Battery pack

Abstract

Embodiments provide a battery pack. The battery pack includes: a battery pack case including a bottom plate; a battery cell assembly disposed on the pack case and including a plurality of battery cells; a thermal interface material (TIM) layer between the battery cell assembly and the pack case; and a tape between the TIM layer and the pack case.

Description

Technical Field

[0001] This disclosure relates to a battery pack. This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0178456, filed on December 11, 2023, and Korean Patent Application No. 10-2024-0146032, filed on October 23, 2024, the entire contents of which are incorporated herein by reference. Background Technology

[0002] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. They are already widely used as a power source for various types of wireless devices, such as mobile phones, laptops, and cordless vacuum cleaners. Recently, the manufacturing cost per unit capacity of secondary batteries has decreased significantly due to increased energy density and economies of scale, and the driving range of battery electric vehicles (BEVs) has increased to the same level as fuel cell vehicles, thus shifting the primary use of secondary batteries from mobile devices to mobility.

[0003] The technological trend for secondary batteries used in mobility services is towards increased energy density and safety. The safety of these batteries is directly related to passenger safety and is therefore of paramount importance. Safety can be achieved through improved mechanical robustness, reliable electrical insulation, and delays in heat transfer during thermal runaway events. Summary of the Invention

[0004] Technical issues This disclosure aims to provide a battery pack that can be serviced aftermarket.

[0005] Technical solution Embodiments of this disclosure provide a battery pack. The battery pack includes: a battery pack housing including a base plate; a battery cell assembly disposed on the battery pack housing and including a plurality of battery cells; a thermal interface material (TIM) layer located between the battery cell assembly and the battery pack housing; and a strip located between the TIM layer and the battery pack housing.

[0006] The battery pack housing may include a lower sidewall protruding from the base plate, and the height of the lower sidewall may be less than the height of the individual battery cells.

[0007] The lower sidewall may include an inclined surface that is tilted relative to the mounting surface of the base plate.

[0008] The inclined surface can face the battery cell module.

[0009] The battery pack may also include a cover configured to cover the individual battery cells, and the cover may include an upper sidewall facing the lower sidewall.

[0010] The height of the upper sidewall can be greater than the height of the lower sidewall.

[0011] The battery pack may also include a cover configured to cover the individual battery cells, and the cover may include an upper sidewall facing the base plate.

[0012] The height of the upper sidewall can be less than the height of the individual battery module.

[0013] The belt can cover the bottom plate.

[0014] The strip can make contact with each of the base plate and TIM layers.

[0015] The TIM layer can be separated from the base plate.

[0016] A battery cell assembly may include battery cell blocks, comprising multiple battery cells; and crossbeams spaced apart from each other, with the battery cell blocks inserted between the crossbeams.

[0017] The crossbeam can be symmetrical with respect to the individual battery cells.

[0018] Each beam may include a stepped structure.

[0019] Beneficial effects According to embodiments of this disclosure, the battery pack includes a strip located between a thermal interface material (TIM) layer and a base plate. By stretching the strip, the adhesiveness of the TIM layer can be removed, and the portion of the battery cell exhibiting quality problems can be separated and replaced with other battery cells.

[0020] The effects achievable by the embodiments of this disclosure are not limited to those described above, and those skilled in the art to which the embodiments of this disclosure pertain will clearly derive and understand other effects not described herein based on the following description. In other words, those skilled in the art can deduce from the embodiments of this disclosure unintended effects achieved when implementing the embodiments of this disclosure. Attached Figure Description

[0021] Figure 1 This is a plan view of the battery pack according to an embodiment.

[0022] Figure 2 It is along Figure 1 The sectional view taken from line 1I-1I'.

[0023] Figure 3 It is along Figure 1 The sectional view taken from line 1II-1II'.

[0024] Figure 4 This is a diagram used to describe the method according to an embodiment.

[0025] Figure 5It is a cross-sectional view used to describe the method according to the embodiment.

