JPH11233164A - Battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery pack capable of easily preventing temperature unbalance between battery cells caused by heat generation in a current route in charge /discharge and efficiently using. SOLUTION: A battery pack is constituted with an electrically insulating outer case 1, a secondary battery group 2 housed in the outer case 1, a wiring circuit part 3 arranged and sealed adjacently to the secondary battery group 2, a wiring circuit part 3 whose one end is connected to the terminals of the secondary battery group 2, having a charge/discharge control and protecting function, and a charging/discharging terminal 4 connected to the other end of the wiring circuit part 3 and introduced into the outside of the outer case 1. A high heat-transmission sheet 5 is attached to the side surfaces of the whole secondary batteries 2a-2g for constituting the secondary battery group 2, and heat generated in the wiring circuit part 3 is integrally conducted to the secondary battery group 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a battery pack,
More specifically, the present invention relates to a battery pack that appropriately processes heat generated in a charge / discharge current path and performs required charge / discharge efficiently.

[0002]

2. Description of the Related Art Secondary batteries typified by nickel-hydrogen secondary batteries, lithium ion secondary batteries, nickel-cadmium secondary batteries, and the like are used in various types of equipment systems, such as portable telephones and portable imaging devices. As an operating power source, a plurality of units are packed for practical use. In other words, the secondary battery can store power by a so-called charging operation, and can repeatedly operate the stored power to drive (discharge) the load. Have been.

[0003] Here, the secondary battery pack is generally provided with an electrically insulating outer case, a secondary battery group sealed in the outer case, and placed and sealed adjacent to the secondary battery group. A wiring circuit unit having a capacity remaining display function, one end of which is connected to the terminal side of the secondary battery, a charge / discharge control and a protection function,
It has a configuration having a charge / discharge terminal connected to the other end of the wiring circuit portion and led out of the exterior case.

[0004] The charging operation of this type of secondary battery pack is controlled based on, for example, a change in the temperature of the secondary battery during constant current charging, in other words, a rising state of the battery temperature accompanying charging. That is, a charger device main body provided with a concave portion on the upper surface side in which a battery pack can be fitted and mounted, and a battery pack installed in the concave portion of the charger device main body and fitted and mounted horizontally A charging terminal connected to the charging terminal of the battery pack, and measuring a temperature associated with constant current charging of the battery pack,
The required charging is performed by a charger device having a configuration including a temperature detection system for displaying the temperature change. The charge control based on the temperature differential detection method utilizes a phenomenon in which the temperature of the battery pack rapidly rises at a point near a fully charged state.

By the way, the secondary battery group forming the battery pack mainly includes a charge / discharge current path at the time of charge / discharge, in other words, a wiring circuit portion having a remaining capacity display function, charge / discharge control and protection functions. Due to the generated heat, the temperature of each battery forming the secondary battery group rises. The rise in temperature of each battery is affected by the configuration of the current path itself and the positional relationship of each battery with respect to the current path. As a result, the temperature of each battery becomes unbalanced, and the difference in the battery temperature causes the charge / discharge efficiency. (Battery capacity) causes a problem.

[0006]

In the above-mentioned battery pack, the following means have been tried as a countermeasure for imbalance in charge / discharge efficiency (battery capacity). That is, at least one end face of each battery arranged and sealed in parallel in the electrically insulating outer case, for example, (a)
A material having a high heat conduction effect such as an aluminum sheet (foil) is bonded and arranged, or (b) a heat conductive silicone layer is inserted and filled between the side surfaces of each battery that are in contact with each other to heat the cells. A configuration has been developed in which overall thermal conductivity is imparted by bonding together.

However, the above-mentioned measures (a) and (b) are not sufficient in terms of the heat conduction effect, and undesired thermal imbalance occurs between the batteries, and the charge / discharge efficiency (battery capacity) It is not a suitable means for improving

The present inventors have conducted intensive studies on the problem of the occurrence of imbalance between batteries (battery cells) in a battery pack. As a result, for example, aluminum foil was placed on the side surfaces of batteries arranged in parallel or in a plane. When sheets having good thermal conductivity such as are integrally attached (attached), the temperature difference between the battery cells can be easily reduced, and the occurrence of imbalance between the secondary battery cells can be eliminated or avoided. Was found. In other words, the heat generated in the current path such as the wiring circuit portion having the remaining capacity display function, charge / discharge control and protection function may cause thermal imbalance when the battery cells are contacted and covered by the wide heat conduction surface. It was confirmed that the battery pack was easily prevented, and as a result, the capacity imbalance of each battery cell was eliminated and the battery cell functioned as a battery pack having high charge / discharge efficiency.

