Automotive energy source device

Abstract

Automotive energy source device, comprising: a plurality of battery cells (1); each battery cell (1) comprising a housing (20) and a current-interrupting device (30) included therein, wherein the current-interrupting device (30) deforms to isolate a connection point and interrupt current when the battery cell (1) internal pressure exceeds a specified pressure; and a high-voltage battery (9) comprising the plurality of battery cells (1) connected in series or in parallel, each battery cell (1) comprising the current interruption device (30) connected to an electrode terminal (32); characterized by the fact that the housing (20) comprises a rectangular outline, having a pair of opposing planar surfaces (20A), an electrode unit (10) which is a layering of positive and negative electrode plates (10A) with separators (10C) in between, and the current interruption device (30) is arranged between the pair of opposing planar surfaces (20A), the multitude of battery cells (1) is stacked with opposing planar surfaces (20A) facing each other to form a battery block (2), a pair of end plates (4) is arranged at the ends of the battery block (2), the pair of end plates (4) is connected by connecting components (5) and the pair of end plates (4) holds the battery cells (1) in the layered configuration, applying pressure in a direction perpendicular to the opposing planar surfaces (20A), wherein the electrode unit (10) is arranged between the opposing planar surfaces (20A) of the housing (20) such that the electrode unit (10) is pressed with a restoring force through inner surfaces of the opposing planar surfaces (20A) of the housing (20) so that the electrode unit (10) and the current interruption device (30) are held in the housing (20) in a stationary manner to prevent vibration.

Description

Background of the invention 1. Field of the invention

[0001] The present invention relates to a car power source device that supplies power to an engine that drives the vehicle. 2. Description of the state of the art

[0002] To increase the power supplied to the motor that drives a vehicle, the car power source device increases the output voltage of a battery pack by connecting many rechargeable batteries in series to form the battery pack. This car power source device is discharged to supply power to the motor when the vehicle is driven and is charged by means of a generator during regenerative braking of the vehicle. The battery discharge current determines the driving torque of the motor, and the battery charging current determines the braking performance of the regenerative braking system. Consequently, to increase the driving torque of the motor, thereby accelerating the vehicle, it is necessary to increase the battery discharge current. To improve regenerative braking, charging at high currents is required. Consequently, batteries of the car power source device are charged and discharged at high currents.In order to improve the safety of batteries charged and discharged with high currents, a battery incorporating a current interruption device has been developed to interrupt current when an internal battery pressure becomes abnormally high (refer to Japanese Laid-Open Patent Publication No. JP 2006128104 A).

[0003] The battery described above can improve safety by interrupting the current when the internal pressure becomes abnormally high. However, this battery has the disadvantage that the current interruption device may be damaged by vibration to interrupt the current, rendering the battery unusable. This is because vehicle vibration may cause the electrodes to move inside the battery case, stressing the connection region of the current interruption device. The connection region of the current interruption device is designed with a connection strength that results in separation and current interruption when the internal battery pressure rises abnormally. If the connection region is too strong, it will be unusable for separating and interrupting the current when the internal pressure rises abnormally.Consequently, there are limitations on the strength of the connection region, and it has the disadvantage of being easily separated due to vibration. In particular, with batteries installed onboard a vehicle, vehicle vibrations during driving cannot be eliminated, and the power interruption device may interrupt the power supply due to the vehicle vibration. If the power interruption device of a battery in a car power source device interrupts the power supply during driving, the engine will stop abruptly, making it impossible to maintain smooth or quiet driving. Similarly, this type of battery has the disadvantage that, in a pure electric car, the vehicle cannot be driven at all.

[0004] US patent application No. US 2008 / 0 038 628 A1 describes a battery cell for use in a vehicle, wherein the battery cell comprises a rectangular cell housing in which electrodes are accommodated in a wound form. A membrane, together with an interruption foil, forms a pressure-sensitive elastic element that deforms with increasing internal pressure, interrupting the connection between the electrode and the electrode terminal.

[0005] US patent application No. US 2008 / 0 280 194 A1 discloses a high-voltage battery for a vehicle. It consists of a battery block with layered, rectangular battery cells. The cells are pressed together by connecting elements perpendicular to their planar surfaces via end plates.

[0006] For further known prior art, reference is made to the patent publications JP 2005-251 548 A, JP H09-92 263 A, JP H08-171 898 A and DE 60 018 852 T2.