[0026] Figure 6 This is a cross-sectional view used to describe a battery pack according to other embodiments. Detailed Implementation

[0027] In the following, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Before describing the embodiments of the present disclosure, the terms or expressions used in this specification and claims should not be construed as limited to terms or expressions as commonly understood or defined in common dictionaries, but should be understood based on the principle that the inventors of this application may appropriately define the terms or expressions to best interpret the present disclosure according to the meanings and concepts corresponding to the present disclosure.

[0028] Therefore, the configurations shown in the embodiments and accompanying drawings described herein are merely examples of this disclosure and do not reflect all the technical concepts of this disclosure. It should be understood that various equivalents and modifications have been made to replace this configuration as of the filing date of this application.

[0029] When it is determined that well-known configurations or functions related to the description of this disclosure obscure the subject matter of this disclosure due to unnecessary details, these configurations or functions will not be described in detail.

[0030] Because embodiments of this disclosure are provided to illustrate the disclosure more fully to those skilled in the art, the shapes, dimensions, etc., of the components shown in the drawings may be shown enlarged, omitted, or schematically for clarity. Therefore, it should not be construed that the dimensions or proportions of the components fully reflect their actual dimensions or proportions.

[0031] (First embodiment) Figure 1 This is a plan view of the battery pack 100 according to an embodiment.

[0032] Figure 2 It is along Figure 1 The sectional view taken from line 1I-1I'.

[0033] Figure 3 It is along Figure 1 The sectional view taken from line 1II-1II'.

[0034] Reference Figure 1 and Figure 2 The battery pack 100 may include a battery pack housing 110, multiple battery cell assemblies 120, a central beam 131, support beams 133 and 135, a strip 141, a thermal interface material (TIM) layer 143, a cover 150, gaskets 160, and bolts 170. The battery pack 100 may be an end product installed in applications such as vehicles.

[0035] The battery pack housing 110 provides space for mounting the battery cell assembly 120 therein. The battery pack housing 110 may include a base plate 111 and side walls 112, 113, 114 and 115.

[0036] Here, two directions that are substantially parallel to the mounting surface 111M of the base plate 111 (i.e., the surface facing the battery cell assembly 120) are defined as the X-axis and Y-axis directions, and a direction that is substantially perpendicular to the upper surface of the base plate 111 is defined as the Z-axis direction. The X-axis, Y-axis, and Z-axis directions may be substantially perpendicular to each other.

[0037] Each of the base plate 111 and side walls 112 and 113 can be configured by an extrusion process. The extrusion direction of each of the base plate 111 and side walls 112 and 113 can be the X-axis direction. Side walls 114 and 115 can also be configured by an extrusion process.

[0038] According to an embodiment, the base plate 111 and the sidewalls 112 and 113 can be joined by friction stir welding. The base plate 111 may include multiple plates joined together by friction stir welding.

[0039] The base plate 111 may include multiple cooling channels CH. The multiple cooling channels CH may be provided with pathways for moving a refrigerant, such as water. The multiple cooling channels CH may be formed by an extrusion process. The multiple cooling channels CH may extend in the X-axis direction. The cooling channels may be spaced apart from each other in the Y-axis direction. Figure 3 Multiple cooling channels CH with circular cross-sections are shown, but this is merely an example and does not limit the technical concept of this disclosure in any way. Each of the multiple cooling channels can have various shapes such as rectangular, elliptical, etc.

[0040] Multiple battery cell assemblies 120 may be located on a base plate 111 of the battery pack housing 110. The base plate 111 may support the multiple battery cell assemblies 120. Side walls 112, 113, 114, and 115 may be horizontally arranged around the multiple battery cell assemblies 120. The side walls 112, 113, 114, and 115 may protect the multiple battery cell assemblies 120.

[0041] For example, the battery pack 100 can be moduleless, and each of the plurality of battery cell assemblies 120 may not include a module frame. As another example, the battery pack 100 can be modular, and each of the plurality of battery cell assemblies 120 may include a module frame.

[0042] Multiple battery cell assemblies 120 may be located on a base plate 111. Each of the multiple battery cell assemblies 120 may include a battery cell block 121 and a crossbeam 125.

[0043] Battery cell block 121 may include multiple battery cells. The multiple battery cells in battery cell block 121 may form multiple groups. Each of the multiple groups may include one or more battery cells connected in parallel. The multiple groups may be connected in series with each other. The number of groups connected in series and the number of battery cells connected in parallel can be determined based on the voltage and current to be output from each of the multiple battery cell assemblies 120.

