Battery module

Abstract

The present application can provide a battery module, a method for manufacturing method the same and a thermally conductive material applied to the manufacturing method. The present application can provide a battery module having excellent output relative to volume and heat dissipation characteristics, with being manufactured in a simple process and at a low cost, a method for manufacturing the same, and a thermally conductive material applied to the manufacturing method.

Claims

1. A battery module comprising: a module case having a bottom plate; a plurality of battery cells; and a resin layer, wherein at least two convex portions for guiding the battery cells are formed on the bottom plate, wherein each of the plurality of battery cells is disposed in a location between adjacent ones of the at least two convex portions, wherein the battery module further comprises either: (a) a plurality of cooling plates, wherein each of the plurality of cooling plates is disposed in a location between adjacent ones of the at least two convex portions and between said battery cells and a surface of the bottom plate, the surface being between adjacent ones of the at least two convex portions, wherein the resin layer fills a space between the bottom plate and each of the plurality of cooling plates disposed in a location between adjacent ones of the at least two convex portions; or (b) a cooling fin disposed in a location between adjacent ones of the plurality of battery cells and positioned on one of the at least two convex portions so as to cover an upper surface of the convex portion, wherein an end portion of the cooling fin facing the one of the at least two convex portions has a shape conforming to the convex portion such that the end portion of the cooling fin extends outward along opposing surfaces of the convex portion, wherein the resin layer is positioned between the convex portion and the end portion of the cooling fin while being in contact with said end portion of the cooling fin and said convex portion.

2. The battery module according to claim 1, wherein the bottom plate comprises a region having a thermal conductivity of 10 W/mK or more.

3. The battery module of claim 1, wherein the bottom plate is in thermal contact with a cooling medium and the resin layer.

4. The battery module according to claim 1, wherein the resin layer covers an area of 10% or more of the entire area of the bottom plate.

5. The battery module according to claim 1, wherein the resin layer has a thermal conductivity of 2 W/mK or more.

6. The battery module according to claim 1, wherein the resin layer has a breakdown voltage of 10 kV/mm or more.

7. The battery module according to claim 1, wherein the resin layer has a specific gravity of 5 or less.

8. The battery module according to claim 1, wherein the resin layer has an 800° C. remaining amount of at least 70% by weight in a thermogravimetric analysis (TGA).

9. The battery module according to claim 1, wherein the resin layer comprises an acrylic resin, an epoxy resin, a urethane resin, an olefin resin, an EVA resin, or a silicone resin.

10. The battery module according to claim 1, wherein the resin layer comprises fillers.

11. The battery module according to claim 10, wherein the fillers are ceramic particles or carbon-based fillers.

12. The battery module according to claim 1, wherein the resin layer comprises a thixotropic agent, a diluent, a dispersant, a surface treatment agent, a flame retardant, or a coupling agent.

13. A battery pack comprising at least two battery modules of claim 1, wherein said at least two battery modules are electrically connected to each other.

14. An automobile comprising the battery module of claim 1.

15. An automobile comprising the battery pack of claim 13.

16. A battery module comprising: a module case having a bottom plate; a plurality of battery cells; and a resin layer, wherein at least two convex portions for guiding the battery cells are formed on the bottom plate, wherein each of the plurality of battery cells is disposed in a location between adjacent ones of the at least two convex portions, wherein the battery module further comprises: a cooling plate disposed in a location between adjacent ones of the at least two convex portions and between said battery cells and a surface of the bottom plate, the surface being between adjacent ones of the at least two convex portions, wherein the resin layer fills a space between the bottom plate and the cooling plate disposed in a location between adjacent ones of the at least two convex portions; and a cooling fin disposed in a location between adjacent ones of the plurality of battery cells and positioned on one of the at least two convex portions so as to cover an upper surface of the convex portion, wherein the resin layer is positioned between the convex portion and the cooling fin while being in contact with said cooling fin and said convex portion, wherein the cooling plate and the cooling fin are in direct contact.

17. The battery module according to claim 16, wherein when the battery module comprises the cooling fin, the cooling fin has a thermal conductivity of 10 W/mK or more, and when the battery module comprises the cooling plate, the cooling plate has a thermal conductivity of 10 W/mK or more.