[0007] The present invention was developed with the objective of correcting the above-described disadvantages. Thus, an important objective of the present invention is to provide a car power source device that enhances battery safety by including a power interruption device incorporated in each battery to interrupt power when internal battery pressure rises abnormally, while effectively preventing the power interruption device from interrupting due to vehicle vibration. Summary of the invention

[0008] The car power source device of the present invention is provided with a current interruption device 30, 40 housed in the casing 20 of each battery cell 1, deforming to separate a connection point and interrupt current when a battery cell 1 internal pressure becomes greater than a predetermined pressure, and a high-voltage battery 9 comprising a plurality of series- or parallel-connected battery cells 1 with current interruption devices 30, 40 connected to the electrode terminals 32. A battery cell 1 casing 20 has a rectangular outline and a pair of opposing planar surfaces 20A. An electrode unit 10, which is a set of positive and negative electrode plates 10A with intervening separators 10C, and a current interruption device 30, 40 are arranged between the pair of opposing planar surfaces 20A.Further, a plurality of battery cells 1 are stacked with opposing planar surfaces 20A facing each other to form a battery block 2. The car power source device includes a pair of end plates 4 disposed at both ends of the battery block 2, and connecting components 5 connecting the pair of end plates 4. The battery block 2 is held with pressure applied in a direction perpendicular to the opposing planar surfaces 20A of the stack of battery cells 1 between the pair of end plates 4. The electrode unit 10 is disposed between the opposing planar surfaces 20A of the casing 20, so that the electrode unit 10 is pressed with a restoring force by inner surfaces of the opposing planar surfaces 20A of the casing 20, so that the electrode unit 10 and the current interruption device 30 are held in the casing 20 in a stationary manner to prevent vibration.

[0009] The automotive power source device as described above realizes the extremely important feature for an automotive power source device of improving battery cell safety by incorporating a current interruption device in each battery cell to interrupt power when internal battery pressure rises abnormally, and effectively preventing interruption of the current interruption device due to vehicle vibration. This is because the casing of each battery cell housing a current interruption device has a pair of opposing planar surfaces of a rectangular shape; and an electrode unit, which is a stack of positive and negative electrode plates with intervening separators, and a current interruption device are arranged between this pair of opposing planar surfaces.A plurality of battery cells are further stacked with opposing planar surfaces facing each other to form a battery block. A pair of end plates is arranged at both ends of the battery block. The two end plates are connected by connecting components. The stack of battery cells held by the end plates is held with pressure applied in a direction perpendicular to the opposing planar surfaces. In this power source device, an electrode unit and a current interruption device are arranged between the opposing planar surfaces of each battery cell. A plurality of these battery cells are stacked to form a battery block. Pressure is applied to both ends of the battery block by means of the end plates to compress the opposing planar surfaces of the battery cell cases.Consequently, the electrode unit and the current interruption device of each battery cell are held in a compressed state by the opposing planar surfaces, and the electrode unit and the current interruption device do not move due to vibration. Consequently, loosening of the connection region and current interruption are prevented by the electrode unit and the current interruption device moving together.

[0010] In the automotive power source device of the present invention, a current interruption device 30, 40 may be provided with a deformable metal plate 33 that deforms with the internal pressure of the battery cell 1, and a connecting metal 34 that locally bonds to the deformable metal plate 33 for electrical connection. When the internal pressure of the battery cell 1 exceeds a predetermined pressure, the deformable metal plate 33 deforms and separates from the connecting metal 34 to interrupt the current. This automotive power source device can reliably interrupt the current when the internal pressure of the battery cell exceeds the predetermined pressure, while the current interruption device has a simple structure.

[0011] In the automotive power source device of the present invention, the deformable metal plate 33 may be a diaphragm 35 curved in an arc shape, and the apex of the arc-shaped diaphragm 35 may be welded to the connecting metal 34 for electrical connection. This automotive power source device has the characteristic that, since the arc-shaped diaphragm deforms with an internal battery cell pressure to interrupt current, current can be reliably interrupted with abnormal internal pressure rise and the interruption state can be maintained.

[0012] In the automotive power source device of the present invention, the diaphragm 35 can be connected to an electrode terminal 32, and the connecting metal 34 can be connected to an electrode tab 31 connected to an electrode plate 10A. This power source device has the characteristic that by accommodating battery cell parts in a case that holds the parts in an immovable manner, sandwiched between opposing planar surfaces, separation of the diaphragm connecting section can be reliably prevented. This is because holding the diaphragm with an electrode terminal and holding the electrode unit by sandwiching it between opposing planar surfaces of the case enables prevention of relative movement between the diaphragm and the connecting metal connected to the electrode tab.

[0013] In the automotive power source device of the present invention, the positive and negative electrode plates 10A and the separators 10C therebetween can be stacked and wound into a spiral-shaped electrode unit 10 having planar sections 10X and U-shaped rounded sections 10Y. This electrode unit 10 can be held in a battery cell 1 casing 20 having planar sections 10X oriented parallel to the opposing planar surfaces 20A of the casing 20. In this automotive power source device, the planar sections of the electrode unit can be compressed in the electrode stacking direction and held in a stationary state by the opposing planar surfaces of the casing, while the electrode unit can be efficiently manufactured by winding it into a spiral shape.Consequently, separation of the power interruption device connection region due to vehicle vibration can be reliably prevented.

[0014] In the car power source device of the present invention, the housing 20 may be a metal housing 20X, and insulating material 39, 49 may be provided between the inner surfaces of the housing 20 and the conductive regions 38, 48 of the current interrupting device 30, 40.

[0015] The car power source device of the present invention may be provided with insulating material 29 between the inner surfaces of the housing 20 and the conductive regions of the electrode unit 10.

