can restrict a rise and a variation of the temperature of the battery cells, thus realizing their cell performance. In addition, the charging state of the battery cells, especially the cell temperature, which can be observed as the charge of the battery cells is controlled safely. Since the battery cells can remain stable, the resulting battery pack has a structure that is highly resistant to external impact and the like, and the energized tool is easy to handle.

P1173 / 00 X BRIEF DESCRIPTION OF THE DRAWINGS OR FIGURES Figure 1 is a cut-away perspective view showing a fundamental configuration of a battery pack, in accordance with the present invention. Figure 2 is a plan view showing the manner in which the battery cells of the battery pack shown in Figure 1 are stored in a trough. Figure 3 is a plan view showing the manner in which the battery cells of another example of the battery pack of the invention are stored in a trough. Figure 4 is a plan view showing the manner in which the battery cells of yet another example of the battery pack of the invention are stored in a tundish. Figure 5 is a plan view showing the manner in which the battery cells of a further example of the battery pack of the invention are stored in a trough. Figure 6 is an exploded perspective view showing another configuration of the battery pack of the invention. Figure 7 is an exploded perspective view showing yet another configuration of the battery pack of the invention. Figure 8 is a perspective view in P1173 / 00 X Exploded showing an additional configuration of the battery pack of the invention. Figure 9 is an exploded perspective view showing a sketch of a battery pack according to a first embodiment of the invention. Figure 10 is a plan view of the battery pack shown in Figure 9. Figure 11 is a side view of the battery pack shown in Figure 9. Figure 12 is a sectional view of the battery pack taken along of line AA of Figure 10. Figure 13 is a sectional view of the battery pack taken along the line BB of Figure 10. Figure 14 is a diagram showing the electrical connection of the battery pack shown in FIG. Figure 9. Figure 15 is an exploded perspective view showing a sketch of a battery pack, in accordance with a second embodiment of the invention. Figure 16 is an exploded perspective view showing a sketch of a battery pack, in accordance with a third embodiment of the invention. Figure 17 is a view showing another P1173 / 00MX configuration of the battery pack of the invention. Figure 18 is a view showing yet another configuration of the battery pack of the invention; and Figure 19 is a plan view showing the manner in which the battery cells of a conventional battery pack are stored in a box.

DETAILED DESCRIPTION OF THE INVENTION A fundamental configuration of a battery pack, in accordance with the present invention, will be described first with reference to Figures 1 and 2. Figure 1 is a cut-away perspective view showing an arrangement of a battery pack, in accordance with the present invention. Figure 2 is a plan view illustrating the manner in which a plurality of battery cells 1 are stored in a box 2. The box 2 is formed by a trough bottom in the form of a substantially rectangular circuit. The box 2 has opposite inner and outer wall portions 21 and 22 and a base portion 23 connecting the respective lower end portions of the wall portions 21 and 22. The height of each wall portion of the box 2 is practically equal or a little higher than the height (axial length) of eachP1173 / 00MX cell 1 of columnar battery. The width of the base portion 23 of the box 2 is practically equal to the outer diameter of each battery cell 1. The interior space of the trough-shaped bottom forms a space for cell storage where a plurality of battery cells 1 (eg, 12 cells) are arranged in such a circuit line that their respective peripheral surfaces are in contact with each other. yes. A central space that is surrounded by the interior wall portion 21 of the tundish (box 2) forms a recess 6 that penetrates the tundish vertically. The battery cells 1, where the electrodes are provided with wires in a regular manner, are stored in the tundish (box 2). In this state, the peripheral surface of each battery cell 1 is in contact with the inner or outer wall portion 21 or 22, or preferably, with both wall portions 21 and 22. More specifically, each of these battery cells 1, are individually placed in the four corners of the box (tundish) 2 in the rectangular circuit that is in contact (in two points) with each of the two corresponding adjacent sides of the outer wall portion 22, according to is shown in Figure 2. Each of the remaining battery cells 1 that are located between the corner battery cells 1 is in contact (at two points) P1173 / 00MX with the inner and outer wall portions 21 and 22. A top opening of the box 2 which is stored with the battery cells 1 or with the upper portion of the cell storage space is closed by means of a cover 4 which has practically the same shape as the upper opening. The battery cells 1 are sealed between the box 2 and the cover 4, whereby a sealed battery pack is formed. The electrode conductors of the battery pack are led out through the cover 4, for example. In accordance with the battery pack, wherein the battery cells 1 are arranged in a line in