Battery pack and energy storage system

Abstract

The invention relates to the technical field of energy storage, and discloses a battery pack which comprises a shell, a battery cell module and a heat insulation part, the shell comprises a top cover, a bottom wall and a side wall, the top cover and the bottom wall are arranged at intervals in the first direction, the side wall is connected between the top cover and the bottom wall, and the top cover, the bottom wall and the side wall jointly define a containing cavity. The battery cell module is arranged in the accommodating cavity; the battery cell module and the bottom wall are arranged at an interval in the first direction; the heat insulation part is arranged between the battery cell module and the bottom wall, the heat insulation part is fixed on the bottom wall, and the heat conductivity coefficient of the heat insulation part at 500 DEG C is less than 0.1 (W / (m.K)). According to the battery pack, the battery cell module and the bottom wall are arranged at an interval, and the heat insulation part is arranged between the battery cell module and the bottom wall, so that on one hand, the heat insulation part can reduce heat transferred to the bottom wall by the battery cell module during thermal runaway, and on the other hand, the heat insulation part has a fireproof function, and the risk that the bottom wall is directly burnt when the battery cell module is on fire is reduced.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of energy storage technology, and in particular to a battery pack and an energy storage system. Background Art

[0002] Energy storage systems can store and release electrical energy. They usually include several battery packs, which can expand the storage capacity of the energy storage system. When a battery pack experiences thermal runaway, the battery cells inside the battery pack will generate a large amount of heat, which is directly transferred to the battery pack shell, causing the shell temperature to be too high. Therefore, temperature control of the battery pack during thermal runaway is particularly important. Summary of the invention

[0003] The main technical problem solved by the embodiments of the present application is to provide a battery pack and an energy storage system that can effectively solve the problem of thermal runaway of the battery pack.

[0004] In order to solve the above technical problems, a technical solution adopted in an embodiment of the present application is: to provide a battery pack, including a shell and a battery cell module and a thermal insulation member arranged inside the shell. The shell includes a top cover and a bottom wall arranged at intervals along a first direction, and a side wall connected between the top cover and the bottom wall, and the top cover, the bottom wall and the side wall together enclose a accommodating cavity. The battery cell module is arranged in the accommodating cavity, and the battery cell module and the bottom wall are arranged at intervals along the first direction. The thermal insulation member is arranged between the battery cell module and the bottom wall, and the thermal insulation member is fixed to the bottom wall. The thermal conductivity of the thermal insulation member at 500°C is less than 0.1 (W / (m·K)).

[0005] In one or more of the above optional embodiments, the thermal insulation element comprises aerogel.

[0006] In one or more optional embodiments above, the bottom wall is provided with a first convex portion and a second convex portion facing the top cover, and the first convex portion and the second convex portion are arranged at intervals. The battery cell module includes a first end wall, a second end wall and a battery cell assembly, and along the second direction, the battery cell assembly is located between the first end wall and the second end wall, the first end wall, the second end wall and the battery cell assembly are fixed, and the second direction is perpendicular to the first direction; the first end wall is fixed to the first convex portion, the second end wall is fixed to the second convex portion, and the heat insulation is arranged between the battery cell assembly and the bottom wall.

[0007] In one or more of the above optional embodiments, the surface of the bottom wall is coated with a heat insulation coating.

[0008] In one or more optional embodiments above, a first gap is formed between the battery cell assembly and the bottom wall along the first direction, and the length D1 of the first gap satisfies: 3mm≤D1≤15mm; and the thermal insulation member is located in the first gap.

[0009] In one or more optional embodiments above, along the first direction, the battery cell assembly and the heat insulating member form a second gap, and the length D2 of the second gap satisfies: 0 mm <D2≤12mm。

[0010] In one or more optional embodiments above, the battery cell assembly includes a plurality of battery cells stacked along a second direction, each battery cell includes a pressure relief portion, and the pressure relief portion and the thermal insulation member are located on different sides of the battery cell; the second direction is perpendicular to the first direction.

[0011] In one or more optional embodiments above, the pressure relief portion is located on one side of the battery cell along the third direction, the battery pack includes a pressure relief valve arranged on the side wall, the pressure relief valve is located on one side of the battery pack along the third direction, and the first direction is perpendicular to the third direction.

