Battery pack

Abstract

The present invention relates to a battery pack (10). The battery pack (10) includes a plurality of battery cells (22) electrically coupled to each other, a BMS module (50) configured to manage the plurality of battery cells (22), a casing (20) configured to store the plurality of battery cells (22), a top cover (30) configured to cover the casing (20) and house the BMS module (50), and a heat sink (40) in thermal contact with the BMS module (50). The heat sink (40) is attached to at least one first portion (57) of the BMS module (50) and is embedded within the top cover (30) or the heat sink (40) is integrally molded to at least a second portion (37) of the top cover (30). The heat sink (40) is configured to dissipate heat from the BMS module (50) to the outside of the casing (20) and the top cover (30).

Description

Technical Field

[0001] The present invention generally relates to battery packs, and more particularly to the top cover, BMS module, and heat sink of a battery pack.

Background Art

[0002] Advances in electric and hybrid electric vehicle technologies herald a new era in which vehicles run on stored electrical energy. Generally, a battery pack serves as the energy source of an electric vehicle. A battery pack includes a plurality of battery cells electrically interconnected with each other. A Battery Management System (BMS) plays an important role in managing the battery pack and monitoring its soundness. The BMS prevents a rechargeable battery pack from operating outside its safe operating range, monitors the state of the battery pack, calculates secondary data, reports the collected data, controls the environment of the battery pack, and protects the battery pack by authenticating and / or balancing the battery pack, etc. It is an electronic system that manages a rechargeable battery pack. The BMS monitors the voltage, charging current, temperature, state of charge, etc. of the battery cells of the battery pack to ensure the effective operation and long life of the battery pack.

[0003] The BMS consists of many electronic components that generate heat during operation. The BMS will continue to operate under any circumstances as long as the battery pack can continue to operate. Therefore, during the vehicle driving state where the battery pack discharges energy or during the vehicle charging state where the battery pack accumulates energy, the BMS can operate and generate a fairly large amount of heat. Conventionally, the BMS is a printed circuit board (PCB) in which various electrical and electronic components including metal oxide semiconductor field effect transistors (MOSFETs) are embedded. The various electrical and electronic components embedded in the BMS heat up and dissipate heat during the operation of the BMS. Furthermore, the battery cells of the battery pack also generate heat during operation, adding to the heat generated by the BMS and causing heat to accumulate in the battery pack. This poses a risk of failure of the entire battery pack. For the safe and reliable operation of the battery pack, the BMS must be maintained within its safe temperature limit. Otherwise, it may lead to the failure of the MS and thus potentially damage the lifespan of the battery pack. The failure of the BMS can even lead to serious accidents that endanger the lives of the vehicle driver and passengers.

[0004] In existing designs, a heat sink can be provided in the battery pack by attaching the heat sink on the PCB of the BMS. However, the entire assembly of the heat sink and the BMS is disposed inside the battery pack surrounded by stagnant air. Air is a very poor heat conductor and does not allow heat to dissipate from the heat sink, thereby collecting heat inside the BMS and increasing the accumulation of heat within the BMS. Furthermore, the hermetically sealed battery pack for safety reasons also acts against efficient heat dissipation. The hot air remains trapped inside the battery pack as stagnant hot air. As time passes, the heat sink becomes less effective in dissipating the heat generated by the BMS, and the temperature of not only the BMS but also the battery pack increases due to the surrounding stagnant hot air. Moreover, the higher temperature of the battery pack has an adverse effect on the multiple battery cells of the battery pack, reducing the battery pack performance and causing customer dissatisfaction.

[0005] Also, the case and its cover for the battery cells of the battery pack are generally made of a resin material and thus do not effectively conduct heat. Therefore, the entire battery pack maintains heating during vehicle operation and charging, leading to very high temperatures and longer cooling periods. Another obvious solution to this problem is to change the material used for the case and its cover of the battery pack to metal and / or use a fan for cooling. However, this increases the weight of the battery pack, increases the power consumption, and further increases the overall cost of the battery pack due to the addition of more components. Therefore, in order to avoid failures of the BMS and thus the battery pack, it is essential to ensure the efficient dissipation of heat generated by the BMS in an efficient manner to the surrounding environment outside the battery pack.

Summary of the Invention

Problems to be Solved by the Invention

[0006] Therefore, there is a need in the art for a battery pack having an efficient and inexpensive heat dissipation mechanism for the BMS of the battery pack that at least addresses the aforementioned problems.

