JP3573919B2 - Battery pack with temperature sensor - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a battery pack having a built-in temperature sensor that shuts off current when the battery temperature rises to an abnormally high temperature.
In the present specification, a temperature sensor detects a battery temperature and directly cuts off a current, and a temperature fuse detects a battery temperature and inputs a signal detected to a control circuit to cut off the battery current by the control circuit. The sensor is used for both meanings.
[0002]
[Prior art]
The battery pack has a built-in temperature sensor to cut off the current when the battery temperature rises to an abnormally high temperature. The temperature sensor is disposed in contact with the battery in order to accurately detect the battery temperature. In a battery pack in which the temperature sensor is a thermal fuse and is connected in series with the battery, when the battery temperature becomes abnormally high, the thermal fuse is turned off to interrupt the current. When the battery temperature drops, the thermal fuse is turned on, and the battery can be used again.
[0003]
As described above, the temperature sensor that detects the temperature of the battery and shuts off the current is disposed on the bottom surface of the battery in a conventional battery pack containing a slim battery. A battery pack in which a plurality of cylindrical batteries are arranged in parallel has a temperature sensor disposed in a valley formed between the batteries.
[0004]
[Problems to be solved by the invention]
A temperature sensor disposed on the bottom of the slim battery or in the valley of the cylindrical battery detects the battery temperature and can shut off the battery current when the battery temperature becomes abnormally high. However, the battery pack having this structure cannot detect the temperature of the exhaust gas when the battery is used in an abnormal state, the safety valve is opened, and the gas is exhausted. If the battery is in an abnormal state, for example, discharged with a large current or overcharged, gas is generated inside the battery, and the internal pressure of the battery may become abnormally high. In this state, the safety valve is opened to discharge gas, thereby preventing the battery case from being broken by an abnormal internal pressure. The state in which the safety valve is opened is an extremely abnormal use state, and almost without exception, the temperature of the battery becomes abnormally high. For this reason, if the temperature of the gas discharged from the opened safety valve is detected and the current can be cut off, the battery pack can be used in a safer state. However, in order to achieve this, conventional battery packs need to be equipped with a temperature sensor to detect the temperature of gas discharged from the safety valve. is there.
[0005]
The present invention provides a pack that can be used extremely safely with a very simple structure without increasing the cost of parts by using a temperature sensor that detects the battery temperature in combination with a sensor that detects the temperature of gas discharged from a safety valve. It was developed for the purpose of realizing a battery.
[0006]
[Means for Solving the Problems]
The battery pack of the present invention includes a slim battery 1 and a temperature sensor 2 that detects the temperature of the slim battery 1 and shuts off current when the battery temperature becomes higher than a set temperature. The temperature sensor 2 is disposed above a sealing plate 4 provided with a safety valve 3. In the battery pack having this structure, when the safety valve 3 of the slim battery 1 is opened and hot gas is discharged, the gas heats the temperature sensor 2. Therefore, the temperature sensor 2 detects the battery temperature and cuts off the current, and when the safety valve 3 is opened, detects the temperature of the discharged gas and cuts off the current.
[0007]
Further packs battery of the present invention, the temperature sensor 2, while being disposed on the slim battery 1 via an insulating cap 5 having the fitting Chakuana 7 temperature sensor 2, the temperature sensor 2 is fitted It is placed in the receiving hole 7 and is disposed on the upper surface of the sealing plate 4. The insulating cap 5 has a gas discharge path 6 for guiding gas discharged from the safety valve 3 to the temperature sensor 2. Therefore, the gas discharged from the safety valve 3 passes through the gas discharge path 6 and heats the temperature sensor 2.
[0008]
[0009]
Battery pack according to claim 2 of the present invention, the outer shape of the insulation cap 5, Ru substantially equal Kushitei the outer shape of the sealing plate 4. In the battery pack of this structure, the insulating cap 5 can be disposed without being bulky, and the temperature sensor 2 can be disposed at a fixed position.