[0012] In one or more of the above optional embodiments, the pressure relief portion of the battery cell is arranged opposite to the pressure relief valve on the side wall.

[0013] In one or more optional embodiments above, each battery cell includes an electrode terminal. The battery cell housing includes a first sealing portion and a second sealing portion, the first sealing portion is connected to the end of the main body, one end of the electrode terminal is connected to the electrode assembly, the other end of the electrode terminal extends from the first sealing portion, and the pressure relief portion includes the first sealing portion.

[0014] In one or more of the above optional embodiments, the battery cell module includes a bracket and a first circuit board, the battery cell assembly is arranged between the bottom wall and the bracket, the first circuit board is arranged on the side of the bracket away from the battery cell assembly, and the first circuit board is electrically connected to the battery cell assembly.

[0015] In one or more optional embodiments above, along the second direction, the bracket is fixed to the first end wall and the second end wall respectively, so as to fix the bracket to the battery cell assembly.

[0016] In one or more optional embodiments above, the battery cell assembly includes a plurality of battery cells stacked along a second direction, each battery cell includes a battery cell shell, and the second direction is perpendicular to the first direction; the battery cell module includes an adhesive, the adhesive bonds the plurality of battery cell shells and the bracket, and the thermal conductivity of the adhesive at 25°C is 0.1-0.5 (W / (m·K)).

[0017] In one or more of the above optional embodiments, the adhesive bonds each battery cell housing and the bracket.

[0018] In one or more of the above optional embodiments, an adhesive bonded each main body portion and the second sealing portion, and the adhesive can transfer heat to reduce the temperature difference between the battery cells.

[0019] In one or more optional embodiments above, the battery module includes a second circuit board, which is located on one side of the battery along the second direction. The battery includes an electrode terminal, which is connected to the second circuit board, and the second circuit board is fixed to the first end wall and / or the second end wall.

[0020] In one or more of the above optional embodiments, the battery pack includes a protective member located outside the accommodating cavity, the protective member is arranged on a side of the bottom wall away from the top cover, and along the first direction, part of the protective member is spaced apart from the bottom wall, and the melting point of the protective member is greater than the melting point of the bottom wall.

[0021] In one or more of the above optional embodiments, the relationship between the melting point Tm1 of the protective member and the melting point Tm2 of the bottom wall satisfies: (Tm1-Tm2)≥50°C.

[0022] In one or more of the above optional embodiments, the protective member is provided with a recessed portion, and along the first direction, the recessed portion is away from the bottom wall, and a third gap is formed between the recessed portion and the bottom wall.

[0023] The present application provides another embodiment of an energy storage system, comprising a plurality of battery packs; the plurality of battery packs are stacked along a second direction, and a plurality of top covers are located on the same side of the energy storage system.

[0024] In one or more of the above optional embodiments, the bottom wall is configured as a mounting surface facing the outside.

[0025] The beneficial effects of the embodiments of the present application are as follows: the battery pack of the embodiments of the present application includes a shell and a battery cell module and a heat insulating member arranged inside the shell. The shell includes a top cover and a bottom wall spaced apart along a first direction, and a side wall connected between the top cover and the bottom wall, and the top cover, the bottom wall and the side wall jointly enclose a receiving cavity. The battery cell module is arranged in the receiving cavity, and the battery cell module and the bottom wall are spaced apart in the first direction. The heat insulating member is arranged between the battery cell module and the bottom wall, and the heat insulating member is fixed to the bottom wall, and the thermal conductivity of the heat insulating member at 500°C is less than 0.1 (W / (m·K)). The battery pack of the present application spaces the battery cell module from the bottom wall, and a heat insulating member is arranged between the battery cell module and the bottom wall. On the one hand, the heat insulating member can reduce the heat transferred from the battery cell module to the bottom wall during thermal runaway, and on the other hand, the heat insulating member has a fireproof function, which reduces the risk of directly burning the bottom wall when the battery cell module catches fire. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application, the following is a brief introduction to the drawings required for describing the specific embodiments. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0027] Figure 1It is a schematic diagram of a battery pack according to an embodiment of the present application.

[0028] Figure 2 It is a cross-sectional view of a partial structure of a battery pack according to an embodiment of the present application.

[0029] Figure 3 The battery pack of the present application embodiment is Figure 2 Enlarged view of part A in the figure.