[0016] In the automotive power source device of the present invention, an insulating layer can be provided on the inner surfaces of the housing 20. This automotive power source device can prevent electrical contact between the housing and the current interruption device or the electrode unit while applying pressure to opposing planar surfaces of the housing to hold the electrode unit and the current interruption device in a stationary manner. Consequently, the housing can be held with pressure applied to opposing planar surfaces, and harmful effects such as internal battery cell short circuits can be prevented.

[0017] In the automotive power source device of the present invention, a current interruption device 30, 40 is housed in the upper section of each battery cell 1, upper and lower sections of the end plates 4 are connected by means of the connecting components 5, and upper sections of the pair of end plates 4 are drawn together by means of the connecting components 5 to hold the battery cells 1 with pressure applied to the upper sections thereof. In this automotive power source device, upper sections of the battery cell cases accommodating current interruption devices can be held with pressure applied by the end plates via the upper connecting components. Furthermore, lower sections of the battery cell cases accommodating electrode units can be held with pressure applied by the end plates via the lower connecting components.This allows both the current interruption device and the electrode unit to be held stationary within the casing of each battery cell. Consequently, this power source device has the property of reliably preventing separation of a current interruption device connection region due to vehicle vibration.

[0018] In the automotive power source device of the present invention, the current interrupting device 30, 40 can be connected between an electrode terminal 32 and an electrode strip 31 connected to the electrode unit 10. This automotive power source device can prevent any movement due to electrode strip vibration by reliably holding the electrode unit and the current interrupting device with pressure applied to opposing planar surfaces of the housing. Consequently, separation of the connection region of the current interrupting device connected to an electrode strip can be effectively prevented. The above and other objects of the present invention, as well as features thereof, will become apparent from the following detailed description taken in conjunction with the accompanying drawings. Short description of the drawings Fig. 1 is an oblique view of a car power source device for an embodiment of the present invention; Fig. 2 is an oblique view showing the layout of high-voltage batteries in the car power source device shown in Fig. 1; Fig. 3 is an oblique view of a high voltage battery shown in Fig. 2; Fig. 4 is an exploded oblique view of the high voltage battery shown in Fig. 3; Fig. 5 is a side view of the high voltage battery shown in Fig. 3; Fig. 6 is an oblique view of a battery cell; Fig. 7 is a vertical cross-sectional view of the battery cell shown in Fig. 6; Fig. Figure 8 is a lateral cross-sectional view of the battery cell shown in Fig. 6; Fig. 9 is a shortened cross-sectional view showing an example of a current interrupting device; Fig. 10 is a shortened cross-sectional view showing the current interrupting device of the Fig. 9 in power interruption state; Fig. 11 is a shortened cross-sectional view showing another example of a current interrupting device. Detailed description of the implementation examples

[0019] The car power source device of the present invention is generally suitable as a power source device for use in an electrically powered vehicle such as a hybrid car or an electric automobile to supply power to a drive motor to drive the vehicle.

[0020] The car energy source device of Fig. 1 to 5 is provided with a high-voltage battery 9 having a plurality of rechargeable battery cells 1 connected in series to increase an output voltage. The power source device of Fig. 1 and Fig. 2 is provided with four high-voltage batteries 9. A high-voltage battery 9 preferably has all battery cells 1 connected in series to increase the output voltage. However, a high-voltage battery can also have a plurality of battery cells connected in parallel, and these parallel-connected battery cells can in turn be connected in series.

[0021] The rechargeable battery cells 1 are lithium-ion batteries. However, any rechargeable batteries, such as nickel-hydride batteries or nickel-cadmium batteries, can be used as battery cells. As shown in Fig. 7 and Fig. 8, a battery cell 1 has an electrode unit 10, which is a stack of positive and negative electrode plates 10A with intervening separators 10C, contained in a housing 20 and filled with electrolyte solution. Furthermore, a battery cell 1 houses a current interruption device 30 in the housing 20.

[0022] When a battery cell 1 internal pressure exceeds a predetermined pressure, the current interruption device 30 deforms to separate a connection point and interrupt or cut off current. Fig. 9 and Fig. 10 are abbreviated cross-sectional views showing a specific example of a current interrupting device 30. In the battery cell 1 of these figures, the current interrupting device 30 is connected between an electrode strip 31 connected to the electrode unit 10 and an electrode terminal 32 mounted on the sealing plate 22. A current interrupting device 30 in the on state connects the electrode strip 31 to the electrode terminal 32. When the current interrupting device switches to the off state, the connection of the electrode strip 31 to the electrode terminal 32 is severed, and battery cell current is interrupted.

[0023] Fig. 9 shows the current interruption device 30 in the non-interruption state and Fig. 10 shows this in the interrupted state. The current interruption device 30 shown in this and other figures is provided with a deformable metal plate 33 that deforms with the battery cell 1 internal pressure, and the connecting metal 34 locally welded to the deformable metal plate 33 for electrical connection. When the battery cell 1 internal pressure becomes greater than the specified pressure, the deformable metal plate 33 of the current interruption device 30 deforms due to pressure and is separated from the connecting metal 34 to interrupt current, as shown in the sequence of Fig. 9 to Fig. 10.

