Battery cell housing comprising a steel body having a thermal conductive layer

Abstract

A housing for a prismatic battery cell includes a housing body including side surfaces, a cover portion, and a bottom portion. The housing body is made of steel. A layer is disposed on the housing body, and the layer includes a material having a higher thermal conductivity than steel. The layer includes a coating or cladding layer.

Description

Technical Field

[0001] The present disclosure relates to battery cells for a battery pack, and more particularly to a battery pack cell housing including a steel body that includes a thermal conductive coating or cladding layer. Background Art

[0002] The information provided in this section is intended to generally introduce the background of the present disclosure. To the extent that the work currently attributed to the inventors is described in this section, and aspects of the specification that may not otherwise be determined to be prior art as of the filing date, are not to be taken as being admitted, either expressly or impliedly, as prior art against the present disclosure.

[0003] The present disclosure relates to battery cells for a battery pack, and more particularly to a battery pack cell housing including a steel body that includes a thermal conductive coating or cladding layer.

[0004] Electric vehicles (EVs), such as battery electric vehicles (BEVs), hybrid vehicles, and / or fuel cell vehicles, include one or more electric motors and a battery pack system including one or more battery cells, modules, and / or battery packs. A power control system is used to control the charging and / or discharging of the battery pack system during charging and / or driving.

[0005] A battery cell includes one or more cathode electrodes, anode electrodes, and separators disposed within a battery cell housing. The cathode electrode includes a cathode active material layer disposed on a cathode current collector. The anode electrode includes an anode active material layer disposed on an anode current collector. Summary of the Invention

[0006] A housing for a prismatic battery cell includes a housing body that includes sides, a lid portion, and a bottom portion. The housing body is made of steel. A layer is disposed on the housing body and includes a material having a higher thermal conductivity than steel.

[0007] In other features, the layer includes a metal coating. The metal coating is selected from copper, copper - zinc, zinc, and aluminum alloys. The aluminum alloy is selected from Al - 6% Si and Al - 55% Zn. The metal coating is applied using electroplating. The metal coating is applied using hot dipping.

[0008] In other features, a nickel coating is disposed on the steel. The metal coating is disposed on the nickel coating, and the metal coating is selected from copper, copper - zinc, and zinc.

[0009] In other features, the layer includes a cladding layer attached to the housing body by an adhesive. The cladding layer contains copper.

[0010] In other features, the layer includes a ceramic coating selected from aluminum nitride, boron nitride, and aluminum oxide. The thickness of the steel is from 0.2 mm to 0.8 mm. The thickness of the metal coating is from 5 μm to 100 μm.

[0011] A system includes a housing and a thermal interface material in contact with at least one of a lid portion and a bottom portion of the housing. A cooling plate is in thermal contact with the thermal interface material.

[0012] A method of manufacturing a prismatic housing for a battery pack cell includes forming a housing body of the prismatic housing using steel. The housing body includes one of the following: a coated layer on the housing body; and a cladding layer attached to the housing body. One of the coated layer and the cladding layer is made of a material having a higher thermal conductivity.

[0013] In other features, the housing body includes a coated layer. The coated layer includes a metal coating selected from copper, copper - zinc, zinc, and aluminum alloy.

[0014] In other features, the method includes applying the metal coating using one of electroplating and hot dipping.

[0015] In other features, the housing body includes a cladding layer, and the cladding layer includes a metal material attached to the housing body by an adhesive.

[0016] In other features, the housing body includes a coated layer, and the coated layer includes a ceramic coating selected from aluminum nitride, boron nitride, and aluminum oxide.

[0017] In other features, the thickness of the steel is from 0.2 mm to 0.8 mm, and the thickness of the metal coating is from 5 μm to 100 μm.

[0018] In other features, forming the housing body includes at least one of the following: deep drawing; bending and welding; and roll forming, welding, and expanding.

