Thermal insulation battery pack and thermal management method

Abstract

The present invention discloses a heat-insulated battery pack, which includes a battery module containing a plurality of rows of battery cells and a heat-insulating member. Two heat-insulating layers are provided on the heat-insulating member. The plurality of rows of battery cells are all installed in one heat-insulating layer. The two heat-insulating layers are installed opposite to each other, and a hollow chamber is installed between the two heat-insulating layers. The hollow chamber is filled with gas to form an air layer, which suppresses heat conduction on both opposite sides of the air layer.

Description

Technical Field

[0001] The present invention claims priority based on a Chinese patent application filed with the China National Intellectual Property Administration on December 30, 2022, with an application number of 202211721974.X, and a Chinese patent application filed with the China National Intellectual Property Administration on December 30, 2022, with an application number of 202223608141.0, and incorporates all the contents of the above Chinese patent applications by reference into the present invention. The present invention relates to the field of batteries, and particularly to a thermal insulation battery pack and a thermal management method.

Background Art

[0002] A battery pack is formed by a plurality of battery modules, and a battery management system, an electrical system, etc. are further installed. Battery thermal management is one of the important functions in the battery management system, and mainly aims to always keep the battery modules operating within an appropriate temperature range, which is to maintain the battery modules in an optimal operating state. Battery thermal management mainly includes functions such as cooling, heating, and temperature equalization. The cooling and heating functions are mainly adjusted according to the influence that the external environmental temperature can exert on the battery. Temperature equalization is to reduce the temperature difference within the battery modules and prevent rapid degradation due to overheating of some batteries.

[0003] In the conventional battery pack, due to the spatial constraints of the battery box body, it is difficult to take effective heat preservation measures for the battery pack. When the temperature of the external environment is low, heat is supplied to the battery pack by the battery thermal management of the battery management system, but there is a problem of rapid heat loss due to the heat preservation performance of the battery pack.

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to solve at least one drawback existing in the above prior art, the present invention provides a thermal insulation battery pack that solves the problem of rapid heat loss of the conventional battery pack and improves the heat preservation performance of the battery pack.

Means for Solving the Problems

[0005] In a first aspect, the present invention provides a heat-insulated battery pack, a battery module including a plurality of rows of battery cells, two heat-insulating layers are provided, all of the plurality of rows of the battery cells are installed in one of the heat-insulating layers, the two heat-insulating layers are installed opposite to each other, a hollow chamber is installed between the two heat-insulating layers, a gas is filled in the hollow chamber to form an air layer, and a heat-insulating member for suppressing heat conduction on both opposite sides of the air layer.

[0006] In one embodiment, a plurality of positioning openings are further provided in the heat-insulating member. The shape and dimension of each positioning opening are adapted to the shape and dimension of each battery cell. Each battery cell is mounted and fixed inside the positioning opening.

[0007] In one embodiment, a heat-insulating ring is installed on the inner side wall of each positioning opening. The heat-insulating ring abuts against the end face of the corresponding battery cell.

[0008] In one embodiment, the heat-insulated battery pack further includes at least one liquid-cooling plate. At least one of the liquid-cooling plates is thermally connected to the battery module.

[0009] In one embodiment, all of the plurality of liquid-cooling plates are vertically distributed with respect to the heat-insulating member. Each liquid-cooling plate is installed between two adjacent rows of the battery cells. The plurality of liquid-cooling plates are connected in parallel by liquid-cooling pipes.

[0010] In one embodiment, the battery cell is a cylindrical cell. The plurality of rows of the battery cells are alternately arranged and distributed. Each liquid-cooling plate is installed in a wavy shape so that the circumferential side surface of each battery cell is attached to the liquid-cooling plate.

[0011] In one embodiment, the heat-insulated battery pack further includes a pallet. The heat-insulating member is installed on the pallet.

[0012] In one embodiment, the thermal insulation battery pack further includes a battery box. The battery module, the thermal insulation member, the pallet, and each of the liquid cooling plates are all mounted and fixed inside the battery box.

[0013] In one embodiment, a plurality of pressure release openings are provided on the pallet. Each battery cell is installed corresponding to each pressure release opening. A pressure release passage is provided between the pallet and the battery box. The inner hole of the thermal insulation ring, the pressure release opening, and the pressure release passage are sequentially communicated to guide the hot gas flow generated in the battery cell in the thermal runaway state to the outside of the battery box.