[0024] The deformable metal plate 33 of the current interrupting device 30 shown in the figures is a diaphragm 35 formed to curve into an arc shape. This diaphragm 35 is connected at its periphery to the lower end of an electrode terminal 32 mounted on the sealing plate 22. The apex of the arc-shaped diaphragm 35 is welded to the connecting metal 34 for electrical connection. The connecting metal 34 is connected to an electrode strip 31. This current interrupting device 30 is provided in the on state so that the diaphragm 35 is connected to the connecting metal 34. Further, the diaphragm 35 and the connecting metal 34 of the current interrupting device 30 of the figures are contained within an inner casing 36 made of insulating material such as plastic.

[0025] In Fig. 9 and Fig. 10, the inner casing 36 allows the bottom surface of the diaphragm 35 to associate with the interior of the battery cell 1, while the upper surface of the diaphragm 35 is sealed in an airtight manner. The battery cell 1 internal pressure does not act on the airtight sealed upper surface of the diaphragm 35. In this current interruption device 30 configuration, the battery cell 1 internal pressure acts on the bottom surface of the diaphragm 35 to push the diaphragm 35 upward. The upward force on the diaphragm 35 increases proportionally to the battery cell 1 internal pressure. Consequently, when the internal battery cell 1 pressure increases, the diaphragm 35 is pushed upward and deforms from the state shown in Fig. 9, to the condition shown in Fig. 10. A diaphragm 35, deformed into the state shown in Fig. 10, is separated from the connecting metal 34 and the battery cell 1 current is interrupted. A deformed diaphragm 35 in the state shown in Fig. 10 is maintained in this state, which is the current interruption state or the off state, and is not returned to the on state. Therefore, when the internal pressure of battery cell 1 exceeds the set pressure, the current interruption device 30 interrupts the current and is then maintained in the current interruption state.

[0026] As shown in Fig. 11, the diaphragm 35 of the current interruption device 40, which is a deformable metal plate 33, can be attached in an airtight manner to a cover plate 47 to hermetically seal the upper surface of the diaphragm 35. In a current interruption device 40 of this configuration, the cover plate 47 and the diaphragm 35 are formed into a disc shape by welding them together at their peripheries or by crimping their peripheries together in an airtight manner. The cover plate 47 of the figures is provided with a stepped flange 47A around its periphery, which protrudes toward the diaphragm 35, and the periphery of the diaphragm 35 is attached to this stepped flange 47A. The projecting apex region of the diaphragm 35 is connected to the connecting metal 34 by welding.When the internal pressure of the battery cell 1 is lower than the specified pressure, this current interruption device 40 has its diaphragm 35 connected to the connecting metal 34 and is in the on state. Specifically, the on state allows the battery current to flow. When the internal pressure of the battery cell 1 increases abnormally and exceeds the specified pressure, the diaphragm 35 deforms to the position shown by the dashed line of FIG. Fig. 11, and separates from the connecting metal 34 to interrupt or cut off current. In this state, the diaphragm 35 is held in the upwardly curved configuration. As shown in Fig. 11, for a current interrupting device 40 having a diaphragm 35 surface sealed in an airtight manner by means of a cover plate 47, it is not necessary for the inner casing 46 to seal the upper surface of the diaphragm 35 in an airtight manner (hermetically), and the structure of the inner casing 46 can be simplified.

[0027] The current interruption device 30, 40 is connected between an electrode terminal 32 mounted on the battery cell-1 sealing plate 22 and the electrode unit 10 accommodated in the housing 20. Consequently, when the current interruption device 30, 40 or the electrode unit 10 moves in the housing 20 due to a condition such as vibration, an excessive force may be applied to the joining region of the diaphragm 35 of the deformable metal plate 33 with the joining metal 34, with the adverse result that the joining region weld may separate.

[0028] As in Fig. 6 and Fig. 8, in order to prevent this adverse effect, a battery cell 1 has a rectangular outline with a pair of opposing planar surfaces 20A, and the electrode unit 10 and the current interruption device 30 are sandwiched between the pair of opposing planar surfaces 20A to form a rectangular battery cell 1. Further, a plurality of these battery cells 1 are stacked with opposing planar surfaces 20A facing each other to form a battery block 2, and the battery block 2 is held with pressure applied by the end plates 5 at both ends of the battery block 2. With a battery cell 1 held in this manner, the opposing planar surfaces 20A are pressed toward each other, and the electrode unit 10 and the current interruption device 30 contained therein are held in a stationary manner that does not vibrate.

[0029] A battery cell 1 casing 20 is made of metal or molded from a hard plastic. A metal casing 20 is made of aluminum, an aluminum alloy, iron, steel, or another iron alloy. A metal casing 20 is manufactured by pressing a deformable metal plate into the shape of a cylinder with a closed bottom to form an outer casing 21, and by locking or closing the open region of this outer casing 21 in an airtight manner with a sealing plate 22. The sealing plate 22 is attached to the outer casing 21 by a method such as laser welding. The outer casing 21 is formed in a rectangular cylindrical shape with rectangular opposing planar surfaces 20A on both sides, or is formed in a cylindrical shape with opposing planar surfaces on both sides connected by U-shaped rounded surfaces.Positive and negative electrode terminals 32 are mounted to pass through the metal sealing plate 22 in a manner that is insulating and airtight.

