BATTERY MODULE WITH THERMOCOUPLE UNIT

Abstract

The present invention refers to a battery module comprising: at least one battery cell; a protective circuit module electrically coupled to the battery cell and including a printed circuit board; and a thermocouple unit being assembled on the printed circuit board and including two wires composed of dissimilar conductors, which are joined together at a sensing point provided at the battery cell, the thermocouple unit providing a value for a temperature T.sub.SENCE at the sensing point.

Claims

1. A battery module, comprising: at least one battery cell; a protective circuit module electrically coupled to the battery cell and including a printed circuit board; and a thermocouple unit being assembled on the printed circuit board and including two wires composed of dissimilar conductors, which are joined together at a sensing point provided at the battery cell, the thermocouple unit providing a value for a temperature T.sub.SENCE at the sensing point.

2. The battery module of claim 1, further comprising a temperature sensitive element provided at a surface of the printed circuit board for measurement of a reference temperature T.sub.REF of the thermocouple unit.

3. The battery module of claim 2, wherein the temperature sensitive element is a negative temperature coefficient (NTC) thermistor.

4. The battery module of claim 2, wherein the temperature T.sub.SENCE at the sensing point is given by equation:
T.sub.SENSE=T.sub.REF+T.sub.REF,SENSE wherein T.sub.REF,SENCE is a temperature difference determined by the thermocouple unit on basis of a voltage difference V of the two wires.

5. The battery module of claim 4, wherein the thermocouple unit comprises an operational amplifier for determination of the voltage difference V of the two wires.

6. The battery module of claim 5, wherein the operational amplifier comprises a non-inverting amplifier with an 100 k resistor in a feedback path.

7. The battery module of claim 1, wherein the thermocouple unit comprises a microcontroller, the microcontroller comprising: a database adapted for storage of a characteristic function E(T) for a thermocouple's behavior; a first input line for the reference temperature T.sub.REF measured by the temperature sensitive element; a second input line for the measured voltage difference V of the two wires; and an evaluation unit for determination of the temperature T.sub.SENCE by equation
E(T.sub.SENSE)=V+E(T.sub.REF).

8. The battery module of claim 1, wherein the battery module comprises at least two battery cells, which terminals are interconnected by a bus bar, wherein the sensing point of the thermocouple unit is provided at a surface of the bus bar.

9. A vehicle including a battery module according to claim 1.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0025] Features will become apparent to those of ordinary skill in the art by describing in detail exemplary embodiments with reference to the attached drawings in which:

[0026] FIG. 1 illustrates a perspective view of a battery module.

[0027] FIG. 2 is a side view on a battery module bearing a printed circuit board with multiple thermocouple units according to an embodiment of the present invention.

[0028] FIG. 3 is a partially view on one of the thermocouple unit of the embodiment of FIG. 2.

[0029] FIG. 4 is thermistor circuit useful for measurement of the temperature on the printed circuit board according to an embodiment of the invention.

[0030] FIG. 5 is thermocouple circuit useful for measurement of a voltage difference of the thermocouple unit according to an embodiment of the invention.

[0031] FIG. 6 is a flow diagram illustrating the process of determination of the sensed temperature using a microcontroller.

MODE FOR THE INVENTION

[0032] Features of the inventive concept and methods of accomplishing the same may be understood more readily by reference to the following detailed description of embodiments and the accompanying drawings. Hereinafter, example embodiments will be described in more detail with reference to the accompanying drawings, in which like reference numbers refer to like elements throughout. The present invention, however, may be embodied in various different forms, and should not be construed as being limited to only the illustrated embodiments herein. Rather, these embodiments are provided as examples so that this disclosure will be thorough and complete, and will fully convey the aspects and features of the present invention to those skilled in the art. Accordingly, processes, elements, and techniques that are not necessary to those having ordinary skill in the art for a complete understanding of the aspects and features of the present invention may not be described. Unless otherwise noted, like reference numerals denote like elements throughout the attached drawings and the written description, and thus, descriptions thereof will not be repeated. In the drawings, the relative sizes of elements, layers, and regions may be exaggerated for clarity.

[0033] Spatially relative terms, such as beneath, below, lower, under, above, upper, and the like, may be used herein for ease of explanation to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or in operation, in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as below or beneath or under other elements or features would then be oriented above the other elements or features. Thus, the example terms below and under can encompass both an orientation of above and below. The device may be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein should be interpreted accordingly.