[0030] Figure 4 It is an exploded diagram of the battery pack according to the embodiment of the present application.

[0031] Figure 5 It is a simplified schematic cross-sectional view of a partial structure of a battery pack according to an embodiment of the present application.

[0032] Figure 6 It is a schematic diagram of the bottom wall of the battery pack according to an embodiment of the present application.

[0033] Figure 7 It is a partial exploded view of the battery cell module in the battery pack of the embodiment of the present application.

[0034] Figure 8 It is a schematic diagram of one of the cells in the cell module of the battery pack according to the embodiment of the present application.

[0035] Fig. 9 It is a partial structural diagram of a battery pack in a battery pack according to an embodiment of the present application.

[0036] Fig.10 It is a schematic diagram of an energy storage system according to another embodiment of the present application. DETAILED DESCRIPTION

[0037] In order to facilitate the understanding of the present application, the present application is described in more detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is described as "fixed to" another element, it can be directly on another element or there can be one or more centered elements therebetween. When an element is described as "connected" to another element, it can be directly connected to another element or there can be one or more centered elements therebetween. The orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "vertical", "horizontal", etc. used in this specification is based on the orientation or positional relationship shown in the accompanying drawings, only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present application. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0038] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in this specification includes any and all combinations of one or more of the related listed items.

[0039] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0040] See also Figures 1 to 3 The embodiment of the present application provides a battery pack 100, which includes a housing 10 and a battery cell module 20 and a heat insulating member 30 disposed inside the housing 10. The housing 10 includes a top cover 11 and a bottom wall 12 spaced apart along a first direction X, and a side wall 13 connected between the top cover 11 and the bottom wall 12, and the top cover 11, the bottom wall 12 and the side wall 13 together enclose an accommodation cavity 14.

[0041] The battery cell module 20 is arranged in the accommodating cavity 14, and the battery cell module 20 is used to store and release electric energy. The battery cell module 20 and the bottom wall 12 are spaced apart in the first direction X to form a first gap 15. The thermal insulation 30 is arranged in the first gap 15, that is, the thermal insulation 30 is located between the battery cell module 20 and the bottom wall 12, and the thermal insulation 30 is fixed to the bottom wall 12. The thermal conductivity of the thermal insulation 30 at 500°C is less than 0.1 (W / (m·K)). When the battery cell module 20 thermally runs away, the thermal insulation 30 reduces the heat transfer to the bottom wall 12, thereby improving the safety of the battery pack 100.

[0042] In some embodiments, insulation 30 comprises aerogel.

[0043] In the embodiment of the present application, the thermal insulation member 30 is fixed on the bottom wall 12 , which can reduce the risk of the thermal insulation member 30 falling off and failing. During the thermal runaway of the battery cell module 20 , the thermal insulation member 30 maintains the thermal insulation function and reduces the heat absorbed by the bottom wall 12 .

[0044] In some embodiments, the bottom wall 12 and the side wall 13 may be an integrally formed structure, and the top cover 11 may be detachably connected to the side wall 13. In other embodiments, the side wall 13 and the top cover 11 may be integrally formed to form a cover structure, and the bottom wall 12 may be detachably connected to the integrally formed side wall 13 and the top cover 11, which helps to facilitate the arrangement of the battery cell module 20 and the thermal insulation member 30 on the bottom wall 12. In a further embodiment, the surface of the bottom wall 12 is coated with a thermal insulation coating, which helps to reduce the heat absorbed by the bottom wall 12 and slow down the rate at which the bottom wall 12 heats up.

[0045] In some embodiments, see Fig.10 , the bottom wall 12 is configured as an installation surface 200 facing the outside, such as a wooden wall, a plastic wall, a cement wall, an energy storage cabinet, etc. When the battery pack 100 has thermal runaway, a large amount of heat inside the battery pack 100 is transferred toward the bottom wall 12, causing the temperature of the bottom wall 12 to rise. The battery pack 100 of the present application sets the battery cell module 20 and the bottom wall 12 at a distance, which can reduce the heat of the battery cell module 20 directly transferred to the bottom wall 12 during thermal runaway. In addition, a heat insulating member 30 is provided at the first gap 15 between the battery cell module 20 and the bottom wall 12, which, on the one hand, further reduces the heat transferred from the battery cell module 20 to the bottom wall 12 during thermal runaway, and on the other hand, the heat insulating member 30 has a fireproof function, which reduces the risk of directly burning the bottom wall 12 when the battery cell module 20 catches fire.