[0044] Multiple battery cells are the basic units of a lithium-ion battery (i.e., a secondary battery). Each of the multiple battery cells includes an electrode assembly, an electrolyte, and a casing. Each of the multiple battery cells can be a cylindrical battery cell, a prismatic battery cell, or a pouch battery cell. The electrode assembly of a cylindrical battery cell is embedded in a cylindrical metal can. The electrode assembly of a prismatic battery cell is embedded in a prismatic metal can. The electrode assembly of a pouch battery cell is embedded in a pouch casing comprising an aluminum laminate.

[0045] An electrode assembly may include a positive electrode, a negative electrode, and a separator between the positive and negative electrodes. The electrode assembly may be a wound electrode assembly or a stacked electrode assembly. A wound electrode assembly may include a structure in which a positive electrode, a negative electrode, and a separator located between the positive and negative electrodes are wound together. A stacked electrode assembly may include multiple positive electrodes and multiple negative electrodes stacked sequentially, with multiple separators located between them.

[0046] The crossbeams 125 may be spaced apart from each other, with the battery cell blocks 121 located between them. The crossbeams 125 may have the same shape. The crossbeams 125 may be arranged symmetrically around the battery cell blocks 121. The crossbeams 125 may be set by, for example, an extrusion process, but are not limited thereto.

[0047] The crossbeam 125 may include a stepped structure. The stepped structure of the crossbeam 125 can be used to connect with the support beams 133 and 135. The crossbeam 125 can be connected to the support beams 133 and 135 by, for example, bolting.

[0048] TIM layer 143 can be disposed on the base plate 111B of battery pack housing 110. TIM layer 143 can be inserted between each of the plurality of battery cell assemblies 120 and the base plate 111. TIM layer 143 can comprise a resin composition. TIM layer 143 can be disposed by a process of applying a hot-applied resin.

[0049] Figure 3It is shown that there is no TIM layer 143 at the center of each of the plurality of battery cell assemblies 120 in the Y-axis direction, and two TIM layers 143 correspond to each of the plurality of battery cell assemblies 120 (i.e., two TIM layers 143 overlap with each of the plurality of battery cell assemblies 120 in the Z-axis direction), but this is merely an example and does not limit the technical concept of this disclosure in any sense.

[0050] The resin composition can be a room-temperature curable composition. That is, the curing reaction of the resin composition can begin and proceed at room temperature. The curing reaction of the resin composition can be promoted at temperatures above room temperature. The curing reaction rate of the resin composition at temperatures above room temperature can be higher than the curing reaction rate of the resin composition at room temperature. As a non-limiting example, the main component of the resin composition can be a silicone resin, a polyol resin, an epoxy resin, or an acrylic resin.

[0051] The curing agent for the resin composition can be selected based on the main component of the resin composition. For example, when the main component of the resin composition is silicone resin, the curing agent can be a siloxane compound; when the main component of the resin composition is polyol resin, the curing agent can be an isocyanate compound; when the main component of the resin composition is epoxy resin, the curing agent can be an amine compound; and when the main component of the resin composition is acrylic resin, the curing agent can be an isocyanate compound.

[0052] The inorganic filler in the resin composition can have a relatively high thermal conductivity. According to an example, the thermal conductivity of the inorganic filler in the resin composition can be about 1 W / mK or higher. According to an example, the thermal conductivity of the inorganic filler in the resin composition can be about 5 W / mK or higher. According to an example, the thermal conductivity of the inorganic filler in the resin composition can be about 10 W / mK or higher. According to an example, the thermal conductivity of the inorganic filler in the resin composition can be about 15 W / mK or higher.

[0053] According to embodiments, the inorganic filler in the resin composition may comprise ceramics. For example, the inorganic filler in the resin composition may comprise alumina (Al₂O₃), aluminum nitride (AlN), boron nitride (BN), silicon nitride (Si₃N₄), silicon carbide (SiC), beryllium oxide (BeO), zinc oxide (ZnO), aluminum hydroxide (Al(OH)₃), or boehmite. The resin composition may comprise carbon fillers. For example, the resin composition may comprise fumed silica, clay, or calcium carbonate.