Means for Solving the Problems

[0007] In one aspect, the present invention is directed to a battery pack. The battery pack includes a plurality of battery cells electrically coupled to each other and a BMS module configured to manage the plurality of battery cells. The battery pack is provided with a casing configured to store the plurality of battery cells and a top cover configured to cover the casing. The top cover is further configured to house the BMS module and a heat sink. The heat sink is configured to dissipate heat from the BMS module to the outside of the casing and the top cover. The heat sink is in thermal contact with at least one first portion of the BMS module. In one embodiment, the heat sink is attached to at least one first portion of the BMS module and embedded in the top cover. In another embodiment, the heat sink is integrally molded into at least a second portion of the top cover.

[0008] In a further embodiment, the casing includes a base portion and four side surfaces. The four side surfaces extend perpendicularly from the edges of the base portion to form the casing. The top cover is disposed on the opposite side of the base portion so as to cover the casing.

[0009] In another embodiment, the plurality of battery cells are stacked in a row such that the lengths of the plurality of battery cells are parallel to the base portion of the casing and the top cover. Also, the width of each of the plurality of battery cells is parallel to any one of the side surfaces of the casing. In one embodiment, the BMS module is disposed adjacent to the far row of the plurality of battery cells.

[0010] In yet another embodiment, the top cover includes a notch configured to receive the heat sink and a corresponding packing. The packing is configured to prevent water and dust from entering the casing through the notch of the top cover. In one embodiment, the heat sink is fixed within the notch of the top cover and the packing is fixed around the notch.

[0011] In a further embodiment, the heat sink includes an inner surface disposed on the BMS module and an outer surface exposed to the outside of the casing. The inner surface is thermally coupled to the BMS module. The outer surface is adapted to dissipate heat to the atmosphere outside the casing and includes a plurality of fins exposed to the outside of the casing. In one embodiment, the plurality of fins are pin fins. In another embodiment, the heat sink has a substantially T-shaped profile when viewed in a direction orthogonal to the top cover.

[0012] In a further embodiment, the BMS module includes a base member having a plurality of interconnected electrical and electronic components for controlling the operation of the battery pack. Further, the base member has a first surface facing the plurality of battery cells and a second surface opposite the first surface facing the top cover.

[0013] In one embodiment, the heat sink is mounted on the base member of the BMS module such that the inner surface of the heat sink is in thermal contact with the second surface of the base member.

[0014] In another embodiment, the plurality of heat-dissipating electronic components of the BMS module are mounted on at least a part of the first surface of the base member on the side opposite to the inner surface of the heat sink. The heat generated within the plurality of heat-dissipating electronic components is dissipated to the heat sink.

[0015] In a further embodiment, the heat sink is made of a metallic material and the top cover is made of a resin material.

[0016] Embodiments of the present invention will be referred to, examples of which may be shown in the accompanying drawings. These drawings are intended to be illustrative and not limiting. It should be understood that the present invention is generally described in the context of these embodiments, but it is not intended to limit the scope of the present invention to these specific embodiments.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Mode for Carrying Out the Invention

[0018] Various features and embodiments of the present invention will become apparent from the following further description of this specification described below. The present invention generally relates to a battery pack, and more particularly to the top cover, BMS module, and heat sink of a battery pack.

[0019] FIG. 1 shows a top perspective view of an exemplary battery pack 10 according to one embodiment of the present invention. The battery pack 10 includes a plurality of battery cells 22 that are electrically coupled to each other (shown in FIG. 4). In one embodiment, the plurality of battery cells 22 may be grouped into one or more battery modules of the battery pack 10. The illustrated embodiment shows the X, Y, and Z axes of the battery pack 10. FIG. 2 shows a plan view of the battery pack 10 according to one embodiment of the present subject matter, and FIG. 3 shows a side view of the battery pack 10. Referring to FIG. 2, for cross-sectional division of the battery pack 10, two virtual planes A and B are defined along the Y axis of the battery pack 10. Plane A is parallel to the X axis of the battery pack 10, and plane B is parallel to the Z axis, respectively. Referring to FIGS. 1, 2, and 3, the battery pack 10 includes a casing 20 adapted to store a plurality of battery cells 22 and a top cover 30. The top cover 30 is adapted to cover the casing 20 from an upper portion. In one embodiment, the casing 20 has a cubic shape. The casing 20 includes a base portion 24 and four side surfaces 26 extending perpendicularly from the edges of the base portion 24. The casing 20 is open at an upper portion opposite to the base portion 24, whereby a plurality of battery cells 22 and other electrical and electronic components of the battery pack 10 are received into the casing 20 through the open upper portion. In the illustrated embodiment, the top cover 30 is disposed on the opposite side of the base portion 24 so as to cover the casing 20 at the open upper portion of the casing 20. Further, the Y axis of the battery pack 10 is orthogonal to the base portion 24 and the top cover 30. In another embodiment, the four side surfaces 26 extending perpendicularly from the edges of the base portion 24 of the casing 20 are adapted to receive the top cover 30 and fix the top cover 30 to the casing 20. In yet another embodiment, the casing 20 and the top cover 30 are made of a resin material.