[0046] In some embodiments, see Figure 3 and Figure 4 The battery pack 100 includes a protective member 40, which is disposed on a side of the bottom wall 12 away from the top cover 11, and is located outside the accommodating cavity 14. Along the first direction X, a portion of the protective member 40 is spaced from the bottom wall 12 to form a third gap 41a, which helps to reduce the heat of the bottom wall 12 transferred to the external mounting surface 200.

[0047] In some embodiments, the protective member 40 is provided with a recess 41, and along the first direction X, the recess 41 is away from the bottom wall 12, and a third gap 41a is formed between the recess 41 and the bottom wall 12. The cross section (XY plane) of the protective member 40 is roughly wavy or continuous "S" shaped, and the protective member 40 is directly connected to the bottom wall 12 at many places to enhance the connection strength between the two. The protective member 40 can also be spaced apart from the bottom wall 12 at many places to reduce the heat transfer between the two. In addition, the wavy or continuous "S" shaped protective member 40 also helps to enhance its own structural strength, which is beneficial to improve the installation stability between the battery pack 100 and the external mounting surface 200.

[0048] In some embodiments, the melting point of the protective member 40 is greater than the melting point of the bottom wall 12. The protective member 40 is fixed to the external mounting surface 200. When the battery pack 100 has thermal runaway and generates a large amount of heat or catches fire, the protective member 40 limits the heat from being further transferred to the mounting surface 200, or helps to prevent the flames from spreading to the mounting surface 200.

[0049] In some embodiments, the relationship between the melting point Tm1 of the protection member 40 and the melting point Tm2 of the bottom wall 12 satisfies: (Tm1-Tm2)≥50°C.

[0050] In some embodiments, see Figure 3 and Figure 5The bottom wall 12 is provided with a first convex portion 121 and a second convex portion 122, and the first convex portion 121 and the second convex portion 122 are arranged at intervals. Optionally, the first convex portion 121 and the second convex portion 122 can be directly integrally formed with the bottom wall 12, and optionally, the first convex portion 121 and the second convex portion 122 can also be parts independent of the bottom wall 12, and the first convex portion 121 and the second convex portion 122 are made of materials with low thermal conductivity, such as plastic, rubber, etc. In this way, the heat transferred from the first end wall 21 and the second end wall 22 to the bottom wall 12 through the first convex portion 121 and the second convex portion 122 can be further reduced.

[0051] In some embodiments, the battery cell module 20 includes a first end wall 21, a second end wall 22, and a battery cell assembly 23. Along the second direction Y, the battery cell assembly 23 is located between the first end wall 21 and the second end wall 22. The first end wall 21, the second end wall 22, and the battery cell assembly 23 are fixed, and the second direction Y is perpendicular to the first direction X. The first end wall 21 is fixed to the first protrusion 121, the second end wall 22 is fixed to the second protrusion 122, and the heat insulation member 30 is arranged between the battery cell assembly 23 and the bottom wall 12. The first protrusion 121 and the second protrusion 122 jointly support the battery cell assembly 23, so that the battery cell assembly 23 and the bottom wall 12 have a first gap 15, so that the heat insulation member 30 is arranged between the battery cell assembly 23 and the bottom wall 12.

[0052] In some embodiments, the first end wall 21 and the first protrusion 121 can be fixed by any connection method such as snap connection, bonding, screw connection, etc. The second end wall 22 and the second protrusion 122 can be fixed by any connection method such as snap connection, bonding, screw connection, etc.

[0053] For example, see Figure 6 and Figure 7 The first end wall 21 is provided with a first hole 211 penetrating along the first direction X, the battery module 20 includes a first fastener 212, the first convex portion 121 is provided with a first screw groove 1211, and the first screw groove 1211 is provided with a thread. The first fastener 212 passes through the first hole 211 along the first direction X and is screwed to the first screw groove 1211 to fix the first end wall 21 on the first convex portion 121.