[0010]
Furthermore, the battery pack according to claim 3 of the present invention, the upper surface of the insulation cap 5, are disposed electrode terminals 8 formed by connecting the temperature sensor 2.
[0011]
Finally, in the battery pack according to the fourth aspect of the present invention , the insulating cap 5 is provided with a positioning projection 10 projecting from the lower surface and fitted into the recess 11 provided on the upper surface of the slim battery 1. . The insulating cap 5 is disposed at a fixed position by the positioning protrusion 10 and the recess 11 of the slim battery 1.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the following examples illustrate the battery pack for embodying the technical idea of the present invention, and the present invention does not specify the battery pack as follows.
[0013]
Further, in this specification, in order to make it easy to understand the claims, the numbers corresponding to the members shown in the embodiments are referred to as “claims” and “means for solving the problems”. Are added to the members indicated by "." However, the members described in the claims are not limited to the members of the embodiments.
[0014]
The battery pack shown in the cross-sectional view of FIG. 1 has a slim battery 1 as a lithium ion secondary battery and a temperature of the slim battery 1 detected in an outer case 12. A temperature sensor 2 for shutting off is built in.
[0015]
However, the battery pack of the present invention does not specify the slim battery 1 housed in the outer case 12 as a lithium ion secondary battery. Nickel-cadmium batteries and nickel-hydrogen batteries can also be used as the slim batteries.
[0016]
The outer case 12 is formed by molding plastic into a square shape, and has electrode windows 13 for exposing the electrode terminals 8 and 9 at two places on the upper surface.
[0017]
When the detected temperature is higher than the set temperature, the temperature sensor 2 can use a temperature fuse that cuts off the current. The thermal fuse is connected in series with the slim battery, and when the detected temperature becomes higher than a set temperature, the thermal fuse is switched to an off state to cut off current. As the temperature sensor, a sensor that detects the temperature and changes the internal resistance can be used instead of the thermal fuse. This sensor is connected to the control circuit to cut off the battery current.
[0018]
The temperature sensor 2 has a cylindrical shape as shown in FIGS. 1 and 2, and has lead wires 2A and 2B protruding from both ends. The temperature sensor 2 is disposed on the slim battery 1 in parallel with the slim battery 1 and has an outer diameter smaller than the width of the slim battery 1 so as not to protrude outside the slim battery 1. .
[0019]
The temperature sensor 2 is disposed on the slim battery 1 via the insulating cap 5. The insulating cap 5 is formed by molding a plastic such as ABS into a plate shape as a whole. The outer shape of the insulating cap 5 is substantially equal to the outer shape of the sealing plate 4 of the slim battery 1, in other words, substantially equal to the upper surface shape of the slim battery 1. This is for placing on the slim battery 1 so as not to protrude from the slim battery 1.
[0020]
. Furthermore, in order to hold the temperature sensor 2 in a fixed position, the insulating cap 5 is provided with a fitting hole 7 into which the temperature sensor 2 is fitted, vertically penetrating therethrough. As shown in the cross-sectional view of FIG. 1, the temperature sensor 2 is inserted into the fitting hole 7 and contacts the upper surface of the sealing plate 4 or approaches the upper surface of the sealing plate 4 until there is almost no gap. Will be arranged.
[0021]
The temperature sensor 2 inserted into the fitting hole 7 is disposed on the slim battery 1 by welding the lead wire 2A at one end to the side surface of the slim battery 1. In the temperature sensor 2 shown in the figure, a lead wire 2A is welded to the side surface of the slim battery 1 via a Ni-Al clad plate 14. The clad plate 14 is welded to the slim battery 1, and the lead wire 2A is welded to the clad plate 14. The lead wire 2A welded to the slim battery 1 is bent at a right angle along the slim battery 1, and the cylindrical portion of the temperature sensor 2 is inserted into the fitting hole 7 and arranged at a fixed position. The temperature sensor 2 connecting the lead wire 2A to the slim battery 1 is inserted into the fitting hole 7 of the insulating cap 5 to hold the insulating cap 5 in place.