[0020] FIG. 4 shows a cross-sectional view of an upper portion of the battery pack 10 along the Z-axis in the plane A shown in FIG. 2 according to an embodiment of the present invention. The plurality of battery cells 22 are stacked in a plurality of rows. The plurality of battery cells 22 are stacked such that the lengths of the plurality of battery cells 22 are parallel to the base portion 24 and the top cover 30 of the casing 20. In the illustrated embodiment, the lengths of the plurality of battery cells 22 are parallel to the Z-axis of the battery pack 10. Further, the width W of each of the plurality of battery cells 22 is parallel to any of the side surfaces 26 of the casing 20. In the illustrated embodiment, the width W of each of the plurality of battery cells 22 is parallel to the shorter pair of the four side surfaces 26 of the casing 20, that is, the width W of each of the plurality of battery cells 22 is parallel to the X-axis of the battery pack 10. In another embodiment, the BMS module 50 is disposed adjacent to the far row 23 of the plurality of battery cells 22 within the battery pack 10.

[0021] FIG. 5 shows a cross-sectional view of an upper portion of the battery pack 10 along the X-axis in the plane B shown in FIG. 2 according to an embodiment of the present invention. The battery pack 10 includes a BMS module 50 adapted to manage a plurality of battery cells 22. The BMS module 50 monitors the voltage, charging current, temperature, state of charge, etc. of the plurality of battery cells 22 and maintains them within a safe operating range to ensure the effective operation and long life of the plurality of battery cells 22 and thus the battery pack 10. In the illustrated embodiment, the BMS module 50 is housed within the top cover 30. The battery pack 10 includes a heat sink 40 in thermal contact with at least one first portion 57 of the BMS module 50. The heat sink 40 is adapted to dissipate heat from the BMS module 50 to the outside of the casing 20 and the top cover 30. In one embodiment, the heat sink 40 includes an inner surface 42 disposed on the BMS module 50. The inner surface 42 of the heat sink 40 is also thermally coupled to the BMS module 50 so as to conduct heat away from the BMS module 50 to the body of the heat sink 40. The heat sink 40 further includes an outer surface 44 having a plurality of fins 46. The plurality of fins 46 are exposed to the outside of the casing 20 and the top cover 30 and are adapted to dissipate heat to the atmosphere outside the casing 20 and the top cover 30. Thus, the heat generated within the BMS module 50 is transferred to the heat sink 40 and effectively dissipated to the outside of the casing 20 and the top cover 30 by the plurality of fins 46.

[0022] In one embodiment, the BMS module 50 includes a base member 51, and a plurality of electrical and electronic components are interconnected with the base member 51 to control the operation of the battery pack 10. The base member 51 is a printed circuit board (PCB) with a plurality of electrical and electronic components including metal-oxide-semiconductor field-effect transistors (MOSFETs) embedded therein. In the illustrated embodiment, the base member 51 includes a first surface 52 facing the plurality of battery cells 22 and a second surface 54 opposite the first surface 52. The second surface 54 faces the top cover 30. In one embodiment, the heat sink 40 is mounted on the base member 51 of the BMS module 50, and the inner surface 42 of the heat sink 40 is in thermal contact with the second surface 54 of the base member 51. In another embodiment, the heat sink 40 is mounted only on a part of the base member 51, and the plurality of electrical and electronic components are mounted on the remaining area of the base member 51. For effective heat dissipation, a thermal paste may be applied to the interface between the second surface 54 of the base member 51 and the inner surface 42 of the heat sink 40.

[0023] FIG. 6 shows a top perspective view of an exemplary top cover 30 of the battery pack 10 according to one embodiment of the present invention. The heat sink 40 is integrally molded into at least a second portion 37 of the top cover 30. This ensures that the top cover 30 and the heat sink 40 form an integral unit with no gaps therebetween, enabling an airtight seal assembly of the battery pack 10.