The present invention has been made based on the above findings, and it is an object of the present invention to provide a battery pack which can easily prevent temperature imbalance between battery cells due to heat generation in a current path during charging and discharging, and can be used efficiently. I do.

[0010]

According to a first aspect of the present invention, there is provided an electric insulating outer case, a secondary battery group sealed in the outer case, and a secondary battery group disposed and sealed adjacent to the secondary battery group. A wiring circuit portion having one end connected to the terminal side of the secondary battery group and having a charge / discharge control and protection function, and a charging / discharging terminal connected to the other end of the wiring circuit portion and led out of the outer case. In a battery pack having a secondary battery group, a high thermal conductive sheet is attached to side surfaces of all the secondary batteries forming the secondary battery group, and heat generated in a wiring circuit portion is integrally conducted to the secondary battery group. It is a battery pack characterized by the following.

According to a second aspect of the present invention, in the battery pack according to the first aspect, a secondary battery group is arranged in parallel, and high thermal conductive sheets are attached to both side surfaces. And

According to a third aspect of the present invention, in the battery pack according to the first or second aspect, the high thermal conductive sheet is an aluminum foil.

That is, in the present invention, at least two secondary batteries (battery cells) are electrically connected in series or in parallel, and the battery group is sealed in a plate-like or planar (parallel) in an outer case. It is basically provided with a configuration and a configuration for mainly generating heat in a current path during charging and discharging. Here, the wiring circuit section has a configuration having at least charge / discharge control and protection functions, and furthermore a function of displaying the remaining capacity of the battery capacity if necessary, and is generally based on a printed wiring board. It is a mounted circuit device.

Further, in order to conduct the heat of the wiring circuit part to each secondary battery in an integrated or uniform manner, one end of the high thermal conductive sheet is in contact with (or connected to) or close to the wiring circuit part. It is necessary to attach or cover at least one side surface of the secondary battery group arranged in a shape or a plane (parallel). Here, examples of the high heat conductive sheet include an aluminum foil (sheet) and a copper foil (sheet) having a thickness of about 30 to 40 μm. The outer case 1 is formed of, for example, a polycarbonate (PC) resin, an ABA resin, or the like, and the basic configuration including a wiring circuit portion and the like is the same as that of a conventional battery pack.

According to the first to third aspects of the present invention, heat generated during charging / discharging of the charging / discharging path in the battery pack is easily conducted over the entire secondary battery in the battery pack, and the temperature of each battery forming the battery group is increased. Is maintained substantially uniform. That is, each of the secondary batteries in the battery pack can easily adopt a state in which there is no battery temperature difference during charging and discharging. Therefore, the occurrence of the so-called thermal imbalance is eliminated, and with the elimination of the thermal imbalance, the difference in charge / discharge efficiency between the secondary batteries (or the imbalance in the battery capacity) is eliminated, and overcharge and overdischarge are prevented. Will be.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described below with reference to FIGS.

FIG. 1 is a cross-sectional view showing an example of a main configuration of a battery pack according to the first embodiment. In FIG. 1, reference numeral 1 denotes an electrically insulating outer case, and 2 denotes a secondary battery group including secondary batteries 2a, 2b, 2c, 2d, 2e, 2f, and 2g sealed in the outer case 1. Here, the outer case 1 includes an outer case body 1a having one end opening made of, for example, PC resin or ABA resin, and a lid 1b for sealing the opening of the outer case body 1a.
And formed. The secondary battery group 2 has a configuration in which, for example, nickel-metal hydride secondary batteries 2a, 2b, 2c, 2d, 2e, 2f, and 2g are connected in series (or in parallel).