[0019] The present invention discloses the following solutions:

[0020] Solution 1. A housing for a prismatic battery pack cell, comprising:

[0021] A housing body including sides, a lid portion, and a bottom portion,

[0022] wherein the housing body is made of steel; and

[0023] A layer disposed on the housing body, and the layer comprises a material having a higher thermal conductivity than the steel.

[0024] Solution 2. The housing according to Solution 1, wherein the layer includes a metal or metal alloy coating.

[0025] Solution 3. The housing according to Solution 2, wherein the metal coating is selected from copper, copper - zinc (Cu - Zn), zinc, and aluminum alloy.

[0026] Solution 4. The outer shell according to Solution 3, wherein the aluminum alloy is selected from Al-6% Si and Al-55% Zn.

[0027] Solution 5. The outer shell according to Solution 3, wherein electroplating is used to apply the metal coating.

[0028] Solution 6. The outer shell according to Solution 3, wherein hot dipping is used to apply the metal coating.

[0029] Solution 7. The outer shell according to Solution 3, which further includes a nickel coating on the steel, wherein the metal coating is applied on the nickel coating and the metal coating is selected from copper, copper-zinc (Cu-Zn), and zinc.

[0030] Solution 8. The outer shell according to Solution 1, wherein the layer includes a cladding layer attached to the outer shell body by an adhesive.

[0031] Solution 9. The outer shell according to Solution 8, wherein the cladding layer contains copper.

[0032] Solution 10. The outer shell according to Solution 1, wherein the layer includes a ceramic coating selected from aluminum nitride (AlN), boron nitride (BN), and aluminum oxide (Al2O3).

[0033] Solution 11. The outer shell according to Solution 1, wherein the thickness of the steel is 0.2 mm to 0.8 mm.

[0034] Solution 12. The outer shell according to Solution 2, wherein the thickness of the metal coating is 5 μm to 100 μm.

[0035] Solution 13. A system, which includes the outer shell according to Solution 1, and further includes:

[0036] A thermal interface material that contacts at least one of the lid portion and the bottom portion of the outer shell; and

[0037] A cooling plate that is in thermal contact with the thermal interface material.

[0038] Solution 14. A method for manufacturing a prismatic outer shell for a battery pack cell, which includes:

[0039] Using steel to form the outer shell body of the prismatic outer shell; and

[0040] Wherein the outer shell body includes one of the following:

[0041] A coating on the outer shell body; and

[0042] A cladding layer attached to the outer shell body,

[0043] Wherein, one of the coating and the cladding layer is made of a material with a higher thermal conductivity than the steel.

[0044] Solution 15. The method according to Solution 14, wherein:

[0045] The housing body includes a coating, and

[0046] The coating includes a metal coating selected from copper, copper-zinc (Cu-Zn), zinc, and aluminum alloy.

[0047] Solution 16. The method according to Solution 15, further comprising applying the metal coating by one of electroplating and hot dipping.

[0048] Solution 17. The method according to Solution 14, wherein:

[0049] The housing body includes a cladding layer, and

[0050] The cladding layer includes a metal material attached to the housing body by an adhesive.

[0051] Solution 18. The method according to Solution 14, wherein:

[0052] The housing body includes a coating, and

[0053] The coating includes a ceramic coating selected from aluminum nitride (AlN), boron nitride (BN), and aluminum oxide (Al2O3).

[0054] Solution 19. The method according to Solution 15, wherein:

[0055] The thickness of the steel is 0.2 mm to 0.8 mm, and

[0056] The thickness of the metal coating is 5 μm to 100 μm.

[0057] Solution 20. The method according to Solution 14, wherein forming the housing body includes at least one of the following:

[0058] Deep drawing;

[0059] Bending and welding; and

[0060] Roll forming, welding, and expansion.