[0054] The second end wall 22 is provided with a second hole 221 that penetrates along the first direction X, the battery module 20 includes a second fastener 222, the second convex portion 122 is provided with a second screw groove 1221, and a thread is provided in the second screw groove 1221. The second fastener 222 passes through the second hole 221 along the first direction X and is screwed with the second screw groove 1221 to fix the second end wall 22 on the second convex portion 122. It is more convenient for the first fastener 212 to be screwed with the first convex portion 121 along the first direction X, and it is more convenient for the second fastener 222 to be screwed with the second convex portion 122 along the first direction X.

[0055] In some embodiments, see Figure 6 and Figure 7 The bottom wall 12 is provided with a third convex portion 123, which is spaced apart from the first convex portion 121 along the third direction Z, and the third convex portion 123 is provided with a third screw groove 1231. The bottom wall 12 is provided with a fourth convex portion 134, which is spaced apart from the second convex portion 122 along the third direction Z, and the fourth convex portion 124 is provided with a fourth screw groove 1241. The first direction X, the second direction Y and the third direction Z are perpendicular to each other.

[0056] In some embodiments, see Figure 6 and Figure 7 The cell module 20 includes two first fasteners 212, and the first end wall 21 includes two first holes 211. One first fastener 212 corresponds to the first protrusion 121, and the first fastener 212 passes through one first hole 211 and is screwed to the first screw groove 1211 on the first protrusion 121. Another first fastener 212 corresponds to the third protrusion 123, and the first fastener 212 passes through another first hole 211 and is screwed to the third screw groove 1231 on the third protrusion 123. In this embodiment, by providing two first fasteners 212 corresponding to the first protrusion 121 and the third protrusion 123, respectively, the connection firmness between the cell module 20 and the bottom wall 12 can be improved.

[0057] The cell module 20 includes two second fasteners 222, and the second end wall 22 includes two second holes 221. One second fastener 222 corresponds to the second protrusion 122, and the second fastener 222 passes through one second hole 221 and is screwed to the second screw groove 1221 on the second protrusion 122. Another second fastener 222 corresponds to the fourth protrusion 124, and the second fastener 222 passes through another second hole 221 and is screwed to the fourth screw groove 1241 on the fourth protrusion 124. In this embodiment, by providing two second fasteners 222, which correspond to the second protrusion 122 and the fourth protrusion 124, respectively, the connection firmness between the cell module 20 and the bottom wall 12 can be improved.

[0058] In some embodiments, see Figure 5 , Figure 5 It is a simplified schematic diagram of a partial structure of the battery cell module 20. Along the first direction X, a first gap 15 is formed between the battery cell assembly 23 and the bottom wall 12, and the length D1 of the first gap 15 satisfies: 3mm≤D1≤15mm. The heat insulating member 30 is arranged in the first gap 15, and the heat insulating member 30 has a heat insulating effect, which is conducive to reducing the heat directly transferred from the battery cell 23 to the bottom wall 12.

[0059] In some embodiments, see Figure 5, along the first direction X, a second gap 16 is formed between the surface of the battery cell assembly 23 and the heat insulation member 30, and the length D2 of the second gap 16 satisfies: 0mm < D2 ≤ 12mm. The second gap 16 can help reduce the heat transfer of the battery cell assembly 23 to the heat insulation member 30.

[0060] In some embodiments, along the first direction X, the battery cell assembly 23 is in abutting connection with the heat insulation member 3, and there is no gap between the surface of the battery cell assembly 23 and the heat insulation member 30 along the first direction X.

[0061] In some embodiments, referring to Figure 7 , the battery cell assembly 23 includes a plurality of battery cells 231 stacked along the second direction Y, and each battery cell 231 includes a pressure relief portion 2312. The pressure relief portion 2312 and the heat insulation member 30 are located on different sides of the battery cell 231. The pressure relief portion 2312 is used for internal pressure relief of the battery cell 231 during thermal runaway. The pressure relief portion 2312 of the battery cell 231 avoids the heat insulation member 30, and when the battery cell 231 undergoes thermal runaway, the heat rushing out from the inside of the battery cell 231 is directly transferred to the heat insulation member 30.

[0062] In some embodiments, when the battery cell 231 is a hard-shell battery cell, the pressure relief portion of the hard-shell battery cell 231 can be located at the top or the side, or can be an independent pressure relief structure, such as an explosion-proof valve, a pressure relief valve, etc. When the battery cell 231 is a soft-pack battery cell, the aluminum-plastic film of the soft-pack battery cell 231 forms the pressure relief portion 2312 at the top after stamping and packaging.