[0034] The electronic or electric devices according to embodiments of the present invention described herein may be implemented utilizing any suitable hardware, firmware (e.g. an application-specific integrated circuit), software, or a combination of software, firmware, and hardware. For example, the various components of these devices may be formed on one integrated circuit (IC) chip or on separate IC chips. Here, the various components of these devices are implemented on a printed circuit board (PCB). Components of these devices may be a process or thread, running on one or more processors, in one or more computing devices, executing computer program instructions and interacting with other system components for performing the functionalities described herein. The computer program instructions are stored in a memory which maybe implemented in a computing device using a standard memory device, such as, for example, a random access memory (RAM). The computer program instructions may also be stored in other non-transitory computer readable media.

[0035] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and/or the present specification, and should not be interpreted in an idealized or overly formal sense, unless expressly so defined herein.

[0036] Referring to FIG. 1, an exemplary embodiment of a conventional battery module 100 includes a plurality of battery cells 10 aligned in one direction and a heat exchange member 110 provided adjacent to a bottom surface of the plurality of battery cells 10. A pair of end plates 18 are provided to face wide surfaces of the battery cells 10 at the outside of the battery cells 10, and a connection plate 19 is configured to connect the pair of end plates 18 to each other thereby fixing the plurality of battery cells 10 together. Fastening portions 18a on both sides of the battery module 100 are fastened to a support plate 31 by bolts 40. The support plate 31 is part of a housing 30. In addition, an elastic member 120 made of rubber or other elastic materials may be interposed between the support plate 31 and the heat exchange member 110.

[0037] Here, each battery cell 10 is a prismatic (or rectangular) cell, the wide flat surfaces of the cells being stacked together to form the battery module. Further, each battery cell 10 includes a battery case configured for accommodation of an electrode assembly and an electrolyte. The battery case is hermetically sealed by a cap assembly 14. The cap assembly 14 is provided with positive and negative electrode terminals 11 and 12 having different polarities, and a vent 13. The vent 13 is a safety means of the battery cell 10, which acts as a passage through which gas generated in the battery cell 10 is exhausted to the outside of the battery cell 10. The positive and negative electrode terminals 11 and 12 of neighboring battery cells 10 are electrically connected through a bus bar 15, and the bus bar 15 may be fixed by a nut 16 or the like. Hence, the battery module 100 may be used as power source unit by electrically connecting the plurality of battery cells 10 as one bundle. Rechargeable secondary batteries may be used as the battery cells 10, especially lithium secondary batteries. The battery module 100 may be a 48V battery for automotive application.

[0038] Generally, the battery cells 10 generate a large amount of heat while being charged/discharged. The generated heat is accumulated in the battery cells 10, thereby accelerating the deterioration of the battery cells 10. Therefore, the battery module 100 further includes a heat exchange member 110, which is provided adjacent to the bottom surface of the battery cells 10 so as to cool down the battery cells 10.

[0039] FIG. 2 is a side view on a battery module 100 bearing a printed circuit board with multiple thermocouple units 200 according to an embodiment of the present invention. FIG. 3 is a partially view on one of the thermocouple units 200 of the embodiment of FIG. 2.

[0040] In general, battery cells of the battery module 100 are electrically connected to a protective circuit module 130. According to the present embodiment, there is only one protective circuit module 130, which is connected to all of the battery cells of the battery module 100. However, there may be also two or more separate protective circuit modules being connected to a group of battery cells or single battery cells.

[0041] The protective circuit module is made to lie down at sides of the battery cells such that there is a gap between the battery cell surface and the side of the protective circuit module facing the battery cells. Here, the protective circuit module is being arranged at the upper surface of the battery cells bearing the electrode terminals and. In particular, the protective circuit module is electrically connected to the bus bars 15 interconnecting battery cells of the battery module 100 to control charging and discharging and preventing the battery cells from being over-charged or over-discharged.

[0042] The protective circuit module includes a rigid printed circuit board (PCB) 131 with connection terminals (not shown) for the terminals of the battery cells and at least one semiconductor device 133 is formed on an upper surface of the PCB 131. The semiconductor device 133 may comprise an integrated circuit that is adapted to compare the measured temperature of a battery cell with a limit value for allowable battery cell temperature. The PCB 131 includes a wiring pattern (not shown) formed on a surface of the PCB 131. A main body of the PCB 131 may be formed of a rigid electrically insulating material like polyimide (PI) or polyethylene (PET). The wiring pattern may be made of an electrically conductive material, such as copper (Cu), titanium (Ti), nickel (Ni), or palladium (Pd).