[0030] By reducing the ratio of battery cell-1 casing-20 thickness (D) to width (W) (ratio (D) / (W)), the internally housed electrode unit 10 and the current interruption device 20 can be compressed by opposing planar surfaces 20A on both sides and held in a manner that is more difficult to move. Consequently, the casing-20 thickness (D) to width (W) ratio (ratio (D) / (W)) is made, for example, less than or equal to 1 / 2, preferably less than or equal to 1 / 3, and most preferably less than or equal to 1 / 4. However, if the ratio of thickness (D) to width (W) (ratio (D) / (W)) is made too small, the casing 20 will become too thin, and the battery capacity efficiency will drop.Therefore, the ratio of thickness (D) to width (W) (ratio (D) / (W)) is formed, for example, greater than or equal to 1 / 50, preferably greater than or equal to 1 / 40, and most preferably greater than or equal to 1 / 30.

[0031] As in Fig. As shown in Figures 7 to 11, a metal casing 20X is provided with insulating material 39, 49 between the inner surfaces of the casing and the conductive regions 38, 48 of the current interruption device 30, 40 to achieve a structure that prevents contact of the metal casing 20X with the conductive regions 38, 48 of the current interruption device 30, 40. In the battery cell 1 of the figures, the current interruption device 30, 40 is housed in an insulating plastic inner casing 36, 46, and the inner casing 36, 46 serves as the insulating material 39, 49 to insulate the conductive regions 38, 48 of the current interruption device 30, 40 from the metal casing 20X. Further, the insulating material 29 is provided between metal shell 20X inner surfaces and conductive regions of the electrode unit 10 to achieve a configuration that avoids contact between the electrode plates 10A, which are the conductive regions of the electrode unit 10, and the metal shell 20X.The electrode unit 10 insulating material 29 may include insulating separators 10C stacked with the electrode unit 10, an insulating layer 28 laminated on inner surfaces of the housing 20, or a coating on the inside of the housing 20 to form an insulating layer 28.

[0032] As in Fig. As shown in Figure 8, the electrode unit 10 is made by rolling positive and negative electrode plates 10A with separators 10 sandwiched therebetween into a spiral shape and pressing this spiral roll from both sides to make it flat. This electrode unit 10 has a spiral structure with planar sections 10X on both sides connected by U-shaped rounded sections 10Y. This electrode unit 10 is inserted into the casing 20 with the planar sections 10X parallel to the opposing planar surfaces 20A of the casing 20. When this electrode unit 10 is held in the casing 20, it is pressed by the opposing planar surfaces 20A of the casing 20 with a force tending to return it to its original flat spiral shape. Consequently, the planar sections 10X of this electrode unit 10 can be pressed with a restoring force by the inner surfaces of the opposing planar surfaces 20A of the casing 20.Consequently, the electrode unit 10 can be held in a more rigid manner by means of a structure that holds the electrode unit 10 with pressure applied by the opposing planar surfaces 20A of the casing 20. However, the power source device of the present invention does not limit the battery cell electrode unit to a unit wound in a spiral shape. This is because a plurality of positive and negative electrode plates and separators therebetween can also be cut, stacked, and held in the casing in the rectangular shape of opposing planar surfaces of the battery cell. This type of electrode unit is held in the casing with electrode plates parallel to the opposing planar surfaces of the casing.

[0033] The electrode unit 10 has electrode strips 31 connected to positive and negative electrode plates 10A. The electrode strips 31 are connected to the positive and negative electrode terminals 32. The battery cell 1 of Fig. 1 has an electrode strip 31 connected to the current interrupting device 30, and this electrode strip 31 is connected to the electrode terminal 32 through the current interrupting device 30. Further, as shown in Fig. 6, the positive and negative electrode terminals 32 are connected to positive and negative output terminals 32 on the upper surface of the sealing plate 22. The sealing plate 22 has positive and negative output terminals 13 attached to both ends of its upper surface via insulating material 14. Thus, the positive and negative output terminals 13 are connected to the respective positive and negative electrode plates 10A accommodated inside.

[0034] Further, the sealing plate 22, which closes the open end of the outer casing 21, is provided with a safety valve 11 opening 12. The safety valve 11 opens to prevent damage to the casing 20 when an internal pressure becomes greater than a predetermined value. The predetermined pressure for opening the battery cell 1 safety valve 11 is set to be greater than the predetermined pressure for activating the current interruption device 30 to interrupt current. Specifically, when the internal pressure of the battery cell 1 rises and exceeds the predetermined pressure for interrupting current, the deformable metal plate 33 of the current interruption device 30 is deformed by the internal pressure and separates from the connecting metal 34 to interrupt current. In this state, the current of the battery cell 1 is interrupted to ensure safety.When the internal pressure continues to rise with the current interruption device 30 in the current interruption state and becomes greater than the set pressure for the safety valve 11 to open, the safety valve 11 will open. In the battery cell 1 of the figures, the safety valve 11 opening 12 is provided in the sealing plate 22. This outer casing 21 can discharge gas from the opening 12 of an open safety valve 11. This is because gas accumulates in the casing 20. A safety valve opening may also be provided on a bottom or side surface of the outer casing. However, when this type of safety valve opens, an electrolyte solution is discharged. If an electrolyte solution, which is a conductive liquid, is discharged, it may cause a short circuit of contacting materials.A battery cell 1 having the safety valve 11 provided in the sealing plate 22 of the casing 20 can reduce internal pressure by discharging gas from an open safety valve 11. Consequently, when the safety valve 11 opens, electrolyte solution discharge is restricted and adverse effects due to the release of electrolyte solution are minimized.