[0054] Strip 141 can be inserted between TIM layer 143 and base plate 111. Strip 141 can contact each of TIM layer 143 and base plate 111. The thermal conductivity of each strip 141 can be in the range of about 1 W / m·K to about 5 W / m·K. Each strip 141 may include a stretchable material.

[0055] The strip 141 can cover the base plate 111, so that each TIM layer 143 does not need to contact the base plate 111. Each TIM layer 143 can be spaced apart from the base plate 111.

[0056] Battery cell assembly 120 may partially cover strip 141. Battery cell assembly 120 may expose a portion of strip 141. Strip 141 may project relative to battery cell assembly 120 in the Y-axis direction. Strip 141 may include a portion between battery cell assembly 120 and sidewall 112 or a portion between battery cell assembly 120 and sidewall 113.

[0057] TIM layer 143 may partially cover strip 141. TIM layer 143 may expose a portion of strip 141. Strip 141 may protrude relative to TIM layer 143 in the Y-axis direction. Strip 141 may include a portion between TIM layer 143 and sidewall 112 or a portion between TIM layer 143 and sidewall 113.

[0058] The intermediate beam 131 can be inserted between multiple battery cell assemblies 120. The intermediate beam 131 can extend in the X-axis direction. The intermediate beam 131 can space the multiple battery cell assemblies 120 in the Y-axis direction. According to an embodiment, the intermediate beam 131 can be configured to be separate from the base plate 111 and can be welded to the base plate 111. According to other embodiments, the intermediate beam 131 can be formed as an integral component with the base plate 111.

[0059] Support beams 133 and 135 can be joined to the base plate 111 by means of welding, for example. Support beam 133 can be inserted between support beams 135. Support beam 133 can be inserted between battery cell modules 120. Support beam 135 can be inserted between battery cell modules 120 and sidewall 114 or between battery cell modules 120 and sidewall 115.

[0060] Support beam 133 can contact two crossbeams 125, and support beam 135 can contact one crossbeam 125. Therefore, the thickness of each support beam 133 can be different from the thickness of each support beam 135. Therefore, the thickness of each support beam 133 can be greater than the thickness of each support beam 135.

[0061] exist Figure 1 In this configuration, the array of multiple battery cell modules 120 can be a 2×2 array. Figure 1The intermediate beam 131, support beams 133 and 135, and the array of multiple battery cell assemblies 120 shown are non-limiting examples and do not limit the technical concept of this disclosure in any way. Based on the above description, those skilled in the art will be able to readily derive multiple battery cell assemblies 120 arranged in an M×N array (where M and N are each integers greater than 2).

[0062] The cover 150 can be attached to the battery pack housing 110. The cover 150 can be attached to side walls 112, 113, 114, and 115. The cover 150 can cover internal components of the battery pack 100, such as battery cell assemblies 120 and electronic components. The cover 150 can be mechanically attached to the battery pack housing 110, for example, by bolting. The cover 150 can be mechanically attached to side walls 112, 113, 114, and 115, for example, by bolting.

[0063] The cover 150 may include a top plate portion 151 and side walls 152 and 153. The top plate portion 151 may be spaced apart from the bottom plate 111, and a plurality of battery cell assemblies 120 are inserted therebetween. The top plate portion 151 may be generally parallel to the bottom plate 111. Side wall 152 may face side wall 112, and side wall 153 may face side wall 113. Each of the side walls 152 and 153 of the cover 150 may be referred to as an upper side wall, and each of the side walls 112 and 113 of the battery pack housing 110 may be referred to as a lower side wall.

[0064] Gasket 160 can be inserted between sidewalls 112, 113, 114, and 115 and sidewalls 152 and 153. For example, gasket 160 can comprise a compressible material, such as ethylene-propylene diene monomer (EPDM). Gasket 160 can be pressed against sidewalls 112, 113, 114, and 115 and sidewalls 152 and 153 to provide a liquid seal for the battery pack housing 100.