the box 2, the cells 1 are in contact with both the inner and outer wall portions 21 and 22. If the battery cells 1 are heating during use (loading and unloading), the heat in each cell 1 can be released smoothly through the inner and outer wall portions 21 and 22. Consequently, the heat released from the battery cells 1 virtually advances same, so that the variation in the temperature of the cell can be restricted. As the heat in each cell 1 is released through the inner and outer wall portions 21 and 22, the heat that releases efficiency is sufficiently high and, an elevation in the cell temperature can be restricted in P1173 / 00MX effective. In this way, in accordance with the battery pack of the invention, the battery cells 1 can be practically equal in the charging efficiency and therefore, in the cell capacity, so that the life performance of the battery pack Battery can be improved. In accordance with the present invention, moreover, the sealed battery pack ensures a dustproof effect. Even in the case where the battery pack is used as a power source for an energized tool, therefore, metal cuts can not enter the battery pack in the work scene, so that the Short circuit production between battery cells 1, safely. In addition, some other components can be incorporated into the battery pack using the gap 6. Since the battery cells 1 in the battery pack generate substantial heat while being charged, it is mandatory to introduce air into the gap 6 to cool the air of the inner wall portion 21 during loading. Preferably, in this case, the inner wall portion 21 must be formed of a metallic material having a high heat transfer coefficient. Even in the case where the inner wall portion 21 is formed of a resin material, its heat release effect P1173 / 00MX can be further improved if its surface is coated with a high transfer paint. In the example described above, the box 2 has an almost rectangular external appearance. Alternatively, however, the battery pack may be constructed such that a plurality of cells 1 are stored in an annular box 2, as shown in Figure 3. In this case also, a space in the form of a circumscribed trough. by inner and outer wall portions 21 and 22 of the box 2 form an annular cell storage space, and a central space encircled by the inner wall portion 21 forms a void 6. The battery cells 1 are arranged in a line , so that they are in contact with the inner and outer wall portions 21 and 22. The battery pack must be constructed in a similar manner in the case where the box 2 is elliptical. As shown in Figure 4, further, an annular box 2 may be designed such that a plurality of battery cells 1 are arranged in a line along an interior wall portion 21 of the box 2 and cells 1 of additional batteries are arranged in another line along an outer wall portion 22 of the box 2 to the outside of the inner cells. In this form, it is only necessary that a plurality of battery cells 1 arranged in two annular lines never leave P1173 / 00 X of being in contact with the inner wall portion 0 outside 21 or 22. Considering the fact that the inner wall portion 21 touches the outer space in a smaller area than the outer wall portion 22, the surface of the inner wall portion 21 may be corrugated so that it can being extensively in contact with the respective peripheral portions of a plurality of battery cells 1 that are arranged in a circuit, as shown in Figure 5, for example. By doing this, the heat release effect of the inner wall portion 21 can be improved. The heat release effect can be freely adjusted by designing adequately the contact area between the inner wall portion 21 and the peripheral portion of each battery cell 1. The contact area between the outer wall portion 22 and the peripheral portion of each battery cell 1 can also be adjusted by shaping the surface of the inner wall portion 21. In the example described above, in addition, the height of the box 2 (tundish) is practically equal to that of each battery cell 1. As shown in Figure 6, however, box 2 may be half as high as it is each battery cell 1, and a battery pack may be constructed using a lid (trough) 4 having the same shape of the box 2. After the P1173 / 00MX battery cells 1 are stored in a trough (box 2), in this case, the two troughs (box 2 and cover 4) meet against each other and are joined together to cover the cells 1. In the case wherein it is expected that a base plate 7 be attached to the underside of the battery pack, an opening (not shown) having the same shape as the recess 6 may be formed in the central portion of the base plate 7. As shown in FIG. Figure 7, however, a plurality of holes 7a can be formed along the interior of an inner wall portion 21 of a box 2. It is further understood that a plurality of battery packs can be stacked in layers (two layers in Figure 8) to form a battery pack unit, as shown in Figure 8. In order to conform the effect of the battery pack constructed in this way, the inventors of the same made an annular battery pack A shown in Figure 5 to test track, using cells secondary nickel-metallic hydride battery batteries of size 4 / 5A (nominal capacity: 1,700 Ah) having a diameter of 17mm and a height of 43mm as the battery cells 1. The polycarbonate resin was used for an annular box (trough) 2 that constitutes the battery pack 1.