[0035] The energy source device of Fig. 1 is provided with gas discharge pipes 18 at the top of the car power source device for discharging gas discharged from the safety valves 11 to the outside. Openings in the bottom of a gas discharge pipe 18 connect to safety valve 11 openings 12 to discharge gas discharged from the safety valves 11 to the outside. With this structure, gas discharged from a battery cell 1 with an open safety valve 11 can be quickly discharged to the outside.

[0036] A plurality of battery cells 1 are stacked with opposing planar surfaces 20A facing each other to form a battery block 2. Adjacent output terminals 13 of the stacked battery cells 1 are connected via connecting hardware (not shown) to connect the battery cells 1 in series. Further, a wire line (not shown) is connected to the output terminals 13 of each battery cell 1. These wire lines are connected to a circuit board (not shown) that implements a protection circuit that detects a battery cell 1 voltage. Although not shown, the circuit board is arranged on top of the car power source device in Fig. 1 and Fig. 2.

[0037] Spacers 15 are sandwiched between battery cells 1. The spacers 15 insulate the outer casings 21 of adjacent battery cells 1 and achieve cooling gaps 16 between battery cells 1 to cool the battery cells 1. Thus, the spacers 15 are formed of insulating material such as plastic. The spacers 15 are provided with grooves 15A on both surfaces to achieve cooling gaps 16 between adjacent battery cells 1. The spacers 15 are provided with grooves 15A extending in the horizontal direction, more specifically, the grooves 15A extend in a direction connecting both side walls of the battery cells 1. Air flows in the horizontal direction through the cooling gaps 16 achieved by these spacers 15 to cool the battery cells 1.

[0038] Battery cells 1 are stacked via the spacers 15 and held in fixed positions via fixing components 3. The fixing components 3 include a pair of end plates 4 disposed at both ends of the stacked battery cells 1, and connecting components 5 having end regions connected to the end plates 4 to hold the stacked battery cells 1 in a compressed state. The battery block 2 is held with the end plates 4 disposed at both ends connected by the connecting components 5 to hold the stacked battery cells 1 with pressure applied in a direction perpendicular to the opposing planar surfaces 20A.

[0039] The end plates 4 are made of aluminum or an aluminum alloy or they are molded from hard plastic. The end plates 4 of Fig. 3 and Fig. 4 are provided with reinforcing ribs 4A extending vertically and horizontally on the outer surface and formed in a one-piece construction with the end plates 4. The bending strength of these end plates 4 is enhanced by the reinforcing ribs 4A. End plates 4 with exceptional bending strength can effectively prevent expansion at the center regions of rectangular batteries. This is because battery cell 1 center region expansion does not occur as long as the end plates 4, connected by connecting components 5, do not deform. In order to sandwich the rectangular batteries over a large area, the end plates 4 are formed with outer shapes that are the same as the rectangular shape of the rectangular battery cells 1. The rectangular end plates 4 are formed with the same size as the rectangular batteries or extremely slightly larger than the rectangular batteries.Furthermore, the end plates 4 of the figures are provided with grooves in the sides facing the battery cells 1 for cooling airflow, and these grooves create cooling gaps 16 between the end plates 4 and the rectangular batteries. However, surfaces of the end plates opposite the battery cells can also be flat planar surfaces, and these planar surfaces can be brought into contact with the surfaces of rectangular batteries or spacers. Plastic end plates 4 can be directly stacked on rectangular batteries, while metal plates can be stacked on rectangular batteries using stacking material.

[0040] The ends of the connecting components 5 are connected to the end plates 4. The ends of the connecting components 5 are connected to the end plates 4 by means of set screws 6, or the end regions are folded inward to connect to the end plates, or nuts are screwed onto the ends of the connecting components, or the ends of the connecting components are connected to the end plates by snapping or crimping into locks. An end plate 4, which connects to connecting components 5 via set screws 6, is provided with screw holes 4a to receive the set screws 6. The screw holes 4a are provided in the outer surface of an end plate 4, and set screws 6, passing through bent regions 5A of the connecting components 5, are screwed into these screw holes 4A to connect the connecting components 5.