[0014] In one embodiment, the battery box includes a bottom protection plate and a square-shaped outer frame. A first step portion, a second step portion, and a third step portion are provided on the inner side wall of the outer frame. The first step portion, the second step portion, and the third step portion are sequentially provided along the height direction of the outer frame from the large side of the outer frame. The bottom protection plate is fixed to the first step portion. The pallet is fixed to the third step portion.

[0015] In one embodiment, the pressure release passage includes a first pressure release chamber and a second pressure release chamber. The first pressure release chamber is formed between the pallet, the bottom protection plate, and the inner side wall of the second step portion. The second pressure release chamber is installed inside the outer frame. The first pressure release chamber communicates with the second pressure release chamber.

[0016] In one embodiment, a temperature-controlled battery chamber is formed by the thermal insulation member and the inner side wall of the outer frame. The battery module is located inside the temperature-controlled battery chamber.

[0017] As a second aspect, the present invention provides a thermal management method for use in a battery pack. In a specific method, the measured temperature value of the observed battery is compared with a preset temperature for evaluation, and the usage state and heat exchange state of the battery are adjusted. The preset temperature includes a first temperature range, a second temperature range, a third temperature range, a fourth temperature range, and a fifth temperature range from a low temperature to a high temperature. In the first state, when the measured temperature value is in the first temperature range, the usage state of the battery is set to a non-charging and non-discharging state, and the heat exchange state of the battery is set to a heating state. In the second state, when the measured temperature value is in the second temperature range, the usage state of the battery is set to a charging state, and the heat exchange state of the battery is set to a heating state. In the third state, when the measured temperature value is in the third temperature range, the usage state of the battery is set to a charging state or a discharging state, and the heat exchange state of the battery is set to a heating state. In the fourth state, when the measured temperature value is in the fourth temperature range, the usage state of the battery is set to a charging state or a discharging state, and the heat exchange state of the battery is set to a non-heating and non-cooling state. In the fifth state, when the measured temperature value is in the fifth temperature range, the usage state of the battery is set to a charging state or a discharging state, and the heat exchange state of the battery is set to a cooling state.

[0018] In one embodiment, the first temperature range is less than -20°C, the second temperature range is -20°C to 5°C, the third temperature range is 5°C to 15°C, the fourth temperature range is 15°C to 37°C, and the fifth temperature range is greater than 37°C.

[0019] In one embodiment, a first end temperature value is further set within the second temperature range, and when the measured temperature value is higher than the first end temperature value, the first state ends.

[0020] In one embodiment, a second end temperature value is further set within the third temperature range, and when the measured temperature value is higher than the second end temperature value, the second state ends.

[0021] In one embodiment, a third end temperature value is further set within the fourth temperature range. When the measured temperature value is higher than the third end temperature value, the third state ends.

[0022] In one embodiment, within the fourth temperature range, a fourth end temperature value is further set. When the measured temperature value is lower than the fourth end temperature value, the fifth state ends.

[0023] Summarizing the above, the heat-insulating battery pack and the thermal management method according to the present invention have the following technical effects. An air layer is skillfully installed within the heat-insulating member. Due to the gradual heat conductivity of the gas flow, the amount of heat cannot be rapidly conducted to both sides of the air layer, thus avoiding rapid heat loss, ensuring and significantly improving the heat-insulating performance of the battery pack with the heat-insulating member installed, solving the problem of rapid heat loss in the battery packs of the prior art, ensuring that the battery pack can be used within an optimal temperature range over a long period of time, maintaining it in an optimal usage state, effectively improving the stability of the battery pack, and further effectively improving the reliability of an electrical device (such as an electric vehicle, etc.) using this battery pack.

Brief Description of the Drawings

[0024]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0025] In the description of the present invention, the orientation or positional relationship indicated by terms such as "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is the orientation or positional relationship shown based on the drawings, and is merely for facilitating the description of the present invention and simplifying the description, and it cannot be understood as a limitation to the present invention because the specified device or element is configured and operated in a specific orientation and a specific direction.

[0026] Example 1 In this embodiment, the power battery (lithium-ion power battery) refers to the battery pack 1 and the battery cell 11. The cruising range, charging time, and usage safety of the power battery are all restricted by the characteristics of the power battery. In addition, the characteristics of the power battery are significantly affected by the environmental temperature. In particular, in a low-temperature environment, the available energy and power attenuation are large. Furthermore, long-term use in a low-temperature environment accelerates the deterioration of the power battery and shortens its service life.