The outer diameter of the box 2 was 00 mm, the diameter of a hole 6 was 42 mm, and the thicknesses P1173 / 00MX of the outer and inner wall portions 22 and 21 were 3 mm. The battery cells 1 were arranged in a line so that they were in contact with the inner wall portion 21. For comparison, a battery pack B of a conventional construction shown in Figure 19 was manufactured to test track, using twelve battery cells 1 of the same type. This battery pack B includes a box-shaped case, made of polycarbonate resin, having a wall portion thickness of 3 mm, a length of 52.4 mm and a width of 82.5 mm. These battery packs A and B were charged rapidly with a constant current of 4.5 A, at an initial temperature (room temperature) of 27 ° C for 20 minutes, and then charged in a complementary manner with a constant current of 0.8 A, 15 minutes. Then, the temperature of each battery cell 1 reached upon completion of the fast charge and the complementary charge were measured. Whereupon, the temperature of each battery cell 1 in the battery pack A reached upon completion of the fast charge increased from the initial temperature by approximately 16 ° C, i.e. to a practically fixed temperature of about 44 ° C . The temperature of each cell 1 reached at P1173 / 00 X completion of the complementary charge was a practically fixed temperature of 46 ° C. In contrast to this, the temperature of each battery cell 1 in the battery pack B of the conventional construction reached, upon completion of the fast charge increased from the initial temperature within the range of 16 to 22 ° C, thus suffering a variation of 43 to 49 ° C. The temperature of each battery cell 1 reached at the completion of the complementary charge was also subject to a variation of 48 to 52 ° C. On the other hand, battery packs A and B, charged in the aforementioned manner, were rapidly discharged by continuous pulse discharge of 10 A for 30 seconds at a time with rest periods of 30 seconds, and the temperature of each cell 1 of battery reached upon completion of the rapid discharge was measured. Whereupon, the temperature of each battery cell 1 in the battery pack A reached upon completion of the rapid discharge was a practically fixed temperature of 48 ° C, while the temperature of each cell 1 of battery in package B of battery reached at the completion of the rapid discharge was subject to a substantial variation of 45 to 51 ° C. In addition, battery packs A and B were charged with a constant current of 1.7 A, and the P1173 / O0 X charge termination was detected by low control -? V. Thereafter, the life performance of the cell was examined by means of a life test of the cycle in which the forced discharge to 12A was carried out in a cycle such that the termination voltage was 9.6 V (0.8 V). for each battery cell). In the? V control, the termination of the load was confirmed when a voltage drop of 120 V (10 mV for each battery cell) from the peak of the charging voltage of the battery pack A and B was detected, then that the peak voltage was reached. In accordance with this cycle life test, the performance of the cell of the battery pack A was ensured in 500 cycles and less, while the cell performance of the battery pack B decreased by 350 cycles. In accordance with the battery pack of the construction of the invention and as seen from these experimental results, the temperature rise of the battery cells 1 could be restricted to a level below the initial temperature, and the variation in the temperature of the cell could be effectively restricted. In accordance with this battery pack, in addition, the charging efficiency of the battery cells 1 was sufficiently high, and the temperature of the cells 1 was not subject to any variation. In this way, the properties of each battery cell 1 (cell performance) can be obtained in P1173 / 00MX safe way to ensure superior life performance. The following is a description of a specific embodiment of the battery pack according to the present invention. In this battery pack, twelve secondary nickel-metal hydride battery cells, columnar (battery cells 1) are connected in series with each other and stored in a box 2. Figure 9 is a perspective and exploded view showing a sketch of the battery pack in accordance with this modality. In Figure 9, the numbers 1 and 2 denote, respectively, the twelve columnar nickel-metal hydride secondary battery cells for use as battery cells in the case where the cells 1 are arranged side by side. The number 3 denotes a terminal block which is superimposed on the cells 1, and 4 denotes a cover for closing the upper opening of the box 2. Figure 10 is a plan view showing the upper structure of the battery pack shown in FIG. Figure 9, and Figure 11 is a side view of the battery pack. Figure 12 is a sectional view taken along line AA of Figure 10, and Figure 13 is a sectional view taken along line BB of Figure 10. Box 2 is formed by molding by P1173 / 00MX injection of ABS resin or polycarbonate, for example. The box 2 includes inner and outer wall portions 21 and 22 which are formed by connecting the respective opposite end portions of a pair of parallel portions by means of curved portions, thereby making an oval circuit. The wall portions 21 and 22 are connected to each other by means of a base portion 23, which thus forms a trough-like bottom having a cell storage space in the form of a passageway. The inner portion of the trough forming the storage space in the form of a passage, that