[0022]
In order to dispose the insulating cap 5 at a fixed position of the slim battery 1 via the temperature sensor 2, the insulating cap 5 protrudes from the lower surfaces at both ends and integrally forms a positioning convex portion 10. The positioning protrusion 10 is fitted into a recess 11 provided on the upper surface of the slim battery 1, and arranges the insulating cap 5 at a fixed position of the slim battery 1. The insulating cap 5 having this structure can be placed on the upper surface of the slim battery 1 and arranged at an accurate position by the temperature sensor 2. Further, the temperature sensor 2 is also disposed at the fixed position via the insulating cap 5 disposed at the fixed position. Therefore, the insulating cap 5 and the temperature sensor 2 having the structure shown in the figure can be disposed on the slim battery 1 at fixed positions without using an adhesive or the like. However, the insulating cap and the temperature sensor can be bonded and fixed using an adhesive.
[0023]
The insulating cap 5 has a gas discharge path 6 for allowing gas discharged from the opened safety valve 3 to flow around the temperature sensor 2 provided in the fitting hole 7. In the insulating cap 5 shown in FIG. 1, a gap is provided between the insulating cap 5 and the sealing plate 4, which serves as a gas discharge path 6. Further, the insulating cap 5 in this figure has a fitting hole 7 opened near the safety valve 3 provided on the sealing plate 4. The insulating cap 5 having this structure has a feature that the gas discharged from the safety valve 3 flows around the temperature sensor 2 so that the temperature sensor 2 can be effectively heated by the discharged gas.
[0024]
Further, the insulating cap 5 shown in FIG. 1 and FIG. 2 has a fitting concave portion 15 on the upper surface in which the electrode terminal 8 to be welded to the lead wire 2B of the temperature sensor 2 is arranged at a fixed position. As shown in FIG. 2, the electrode terminal 8 of a metal plate is fitted into the fitting concave portion 15 and arranged at a fixed position. The electrode terminal 8 provided in the fitting recess 15 is fixed to the lower surface by welding a lead wire 2B of the temperature sensor 2 to the lower surface. The lead wire 2 </ b> B welded to the electrode terminal 8 is fitted into a groove provided on the lower surface of the insulating cap 5, and extends from the fitting hole 7 to the fitting recess 15. The fitting recess 15 is provided with upper and lower holes penetrating partly up and down, and the lead wire 2B is welded to the lower surface of the electrode terminal 8 at the upper and lower holes. In this connection structure, the upper and lower sides of the insulating cap 5 are sandwiched between the lead wire 2B of the temperature sensor 2 and the electrode terminal 8. For this reason, there is a feature that the electrode terminal 8 can be attached to the insulating cap 5 so as not to come off.
[0025]
Further, the insulating cap 5 has a through hole 16 for exposing the electrode terminal 9 which is insulated and fixed to the sealing plate 4. In the battery pack shown in the figure, one electrode terminal 9 is exposed through a through hole 16 of the insulating cap 5, and the other electrode terminal 8 is fitted in the fitting recess 15 of the insulating cap 5.
[0026]
As shown in the sectional view of FIG. 1, the sealing plate 4 of the slim battery has the electrode terminals 9 fixed insulated. The electrode terminal 9 is connected to the electrode tab 18 of the electrode body 17 on the lower surface of the sealing plate 4. The other electrode tab 18 provided on the electrode body 17 is connected to a sealing body tab 19 which is directly fixed to the sealing plate 4. Therefore, the slim battery 1 includes the battery case as one electrode and the electrode terminal 9 provided with the other electrode insulated from the sealing plate 4.
[0027]
The sealing plate 4 is air-tightly fixed to the opening of the battery case by a method such as laser welding. The sealing plate 4 has a built-in safety valve 3 that opens when the internal pressure of the battery case becomes abnormally high. In the slim battery 1 shown in the figure, the safety valve 3 includes a metal ring 3A and a metal foil 3B. The metal foil 3B is airtightly adhered to the lower end of the metal ring 3A by a method such as cladding. The metal foil 3B is a metal foil such as an aluminum foil that is broken when the internal pressure of the battery becomes higher than a set pressure of, for example, 10 to 20 kg / cm ² .