[0027] Conventional power batteries show that at -10°C, the capacity and operating voltage clearly decrease, and at -20°C, the performance deteriorates further, the available discharge capacity drops sharply, and only about 30% of the specific capacity at room temperature can be maintained.

[0028] In addition, in a low-temperature environment, it is difficult to charge a lithium-ion battery, and metallic lithium is likely to be formed on the surface of its negative electrode by deposition during charging. The growth of lithium dendrites not only opens holes in the battery separator, causing internal short circuits in the battery, permanently damaging the battery, but also causes thermal runaway of the battery, significantly reducing the safety during use.

[0029] Regarding the heat preservation problem of the power battery, the present invention provides a heat-preserving battery pack. Specifically, FIGS. 1 and 2 clearly show the assembly relationship between each of the pallet 4 and the heat-preserving member 2 and the battery box 5, and are cross-sectional views of the battery box 5. This heat-preserving battery pack includes the battery box 5, and the battery pack 1, the heat-preserving member 2, and the pallet 4 installed inside the battery box 5. Note that the battery pack 1 includes a plurality of rows of battery cells 11.

[0030] The main principle of this technical solution is as follows. In the heat insulation member 2, two heat insulation layers 21 are installed. A plurality of rows of battery cells 11 are all installed in one heat insulation layer 21. The two heat insulation layers 21 are installed opposite to each other, and a hollow chamber is installed between the two heat insulation layers 21. The hollow chamber is filled with gas to form an air layer 22. The gas here may be air or an inert gas. In this case, the air layer 22 forms a sandwich structure with the two heat insulation layers 21.

[0031] The heat conduction is blocked by the non-flowing gas inside the hollow chamber and outside the heat insulation member 2. That is, since the gas in the hollow chamber has excellent low thermal conductivity, the conduction speed from the heat insulation layer 21 with a large amount of heat to the heat insulation layer 21 with a small amount of heat is reduced, and the heat conduction on both opposite sides of the air layer 22 is suppressed, thus achieving the purpose of improving the heat insulation effect of the heat insulation member 2 and enhancing the heat insulation performance of the heat insulation member 2.

[0032] Note that here, the heat insulation material of the heat insulation member 2 is not limited, and a material with a lower thermal conductivity or a higher strength may be selected according to the use environment of the battery pack and the needs of the electric vehicle. Also, the heat insulation material of the heat insulation member 2 may be arranged in different regions according to the heat transfer path to obtain an optimal heat insulation effect.

[0033] Specifically, as shown in FIGS. 1 and 2, the battery box 5 includes a bottom protection plate 52 and a square-shaped outer frame 51. When a large surface of the outer frame 51 is defined as a horizontal plane, the direction perpendicular to the horizontal plane of the outer frame 51 is the height direction of the outer frame 51. On the inner wall of the outer frame 51, a first step portion 511, a second step portion 512, and a third step portion 513 are sequentially installed along the height direction from one side of the horizontal plane. Also, the first step portion 511, the second step portion 512, and the third step portion 513 are all uniformly distributed along the inner peripheral side of the outer frame 51. The bottom protection plate 52 is embedded inside the outer frame 51 and welded to the first step portion 511, making the whole battery box 5 flatter and stronger. Furthermore, excellent airtightness of the whole battery box 5 is ensured.

[0034] Furthermore, as shown in FIGS. 2, 4, and 5, the pallet 4 is fitted inside the outer frame 51 and is fixed by welding to the third step portion 513. The heat insulation member 2 is installed on the pallet 4, that is, supported on the top of the pallet 4. In this case, the temperature control battery chamber 6 is formed by the heat insulation member 2 and the inner side wall of the outer frame 51. When the top of the battery box 5 is covered with a box lid, a relatively sealed space is formed inside the temperature control battery chamber 6.

[0035] When the temperature of the external environment of the battery box 5 is lower than the temperature inside the temperature control battery chamber 6, that is, when the amount of heat inside the temperature control battery chamber 6 is more than the amount of heat in the external environment of the battery box 5, the amount of heat of each battery cell 11 of the assembled battery 1 is also more than the amount of heat in the external environment of the battery box 5. Also, since each battery cell 11 is installed on the heat insulation member 2, the amount of heat of each battery cell 11 is not easily directly conducted to the surface of the battery box 5 and diffused to cause loss.