[0061] From the detailed description, the claims, and the drawings, further applicable fields of the present disclosure will become apparent. The detailed description and specific examples are only intended to illustrate and are not intended to limit the scope of the present disclosure. Description of the Drawings

[0062] The present disclosure will be more fully understood through the detailed description and the drawings, wherein:

[0063] Figure 1 is a functional block diagram of an example of a battery cell of a battery pack according to the present disclosure, the battery cell of the battery pack including a battery cell stack having an anode electrode, a cathode electrode, and a separator disposed in a steel housing having a heat conducting layer;

[0064] Figure 2A and Figure 2B is a perspective view of an example of a prismatic battery cell housing made of steel and having a heat conducting layer according to the present disclosure; and

[0065] Figure 3 is a side cross-sectional view of an example illustrating heat transfer in a prismatic battery cell including a housing made of steel without a heat conducting layer;

[0066] Figure 4 is a side cross-sectional view of an example illustrating heat transfer in a prismatic battery cell according to the present disclosure, the prismatic battery cell including a housing having a steel body including a heat conducting coating layer;

[0067] Figure 5A and Figure 5B is a side cross-sectional view of an example illustrating heat transfer in a prismatic battery cell according to the present disclosure, the prismatic battery cell including a housing having a steel body including a heat conducting layer;

[0068] Figure 6 is a perspective view of an example of a rolled steel plate including a heat conducting layer according to the present disclosure;

[0069] Figure 7 is a perspective view of a manufacturing process of a steel plate having a heat conducting coating layer according to the present disclosure;

[0070] Figure 8 is a plan view and a perspective view of an example illustrating roll forming, welding, and expansion of a steel plate including a heat conducting layer to form a housing according to the present disclosure;

[0071] Figure 9 is a plan view and a perspective view of an example illustrating bending and welding of a steel plate including a heat conducting layer to form a housing according to the present disclosure;

[0072] Figure 10 is a plan view and a perspective view of an example illustrating deep drawing of a steel plate including a heat conducting layer to form a housing according to the present disclosure;

[0073] Figure 11 is a side cross-sectional view of an example illustrating welding of a cover to a main body of a housing according to the present disclosure;

[0074] Figure 12 is a side cross-sectional view of an example illustrating brazing of a cover to a main body of a housing according to the present disclosure; and

[0075] Figures 13A to 13C FIG. 3 is a side cross-sectional view illustrating an example of a double seam of a steel plate including a heat conductive layer according to the present disclosure.

[0076] In the drawings, reference numerals may be reused to identify similar and / or identical elements. DETAILED DESCRIPTION

[0077] Although the battery pack enclosure according to the present disclosure is shown in the context of an electric vehicle, the battery pack enclosure may be used in stationary applications and / or other applications.

[0078] Prismatic enclosures are typically made by extruding aluminum, which is an expensive material. Aluminum also has limitations when used with high-energy battery pack cells that may experience thermal runaway. Thermal runaway can result in sustained high temperatures that can melt the battery pack cell enclosure.

[0079] During thermal runaway, hot gases are released inside the battery pack cell. The temperature of the hot gases exceeds 800°C to 900°C, which is high enough to melt the aluminum battery pack enclosure (the melting temperature is 600°C to 630°C). Even at lower temperatures (above 300°C), aluminum softens, thereby reducing the strength of the aluminum battery pack enclosure (e.g., the tensile strength of aluminum at 300°C is about 25% to 35% of the tensile strength at room temperature). Melting of the enclosure can result in the ejection of highly oxidizing aluminum fragments and particles, thereby exacerbating the thermal runaway event.

[0080] The battery pack cell enclosure can use steel instead of aluminum. Steel is less costly than aluminum and has a much higher melting point (1500°C). The higher melting temperature of steel enables the battery pack cell enclosure to resist melting during thermal runaway. However, a disadvantage of steel is that it has a lower thermal conductivity compared to aluminum. The lower thermal conductivity of steel increases the temperature of the battery pack cell during rapid charge / discharge events.