[0063] In some embodiments, each battery cell 231 includes a battery cell housing 2311 and an electrode assembly (not shown in the figure). The battery cell housing 2311 includes a main body portion 23111, and the electrode assembly is received in the main body portion 23111. The electrode assembly includes a positive electrode plate, a negative electrode plate, and a separator, and the separator is located between the positive electrode plate and the negative electrode plate.

[0064] In some embodiments, multiple battery cells 231 can be connected in series, parallel, or in a hybrid connection, and the present application does not limit this.

[0065] In some embodiments, referring to Figure 7 and Figure 8Each battery cell 231 includes an electrode terminal 2313. The battery cell housing 2311 includes a first sealing portion 23112 and a second sealing portion 23113. The first sealing portion 23112 is connected to the end of the main body 23111. One end of the electrode terminal 2313 is connected to the electrode assembly, and the other end of the electrode terminal 2313 extends from the first sealing portion 23112. The second sealing portion 23113 is connected to the side of the main body 23111. The second sealing portion 23113 and the first sealing portion 23112 are respectively located on different sides of the main body 23111. The first sealing portion 23112 and the second sealing portion 23113 are used together to seal the main body 23111, thereby reducing the risk of electrolyte leakage in the main body 23111.

[0066] In some embodiments, see Figure 8 The battery cell housing 2311 includes two second sealing portions 23113 . Along the first direction X, the two second sealing portions 23113 are located on both sides of the main body 23111 .

[0067] In some embodiments, the battery cell 231 includes a soft-pack battery cell, and the battery cell housing 2311 includes an aluminum-plastic film.

[0068] In some embodiments, the pressure relief portion 2312 includes a first sealing portion 23112 .

[0069] In some embodiments, the pressure relief portion 2312 is located on one side of the battery cell 231 along the third direction Z. Figure 1 The battery pack 100 includes a pressure relief valve 50, which is disposed on the side wall 13. The pressure relief valve 50 is located on one side of the battery pack 100 along the third direction Z, and the third direction Z is perpendicular to the first direction X. When one or more soft-packed cells 23 in the cell module 20 have thermal runaway, high-temperature and high-pressure gas and / or liquid leaks into the accommodating cavity 14, and the temperature and pressure in the accommodating cavity 14 rise sharply. The pressure relief valve 50 on the side wall 13 discharges the high-temperature and high-pressure gas in the accommodating cavity 14 in time.

[0070] The pressure relief portion 2312 of the battery cell 231 is arranged opposite to the pressure relief valve 50 on the side wall 13, so that the high-temperature and high-pressure gas released from the pressure relief portion 2312 can be directly released to the outside through the pressure relief valve 50, thereby further accelerating the pressure relief speed of the battery pack 100 and reducing the probability of explosion of the battery pack 100. In some embodiments, both ends of the battery cell 23 along the third direction Z have a pressure relief portion 2312 for pressure relief, and correspondingly, at least one pressure relief valve 50 is also provided on the two side walls 13 corresponding to the pressure relief portion 2312 in the third direction Z.

[0071] In some embodiments, see Fig. 9The battery module 20 includes a bracket 24 and a first circuit board 25. Along the first direction X, the battery assembly 23 is arranged between the bottom wall 12 and the bracket 24. The first circuit board 25 is arranged on the side of the bracket 24 away from the battery assembly 23, and the bracket 24 separates the battery assembly 23 and the first circuit board 25. The first circuit board 25 is electrically connected to the battery assembly 23 to achieve the control of the charging and discharging of the battery assembly 23. The first circuit board 25 generates a certain amount of heat when working. By arranging the first circuit board 25 on the side of the bracket 24 away from the battery 23, on the one hand, under normal working conditions, the heat of the first circuit board 25 can be reduced from being transferred to the battery 23 and the bottom wall 12, reducing the risk of thermal runaway caused by excessive heating of the battery assembly 23, and at the same time, it can also reduce the risk of a large temperature rise caused by the bottom wall 12 absorbing heat; on the other hand, when the battery assembly 23 generates a large amount of heat due to thermal runaway, the bracket 24 also helps to reduce the heat directly transferred to the first circuit board 25, which has a protective effect on the first circuit board 25.