[0036] Also, when the battery pack is in a low-temperature environment for a long time, due to the low conductivity of the air layer 22, only a small part of the heat of the battery cell 11 is conducted to the surface of the battery box 5 and dissipated, thereby improving the heat dissipation drawback of the battery pack. When the battery pack is in a low-temperature environment for a long time, the battery management system performs optimal heat management measures within a sufficient time so that the assembled battery 1 remains within the optimal temperature range.

[0037] Similarly, when the temperature of the external environment of the battery box 5 is higher than the temperature inside the temperature control battery chamber 6, that is, when the amount of heat inside the temperature control battery chamber 6 is less than the amount of heat in the external environment of the battery box 5, the amount of heat of each battery cell 11 of the assembled battery 1 is also less than the amount of heat in the external environment of the battery box 5. Due to the heat insulation member 2, the amount of heat in the external environment cannot be rapidly transmitted directly to each battery cell 11. Or, when the battery pack is in a high-temperature environment for a long time, the battery management system performs optimal heat management measures within a sufficient time so that the assembled battery 1 is within the optimal temperature range.

[0038] In accordance with the thermal management of the battery management system of the battery pack itself, the temperature in the temperature-controlled battery chamber 6 and the temperature of each battery cell 11 are both in a relatively stable state, ensuring that each battery cell 11 can be used within the optimal temperature range even under external low-temperature or high-temperature conditions.

[0039] Furthermore, as shown in FIG. 3, a plurality of positioning openings 23 are further installed in the heat-insulating member 2. The shape and dimensions of each positioning opening 23 are compatible with the shape and dimensions of each battery cell 11. Each battery cell 11 is fixedly attached inside the positioning opening 23. That is, the end of each battery cell 11 is inserted and connected to the corresponding positioning opening 23. Preferably, the shape and dimensions of the heat-insulating member 2 are compatible with the shape and dimensions of the temperature-controlled battery chamber 6. Thereby, the heat-insulating member 2 is constrained and fixed inside the temperature-controlled battery chamber 6, that is, the large surface at the bottom of the heat-insulating member 2 abuts against and acts on the bottom protection plate 52, and the peripheral side of the heat-insulating member 2 is uniformly distributed on the peripheral side of the outer frame 51.

[0040] By skillfully utilizing the rigidity and structural strength of the heat-insulating layer 21, the peripheral side of each battery cell 11 is uniformly biased and acts on the side wall of the positioning opening 23. Preferably, when the battery cell 11 is a cylindrical cell and correspondingly the positioning opening 23 is installed as a round hole, the peripheral side of the positioning opening 23 and the side wall of the battery cell 11 are biased towards the central axis of the battery cell 11 respectively, that is, the structure of the positioning opening 23 is compatible with the structural strength of the heat-insulating layer 21, and it can effectively ensure that each battery cell 11 is fixed to the heat-insulating member 2, exerting an unexpected effect of firmly attaching and fixing the assembled battery 1 in the battery box 5.

[0041] During the process of inserting, connecting, and assembling the end of the above-mentioned battery cell 11, the bottom surface of the battery cell 11 abuts against and acts on the pallet 4, and the weight of the battery cell 11 is entirely borne by the pallet 4 as it is. However, although the battery cell 11 is in direct contact with the pallet 4, since the pallet 4 is fixedly connected to the battery box 5, part of the heat quantity of the battery cell 11 is transmitted along the pallet 4, and finally, the heat quantity is conducted from the pallet 4 to the battery box 5, thereby causing the problem of a small amount of heat loss from the battery pack.

[0042] In response to the above problems, the present invention further discloses a further improvement. Specifically, as shown in FIG. 3, a heat preservation ring 24 is installed on the inner wall of each positioning port 23, that is, the inner wall of one end of the positioning port 23 close to the pallet 4 extends into the positioning port 23 to form the heat preservation ring 24. The heat preservation ring 24 is preferably integrally formed with the heat preservation member 2 and abuts against the end face of the corresponding battery cell 11. Note that the inner diameter dimension of the heat preservation ring 24 is determined by the battery design or design requirements.