is, the central portion of the box 2 that is surrounded by the interior wall portion 21, forms a recess 6 that penetrates the trough from the upper part. to the bottom. The height of the inner and outer wall portions 21 and 22 defining the cell storage space or the depth of the trough forming the storage space is a little greater than the height (length) of each columnar battery cell 1 . The width of the base portion 23 is slightly larger than the diameter of each battery cell 1. The respective upper end portions of the wall portions 21 and 22 are inclined outwardly at an angle of about 0.5 ° to 5 ° so that the wall portions can be easily released from the molds P1173 / 00 X by injection molding. As the inner wall portion 21 is inclined in this manner, further the sectional area of the recess 6, which is surrounded by the inner wall portion 21, is gradually reduced upwards. Each columnar battery cell 1, which is of size 4 / 5A, has a diameter of 17 mm and a height of 43 mm, for example. Twelve battery cells 1 are stored side by side in a circuit in the trough-like, cell-storage space of the box 2 so that their respective peripheral surfaces are in contact with each other. More specifically, five battery cells 1 are arranged side by side in the longitudinal direction in each of the two rows, and a battery cell 1 is located in each end portion between the two rows in such a way that it is of some type. way, eccentric out. Thus, the battery cells 1, twelve in total, are arranged in an oval circuit. A notch 24 for a retainer 5 (mentioned below) is formed on each of the longitudinal sides of the outer wall portion 22. Within the trough-like cell storage space, four screw lugs 25 are arranged along the outer wall portion. 22. The projections 25 are formed using spaces adjacent to the columnar battery cells 1 that are stored in the space of P1173 / 00MX storage with their respective peripheral surfaces in reciprocal contact The projections 25 are positioned so as not to hinder the storage of the battery cells 1. The projections 25 considerably limit the respective storage positions of the cells 1, thus preventing the cells 1 from becoming unstable. A flange 26 is provided on the upper end portion of the inner wall portion 21 to extend outwardly from the trough-like cell storage space. In other words, the flange 26 projects towards the recess that is formed in the central portion of the box 2. The flange 26 serves to support the terminal block 3 on its upper portion and to support the central portion of the cap 4 from below being embedded in it, as mentioned below. On the other hand, the battery cells 1 that are stored in the storage space of trough-shaped cells of the box 2 are arranged in a circuit along the storage space, as mentioned above. The battery cells 1 are connected in series by means of conductors (not shown). The upper end portion of the circuit row of the battery cells 1 is covered by a cover member 11 which is formed of an insulating material, for example, whereby the row configuration is P1173 / 00MX keeps stable. The terminal block 3 which is superimposed on the bank cell row is a block practically U-shaped, of an insulating material. A pair of positive and negative electrode conductor terminals 31 and 32 are provided individually on the opposite side portions of the terminal block 3 in the longitudinal direction of the row of battery cells which are arranged in a circuit. In addition, three auxiliary terminals 33, 34 and 35 are provided in a curved lateral portion that extends in the transverse direction and connects the opposite side portions. The electrode leads of a battery set which is composed of a plurality of battery cells 1 connected in series, are connected to the positive and negative terminals 31 and 32 of the electrode conductor individually. The three auxiliary terminals 33, 34 and 35, which are used to charge the battery cells 1, are individually connected to the electrode conductors of the battery set through resistors incorporated in the terminal block 3 and thermistors and thermostats on the surfaces respective peripherals of the battery cells 1 in circuit. The respective functions of the auxiliary terminals 33, 34 and 35 will be described below with reference to Figure 14. P1173 / 00MX The lid 14 closing the upper opening of the box 2 is located covering the row of battery cells in the box 2 and the terminal block 3 that overlaps it. The cover 4 includes a portion 41 of substantially flat body, adapted to fit over the respective upper end portions of the inner and outer wall portions 21 and 22 of the box 2, and projections 42 formed by partially elevating that region of the body portion 41 which faces the terminal block 3. A storage space for the terminal block 3 is formed on the rear side of the projection 42. A side wall portion of the projection 42 is provided with five rectangular openings 43 ( 43a, 43b, 43c, 43d and 43e) through which the electrode conductor terminals 31 and 32 and the three auxiliary terminals 33, 34 and 35 are exposed for external connection. Adjacent to the projection 42, an opening 44 for communication with the hollow of the box 2 is formed in the central portion of the body portion 41. In addition, the sloping walls 45 are formed individually on two longitudinal side portions of the body portion. 41. The walls 45, in cooperation with the recesses 24 in the outer wall portion 22 of the box 2, define substantially rectangular openings for the seals 5.