[0081] The present disclosure relates to systems and methods for improving the cooling efficiency of a prismatic battery pack cell enclosure including a housing body made of steel when bottom cooling a prismatic battery stack by placing the bottom on a liquid cooling plate (instead of directly cooling the battery surface). In some examples, the outer surface of the battery pack cell enclosure is coated with a heat conductive coating or cladding layer made of a material having a higher thermal conductivity than the steel body. In some examples, the coating includes an electroplated or dip-coated metal layer. In some examples, the coating includes a ceramic layer. The heat conductive layer reduces the temperature of the battery during rapid charging by providing a conduction path through which the heat of the battery pack cell is discharged to the cooling plate.

[0082] Now referring to Figure 1, the battery cell 10 of the battery pack includes C cathode electrodes 20, A anode electrodes 40, and S separators 32 arranged in a battery cell stack 12 of the battery pack in a predetermined order, where C, S, and A are integers greater than zero. The C cathode electrodes 20-1, 20-2,..., and 20-C include cathode active material layers 24 arranged on one or both sides of a cathode current collector 26.

[0083] The A anode electrodes 40-1, 40-2,..., and 40-A include anode active material layers 42 arranged on one or both sides of an anode current collector 46. In some examples, the A anode electrodes 40 and the C cathode electrodes 20 exchange lithium ions during charging / discharging. In some examples, the cathode active material layer 24 and / or the anode active material layer 42 includes a coating applied to the current collector (e.g., using a wet or dry roll-to-roll process), the coating containing one or more active materials, one or more conductive additives, and / or one or more adhesive materials.

[0084] In some examples, the cathode current collector 26 and / or the anode current collector 46 includes a metal foil, a metal mesh, a perforated metal, a three-dimensional (3D) metal foam, and / or a porous metal mesh. In some examples, the current collector is made of one or more materials selected from copper, stainless steel, brass, bronze, zinc, aluminum, and / or their alloys. The external tabs 28 and 48 are respectively connected to the current collectors of the cathode electrode and the anode electrode, and can be arranged on the same side or different sides of the battery cell stack 12 of the battery pack. The external tabs 28 and 48 are connected to the terminals of the battery pack.

[0085] Now refer to Figure 2A and Figure 2B , the battery cell 58 of the battery pack includes a housing 60. In some examples, the housing 60 has a prismatic shape with a rectangular cross-section in the x-axis, y-axis, and z-axis planes. In some examples, the housing 60 includes a housing body 61, and the housing body 61 includes side faces 80 corresponding to the narrow faces and side faces 82 corresponding to the wide faces. The housing body 61 defines a rectangular prism with an open or closed end face. In some examples, the housing 60 includes a cover portion 84 and a bottom portion 86. In other examples, the bottom portion 86 is attached after the housing body 61 is formed. Edges 83 are arranged between the side faces 80 and 82, between the side faces 80 and 82 and the cover portion 84, and between the side faces 80 and 82 and the bottom 86.

[0086] The cover portion 84 and the optional bottom portion 86 are attached to the housing body 61 to respectively close the top opening and the bottom opening of the housing body 61. The battery cell 58 of the battery pack includes external terminals 62 and 64 passing through the cover portion 84. The battery cell stack 12 of the C cathode electrodes 20, the A anode electrodes 40, and the S separators 32 is arranged in the housing 60.

[0087] The external terminals 62 and 64 are respectively connected to the external tabs 28 and 48 of C cathode electrodes 20 and A anode electrodes 40. In Figure 2A , the cover portion 84 does not include a pressure-type exhaust cover. In Figure 2B , the cover portion 84 (and / or the bottom portion 86) includes a pressure-type exhaust cover 66. The pressure-type exhaust cover 66 is configured to release exhaust gas when the pressure inside the inner case is greater than a predetermined pressure.