[0043] During the mounting process, each battery cell 11 is inserted and connected to the corresponding positioning port 23 until the end of the battery cell 11 abuts against the heat preservation ring 24. Thereby, each battery cell 11 directly acts on the heat preservation ring 24 to avoid the collision phenomenon between the battery cell 11 and the pallet 4. In addition, the battery cell 11 and the pallet 4 are separated by the heat preservation ring 24, avoiding the direct transmission of the heat quantity of the battery cell 11 to the pallet 4, and effectively solving the problem of heat loss from the battery cell 11 along the pallet 4.

[0044] Furthermore, specifically, as shown in FIG. 3, a plurality of pressure relief openings 41 are installed in the pallet 4, and each battery cell 11 is installed corresponding to each pressure relief opening 41. Therefore, when thermal runaway occurs in any one of the battery cells 11, the high-temperature and high-pressure gas flow generated in the battery cell 11 flows sequentially from the end of the battery cell 11 through the inner hole of the heat preservation ring 24 and the pressure relief opening 41, and finally flows out from the pressure relief opening 41.

[0045] As a supplement, the pressure release port 41 is preferably a through hole. In this case, the pressure release port 41 of the pallet 4 is formed by punching, with a simple process and low cost. The aperture diameter of the through hole is preferably the same as the inner diameter of the heat preservation ring 24, but it may also be larger than the inner diameter of the heat preservation ring 24. Also, the pressure release port 41 may be a counterbore or a dish-shaped hole. The inner hole of the counterbore or the dish-shaped hole is preferably the same as the inner diameter of the heat preservation ring 24, but it may also be larger than the inner diameter of the heat preservation ring 24. Naturally, the pressure release port 41 may also be a concave groove structure with a through hole installed. The aperture diameter of the through hole is not less than the inner diameter of the heat preservation ring 24.

[0046] When the dimension of the pressure release port 41 is larger than the inner diameter of the heat preservation ring 24, one side of the heat preservation ring 24 close to the pressure release port 41 can extend into the interior of the pressure release port 41 along the central axis direction of the heat preservation ring 24 to form a protrusion structure (not shown). The shape and dimension of the protrusion structure are compatible with the shape and dimension of the pressure release port 41, or an assembly tolerance is reserved between the protrusion structure and the pressure release port 41.

[0047] Specifically, as shown in FIGS. 3, 4, and 5, a pressure release passage is installed between the pallet 4 and the battery box 5. The pressure release passage includes a first pressure release chamber 531 formed between the pallet 4, the bottom protection plate 52, and the inner side wall of the outer frame 51 (i.e., the first pressure release chamber 531 formed between the pallet 4, the bottom protection plate 52, and the inner side wall of the second step portion 512), and a second pressure release chamber 532 installed inside the outer frame 51. The outer frame 51 is further provided with at least one communication port and at least one exhaust port (not shown). The second pressure release chamber 532 communicates with the first pressure release chamber 531 through at least one communication port and communicates with the external environment of the battery box 5 through at least one exhaust port.

[0048] Therefore, when any one of the battery cells 11 is in a thermal runaway state, the high-temperature and high-pressure gas (thermal gas flow) released from the battery cell 11 sequentially flows through the inner hole of the heat-insulating ring 24 and the pressure release port 41 of the pallet 1 and flows out into the first pressure release chamber 531. The high-temperature and high-pressure gas flows into the interior of the second pressure release chamber 532 via the communication port under the guidance of the first pressure release chamber 531, and finally flows in a certain direction along the second pressure release chamber 532 to the exhaust port and is discharged to the outside of the battery box 5. Thereby, the thermal gas flow generated from the battery cell 11 in the thermal runaway state is induced and discharged to the outside of the battery box 5 in sequence, exerting the effect of discharging the thermal gas flow generated from the battery cell 11 in the thermal runaway state to the outside of the battery box 5 in sequence.

[0049] Unexpectedly, by combining the heat-insulating ring 24 of the heat-insulating member 2, the pressure release port 41 of the pallet 4, the second pressure release chamber 532 of the outer frame 51, and the first pressure release chamber 531 installed between the bottom protection plate 52 and the pallet 4, the high-temperature and high-pressure gas is directly discharged into the temperature-controlled battery chamber 6 without diffusing, ensuring that the influence on other battery cells 11 of the battery pack 1 caused by the high-temperature and high-pressure gas flow is reduced and further avoided. Thereby, the problem that the thermal gas flow generated when any one of the battery cells 11 of the battery pack 1 is in a thermal runaway state irregularly diffuses in the temperature-controlled battery chamber 6 and causes heat diffusion is avoided, the influence on the battery pack 1 caused by the thermal runaway is reduced, and the stability of the battery pack during use is improved.