P1173 / 00 More specifically, the sloping walls 45 are individually accommodated in the respective upper portions of the recesses 24, thereby forming the apertures, when the cover 4 is placed on the upper opening of the box 2. The screws 49 they are used to fix the lid 4 to the box 2 which stores the battery cells 1. The screws 49 are passed individually through the holes 47 in the body portion 41 from above the lid 4 and are accommodated Individually in the respective upper portions of their respective projections 25. If necessary, the packing members (not shown) are interposed between the lid 4 and the respective upper end portions of the inner and outer wall portions. 21 and 22 of box 2, whereby the cell storage space is hermetically closed. The following is a description of the detents 5 that are accommodated in the openings defined between the network structure of the notches 24 and the sloping walls 45. Each retainer 5 is composed of a pushing portion 51 in the form of a substantially rectangular projection , and an arm portion 52 extending from a side portion of the push portion 51. The brazi portion > 52 has a hook 53 at its distal end. As the picture shows P1173 / 00MX 13, each detent 5 is fitted in its corresponding opening from the rear side so that its hook 53 projects from each corresponding hook hole 46, in the cover 4. The retainer 5 is supported in such a way that it is pushed outwardly from the box 2 by means of a plate spring 55 on the back side. When the retainer 5 is pushed by a finger or the like, it is pressed inward to cause the hook 53 to be immersed in the hook hole 46. Each hook 53 can couple its corresponding coupling projection in an enclosure 70 of the energized tool to which the battery pack is to be attached, thereby ensuring the connection of the battery pack to the tool. In this way, the upper part of the cover 4 of the battery pack serves as a mounting portion that is to be attached to the lower part of the enclosure 70 of the energized tool. The battery pack can be attached with a single movement to the energized tool in such a way that each hook 53 in engagement with the coupling projection is elastically pressed inwardly. By separating the battery pack, each thrust portion 51 is pushed to force the hook 53 inward. After this, the hook 52 is uncoupled from its corresponding coupling projection in the enclosure 70 of the energized tool, so P1173 / 00MX that the battery pack can be removed down from the enclosure 70. On the other hand, the thermistors, resistors and thermostats in the terminal block 3 serve to ensure the safety of the battery pack during charging. Figure 14 shows an electrical configuration of the battery pack. As shown in Figure 14, the battery cells 1 are connected in series center yes, and the positive and negative conductor electrodes at the opposite ends are connected to the electrode conductor terminals 31 and 32, respectively. The battery pack is connected to a conductor, for example to an electric motor of the energized tool, through the positive and negative electrode terminals 31 and 32. A thermistor 81 in the box 2 is a temperature transducer which is used to determine the surface temperature of the battery cells 1. The thermistor 81 is interposed between the auxiliary terminal (Th) 33 and the terminal 32 of the electrode conductor. While the battery pack is being charged, the resistance value of the thermistor 81 is monitored to observe the temperature of the battery cells 1. The thermistor 81 is stuck on the peripheral surface of the predetermined cell of the battery cells 1. A resistor 82, which is interposed between P1173 / 00 X the auxiliary terminal (ID) 34 and the terminal 32 of the electrode conductor, has a resistance value corresponding to the specifications of the battery pack. By determining the resistance value of the resistor 82, the number of battery cells 1 connected in series, their current capacity, etc., can be obtained as ID information. Overload and the like can be avoided by controlling the charge of the battery pack, according to the ID information. Thus, despite the uniform external appearance, the battery pack may sometimes vary in its internal configuration, including the number of battery cells 1 therein. The battery pack is charged in optimal conditions on electrical specifications that are obtained from the ID information. In addition, the auxiliary terminal 35, which can be used in place of the electrode conductor terminal 32 during charging of the battery pack, is charged in such a way that the charging current is supplied between the electrode conductor terminal 31 and the auxiliary terminal 35 The temperature protection elements or two thermostats 83 and 84 are interposed in series between the auxiliary terminal 35 and the negative side (terminal 32 of the electrode conductor) of the battery cells 1. The thermostats 83 and 84 allow the battery pack to cut its own charging path in P1173 / 00MX response to the cell temperature. The thermostats 83 and 84 are individually glued on the respective peripheral surfaces of those battery cells 1 which constitute the two curved side portions, in the arrangement direction of the battery cells 1 in circuit. The thermostats 83 and 84 are driven to cut the charging path if the temperature of any of the circuit battery cells 1 rises. A charger which is connected to the terminal block 3 and which serves to charge the battery pack observes the charging status of the battery cells 1 (battery pack) through the auxiliary terminals 33, 34 and 35 while controlling the current of the battery. loaded, loading time, etc. In this way, the charger can efficiently charge the battery pack with stability. In case the temperature of the cell increases despite the charge control for the battery pack, the thermostats 83 and 84 can protect the battery cells 1 (battery pack) by cutting the charging path of the battery pack. In this way, according to the battery pack constructed in this way, the battery cells 1 are arranged side by side in a circuit between the inner and outer wall portions 21 and 22 of the battery cell 1 in the form of a corridor in