18. A battery module comprising: a module case having a bottom plate; a plurality of battery cells; and a resin layer, wherein a plurality of convex portions for guiding the battery cells are formed on the bottom plate, wherein each of the plurality of battery cells is disposed in a location between adjacent ones of the plurality of convex portions, wherein the battery module further comprises: a plurality of cooling plates each respectively disposed in a location between adjacent ones of the a plurality of convex portions and between said battery cells and a surface of the bottom plate, the surface being between adjacent ones of the plurality of convex portions; and a plurality of cooling fins each respective disposed in a location between adjacent ones of the plurality of battery cells and positioned on one of the plurality of convex portions so as to cover an upper surface of the respective convex portion, wherein the resin layer fills spaces between the bottom plate and the plurality of cooling plates and is positioned between the plurality of convex portion and the plurality of cooling fins while being in contact with said plurality of cooling fins and said plurality of convex portions, and wherein each of the plurality of cooling plates is in direct contact with two of the plurality of cooling fins.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIGS. 1 and 2 are views showing the structure of an exemplary battery module.

(2) FIGS. 3 and 4 are views showing an exemplary pouch type battery.

DESCRIPTION OF REFERENCE NUMERALS

(3) 100: battery cell assembly 200: housing 210: bottom plate 301: cooling plate 302: cooling fin 400: battery cell 100: pouch type battery 110: electrode assembly 120: exterior material 121: upper pouch 122: lower pouch S: sealing portion

MODE FOR INVENTION

(4) Hereinafter, a battery module according to the present application will be described with reference to examples and comparative examples, but the scope of the present application is not limited by the scope set out below.

(5) 1. Evaluation Method for Thermal Conductivity of Resin Layer

(6) The thermal conductivity of the resin layer was measured according to ASTM D5470 standard. That is, according to the standard of ASTM D5470, a resin layer was positioned between two copper bars and then, after contacting one of the two copper with a heater and contacting the other with a cooler, the heater was maintained at a constant temperature and the capacity of the cooler was adjusted to create a thermal equilibrium state (a state showing a temperature change of about 0.1° C. or less for 5 minutes). The temperature of each copper bar was measured in the thermal equilibrium state, and the thermal conductivity (K, unit: W/mK) was evaluated according to the following equation. On evaluating the thermal conductivity, the pressure applied to the resin layer was adjusted to be about 11 Kg/25 cm.sup.2 and the thermal conductivity was calculated based on the final thickness when the thickness of the resin layer was changed during the measurement.
K=(Q×dx)/(A×dT)  <Thermal Conductivity Equation>

(7) In the above equation, K is the thermal conductivity (W/mK), Q is heat moving per unit time (unit: W), dx is the thickness (unit: m) of the resin layer, A is the cross sectional area (unit: m2) of the resin layer, and dT is the temperature difference (unit: K) of the copper bars.

(8) 2. Evaluation Method for Specific Gravity

(9) The specific gravity of the resin layer was measured according to ASTM D792 standard. For example, according to the above standard, after measuring the weight of the resin layer and again measuring the weight in water, the density and specific gravity may be calculated through the difference in the measured weights, or after putting a predetermined amount of powder or pellet (for example, about 5 g) into the already measured volume in the pyrometer, the specific gravity may be calculated at 73.4F° through the difference of the weight and the volume.

(10) 3. Thermogravimetric Analysis (TGA) Method

(11) The thermogravimetric analysis was performed using a TA400 instrument from TA Instrument. Analysis was carried out using about 10 mg of the resin layer, and the analysis was carried out in a temperature range of 25° C. to 800° C. and at a heating rate of 20° C./min under a nitrogen (N2) atmosphere of 60 cm.sup.3/min

(12) 4. Measurement of Breakdown Voltage

(13) The breakdown voltage of the resin layer was evaluated according to ASTM D149 standard. The breakdown voltage means a voltage applied until the moment that a material loses insulation, and the insulation is lost by rapidly increasing conductivity at a high voltage equal to or higher than a certain level. The minimum voltage required to cause insulation breakdown is called the breakdown voltage, and the insulation is generated by completely conducting an arc through a specimen. A voltage gradient may be obtained by dividing the voltage at the moment of breakdown by the insulation thickness. The breakdown voltage was measured using a Backman Industrial PA70-1005/202 instrument, where the thickness of the specimen (resin layer) was about 2 mm and the diameter was about 100 mm

(14) 5. Adhesive Force Measurement

(15) A bottom plate of an aluminum module case, on which an insulating film (epoxy and/or polyester insulating layer) is formed, and a PET (poly(ethylene terephthalate)) film were attached using a resin layer, where the width to be attached was about 10 mm. At this time, the thickness of the resin layer was about 1 mm. The attachment is performed by loading the uncured resin composition between the insulating film and the PET film, and curing it. Thereafter, while peeling the PET film from the insulating side with a speed of about 300 mm/min and a peel angle of 180 degrees, the adhesive force is measured.