[0050] When the battery cell 11 or the battery pack 1 is in a thermal runaway state, or when the battery cell 11 is overcharged or overdischarged, the temperature of the battery cell 11 rises significantly. Since the battery pack 1 mainly consists of a plurality of battery cells 11, if any one of the battery cells 11 does not immediately dissipate heat when the temperature rises, heat accumulation will occur. Furthermore, since the battery pack 1 is installed and fixed in the relatively sealed temperature-controlled battery chamber 6, it is easy to rapidly increase the temperature of the temperature-controlled battery chamber 6.

[0051] To avoid the impact on the usability of each battery cell 11 due to the temperature rise of the battery pack 1 or the temperature-controlled battery chamber 6, the applicant proposes a further improvement. Specifically, as shown in FIGS. 1, 2, and 6, a liquid-cooling plate 3 is installed inside the battery box 5, that is, a liquid-cooling plate 3 thermally connected to the battery pack 1 is installed inside the temperature-controlled battery chamber 6.

[0052] When a heat exchange medium (such as water) is sent into the liquid-cooling plate 3, a temperature difference occurs between the heat exchange medium and the temperature-controlled battery chamber 6. In particular, when the battery cell 11 undergoes thermal runaway, that is, when the temperature of the battery pack 1 is higher than the temperature of the battery cell 11, the heat quantity of the battery pack 1 is transmitted to the heat exchange medium of the liquid-cooling plate 3 and is released from the battery pack along with the flow of the heat exchange medium. Thereby, through the heat exchange between the liquid-cooling plate 3 and the battery pack 1, immediate and real-time heat dissipation is effectively performed on the battery pack 1, and the risks of thermal runaway and heat diffusion in the battery pack 1 are effectively avoided.

[0053] Note that the liquid-cooling plate 3 may be installed on the top of the battery pack 1 or on the peripheral side of the battery cell 11. Here, the liquid-cooling plate 3 arranged on the top of the battery pack 1 is defined as the first liquid-cooling plate 3, and the liquid-cooling plate arranged on the peripheral side of the battery cell 11 of the battery pack 1 is defined as the second liquid-cooling plate 32. However, this is not to limit the difference in their structures, but for the purpose of easily distinguishing the positions of the liquid-cooling plates 3 described later.

[0054] The number of the liquid-cooling plates 3 may be one. To ensure that each battery cell 11 can exchange heat with the liquid-cooling plate 3 and achieve the purpose of dissipating heat and cooling each battery cell 11, as shown in FIG. 6, the first liquid-cooling plate 31 is distributed in parallel with the heat-insulating member 2 and installed on the top of the battery pack 1 and covers at least each battery cell 11. Thereby, the heat quantity released from each battery cell 11 is conducted from the top of the battery cell 11 to the first liquid-cooling plate 31. The first liquid-cooling plate 31 may cover not only the battery pack 1 but also the temperature-controlled battery chamber 6. By doing so, the heat quantity inside the temperature-controlled battery chamber 6 can be transmitted to the first liquid-cooling plate 31.

[0055] Preferably, the number of the second liquid cooling plates 32 may be plural. Specifically, as shown in FIGS. 1 and 2, the plurality of second liquid cooling plates 32 are all vertically distributed with respect to the heat insulation member 2 and are installed between two adjacent rows of battery cells 11. That is, by bringing the large surface of the second liquid cooling plate 32 into contact with the peripheral side of the battery cell 11, the heat exchange surface between the second liquid cooling plate 32 and the battery cell 11 is increased, and it is effectively ensured that the amount of heat released from the battery cell 11 can be rapidly conducted to the second liquid cooling plate 32, improving the heat dissipation performance of the battery pack.