circuit, so that the heat produced in each P1173 / 00MX battery cell 1 can be efficiently discharged through the wall portions 21 and 22. As the exterior of the inner wall portion 21 in the central portion of the box 2 forms a hole that penetrates into shape vertical the box 2, in addition the heat coming from the battery cells 1 can be discharged very efficiently through the hole. Since the sectional area of the gap is gradually reduced towards the upper end, in particular, the speed of movement of the air that is introduced through the bottom of the hollow and ascending is higher on the upper end side, so that the Cooling efficiency can be improved. Since the battery cells 1 are arranged in a circuit, the effect of releasing the heat for the battery cell 1, compared to the battery cells of a conventional array configuration, can practically equalize. Consequently, the temperature increase of the battery cells 1 can be effectively avoided in order to restrict the variation in the temperature of the cell. In this way, the performance of each cell 1 of the battery can be performed to improve the performance of the cell for the battery pack. In addition, the terminal block 3 overlies the battery cells 1 that are stored in a circuit in the box 2, and the electrode conductors P1173 / 00MX can match in length. Each electrode conductor can be shortened while the terminal block 3 is located on each end portion of a battery set including battery cells 1 connected in series. In this way, a loss in resistance that is caused by the electrode leads can be minimized. If the electrode conductors are arranged along an inner wall portion 21, these can be effectively protected against external impact or the like, which acts on the box 2, so that the structural or mechanical stability of the battery pack can be fully augmented As mentioned before, the battery pack is provided with the auxiliary terminals 33, 34 and 35 which are connected to each other through the thermostats 83 and 84 as well as the thermistor 81 and the resistor 82. Accordingly, the specifications of the Battery pack can be identified according to the auxiliary terminals 33, 34 and 35 and the temperature of the cell can be observed while the charge of the battery pack is controlled. In this way, the battery pack can be safely charged without including an increase in battery temperature. If the charge control is delayed when the cell temperature increases, any of the thermostats 83 and 84 that are P1173 / 00MX located along the battery cells 1 circuit can cut the load path in response to the temperature of the cell. Thus, double security measures can be taken for the cargo. The battery pack with the aforementioned construction is designed so that the cover 44 can be attached to the enclosure 70 of the energized tool or the like, and the enclosure 2 is mounted in the enclosure 70 with the cover 4 therebetween. Therefore, the cover 4 can not be removed from the box 2 unless the battery pack is uncoupled from the enclosure 70. In this way, there is no possibility that the cover 4 will slide unexpectedly during the operation of the energized tool . In addition, the projection 42 of the lid 4, which projects to form the storage space for the terminal block 3 on the rear side, is attached to the enclosure 70 to be covered by it. In this operating state, therefore, the battery pack has an external appearance that is free of any projection. If the outer peripheral surface of the box 2 or the corner portions of the outer wall portion 22 and the boundaries between the outer wall portion 22 and the base portion 23, in particular, are curved, the battery pack can enjoy a smooth overall shape regardless of the presence of the projection 42 on the cover 4. In this form, the manageability of the battery pack P1173 / 00MX can be improved. The projection 42 need not be very high, only if it can house the terminal block 3 on its rear side and allow the electrode conductor terminals 31 and 32 and the auxiliary terminals 33, 34 and 35 to be exposed for external connection through its side wall surface. Consequently, the height of the projection 442 of the lid 4 can be easily restricted, so that the overall structure can be made compact. In addition, the resulting structure can be highly resistant to external impact. The energized tool made with the battery pack constructed in this way can be designed so that an integrated fan is driven to cause air to flow into its motor through the housing recess using the rotating force of the motor. According to this arrangement, the motor of the energized tool can be cooled in such a way that the battery pack itself is cooled by the air stream. In this way, the cooling effect can be improved. Since box 2 itself has a round external conformation as a whole, its corner portions can not catch clothes or the like easily, during operation using the energized tool. Since box 2 has no angled portions, it can enjoy P1173 / 00 X a solid structure that is subject only to a lower concentration of local pressure if it falls. If the inner and outer wall portions 21 and 22 of the box 2 are flared so that the box 2 widens towards its upper opening, as shown in Figures 12 and 13, for example, the box 2 can be easily released from the box 2. the molds during the injection molding operation. The required angle of inclination varies from approximately 0.5 ° to 5 °. The flared structure facilitates the storage of the battery cells 1 if the depth of the trough is equal to the height of each battery cell 1. Since the respective positions of the battery cells 1 in the tundish are regulated by means of projections 25 or the like, it can be effectively avoided that the cells 1 become unstable. In this way, the storage of the battery cells 1 can remain stable despite the use of the simple structure, and the resulting battery pack enjoys good strength. As shown in Figure 15, the electrodes of a battery pack can be directed into a gap 6. More specifically, a pair of electrode lead terminals 31 and 32, positive and negative, are provided inside the the opposite side portions of a terminal block 3 in the form of a shaped block