[0041] The high-voltage battery 9 of the Fig. 3 and Fig. 4 has first connecting components 5 arranged along the upper ends of the battery cells 1, which are rectangular batteries, and second connecting components 5 arranged along the lower ends of the rectangular batteries, connected to the end plates 4. In this high-voltage battery 9, screw holes 4a are provided in the upper and lower ends on both sides of the outer surfaces of the end plates 4. This high-voltage battery 9 holds the upper and lower parts of the rectangular battery cells 1 with connecting components 5. For connecting the ends of the connecting components 5 to the end plates 5 via adjusting screws 6, screw holes 4 are provided at locations where the ends of the connecting components 5 are attached to the end plates 4.

[0042] The connecting components 5 are made of sheet metal, formed with a prescribed thickness and a prescribed width. The ends of the connecting components 5 connect to end plates 4 to connect the pair of end plates 4 and hold battery cells 1 in a compressed state between the end plates 4. The connecting components 5 are attached with prescribed dimensions to the pair of end plates 4 to hold the battery cells 1 sandwiched between the end plates 4 in a prescribed compressed state. If the connecting components 5 expand with the battery cell 1 expansion pressure, the battery cell 1 expansion cannot be prevented.Consequently, the connecting components 5 are formed from sheet metal strong enough to avoid stretching under the battery cell 1 expansion pressure, and are formed with a width and thickness sufficient for strength from stainless steel, such as SUS304, steel, or other sheet metal. Furthermore, connecting components can also be formed with sidewalls in the form of channels or rails. Since connecting components with this shape can improve bending strength, they have the property of robustly holding layered rectangular batteries in a prescribed compression state while reducing the connecting component width.

[0043] A connecting component 5 is provided with bent regions 5A at its ends, and these bent regions 5A are connected to the end plates 4. Adjustment screw through holes 6 are provided in the bent regions 5A, and the connecting components 5 are attached to the end plates 4 via adjustment screws 6 inserted through the through holes.

[0044] Although not shown, a single long connecting component may be bent at its mid-region to connect the bent region around the outer surface of one end plate and connect both ends to the other end plate. This type of connecting component may be rigidly connected to an end plate at its bent mid-region, looping around this end plate. Furthermore, the connecting component may also be attached to this end plate in a one-piece construction. This type of connecting component may be attached to an end plate with maximum robustness.

[0045] The car power source device as described above is assembled by the following process. The high-voltage battery 9 of Fig. 3 to 5 are assembled in the following manner. Battery block compression process

[0046] Spacers 15 are arranged between the battery cells 1, which are rectangular batteries. The spacers 15 and the battery cells 1 are stacked to form a battery block 2, and end plates 4 are arranged at both ends of the battery block 2. In this configuration, both end plates 4 are pressed and held in a holding die. The unit is compressed until a prescribed dimension is achieved between the end plates 4, and this configuration is maintained. Connecting component attachment process

[0047] The battery pack 2 is held in the compressed state, and both ends of the connecting components 5 are attached to the end plates 4. The connecting components 5 of the figures have curved regions 5A with through holes provided at both ends. These connecting components 5 are attached to the end plates 4 by screwing adjusting screws 6, inserted through the through holes in the curved regions 5A, into screw holes 4a in the end plates 4. Holder tool removal process

[0048] After all the connecting components 5 have been attached to the end plates 4, the holding tool is removed. Through the assembly process as described above, stacked battery cells 1, which are rectangular batteries, are held in a compressed state between a pair of end plates 4. Consequently, even if battery cells 1 tend to expand due to a condition such as overcharging, the distance between the end plates 4 does not change, and battery cell 1 expansion is prevented by the end plates 4. In this high-voltage battery 9, since both ends of the connecting components 5 are attached to the end plates 4 by means of adjusting screws 6, the connecting components 5 are robustly connected to the end plates 4, and prescribed dimensions are maintained between the end plates 4 via the connecting components 5.Further, in this state, battery cells-1, electrode units 10 and current interrupting devices 30 are held with pressure applied by opposing planar surfaces 20A of the casings 20. Consequently, there is no movement of the electrode units 10 or the current interrupting devices 30 due to vibration, and relative movement between an electrode unit 10 and a current interrupting device 30 to separate the connection region and interrupt current is prevented.

[0049] Those skilled in the art will appreciate that while various preferred embodiments of the invention have been shown and described, the invention is not intended to be limited to the specific embodiments disclosed, which are merely illustrative of the inventive concepts and are not to be interpreted as limiting the scope of the invention, and are susceptible to all modifications and changes falling within the spirit and scope of the invention as defined in the appended claims. This application is based on application number JP 2008335518 A, filed in Japan on December 27, 2008, the contents of which are incorporated herein by reference.