[0072] In some embodiments, along the second direction Y, the bracket 24 is fixed to the first end wall 21 and the second end wall 22 respectively, so as to achieve the fixation of the bracket 24 and the battery cell assembly 23. The bracket 24 can be a hard plastic plate or a metal plate.

[0073] In some embodiments, see Fig. 9 The cell module 20 includes an insulating member 26, which is located between the cell assembly 23 and the bracket 24. The insulating member 26 is respectively abutted against the cell assembly 23 and the bracket 24. By providing the insulating member 26 between the cell assembly 23 and the bracket 24, on the one hand, the heat exchange between the cell assembly 23 and the bracket 24 can be reduced, and on the other hand, the cell assembly 23 and the bracket 24 can be insulated, thereby reducing the risk of the bracket 24 being charged and affecting the operation of the first circuit board 25.

[0074] In some embodiments, see Fig. 9 The battery cell module 20 includes an adhesive 27, which is disposed between the battery cell 231 and the bracket 24. The adhesive 27 respectively bonds the multiple battery cell shells 2311 and the bracket 24, and the thermal conductivity of the adhesive 27 at 25°C is 0.1-0.5 (W / (m·K)). The adhesive 27 makes the adjacent battery cells 231 relatively fixed, thereby reducing the risk of movement when the battery cell 231 is subjected to a force in the third direction Z. The adhesive 27 also helps to fix the bracket 24 on the surface of the battery cell assembly 23, reducing the risk of the bracket 24 separating from the battery cell assembly 23.

[0075] In some embodiments, the adhesive 27 bonds each battery cell housing 2311 and the bracket 24 .

[0076] In some embodiments, the adhesive 27 bonds each main body portion 23111 and the second sealing portion 23113 . The adhesive 27 can transfer heat and reduce the temperature difference between the battery cells 231 .

[0077] In some embodiments, see Figure 7 The battery cell module 20 includes a second circuit board 28, which is arranged at the end of a plurality of battery cells 231 along the third direction Z. The battery cells 231 have protruding electrode terminals 2313, and the electrode terminals 2313 are electrically connected to the second circuit board 28, thereby realizing series or parallel connection between the plurality of battery cells 231.

[0078] The second circuit board 28 extends along the second direction Y, the second circuit board 28 is fixed to the first end wall 21, and the other end of the second circuit board 28 is fixed to the second end wall 22. By fixing the second circuit board 28 to the first end wall 21 and the second end wall 22 respectively, the fixing effect of the first end wall 21 and the second end wall 22 on the plurality of battery cells 231 can be enhanced, and the movement of the battery cells 231 can be restricted.

[0079] When one or more battery cells 231 deform due to thermal runaway, the second circuit board 28 is fixed to the first end wall 21 and the second end wall 22, and the electrode terminals 2313 of other battery cells 231 that have not experienced thermal runaway remain connected to the second circuit board 28, lowering the second circuit board 28 to separate from the battery cells 23, thereby pulling the electrode terminals of other battery cells 23.

[0080] In some embodiments, the second circuit board 28 is spaced apart from the bottom wall 12 along the first direction X. The second circuit board 28 is connected to a plurality of electrode terminals 2313, and the heat generated by the electrode terminals 2313 is accumulated on the second circuit board 28, so that the second circuit board 28 has a certain amount of heat. The second circuit board 28 is spaced apart from the bottom wall 12 in the first direction X, which can reduce the heat on the second circuit board 28 directly transferred to the bottom wall 12.

[0081] In some embodiments, see Figure 4 and Fig. 9 Along the first direction X, an insulating member 26 is provided between the second circuit board 28 and the bottom wall 12 , and the insulating member 26 limits the contact between the second circuit board 28 and the bottom wall 12 to form an electrical connection, thereby reducing the harm caused by the bottom wall 12 being charged.

[0082] See also Fig.10 The present application further provides an energy storage system 1000 embodiment, the energy storage system 1000 includes a plurality of battery packs 100, and the plurality of battery packs 100 are stacked along a second direction Y.

[0083] The pressure relief portion 2312 and the pressure relief valve 50 of the battery pack 100 are distributed along the third direction Z, and the stacking arrangement of several battery packs 100 along the second direction Y will not affect the pressure relief of the battery pack 100. Several top covers 11 are located on the same side of the energy storage system 1000, and several bottom walls 12 are located on the same side of the energy storage system 1000, which is conducive to the installation of the energy storage system 1000 on the external installation surface 200, so that the heat transferred from the inside of the battery pack 100 to the bottom wall 12 is reduced, and the risk of the bottom wall 12 being too high in temperature is reduced. In addition, each bottom wall 12 is fixedly connected to the installation surface 200, which strengthens the connection strength between the entire energy storage system 1000 and the installation surface 200.