P1173 / 00MX practically in U, and three auxiliary terminals 33, 34 and 35 are provided in a curved inner portion extending in the transverse direction and connecting the opposite side portions. The electrode conductor terminals 31 and 32 and the auxiliary terminals 33, 34 and 35 are exposed to the gap 6 through their corresponding openings 43 (43a, 43b, 43c, 43d and 43e) which are arranged along the portion inner periphery or the opening edge portion of a lid 44. With this construction wherein the electrode conductor terminals 31 and 32 and the three auxiliary terminals 33, 34 and 35 are directed inwardly or towards the gap 6 , the external impact, if any, on a projection 442 of the cover 44, never exerts direct influence on the terminals 31 to 35. In this way, the terminals 31 to 35 can be effectively protected. In addition, the terminals 31 to 35 are oriented towards the inside of the box 2. If a metal tool or the like touches the battery pack, the new one is directly in contact with any of the terminals 31 to 35. In other words, no External material (tool or the like) can touch any of terminals 31 to 35 unless the tool or the like is intentionally inserted into the gap 6. In this way, terminals 31 to 35 can be protected P1173 / 00MX effectively and prevents them from suffering an unexpected short circuit between them. As shown in Figure 16, a box 2 can be formed having a substantially rectangular shape. As shown in Figure 16, the top surface of a lid 4 can be flattened so that a terminal block 3 can be located above it in a row of battery cells. In this case, it is advisable to form a step portion 26a on a flange 26 projecting from the upper end portion of an inner wall portion 21 into a recess 6 and utilizing a step portion 26a to support the terminal block 3 in a lowered position from its upper surface. Alternatively, a plurality of battery packs each include a plurality of battery cells 1 arranged in a circuit in a trough-like cell storage space defined between the inner and outer wall portions 21 and 22, they can be stored side by side in box 2 to form a large-scale battery pack (large capacity). In this box, the outer wall portion 22, which forms an outer wall of the box 2, is provided with a partition wall 27 for dividing the internal space of the box 2, as shown in Figure 17, for example. In addition, the wall portion P1173 / 00MX interior 21, which is combined with the outer wall portion 22 and the partition wall 27, is located in each of the spaces that are divided by the wall 27. The loop spaces defined by the outer wall portion 22, the partition wall 27 and the interior wall portions 21 are used as trough-like cell storage spaces, while the central spaces enclosed by the interior wall portions 21 serve as recesses 6a that are open from the part top to bottom In this way, two cell storage spaces in circuit or in the form of a trough are formed side by side in the box 2. Ten cells 1 of battery are stored in a circuit in each of the cell storage spaces with their respective peripheral surfaces in contact with each other. Preferably, in this box, the contact area must be increased in such a way that the battery cells 1 are in contact with the inner wall portions 21, the outer wall portion 22, or the partition wall 27 and that the The curvature of each corner of the outer wall portion 22 is equal to that of the battery cell 1. As shown in Figure 18, the respective inner surfaces of the portions of the inner wall 21 should preferably be non-corrugated so that they can be P1173 / 00 X be widely in plane contact with the respective outer peripheral surfaces of the battery cells 1. Preferably, the partition wall 27 must be designed so that the two partition wall plates 27a, for example, are arranged with a specific space 27b therebetween, so that the transfer of heat between the battery cells 1 can be prevented. they adjoin each other through the partition wall 27. With this arrangement, even those battery cells 1 which are arranged in the central portion of the box 2 at a distance from the outer wall portion 22 never cease to be in contact with one of the two inner wall portions 21, and the heat can be released through the openings 6a which are surrounded by the inner wall portions 21. In this way, the elevation of the temperature of the cells can be effectively limited 1. Even in the case where a large number of battery cells 1 are stored in box 2, this arrangement can effectively restrict the temperature rise of cells 1 without increasing the outer dimensions of the box 2. Since the partition wall 27 supports the outer wall portion 22 from the inside, it also serves to increase the mechanical strength of the box 2. In the examples shown in Figures 17 and 18 , the internal space of box 2 is divided into P1173 / 0OMX two. Alternatively, however, the internal space of the box 2 can be divided into four by means of two separation walls 27 that cross each other. In this case, the inner wall portion 21 is formed to define a circuit cell storage space for each divisional space. In addition, a plurality of boxes 2 of this construction can be stacked vertically in layers with their respective recesses 6 in alignment so that a battery pack with a larger capacity can be obtained. The battery pack of this capacity can be used as a backup power source for various electronic devices. The present invention is not limited to the modalities described in the foregoing. For example, the type and number of battery cells 1 that are to be stored in box 2 should be set only depending on the necessary specifications of the battery pack. It will be understood that, a battery pack with an increased current capacity can be obtained by appropriately connecting a plurality of battery cells 1 in parallel with each other. In addition, more temperature protection elements (thermostats) can be arranged along battery cells 1 in circuit. The number of circuits formed P1173 / 00MX in the box is also not limited in particular. In addition, various changes and modifications to the invention can be made by a person skilled in the art, without departing from the scope or spirit of the invention.