Reference numeral 3 denotes a wiring circuit portion which is disposed and sealed adjacent to the secondary battery group 2 and has one end connected to the terminal side of the secondary battery group 2 and which has a charge / discharge control and protection function. A charging / discharging terminal connected to the other end of the unit 3 and led out of the outer case 1 (one side wall of the outer case body 1a). Here, the wiring circuit unit 3 includes a circuit or an element having at least charge / discharge control and protection functions on the main surface of the printed wiring board 3a. Further, if necessary, the battery group 2 also has a remaining capacity display function (mechanism). In this case, the display unit is exposed on the outer case 1 (for example, one side wall of the outer case body 1a).

Reference numeral 5 denotes a high thermal conductive sheet, for example, an aluminum sheet, which is attached to and disposed on the side surfaces of the secondary batteries 2a, 2b, 2c, 2d, 2e, 2f, 2g forming the battery group 2. Here, one end of the aluminum sheet 5 is connected to the wiring circuit section 3.
Is wound around and fixed to the side wall surface of the secondary battery 2a adjacent thereto, and the other end is attached along the side wall surface of the secondary battery 2a, 2b, 2c, 2d, 2e, 2f, 2g.

That is, the heat generated by the wiring circuit section 3 which forms the main part of the current path is conducted integrally to the secondary battery group 2, and all the secondary batteries 2a, 2b, 2c, 2d, 2e, 2f, 2g It is configured such that a substantially uniform battery temperature can be easily taken. The aluminum sheet 5 has a thickness of about 35 μm.
The width is about 50 mm, and the side wall surface of the battery group 2 is covered by about 2/3.

FIG. 2 is a sectional view showing an example of a configuration of a main part of a battery pack according to a second embodiment. In the case of this configuration example, the same configuration as that of the first embodiment is adopted except that the aluminum sheet 5 is attached and arranged over both side walls of the secondary battery group 2 having the configuration arranged in parallel. Therefore, detailed description is omitted.

In any case, the battery pack according to each of the above-described embodiments has a current path (mainly a wiring circuit section) in a constant current charge of 2 A or constant current discharge of 4 A, for example.
Heat is easily and efficiently conducted to the entire rechargeable battery, and the rechargeable batteries 2a, 2b, 2c, 2d, 2e, 2f, 2g
The temperature difference between the two is eliminated, and the two batteries (secondary batteries 2a,
2b, 2c, 2d, 2e, 2f, 2g), it was confirmed that the occurrence of thermal imbalance was easily prevented, and the charge / discharge efficiency of the battery pack was improved.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the invention. For example, the material of the outer case 1 and the type, standard, and number of batteries forming the secondary battery group 2 can be appropriately selected and changed according to the application.

[0024]

According to the first to third aspects of the present invention, in a plurality of batteries incorporated in a battery pack, heat generated in a current path during charge / discharge in the battery pack is easily conducted to the entire battery group. The risk of temperature difference between batteries is completely avoided.
Will be resolved. That is, the occurrence of thermal imbalance in the battery pack is prevented, and accordingly, the occurrence of battery capacity imbalance among a plurality of rechargeable batteries contained therein is also prevented. Will be prevented. Therefore, it is possible to provide a battery pack that is easy to operate and has excellent charge / discharge efficiency.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a configuration of a main part of a battery pack according to a first embodiment.

FIG. 2 is a sectional view showing an example of a configuration of a main part of a battery pack according to a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Insulating outer case 1a ... Insulating outer case main body 1b ... Insulating outer case lid 2 ... Secondary battery group 2a-2g ... Secondary battery 3 ... Wiring circuit part 3a ... Printed wiring Plate 4: Charge / discharge terminal 5: High thermal conductive sheet

Claims (3)

[Claims] 1. An electrically insulating outer case, a secondary battery group sealed in the outer case, and disposed and sealed adjacent to the secondary battery group, one end of which is provided on a terminal side of the secondary battery group. A wiring circuit unit having a charge / discharge control and protection function to be connected;
In a battery pack having a charge / discharge terminal connected to the other end of the wiring circuit portion and led out of the outer case, a high heat conductive sheet is provided on a side wall portion of all the secondary batteries forming the secondary battery group. A battery pack, wherein the battery pack is attached, and heat generated by a wiring circuit portion is conducted integrally to a secondary battery group. 2. The battery pack according to claim 1, wherein the secondary battery group has a configuration in which the secondary batteries are arranged in parallel, and the high thermal conductive sheets are attached to both side surfaces. 3. The battery pack according to claim 1, wherein the high thermal conductive sheet is an aluminum foil.