(16) 6. Measurement of Hardness

(17) The hardness of the resin layer was measured according to ASTM D 2240 and JIS K 6253 standards. It was performed using Shore A, durometer hardness apparatus, where the initial hardness was measured by applying a load of 1 Kg or more (about 1.5 Kg) to the surface of the flat sample (resin layer) and the hardness was evaluated by identifying the measured value stabilized after 15 seconds.

(18) 7. Reliability Evaluation of Battery Module

(19) The reliability of the battery module was evaluated by measuring the thermal resistance and temperature of the module. The thermal resistance of the battery module was evaluated by positioning the module between the upper and lower blocks of the measuring instrument, executing the DynTIM tester software of the controlling computer, determining the heating current and the measuring time on the software to input them, completing the setting of parameters such as the measurement pressure and the thermal resistance measurement conditions, and allowing the T3Ster and DynTIM tester controlled by the software to measure thermal resistance values based on the measurement conditions. The module temperature was measured by attaching a contact type thermometer based on location of the module. The thermal resistance and the module temperature were measured in a state of the bottom plate of the battery module in contact with the water cooling system. The reliability of each evaluation result was classified into the following criteria.

(20) <Reliability Evaluation Criteria According to Thermal Resistance Evaluation>

(21) Good: thermal resistance of 2.5 K/W or less

(22) Fair: thermal resistance of more than 2.5 K/W up to 3 K/W

(23) Poor: thermal resistance of more than 3 K/W

(24) <Reliability Evaluation Criteria According to Module Temperature>

(25) Good: temperature of 50° C. or less

(26) Poor: temperature of more than 50° C.

Example 1

(27) Preparation of Resin Composition

(28) Alumina (particle size distribution: 1 μm to 60 μm) was mixed with a two-component type urethane adhesive composition (main component: HP-3753 (KPX Chemical), hardener: TLA-100 (manufactured by Asahi Kasei)) in an amount that the two-component type urethane adhesive composition can exhibit a thermal conductivity of about 3 W/mK after curing (in a range of about 600 to 900 parts by weight relative to 100 parts by weight of the two-component total solid content) to produce a resin composition having a viscosity at room temperature of about 250,000 cP, which was applied in manufacturing the following battery module.

(29) Manufacture of Battery Module

(30) Using the prepared resin composition, a battery module having a shape as shown in FIG. 2 was produced. In the form of FIG. 2, the bottom plate (101), the cooling fins (201) and the cooling plate (202) were all made of aluminum. After coating the resin composition on the surface of the bottom plate so as to cover the entire bottom plate, the cooling fins and the cooling plate were mounted on the top of the bottom plate, respectively, the battery cells were mounted between the cooling fins mounted so as to cover the surface of the convex portion, and the resin composition was cured to prepare a battery module.

Example 2

(31) Preparation of Resin Composition

(32) Alumina (particle size distribution: 1 μm to 60 μm) was mixed with a two-component type silicone adhesive composition (main component: SL5100A (manufactured by KCC), hardener: SL5100B (manufactured by KCC)) in an amount that the two-component type silicone adhesive composition can exhibit a thermal conductivity of about 3 W/mK after curing (in a range of about 800 to 1200 parts by weight relative to 100 parts by weight of the two-component total solid content) to produce a resin composition having a viscosity at room temperature of about 130,000 cP, which was applied in manufacturing the following battery module.

(33) Manufacture of Battery Module

(34) A battery module was produced in the same manner as Example 1, except for using the prepared resin composition.

Example 3

(35) A battery module was produced in the same manner as Example 1, except for using the resin composition prepared so as to have a viscosity at room temperature of about 350,000 cP by mixing alumina (particle size distribution: 1 μm to 60 μm) with a two-component type urethane adhesive composition (main component: PP-2000 (KPX Chemical), hardener: TLA-100 (manufactured by Asahi Kasei)) in an amount that the two-component type urethane adhesive composition can exhibit a thermal conductivity of about 3.5 W/mK after curing (in a range of about 600 to 900 parts by weight relative to 100 parts by weight of the two-component total solid content).

Example 4

(36) A battery module was produced in the same manner as Example 1, except for using the resin composition prepared so as to have a viscosity at room temperature of about 500,000 cP by mixing alumina (particle size distribution: 1 μm to 60 μm) with an ambient temperature curable type epoxy adhesive composition obtained from Kukdo Chemical in an amount that the adhesive composition can exhibit a thermal conductivity of about 3 W/mK after curing (in a range of about 600 to 900 parts by weight relative to 100 parts by weight of the two-component total solid content).