P1173 / 00MX

Claims (14)

1. NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following CLAIMS is claimed as property; 1. A battery pack comprising: a plurality of battery cells; and a box for storing the battery cells side by side, the box includes a bottom in the form of a trough and a lid, the trough has a space that serves as a cell storage portion, defined between the inner and outer wall portions paired to form a circuit, and a central space serving as a recess enclosed by the inner wall portion and penetrating the tundish from the top to the bottom, the cap closes an upper opening of the cell storage portion . The battery pack according to claim 1, wherein the tundish is designed such that the battery cells in the form of pillars stored in the cell storage portion are arranged side by side in a circuit with the respective outer peripheral surfaces of them in reciprocal contact. The battery pack according to claim 1 or 2, wherein each battery cell is a nickel-hydride secondary battery cell P1173 / 00MX metallic. The battery pack according to claim 1, further comprising a terminal block which is superimposed on the battery cells stored in the cell storage portion of the tundish and which has electrode leads from the group of battery cells conducted outside of them, and wherein the lid has openings in those regions thereof that are oriented towards the electrode conductors, through which the electrode conductors are exposed for their external connection. The battery pack according to claim 4, wherein the terminal block has electrode leads in a region opposite the gap, and the openings through which the electrode leads are exposed for external connection are arranged along the inner peripheral portion of the lid, opposite the hollow. The battery pack according to claim 4 or 5, wherein the terminal block is provided with a pair of electrode conductor terminals, positive and negative, individually connected to the electrode conductors of the group of cells and one or a plurality of auxiliary terminals for the group of cells. 7. The battery pack according to P1173 / 00MX claim 6, wherein the auxiliary terminals are used when the group of cells is loaded and includes a terminal for the load connected in series with the group of cells through the elements for temperature protection to cut a path of charged to the group of cells in response to the temperature of the cells, a terminal for temperature sensing connected to a temperature transducer to detect the temperature of the cell, and a terminal for identifying the type of cell that is connected to a resistor that has a resistance value that corresponds to the specifications of the cells. The battery pack according to claim 7, wherein the temperature protection elements are provided individually at a plurality of points in the arrangement direction of the battery cells stored in a circuit in the storage portion of the cells of the tundish and are interposed in series between the group of cells and the loading terminal. The battery pack according to claim 1, wherein the inner wall portion of the tundish is inclined outwardly from the base portion thereof to the upper opening, thereby reducing the sectional area of the upper opening from the hole P1173 / 00MX surrounded by the inner wall portion. The battery pack according to claim 9, wherein the inner wall portion is inclined at an angle of 0.5 ° to 5 ° in the vertical direction. 11. The battery pack according to claim 1, wherein the interior and exterior wall portions of the tundish are as high as the cylindrical battery cells. The battery pack according to claim 1, wherein a plurality of the inner wall portions are formed by defining a plurality of circuit cell storage portions, between the inner and outer wall portions and defining, individually , holes surrounded by them. 13. An energized tool accommodated with the battery pack according to any of claims 1 to 11, as a power source of the tool. The energized tool according to claim 13, comprising a motor that can be rotated by means of the battery pack as the power source and a mechanism for circulating the air in the recess enclosed by the interior wall portion of the trough using the rotation of the engine. P1173 / 00MX