[0065] Bolt 170 can secure sidewalls 112 and 113, as well as sidewalls 152 and 153. Bolt 170 can be tightened to sidewalls 112 and 113, as well as sidewalls 152 and 153. Each bolt 170 may include a flange and a shank. The flange of each bolt 170 can contact the base plate 111.

[0066] The heights of each sidewall 112 and 113 may be less than the heights of each individual battery cell assembly 120. The heights of each sidewall 112 and 113 of the battery pack housing 110 may differ from the heights of each sidewall 152 and 153 of the cover 150. The heights of each sidewall 112 and 113 of the battery pack housing 110 may be less than the heights of each sidewall 152 and 153 of the cover 150. The sum of the heights of each sidewall 112 and 113 and the heights of each sidewall 152 and 153 of the cover 150 may be greater than the height of each individual battery cell assembly 120.

[0067] Sidewall 112 may include inclined surface 112S, and sidewall 113 may include inclined surface 113S. Each of inclined surfaces 112S and 113S may be inclined relative to the mounting surface 111M of the base plate 111. Each of inclined surfaces 112S and 113S may face the battery cell assembly 120.

[0068] The battery pack 100 may also include a venting device integrated into the sidewalls 114 and 115 or the cover 150. The sidewalls 114 and 115 or the cover 150 may include vent holes connected to the venting device. The venting device may be configured to delay heat propagation by venting hot gases from the interior of the battery pack 100 to the exterior in the event of a thermal runaway event in the plurality of battery cell assemblies 120.

[0069] Here, the thermal runaway event of multiple battery cell modules 120 is a state in which the temperature change of multiple battery cell modules 120 accelerates the temperature change, that is, runaway positive feedback. The temperature of the multiple battery cell modules 120 in the thermal runaway state rises sharply, and a large amount of high-pressure gas and burning debris are emitted.

[0070] The battery pack 100 may also include a battery management system (BMS). The BMS can be configured to monitor, balance, and control the battery pack 100. Monitoring of the battery pack 100 may include measuring the voltage and current at certain nodes in the plurality of battery cell assemblies 120 and measuring the temperature at designated locations within the battery pack 100. The battery pack 100 may include measuring devices for measuring the voltage, current, and temperature as described above.

[0071] Balancing of the battery pack 100 is an operation to reduce deviations between the multiple battery cell assemblies 120. Control of the battery pack 100 includes prevention of overcharging, over-discharging, and overcurrent. Through monitoring, balancing, and control, the battery pack 100 can operate under optimal conditions, thereby preventing shortening of the lifespan of the individual battery cell assemblies 120.

[0072] The battery pack 100 may also include additional electronic components, such as a cooling device, a power relay assembly (PRA), and a safety plug. The cooling device may include a cooling fan. The cooling fan circulates air within the battery pack 100 to prevent overheating of the individual battery cells in the plurality of battery cell assemblies 120. The PRA may be configured to supply power from the high-voltage battery to an external load (e.g., the vehicle's engine) or to disconnect power. In the event of an abnormal voltage, such as a voltage surge, the PRA may disconnect power to the external load (e.g., the vehicle's engine) to protect the plurality of battery cell assemblies 120 and the external load.

[0073] The battery pack 100 may further include a plurality of busbars configured to be electrically connected to a plurality of battery cell assemblies 120. The plurality of battery cell assemblies 120 may be connected in series via the plurality of busbars. Therefore, the battery pack 100 may be configured to output high voltage to an external load (e.g., a vehicle's engine).

[0074] (Second Embodiment) Figure 4 This is a diagram used to describe the method according to an embodiment.

[0075] Figure 5 It is a cross-sectional view used to describe the method according to the embodiment.

[0076] Reference Figures 3 to 5 In P110, the cover 150 can be separated from the battery pack housing 110.

[0077] Next, in P120, strip 141 can be removed. During this process, the strip 141 overlapping the problematic battery cell assembly 120 in the Z-axis direction can be removed. Strip 141 can be removed by tension. Strip 141 can have sufficient tensile strength so that it will not break when removed. According to the embodiment, because the heights of sidewalls 112 and 113 are sufficiently low and sidewalls 112 and 113 include inclined surfaces 112S and 113S, the angle between the stretching direction of strip 141 and the main surface of strip 141 (or the mounting surface 111M of the base plate 111) can be sufficiently small. Therefore, breakage of strip 141 when stretched can be prevented.