Example 5

(37) A battery module was produced in the same manner as Example 1, except for using the resin composition prepared so as to have a viscosity at room temperature of about 150,000 cP by mixing alumina (particle size distribution: 1 μm to 60 μm) with a two-component type urethane adhesive composition (main component: PP-2000 (KPX Chemical), hardener: TLA-100 (manufactured by Asahi Kasei)) in an amount that the two-component type urethane adhesive composition can exhibit a thermal conductivity of about 2 W/mK after curing (in a range of about 400 to 900 parts by weight relative to 100 parts by weight of the two-component total solid content).

Example 6

(38) A battery module was produced in the same manner as Example 5, provided that the module was produced by covering about 50% of the bottom plate area with the resin composition.

Comparative Example 1

(39) A battery module was produced in the same manner as Example 2, except for using the resin composition prepared so as to have a viscosity at room temperature of about 2,000,000 cP by mixing graphite with a two-component type silicone adhesive composition (main component: SL5100A (manufactured by KCC), hardener: SL5100B (manufactured by KCC)) in an amount that the two-component type silicone adhesive composition can exhibit a thermal conductivity of about 1.5 W/mK after curing (in a range of about 100 to 300 parts by weight relative to 100 parts by weight of the two-component total solid content).

Comparative Example 2

(40) A battery module was produced in the same manner as Example 2, except for using the resin composition prepared so as to have a viscosity at room temperature of about 100,000 cP by mixing alumina (particle size distribution: 1 μm to 60 μm) with a two-component type silicone adhesive composition (main component: SL5100A (manufactured by KCC), hardener: SL5100B (manufactured by KCC)) in an amount that the two-component type silicone adhesive composition can exhibit a thermal conductivity of about 1.5 W/mK after curing (in a range of about 300 to 500 parts by weight relative to 100 parts by weight of the two-component total solid content).

Comparative Example 3

(41) A battery module was produced in the same manner as Example 1, except that the resin composition was not used, that is, the resin layer was not formed.

(42) The physical properties of the resin layer and the reliability of the battery module measured for the above Examples and Comparative Examples are summarized in Tables 1 and 2 below.

(43) TABLE-US-00001 TABLE 1 Example 1 2 3 4 5 6 Resin Layer Thermal Conductivity(W/mK) 3 3 3.5 3 2 2 Specific Gravity 3.1 3.1 3.2 3.2 2.6 2.6 Residue at 800° C. (% by weight) >80 >80 >80 >80 ca. 50 ca. 50 Adhesive Force(gf/10 mm) 500 100 450 600 500 500 Hardness(Shore A) 90 60 90 100 70 70 Breakdown Voltage(kV/mm) 15 11 10 <8 4 4 Reliability (thermal resistance) good good good good fair fair Reliability (module temperature) good good good good Good good

(44) TABLE-US-00002 TABLE 2 Comparative Example 1 2 3 Resin Layer Thermal Conductivity(W/mK) 1.5 1.5 — Specific Gravity 2 2 — Residue at 800° C. ca. 60 ca. 60 — (% by weight) Adhesive Force(gf/10 mm) 80 90 — Hardness(Shore A) 40 40 — Breakdown Voltage(kV/mm) 2 5 — Reliability (thermal resistance) poor poor poor Reliability (module temperature) poor poor poor

(45) From the results of Tables 1 and 2, it can be seen that the physical properties of the resin layer are changed by the kind of resin used in the resin layer, and the kind and ratio of the filler, and thus the reliability of the module is affected.

(46) For example, when comparing the results of Examples 1, 2 and 4, it can be seen that the adhesive force on adding alumina in order to secure the same level of thermal conductivity, increases in the order of epoxy, urethane and silicone adhesives, and the hardness increases in the order of epoxy, urethane and silicone adhesives, and it can be confirmed that the specific gravity and the heat resistance (TGA analysis result) are adjusted to a similar level.

(47) In addition, when comparing the results of Examples 1, 3 and 5, it can be confirmed that when the same series of resins have been used, thermal conductivity, specific gravity, heat resistance (TGA analysis result), hardness, and the like are changed depending on the kind and content of the filler. For example, in Example 5, in which a small amount of filler was applied compared to Examples 1 and 3, the thermal conductivity and the specific gravity showed somewhat low values, the heat resistance (TGA analysis) was lowered, the adhesive force was in a similar level, but the hardness was lowered, and the breakdown voltage was lowered as the ratio of the filler influencing on securing insulation was lowered.