Claims

[1] A car power source device comprising: a plurality of battery cells (1); each battery cell (1) comprising a housing (20) and a current interruption device (30) received therein, the current interruption device (30) deforming to separate a connection point and interrupt current when the battery cell (1) internal pressure exceeds a predetermined pressure; and a high-voltage battery (9) comprising the plurality of battery cells (1) connected in series or parallel, each battery cell (1) having the current interruption device (30) connected to an electrode terminal (32); characterized by , that the housing (20) comprises a rectangular outline, having a pair of opposing planar surfaces (20A), an electrode unit (10) which is a layering of positive and negative electrode plates (10A) with separators (10C) therebetween, and the current interruption device (30) is arranged between the pair of opposing planar surfaces (20A), the plurality of battery cells (1) are layered with opposing planar surfaces (20A) facing each other to form a battery block (2), a pair of end plates (4) is arranged at the ends of the battery block (2), the pair of end plates (4) are connected by connecting components (5) and the pair of end plates (4) holds the battery cells (1) in the layered configuration, applying pressure in a direction perpendicular to the opposing planar surfaces (20A), wherein the electrode unit (10) is arranged between the opposing planar surfaces (20A) of the housing (20), so that the electrode unit (10) is pressed with a restoring force by inner surfaces of the opposing planar surfaces (20A) of the housing (20), so that the electrode unit (10) and the current interruption device (30) are held in the housing (20) in a stationary manner to prevent vibration. [2] The car power source device according to claim 1, wherein the current interruption device (30, 40) is provided with a deformable metal plate (33) that deforms with the battery cell (1) internal pressure, and a connecting metal (34) that locally electrically connects to the deformable metal plate (33); wherein when the battery cell (1) internal pressure becomes greater than the set pressure, the deformable metal plate (33) deforms due to pressure and separates from the connecting metal (34) to interrupt current. [3] The car power source device according to claim 2, wherein the deformable metal plate (33) is a diaphragm (35) formed in a curved arc shape, and the apex region of the diaphragm (35) is welded to the connecting metal (34) for electrical connection. [4] A car power source device according to claim 3, wherein the diaphragm (35) is connected to an electrode terminal (32) and the connecting metal (34) is connected to an electrode strip (31) which is connected to an electrode plate (10A). [5] The car power source device according to claim 3, wherein the current interrupting device (30) accommodates the diaphragm (35) and the connecting metal (34) in an inner casing (36) formed of insulating material. [6] The car power source device according to claim 5, wherein the inner case (36) connects one side of the diaphragm (35) to the inside of the battery cell (1) and closes the other side of the diaphragm (35) in an airtight manner. [7] The car power source device according to claim 3, wherein the current interrupting device (40) has the bottom surface of a cover plate (47) attached in an airtight manner to one side of the diaphragm (35) which is the deformable metal plate (33) to hermetically seal one side of the diaphragm (35). [8] The car power source device according to claim 7, wherein the current interrupting device (40) comprises the cover plate (47) and the diaphragm (35) shaped as discs, and the cover plate (47) and the diaphragm (35) are mounted in an airtight manner around the peripheral edge. [9] The car power source device according to any one of claims 1-8, wherein the current interrupting device (30, 40) is connected between an electrode terminal (32) provided on the battery cell (1) and the electrode unit (10) accommodated in the casing (20). [10] The car power source device according to any one of claims 1-9, wherein the battery cell (1) is provided with a safety valve (11) that opens when internal pressure increases, and the pressure for the safety valve (11) opening is set greater than the pressure for current interruption by the current interruption device (30). [11] The car power source device according to any one of claims 1-10, wherein the electrode unit (10) comprises positive and negative electrode plates (10A) and separators (10C) therebetween, laminated and wound in a spiral shape, with planar sections (10X) and U-shaped rounded sections (10Y), and the electrode unit (10) is set in the casing (20) with the planar sections (10X) parallel to the opposing planar surfaces (20A) of the casing (20). [12] The car power source device according to any one of claims 1-11, wherein the housing (20) is a metal housing (20X) and insulating material (39, 49) is provided between the inner surfaces of the housing (20) and the conductive regions (38, 48) of the current interrupting device (30, 40). [13] A car power source device according to any one of claims 1-12, wherein insulating material (29) is provided between the inner surfaces of the housing (20) and the conductive regions of the electrode unit (10). [14] A car power source device according to any one of claims 1-13, wherein the end plates (4) are provided with reinforcing ribs (4A) extending vertically and horizontally on the outer surface and formed in an integral construction with the end plates (4). [15] The car power source device according to any one of claims 1-14, wherein the outline of the end plates (4) is formed in the same rectangular shape as the rectangular batteries of the battery cells (1). [16] A car power source device according to claim 15, wherein the rectangular end plates (4) have the same size as the rectangular batteries or are slightly larger than the rectangular batteries. [17] A car power source device according to any one of claims 1-16, wherein the connecting components (5) are made of sheet metal having a prescribed width and thickness. [18] A car power source device according to any one of claims 1-17, wherein the connecting components (5) have bent regions (5A) at their ends, and these bent regions (5A) are attached to the end plates (4). [19] A car power source device according to claim 18, wherein the bent regions (5A) have through holes for adjusting screws (6), and the connecting components (5) are attached to the end plates (4) via adjusting screws (6) inserted in the through holes. [20] The car power source device according to any one of claims 1-19, wherein the battery cell (1) has the current interrupting device (30, 40) housed in the upper section of the casing (20), connecting components (5) are connected to upper and lower sections of the end plates (4), and upper sections of the pair of end plates (4) are pulled together by the connecting components (5) to hold the battery cells (1) with pressure applied to the upper sections thereof.

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