[0088] Now referring to Figure 3 , heat transfer in a prismatic battery pack cell is shown. The bottom surface of the battery pack cell is located on a thermal interface material (TIM) 110. The TIM 110 is located on a cooling plate 114. Heat from the battery pack cell stack 12 mainly flows outward, as indicated by the arrows. When the battery pack cell is cooled by a cooling plate 114 arranged adjacent to the cover or the bottom (instead of direct sidewall cooling), the main heat transfer path is through the side 82 of the outer case 60 downward via the thermal interface material (TIM) 110 to the cooling plate 114. Steel (which has a lower thermal conductivity compared to aluminum) reduces the heat transfer flux entering the cooling plate 114 through the side 82 of the outer case 60. In some instances, an electrolyte layer 85 is arranged between the battery pack cell stack 12 and the bottom portion 83. In some instances, the electrolyte layer 85 is made of a non-thermally conductive material. Due to the electrolyte layer 85, the main heat transfer path passes through the sides 80 and 82.

[0089] Now referring to Figure 4 , heat transfer in a prismatic battery pack cell including an inner cladding layer and / or an outer cladding layer 118 adjacent to a steel wall 120 is shown. The inner cladding layer and / or the outer cladding layer 118 includes a metal sheet having a higher thermal conductivity than the material used for the outer case. Heat from the battery pack cell stack 12 mainly flows outward, as indicated by the arrows. The heat flows through the steel wall 120 and the inner cladding layer and / or the outer cladding layer 118 of the outer case 116 downward via the thermal interface material (TIM) 110 to the cooling plate 114. In some instances, both the inner cladding layer and / or the outer cladding layer 118 are used. In other instances, only the inner cladding layer or only the outer cladding layer is used. In some instances, the inner cladding layer and / or the outer cladding layer 118 are made of copper or a copper alloy, but other materials can also be used.

[0090] Now referring to Figure 5A and Figure 5B , heat transfer in a prismatic battery pack cell including an inner coating and an outer coating 124 adjacent to a steel wall 122 is shown. Heat from the battery pack cell stack 12 mainly flows outward, as indicated by the arrows. The heat flows through the steel wall 122 and the inner coating and the outer coating 124 of the outer case via the thermal interface material (TIM) 110 to the cooling plate 114. The inner coating and the outer coating 124 provide a high thermal conductivity path for heat transfer to the cooling plate 114.

[0091] In some instances, the inner coating and the outer coating 124 include a conductive and thermally conductive metal coating. Examples of the metal coating include pure copper with a thermal conductivity of 400 W / m·K, a copper-zinc (Cu-Zn) coating (such as brass) with a thermal conductivity of 150 W / m·K, pure zinc with a thermal conductivity of 112 W / m·K, or an aluminum alloy. Examples of the aluminum alloy include Al-6% Si (with a thermal conductivity of 155 W / m·K) or Al-55% Zn (with a thermal conductivity of 122 W / m·K). In some instances, electroplating or hot dipping is used to apply the metal coating.

[0092] In Figure 5B it, a thin electroplated nickel layer 125 can be applied before the coating 126 including pure Cu, Cu-Zn, or Zn to improve solderability by avoiding liquid copper embrittlement at the steel grain boundaries.

[0093] For example, the steel wall 122 can be coated with a copper coating using electroplating. The thermal conductivity of the steel is 45 W / m·K, and the thermal conductivity of the copper is 400 W / m·K. The thermal conductivity of the TIM 110 is 1 - 2 W / m·K, and the thermal conductivity of the cooling plate is 273 W / m·K. For example, for a steel housing without a cladding layer or coating, the battery cell temperature during 2C charging can be about 41°C, while for an aluminum housing, it is about 35.5°C. During 2C charging, the battery cell temperature inside the housing with 20 μm, 30 μm, 40 μm, and 50 μm copper coatings drops to 38.5°C, 37.5°C, 36.9°C, and 36.1°C, respectively.