[0024] FIG. 7 shows an exploded view of the top cover 30 of the battery pack 10 according to an embodiment of the present invention. The heat sink 40 is attached to at least one first portion 57 (shown in FIG. 5) of the BMS module 50 and is embedded in the top cover 30. In one embodiment, the top cover 30 includes a notch 32 configured to receive the heat sink 40 and a packing (not shown). The heat sink 40 is fixed within the notch 32 of the top cover 30. The packing is fixed around the notch 32 and is configured to prevent water, dust, and any foreign matter from entering the casing 20 through the notch 32 of the top cover 30. In this case, the top cover 30 is molded separately from the heat sink 40, and they are mechanically assembled by attaching the heat sink 40 within the notch 32. The packing helps to waterproof the battery pack 10 on the side of the top cover 30. In yet another embodiment, the heat sink 40 is adhered to the top cover 30 so as to be disposed within the notch 32 using an adhesive. The adhesive serves the purpose of fixing the heat sink 40 to the top cover 30 and also seals the edge of the notch 32 to provide an airtight seal at the interface.

[0025] FIG. 8 shows a top perspective view of an exemplary heat sink 40 of the battery pack 10 according to an embodiment of the present invention. In one embodiment, the heat sink 40 has a substantially T-shaped profile (also shown in FIG. 2) when viewed in a direction orthogonal to the top cover 30. The T-shaped profile of the heat sink 40 is designed to provide effective heat dissipation from the BMS module 50 without compromising the strength and integrity of the top cover 30. In another embodiment, the plurality of fins 46 on the outer surface 44 of the heat sink 40 are pin fins. The pin fins provide more surface area for heat dissipation and thus increase the effectiveness in cooling the BMS module. In yet another embodiment, the heat sink 40 is composed of a metallic material. A metallic material such as aluminum, which is conductive and lightweight, is preferred. By ensuring that the fins 46 of the heat sink 40 are exposed outside the battery pack 10, the fins 46 allow direct conduction, convection, and radiation of the accumulated heat to the environment outside the battery pack 10, thus achieving effective cooling of the BMS module 50.

[0026] FIG. 9 shows a schematic cross-sectional view of the upper portion of the battery pack 10 along the X-axis in plane B shown in FIG. 2 according to an embodiment of the present invention. A plurality of heat-dissipating electronic components 56 of the BMS module 50 are attached to at least a part of the first surface 52 of the base member 51 in order to dissipate the heat generated within the plurality of heat-dissipating electronic components 56 to the heat sink 40. Accordingly, the plurality of heat-dissipating electronic components 56 of the BMS module 50 are attached on the side opposite to the inner surface 42 of the heat sink 40, and the heat generated within the plurality of heat-dissipating electronic components 56 is transmitted through the BMS module 50 to the second surface 54 of the base member 51 and dissipated so as to move away from the heat sink 40. In one embodiment, the plurality of heat-dissipating electronic components 56 may be attached on the second surface 54 of the base member 51 on the same side as that of the inner surface 42 of the heat sink. In one embodiment, the plurality of heat-dissipating electronic components 56 are composed of MOSFETs. The MOSFETs generate the maximum heat energy that needs to be dissipated since they are the main heat generation sources within the BMS module 50.

[0027] Advantageously, the present invention provides a battery pack having a heat sink provided on a top cover and an improved design of the top cover for the casing of the battery pack to effectively dissipate heat mainly generated within the BMS module of the battery pack to the outer ambient environment. The present invention provides a direct conduction path from the heat source, which is the BMS module, to the ambient environment via the heat sink. This enables effective and efficient heat dissipation. Since the heat sink is integrated with the top cover of the battery pack, the number of component sub-parts required for the heat sink assembly within the battery pack is reduced. This results in a reduction in the overall weight and cost of the battery pack. The efficient heat dissipation by the heat sink prevents heat confinement within the area of the battery pack, ensures that the battery system operates within the intended operating temperature, brings about an improvement in product life, durability, and performance, and also ensures safety. Further, the present invention proposes effective passive cooling of the BMS module, thereby eliminating the need for any external active energy source for cooling the BMS module. Thus, the claimed mechanism is simple and economical. Integrating the heat sink with the top cover forms a sub-assembly, thereby making the assembly process easier. The claimed system efficiently dissipates heat, so the heat mass required for the heat sink is relatively small.