[0084] The above descriptions are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A battery pack, characterized in that: include: A housing, comprising a top cover and a bottom wall spaced apart along a first direction, and a side wall connected between the top cover and the bottom wall, wherein the top cover, the bottom wall and the side wall jointly enclose a receiving cavity; A battery cell module is disposed in the accommodating cavity, and the battery cell module and the bottom wall are spaced apart along the first direction; A heat insulating member is disposed between the battery core module and the bottom wall. The heat insulating member is fixed to the bottom wall. The heat insulating member has a thermal conductivity of less than 0.1 (W / (m·K)) at 500°C.

2. The battery pack according to claim 1, characterized in that: The bottom wall is provided with a first convex portion and a second convex portion facing the top cover, and the first convex portion and the second convex portion are arranged at intervals; The battery cell module includes a first end wall, a second end wall and a battery cell assembly. Along the second direction, the battery cell assembly is located between the first end wall and the second end wall. The first end wall, the second end wall and the battery cell assembly are fixed, and the second direction is perpendicular to the first direction; the first end wall is fixed to the first protrusion, the second end wall is fixed to the second protrusion, and the thermal insulation component is arranged between the battery cell assembly and the bottom wall.

3. The battery pack according to claim 2, characterized in that: Along the first direction, a first gap is formed between the battery cell assembly and the bottom wall, and a length D1 of the first gap satisfies: 3mm≤D1≤15mm; and the heat insulating member is located in the first gap.

4. The battery pack according to claim 3, characterized in that: Along the first direction, the battery cell assembly and the thermal insulation member form a second gap, and the length D2 of the second gap satisfies: 0 mm <D2≤12mm。 5. The battery pack according to any one of claims 1 to 4, characterized in that: The battery cell assembly includes a plurality of battery cells stacked along a second direction, each of the battery cells includes a pressure relief portion, and the pressure relief portion and the heat insulation component are located on different sides of the battery cell; the second direction is perpendicular to the first direction.

6. The battery pack according to claim 5, characterized in that: The pressure relief portion is located on one side of the battery cell along the third direction. The battery pack includes a pressure relief valve arranged on the side wall. The pressure relief valve is located on one side of the battery pack along the third direction. The first direction is perpendicular to the third direction.

7. The battery pack according to any one of claims 1 to 6, characterized in that: The battery cell module includes a bracket and a first circuit board. The battery cell assembly is arranged between the bottom wall and the bracket. The first circuit board is arranged on a side of the bracket away from the battery cell assembly. The first circuit board is electrically connected to the battery cell assembly.

8. The battery pack according to claim 7, characterized in that: The battery cell assembly includes a plurality of battery cells stacked along a second direction, each of the battery cells includes a battery cell shell, and the second direction is perpendicular to the first direction; The battery cell module includes an adhesive member, the adhesive member bonds the plurality of battery cell shells and the bracket, and the thermal conductivity of the adhesive member at 25° C. is 0.1-0.5 (W / (m·K)).

9. The battery pack according to any one of claims 1 to 8, characterized in that: The battery cell module comprises a second circuit board, and the second circuit board is located on one side of the battery cell along the second direction; The battery cell includes an electrode terminal, the electrode terminal is connected to the second circuit board, and the second circuit board is fixed to the first end wall and / or the second end wall.

10. The battery pack according to any one of claims 1 to 9, characterized in that: The battery pack includes a protective member located outside the accommodating cavity, the protective member is arranged on a side of the bottom wall away from the top cover, and along the first direction, part of the protective member is spaced apart from the bottom wall, and the melting point of the protective member is greater than the melting point of the bottom wall.

11. An energy storage system, characterized in that: It comprises a plurality of battery packs as described in any one of claims 1 to 10; the plurality of battery packs are stacked along the second direction, and the plurality of top covers are located on the same side of the energy storage system.

12. The energy storage system according to claim 11, characterized in that: The bottom wall is configured as a mounting surface facing the outside.

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