[0094] In other instances, the inner coating and the outer coating 124 include a thermally conductive and electrically insulating ceramic coating. In some instances, the ceramic coating is selected from aluminum nitride (AlN), boron nitride (BN), and aluminum oxide or alumina (Al2O3). The thermal conductivity of aluminum nitride (AlN) is 220 W / m·K. The thermal conductivity of boron nitride (BN) is 70 W / m·K. The thermal conductivity of aluminum oxide or alumina (Al2O3) is 112 W / m·K.

[0095] In some instances, a siphon feed hookup is used to apply the ceramic coating to the housing by spray drying. Particles of the ceramic coating (e.g., AlN) are dispersed in a solvent (e.g., ethanol), and air drying evaporates the ethanol from the ceramic coating.

[0096] Now referring to Figure 6 and Figure 7 it, steel plates or clad steel plates coated with a metal or ceramic coating can be used respectively. In Figure 6In [the figure], the steel plate 128 includes a coating 129 on its inner surface and / or outer surface. In some examples, the coating 129 is, for example, a metal coating or a ceramic coating. Although the coating is shown on the steel plate before rolling, bending, or stamping, the coating can also be applied after rolling, bending, or stretching. In some examples, the coating 129 is applied to low-carbon steel or stainless steel by electroplating or hot dipping, but other methods can also be used.

[0097] In some examples, the thickness of the steel is from 0.2 mm to 0.8 mm. In some examples, the thickness of the steel is from 0.3 mm to 0.4 mm. In some examples, the thickness of the coating 129 is from 5 μm to 100 μm. In some examples, the thickness of the coating 129 is from 10 μm to 50 μm. In some examples, the coating 129 is deposited on both sides of the steel housing body.

[0098] In Figure 7 [the figure], the roll 130 includes a steel plate 132 supplied between rollers 134 and 136. A roll 140 including an adhesive layer 142 is supplied between rollers 134 and 136. The roll 150 includes a cladding layer 152 made of a metallic material, which is supplied between rollers 134 and 136. The rollers 134 and 136 press and / or heat these layers to form a clad sheet 160. This process can be repeated for the cladding layer on the opposite side, or additional rollers including an adhesive layer and a cladding layer can be supplied between rollers 134 and 136 to perform double-sided cladding. In some examples, the adhesive includes a thermally conductive adhesive. Although the cladding layer is shown on the steel plate before rolling, bending, or stretching, the cladding layer can be applied before and / or after rolling, bending, or stamping.

[0099] Now referring to Figures 8 to 10 [the figure], an example of forming a housing body of a three-piece housing using a steel plate with a coating or a clad steel plate is shown. In Figure 8 [the figure], roll forming, welding, and / or expanding are used to form the housing body. The coated or clad steel plate 210 is cut to size and includes edges 214 to be welded. The steel plate 212 is roll formed into a cylinder 218 and welded along the seam at the edges 214 (for example, using resistance welding, laser welding, induction welding, or friction stir welding). The steel plate 212 is expanded into the housing body at 218'.

[0100] In Figure 9 [the figure], bending and welding are used to form the housing. The coated or clad steel plate 222 is cut along the dotted line at 224 and bent to form the housing body 230. After bending, the edges are seam welded at 226 on one side (for example, the narrow side).

[0101] In Figure 10In [reference], the housing body 250 of the two-piece housing is formed using deep drawing. The housing body 250 is formed from deep-drawn steel 240. The housing body 260 includes an integral bottom portion 254 on one side and an opening 256 on the opposite side that is enclosed by a lid portion. In some instances, the housing body 250 is coated or clad before and / or after deep drawing.