[0078] Because the TIM layer 143 is cured during the assembly of the battery pack 100, there is no adhesion between the TIM layer 143 and the base plate 111 when the tape 141 is removed. Therefore, in P130, the problematic battery cell assembly 120 can be replaced with a normal battery cell assembly.

[0079] (Third embodiment) Figure 6 This is a cross-sectional view used to describe a battery pack 101 according to other embodiments. More specifically, Figure 6 It shows the relationship with Figure 3 The corresponding part.

[0080] Reference Figure 6 The battery pack 101 may include a battery pack housing 110', multiple battery cell assemblies 120, a central beam 131, and support beams 133 and 135 (see [link to documentation]). Figure 2 ), with 141, TIM layer 143, cover 150', gasket 160 and bolt 170. Battery pack 101 can be the final product installed in applications such as vehicles.

[0081] Multiple battery cell modules 120, intermediate beam 131, support beams 133 and 135 (see...) Figure 2 ), with 141 and TIM layer 143 as referenced above. Figures 1 to 3 The components described are largely the same, so their redundant descriptions are omitted here.

[0082] Battery pack housing 110' may not include side walls 112 and 113 (see Figure 2 The cover 150' may include a top plate 151 and side walls 152' and 153', and the side walls 152' and 153' may contact the base plate 111. The height of each of the side walls 152' and 153' may be greater than the height of the respective battery cell assembly 120.

[0083] Each of sidewalls 152' and 153' may face the base plate 111. Washers 160 may be inserted between sidewalls 152' and 153' and the base plate 111. Bolts 170 may secure the base plate 111 to the sidewalls 152' and 153'. Bolts 170 may be tightened to the base plate 111 and the sidewalls 152' and 153'.

[0084] The present disclosure has been described in more detail above with reference to the accompanying drawings, embodiments, etc. However, the configurations shown in the drawings or embodiments described in this disclosure are merely embodiments of the present disclosure and do not reflect all the technical concepts of the present disclosure. Therefore, it should be understood that various equivalents and modifications have been made to replace the configurations as of the filing date of this application.

Claims

1. A battery pack, comprising: Battery pack housing, including the base plate; A battery cell assembly is disposed on the battery pack housing and includes multiple battery cells; The thermal interface material layer, or TIM layer, is located between the battery cell assembly and the battery pack housing; as well as The strip is located between the TIM layer and the battery pack housing.

2. The battery pack according to claim 1, wherein, The battery pack housing includes a lower sidewall that protrudes from the base plate. The height of the lower sidewall is less than the height of the battery cell assembly.

3. The battery pack according to claim 2, wherein, The lower sidewall includes an inclined surface that is tilted relative to the mounting surface of the base plate.

4. The battery pack according to claim 3, wherein, The inclined surface faces the battery cell assembly.

5. The battery pack of claim 2, further comprising a cover plate configured to cover the battery cell assembly. in, The cover plate includes an upper sidewall facing the lower sidewall.

6. The battery pack according to claim 5, wherein, The height of the upper sidewall is greater than the height of the lower sidewall.

7. The battery pack of claim 1, further comprising a cover plate configured to cover the battery cell assembly. in, The cover plate includes an upper sidewall facing the base plate.

8. The battery pack according to claim 7, wherein, The height of the upper sidewall is less than the height of the battery cell assembly.

9. The battery pack according to claim 1, wherein, The strip covers the base plate.

10. The battery pack according to claim 1, wherein, The strip contacts each of the base plate and the TIM layer.

11. The battery pack according to claim 1, wherein, The TIM layer is spaced apart from the base plate.

12. The battery pack according to claim 1, wherein, The battery cell assembly includes: a battery cell block comprising multiple battery cells; and crossbeams spaced apart from each other, with the battery cell block inserted between the crossbeams.

13. The battery pack according to claim 12, wherein, The crossbeam is symmetrical with respect to the battery cell block.

14. The battery pack according to claim 12, wherein, Each of the beams includes a stepped structure.

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