[0028]
The metal ring 3A is air-tightly fixed to a connection hole opened in the sealing plate 4 by a method such as laser welding. When the internal pressure of the battery becomes higher than the set pressure, the safety valve 3 of this structure breaks the metal foil 3B and discharges gas in the battery. However, the battery pack of the present invention does not specify the safety valve 3 in the above-described structure. As the safety valve, any of the mechanisms that are employed in current batteries or that will be developed in the future, for example, self-returning valves that open the valve body with the internal pressure of the battery can be used.
[0029]
In the above battery pack, the temperature sensor 2 is disposed at a fixed position above the slim battery 1 via the insulating cap 5 formed in a predetermined shape. However, in the battery pack of the present invention, it is not always necessary to dispose the temperature sensor above the slim battery using the insulating cap. For example, without using an insulating cap, attach the temperature sensor directly to the sealing plate and place it above the slim battery, or connect the temperature sensor lead to the battery case and use the insulating cap. Instead, they can be placed in place.
[0030]
【The invention's effect】
In the battery pack of the present invention, since the temperature sensor is disposed above the sealing plate of the slim battery equipped with the safety valve, the temperature sensor for detecting the temperature of the battery is used to detect the gas discharged from the safety valve. Temperature can also be detected. For this reason, the battery current can be cut off by detecting both the temperature of the battery itself and the temperature of the gas discharged from the safety valve with the temperature sensor, despite the extremely simple structure. Therefore, the battery pack of the present invention realizes an excellent feature that the current can be reliably shut off in an abnormal use state by reducing the cost of parts, and the battery can be used extremely safely.
[Brief description of the drawings]
1 is a schematic sectional view showing a battery pack according to an embodiment of the present invention; FIG. 2 is a plan view of an insulating cap incorporated in the battery pack shown in FIG. 1;
DESCRIPTION OF SYMBOLS 1 ... Slim battery 2 ... Temperature sensor 2A ... Lead wire 2B ... Lead wire 3 ... Safety valve 3A ... Metal ring 3B ... Metal foil 4 ... Sealing plate 5 ... Insulating cap 6 ... Gas exhaust path 7 ... Fitting hole 8 ... Electrode terminal 9 ... Electrode terminal 10 ... Positioning convex part 11 ... Concave part 12 ... Outer case 13 ... Electrode window 14 ... Clad plate 15 ... Fit concave part 16 ... Through hole 17 ... Electrode body 18 ... Electrode tab 19 ... Sealing body tab

Claims (4)

In a slim battery (1) and a battery pack having a temperature sensor (2) that detects the temperature of the slim battery (1) and shuts off current when the battery temperature becomes higher than a set temperature,
A temperature sensor (2) is arranged above a sealing plate (4) equipped with a safety valve (3) ,
Further, a temperature sensor (2) with is disposed on the slim battery (1) through an insulating cap (5) having a Chakuana (7) fitting the temperature sensor (2), the temperature sensor (2) Is placed in the fitting hole (7) and disposed on the upper surface of the sealing plate (4) , and the insulating cap (5) transfers the exhaust gas discharged from the safety valve (3) to the temperature sensor (2) . A battery pack having a temperature sensor having a gas discharge path (6) for guiding . Battery pack having a temperature sensor as described in approximately equal claim 1 to the outer shape of the outer shape sealing plate of insulation cap (5) (4). The upper surface of the insulation cap (5), the battery pack having a temperature sensor as set forth in claim 1, the electrode terminal connected to the temperature sensor (2) (8) is disposed. Insulation cap (5) is projected on the lower surface, according to claim 1, position Kettotsu portion which is fitted in the recess (11) provided on the upper surface of the slim battery (1) (10) is provided Battery with a temperature sensor to be used.

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