[0102] Now refer to Figures 11 to 12 , the lid 310 includes a steel plate 314 having an inner layer and / or an outer layer 316 (e.g., a cladding layer or a coating). The housing body 330 includes a steel plate 314 having an outer layer 336 (e.g., a cladding layer or a coating). For thinner layers / coatings, the edge of the lid 310 is heated (induction or laser heating) onto the sidewall of the housing body 330. The heat forms a bonding point between the lid 310 and the sidewall of the housing body 330. For thicker layers / coatings, laser brazing can be used with a filler wire (e.g., a copper-silicon alloy). Brazing is used to weld the sidewall of the lid to the top of the housing body. Brazing avoids melting of the steel and overheating of the electrodes of the battery pack stack.

[0103] Now refer to Figures 13A to 13C , which is a side cross-sectional view illustrating an example of curling of a double seam that joins a lid or a bottom portion to a housing body. In Figure 13A and Figure 13B , a double seam is used to curl the housing body 360 and the lid 364.

[0104] Brazing can be used to strengthen the crimp. Brazing involves moving a heat source around the periphery of the crimp to melt and bond the coatings of adjacent steel layers. In some instances, one or more laser beams are directed onto the double seam after curling to melt the coatings together, as shown at 350 in Figure 13C . The facing layers of the coating or cladding layer melt and fuse together between the outer different layers to improve the quality of the airtight seal. Although laser heating is shown, in other instances, induction heating can be used.

[0105] The thermal conductive layer on the inner surface and / or the outer surface of the steel housing body enhances the thermal conductivity of the battery pack cells during charging / discharging to control the temperature of the battery pack cells. The cladding layer / coating provides a thermal conductive path for efficient heat transfer to a cooling plate in the case of edge cooling.

[0106] The foregoing description is merely exemplary in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Thus, while the disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon study of the drawings, the specification, and the following claims. It should be understood that one or more steps within a method may be performed in a different order (or concurrently) without altering the principles of the disclosure. Further, although each of the embodiments is described above as having certain features, any one or more of the features described with respect to any one embodiment of the disclosure may be implemented in and / or combined with the features of any other embodiment, even if not explicitly described in combination. In other words, the described embodiments are not mutually exclusive, and the permutation of one or more of the embodiments is still within the scope of the disclosure.

[0107] Spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.) are described using a variety of terms, including “connected,” “engaged,” “coupled,” “adjacent,” “next to,” “on top of,” “above,” “below,” and “disposed.” Unless explicitly described as “direct,” when a relationship between a first element and a second element is described in the foregoing disclosure, the relationship can be a direct relationship in which no other intervening elements exist between the first element and the second element, or an indirect relationship in which one or more intervening elements exist (spatially or functionally) between the first element and the second element. The phrase “at least one of A, B, and C” as used herein should be construed to mean a logical (A OR B OR C) using a non-exclusive logical OR and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”

Claims

1. A housing for a prismatic battery cell, comprising: A housing body including sides, a lid portion, and a bottom portion, wherein the housing body is made of steel; and A layer disposed on the housing body, and the layer comprises a material having a higher thermal conductivity than the steel.

2. The housing according to claim 1, wherein the layer comprises a metal or metal alloy coating.

3. The housing according to claim 2, wherein the metal coating is selected from copper, copper - zinc (Cu - Zn), zinc, and aluminum alloy.

4. The housing according to claim 3, wherein the aluminum alloy is selected from Al - 6% Si and Al - 55% Zn.

5. The housing according to claim 3, wherein electroplating is used to apply the metal coating.

6. The housing according to claim 3, wherein hot dipping is used to apply the metal coating.

7. The housing according to claim 3, further comprising a nickel coating on the steel, wherein the metal coating is applied on the nickel coating and the metal coating is selected from copper, copper - zinc (Cu - Zn), and zinc.

8. The housing according to claim 1, wherein the layer comprises a cladding layer attached to the housing body by an adhesive.

9. The housing according to claim 8, wherein the cladding layer comprises copper.

10. The housing according to claim 1, wherein the layer comprises a ceramic coating selected from aluminum nitride (AlN), boron nitride (BN), and aluminum oxide (Al2O3).

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