JPH0714616A - Storage battery pack - Google Patents

Abstract

PURPOSE:To effectively cool storage batteryies constituting a storage battery pack by moving radiant heat from the container surface of each storage battery to a metallic spacer pressed against the container to unify the temperature difference between batteries, and by transporting the heat with a heat pipe in the form of latent heat. CONSTITUTION:In a storage battery pack 1 fabricated by uniting plural storage batteries, a module battery 2 is formed with a battery assembly consisting of several or several tens batteries. The battery 2 and the heating part of heat pipe 6 are connected with a metallic spacer 5 with high heat-conductivity, and heat of the battery is moved to the heating part of the heat pipe with the spacer 5. An air flow path is generated between batteries to cool the battery. The pipe 6 is made of aluminium, for example, and the spacer 5 is brought into contact with the container surface of the battery 2 by applying pressure. The heat radiation part 7 of the pipe is formed in the form of fins to increase heat radiation effect.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a secondary battery which remarkably generates heat by charging and discharging, especially a lithium battery using an organic electrolyte as an electrolyte, a sealed alkaline battery using nickel as a positive electrode plate, or a dilute sulfuric acid electrolyte. The present invention relates to a storage battery pack in an electric vehicle or the like in which the sealed lead batteries and the like used in the above are collectively used.

[0002]

2. Description of the Related Art In recent years, environmental pollution due to exhaust gas from automobiles has become serious, and therefore low-pollution vehicles and non-pollution vehicles have been actively developed. Electric vehicles are the most promising candidates for pollution-free vehicles, and research and development of storage batteries installed in them are progressing in order to improve their performance and maintainability. Conventionally used lead batteries, nickel-cadmium batteries, and some nickel-metal hydride batteries that have begun to be put into practical use are hermetically sealed for the purpose of maintenance-free. Therefore, during charging / discharging, the battery temperature rises due to the reaction heat associated with the gas absorption reaction in addition to the Joule heat. Since it is necessary to store a large number of batteries in a limited mounting space, the temperature of the battery group rises, reaching 80 ° C. or higher particularly during charging in the summer, and the temperature varies among the batteries. This not only accelerates the deterioration of the batteries, but also the temperature difference between the batteries causes variations in the performance of the batteries and thus variations in the deterioration.

Especially, the variation in the performance between the batteries at the end of life is not only the deterioration of the running performance of the electric vehicle, but also the deteriorated battery is significantly over-discharged and over-charged.
There is a problem in terms of safety, such as the battery smoking or igniting. Therefore, it is more important in practice to make the temperatures of the storage battery groups, that is, the storage batteries uniform, than to raise the temperature of the storage batteries.

Conventionally, in order to suppress the temperature rise of the battery as much as possible, a metal plate is inserted between the batteries to radiate heat from one end (for example, No. Shokai 78-78576), or a heat pipe is built into the battery ( For example, actual exploitation No. 57-117569, actual exploitation
64-1468) or a heat pipe is placed on the side wall of the battery case (Japanese Patent Laid-Open No. 60-107274). However, in these methods, for example, if a heat pipe is attached to each unit battery, it is difficult to apply to a small battery and it is not practical in terms of cost. In the method in which one heat pipe is attached to a plurality of batteries, the battery to which the heat pipe is attached can be cooled, but other batteries are difficult and the temperature difference between the batteries cannot be eliminated.

[0005]

According to the present invention, the heat radiation from the surface of the battery case of each battery is transferred to a pressure-contacted metal spacer to make the temperature difference between the batteries as uniform as possible, and the amount of heat is It is characterized in that it is transported in the form of its latent heat by a pipe. That is, in order to cool the battery uniformly, the heat pipe heating part is brought into contact with the battery surface through a spacer having good thermal conductivity, for example, copper, aluminum, or magnesium alloy body, and the cooling part of the heat pipe radiates heat. Contact with the outside world via fins. Further, the metal spacer has a shape that serves as an air flow path between the batteries.

[0006]

[Function] The heat generated from each battery constituting the storage battery pack is rapidly transferred to the heat pipe through the metal spacer having excellent thermal conductivity which is in close contact with the battery case surface,
Heat is radiated from the heat radiating portion of the heat pipe to reduce the temperature rise of the batteries, and the temperature difference between the batteries is also reduced.

[0007]

The present invention will be described below with reference to the embodiment shown in FIG. In the figure, reference numeral 1 denotes a storage battery pack in which a plurality of storage batteries are integrated, and the constitutional unit thereof is several to several tens or more storage battery assemblies. Reference numeral 2 is a unit cell that constitutes a storage battery pack or a module battery in which several unit cells are integrally connected. 3 and 4 indicate the positive and negative terminals of the battery. Six batteries 2 are used in this embodiment, but the connection wiring between the batteries is omitted. Reference numeral 5 is a metal spacer having good thermal conductivity that connects the battery 2 and the heating portion of the heat pipe 6, and its role is to move the heat of the battery to the heating portion of the heat pipe, and also to provide an air flow path between the batteries. Has the function of forming and cooling. Aluminum was used in this example.
The metal spacer 5 is brought into contact with the battery case surface of each battery 2 as closely as possible. 7 is a heat dissipation part of the heat pipe,
Fins are formed to enhance the heat dissipation effect.

In this embodiment, two heat pipes 6 are attached to the storage battery pack 1, but this varies depending on the size and type of the battery, the charging method, the operating environment and the like. Further, the number and type of the heat pipes 6 used depend on how many times the temperature of the storage battery pack 1 is controlled.

The heat pipe 6 has a heat transfer amount per weight larger than that of general solid heat conduction by one digit or more. In the case of cooling the battery 2 by conventional air cooling, the temperature of the sealed lead-acid battery having a capacity of 100 Ah increased up to 90 ° C. at the time of charging, but in this embodiment, the maximum temperature was 60 ° C. (when the fins were forced to cool) and the battery temperature was low at 30 ° C. It is possible, and the temperature variation between each battery 2 is about 5 ° C.
I was able to hold it within. In an experiment using a lithium secondary battery with a capacity of 30 Ah, the battery temperature exceeded 110 ° C by the conventional method, but the maximum temperature could be suppressed to 70 ° C by the heat pipe method.

[0010]

As described above, according to the present invention, the heat generated from the battery is transmitted to the heat pipe through the metal spacer without providing the movable portion, and the heat is radiated from the heat radiating portion of the heat pipe to lower the battery temperature. The temperature difference between the batteries can be reduced, and the practical value for electric vehicles is extremely high.

[Brief description of drawings]

FIG. 1 is an explanatory view of a main part of an embodiment of a storage battery pack for an electric vehicle according to the present invention.

[Explanation of symbols]

 1 Storage battery pack 2 Storage battery 3 Positive electrode terminal 4 Negative electrode terminal 5 Metal spacer 6 Heat pipe 7 Heat dissipation part (fin) of heat pipe

Claims (2)

[Claims] 1. A metal spacer made of a metal plate or a metal frame having excellent thermal conductivity is pressure-contacted to the battery case surfaces of a plurality of storage batteries that generate heat by charging and discharging, and heat is applied to a part of the metal spacers. A storage battery pack in which a pipe is attached and an air flow path is formed in the metal spacer. 2. The storage battery pack according to claim 1, wherein the heat radiating portion of the heat pipe is forcibly cooled by air.