[0043] The semiconductor device 133 applies signals for controlling operations of the battery cells. In particular, the semiconductor device 133 controls charging or discharging extents through high current lines of the battery cells. In addition, the semiconductor device 133 applies signals indicating voltages, current and temperatures of the battery cells to prevent for example over-charge or over-discharge.

[0044] To this end, the semiconductor device 133 applies information about the temperatures of the battery cells from a thermocouple unit 200 and controls the operations of the battery cells. Here, the information about the voltages, currents and temperatures may be transferred to the semiconductor device 133 through the wiring pattern of the PCB 131.

[0045] The thermocouple unit 200 includes a first wire 210 and second wire 220 each connecting the bus bar 15 and the PCB 131. More precisely, the first wire 210 and the second wire 220 are welded to a common area 230 provided at the PCB 131. Within the common area 230 the temperature of the PCB 131 should not deviate. The other ends the first wire 210 and the second wire 220 are welded to the bus bar 15 providing a common sensing point 240 (or junction). Within the sensing point 240 the temperature of the bus bar 15 should not deviate.

[0046] The first wire 210 and the second wire 220 are made of dissimilar thermal conducting materials, especially metallic materials like pure metal elements of alloys thereof. For example, the first wire 210 may be made of aluminum (Al) and the second wire 220 may be made of copper (Cu), however not limited thereto.

[0047] The physical principle of Seebeck effect refers to an electromotive force whenever there is a temperature gradient in a conductive material. Where there is no internal current flow, the gradient of voltage is directly proportional to the gradient in temperature. The proportional factor is called Seebeck coefficient and represents a material specific characteristics. Keeping in mind that the thermocouple unit 200 includes two wires 210, 220 of different materials a characteristic function E(T) could be determined for capturing thermocouple's behavior.

[0048] FIG. 4 is thermistor circuit 300 useful for measurement of the temperature on the PCB 131 according to an embodiment of the invention. The thermistor circuit 300 is implemented within the PCB 131 andaccording to the illustrated embodimentthe thermistor is an NTC thermistor. Such a thermistor circuit 300 is common knowledge and for the purpose of the present invention, the only important aspect is that the circuit 300 is assembled on the PCB 131 such that it provides a reference temperature T.sub.REF for the common area 230 of the PCB 131.

[0049] FIG. 5 is thermocouple circuit 400 useful for measurement of a voltage difference V of the thermocouple unit 200 according to an embodiment of the invention. The thermocouple circuit 400 is assembled on the PCB 131. The temperature T.sub.SENCE at the sensing point 240 is given by equation

T.sub.SENCE=T.sub.REF+T.sub.REF;SENSE

[0050] where T.sub.REF,SENCE is a temperature difference determined by the thermocouple unit 200 on basis of a voltage difference V of the first and second wires 210, 220.

[0051] Therefore, the thermocouple circuit 400 of the thermocouple unit 200 includes an operational amplifier for determination of the voltage difference V of the two wires 210, 220. The operational amplifier includes a non-inverting amplifier with an 100 k resistor R1803 in a feedback path. The first wire 210 is electrically coupled to a non-inverting input terminal 1 of the amplifier via a resistor R1801. The second wire 220 is electrically coupled to an inverting input terminal 3 of the amplifier via a resistor R1802. The output terminal 4 of the amplifier is passed through resistor 1807 so as to provide a characteristic signal for the voltage difference V. In this embodiment, the resistors R1801 and R1802 exemplarily have the same value of 2.2 k The resistor 1807 has a value of 1.5 k

[0052] FIG. 6 is a flow diagram illustrating the process of determination of the sensed temperature T.sub.SENSE using a microcontroller 500. Basically, the input data of the microcontroller 500 include the reference temperature T.sub.REF provided by the thermistor circuit 300 and the voltage difference V provided by the thermocouple circuit 400. The microcontroller 500 further includes a memory unit for storage of a characteristic function E(T) for the specific thermocouple's behavior (not shown). The microcontroller 500 numerically determines the sensed temperature T.sub.SENSE under consideration of the characteristic function E(T) by equation

E(T.sub.SENSE)=V+E(T.sub.REF).