[0028] The claimed configuration of the battery pack as described above enables the following solutions to the existing problems in the prior art. Therefore, the claimed configuration of the battery pack is not commonplace, not conventional, and not well understood in the art. Specifically, the present invention achieves effective heat dissipation of the heat mainly generated in the BMS module of the battery pack. It provides a direct conduction path from the heat source, which is the BMS module, to the surrounding environment via the heat sink. This enables effective and efficient heat dissipation. The efficient heat dissipation by the heat sink prevents heat confinement within the area of the battery pack, ensures that the battery system operates within the intended operating temperature, brings about improvements in product life, durability, and performance, and also ensures safety.

[0029] Although the present invention has been described with respect to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the scope of the invention as defined in the following claims.

Explanation of Reference Numerals

[0030] 10 Battery pack 20 Casing 22 Plurality of battery cells 23 Remote row of plurality of battery cells 24 Base portion of the casing 26 Side surface of the casing 30 Top cover 32 Notch in the top cover 37 Second portion of the top cover 40 Heat sink 42 Inner surface of the heat sink 44 Outer surface of the heat sink 46 Plurality of fins 50 BMS module 51 Base member of the BMS module 52 First surface of the base member 54 Second surface of the base member 56 Heat - dissipating electronic components of the BMS module One first part of the 57 BMS modules W Width of each of the plurality of battery cells X, Y, Z Axes of the battery pack A, B Virtual planes defined for cross-sectional division of the battery pack

Claims

1. A plurality of battery cells (22) electrically coupled to each other, a BMS module (50) configured to manage the plurality of battery cells (22), a casing (20) configured to store the plurality of battery cells (22), a top cover (30) configured to cover the casing (20) and house the BMS module (50), a heat sink (40) in thermal contact with at least one first portion (57) of the BMS module (50), wherein the heat sink (40) is attached to the at least one first portion (57) of the BMS module (50) and embedded in the top cover (30), and is one of integrally molded with at least a second portion (37) of the top cover (30), and the heat sink (40) is configured to dissipate heat from the BMS module (50) to the outside of the casing (20) and the top cover (30), a battery pack (10).

2. The casing (20) includes a base portion (24) and four side faces (26), and the four side faces (26) extend perpendicularly from an edge of the base portion (24) to form the casing (20). The battery pack (10) according to Claim 1.

3. The top cover (30) is disposed on the side opposite to the base portion (24) so as to cover the casing (20). The battery pack (10) according to Claim 2.

4. The plurality of battery cells (22) are stacked in a row, the length of the plurality of battery cells (22) is parallel to the base portion (24) of the casing (20) and the top cover (30), and the width (W) of each of the plurality of battery cells (22) is parallel to any of the side faces (26). The battery pack (10) according to Claim 3.

5. The BMS module (50) is disposed adjacent to the outermost row (23) of the plurality of battery cells (22). The battery pack (10) according to Claim 4.

6. The top cover (30) includes a notch (32) configured to receive the heat sink (40) and packing. The battery pack (10) according to Claim 1.

7. The heat sink (40) is fixed within the notch (32) of the top cover (30), the packing is fixed around the notch (32), and the packing is configured to prevent water and dust from entering the casing (20) through the notch (32). The battery pack (10) according to claim 6.

8. The heat sink (40) has an inner surface (42) disposed on and thermally coupled to the BMS module (50), and an outer surface (44) having a plurality of fins (46) exposed to the outside of the casing (20) and configured to dissipate heat to the atmosphere outside the casing (20). The battery pack (10) according to claim 1.

9. The plurality of fins (46) are pin fins. The battery pack (10) according to claim 8.

10. When viewed in a direction orthogonal to the top cover (30), the heat sink (40) has a substantially T-shaped profile. The battery pack (10) according to claim 3.

11. The BMS module (50) includes a base member (51) having a plurality of interconnected electrical and electronic components for controlling the operation of the battery pack (10). A first surface (52) of the base member (51) faces the plurality of battery cells (22). A second surface (54) of the base member (51) is on the opposite side of the first surface (52) and faces the top cover (30). The battery pack (10) according to claim 5.

12. The heat sink (40) is attached to the base member (51) of the BMS module (50), and the inner surface (42) of the heat sink (40) is in thermal contact with the second surface (54) of the base member (51). The battery pack (10) according to claim 11.

13. The BMS module (50) includes a plurality of heat-dissipating electronic components (56). The plurality of heat-dissipating electronic components (56) are attached to at least a part of the first surface (52) of the base member (51) on the opposite side of the inner surface (42) of the heat sink (40) to dissipate heat generated by the plurality of heat-dissipating electronic components (56) to the heat sink (40). The battery pack (10) according to claim 12.

14. The heat sink (40) is a metal material, and the top cover (30) is a resin material, the battery pack (10) according to claim 1.

Images