[0056] Specifically, as shown in FIGS. 1 and 2, since the plurality of the above-mentioned second liquid cooling plates 32 are connected in parallel by liquid cooling pipes, when a heat exchange medium is sent to each of the second liquid cooling plates 32 at the same time, the two rows of battery cells 11 on both opposite sides of the second liquid cooling plate 32 can both conduct heat to the second liquid cooling plate 32, achieving the purpose of simultaneously and evenly dissipating heat from the two rows of battery cells 11. That is, it is possible to keep each row of battery cells 11 operating at an optimal ambient temperature. In addition, by assembling and fixing the second liquid cooling plate 32 between the two rows of battery cells 11, the volume of the entire battery pack can also be effectively reduced. Furthermore, since the heat exchange medium supplied from the outside is shunted by the plurality of second liquid cooling plates 32, an unexpected effect of reducing the flow resistance of the battery liquid cooling system is exerted.

[0057] Furthermore, as shown in FIGS. 1 and 2, since the battery cell 11 is preferably a cylindrical cell, the side wall of the battery cell 11 becomes a curved surface. In order to make the assembly of the plurality of battery cells 11 more compact, the battery cells 11 in a plurality of rows are alternately arranged and distributed. Also, each second liquid cooling plate 32 is installed in a wavy shape, and the circumferential side surface of each battery cell 11 is bonded to the second liquid cooling plate 32. That is, each second liquid cooling plate 32 has a plurality of valleys of an arcuate curved surface. Each battery cell 11 is abutted and bonded to the corresponding valley. Also, the shape dimensions of each valley are adapted to the shape dimensions of the battery cell 11, so as to increase the heat exchange area between the battery cell 11 and the second liquid cooling plate 32, achieve the purpose of maximizing the heat exchange efficiency of the battery cells 11 of the assembled battery 1, and exhibit an optimal heat dissipation effect.

[0058] Example 2 The above first embodiment discloses a heat-insulating battery pack with excellent heat-insulating performance. Also, since this heat-insulating battery pack can also obtain an excellent heat dissipation effect in combination with the liquid cooling plate 3, it solves the problem that there is a contradiction between the heat insulation and heat dissipation of the battery pack of the prior art, and maintains a relatively balanced relationship between heat insulation and heat dissipation. Thereby, it is ensured that the heat-insulating battery pack is in an optimal use state, and the stability and reliability of the heat-insulating battery pack and the electrical device using this battery pack are improved.

[0059] Based on the heat-insulating battery pack disclosed in the first embodiment, the present invention further discloses a heat management method, which compares and evaluates the measured temperature value of the monitored battery with a preset temperature, and adjusts the use state and heat exchange state of the battery. The preset temperature includes a first temperature range, a second temperature range, a third temperature range, a fourth temperature range, and a fifth temperature range from a low temperature value to a high temperature value. In the first state, when the measured temperature value is in the first temperature range, the use state of the battery is set to a non-charging and non-discharging state, and the heat exchange state of the battery is set to a heating state. In the second state, when the measured temperature value is in the second temperature range, the use state of the battery is set to a charging state, and the heat exchange state of the battery is set to a heating state. In the third state, when the measured temperature value is within the third temperature range, set the usage state of the battery to the charging state or the discharging state, and set the heat exchange state of the battery to the heating state. In the fourth state, when the measured temperature value is within the fourth temperature range, set the usage state of the battery to the charging state or the discharging state, and set the heat exchange state of the battery to the non-heating and non-cooling state. In the fifth state, when the measured temperature value is within the fifth temperature range, set the usage state of the battery to the charging state or the discharging state, and set the heat exchange state of the battery to the cooling state.

[0060] Note that the measured temperature value of the monitored battery here may be the temperature of the monitored battery cell 11, may be the problem of the monitored battery pack 1, or may be the problem of the monitored battery box 5. Of course, it may also be the temperature combined with any two or three of them.

[0061] In this embodiment, when the first temperature range is within the lowest temperature range, considering that the performance of the power battery deteriorates rapidly when it is -20°C or lower, the first temperature range is preferably less than -20°C. In order to achieve the purpose of optimally protecting the battery within this temperature range, the battery cell 11 is in a state of charge and discharge stop, and in accordance with the thermal management of the battery management system, it is controlled to send the heated heat exchange medium to the liquid cooling plate 3, so that the heat quantity of the heat exchange medium can be effectively transmitted to each battery cell 11, and the purpose of preheating and thawing the battery cell 11 can be realized. In addition, the heat preservation member 2 can effectively avoid the problem that the heat quantity supplied to the battery cell 11 is conducted to the battery box 5 and causes loss, and can quickly adjust the battery pack to return to the optimal temperature range.

[0062] Through long-term research and development and experiments in the battery field, it has been found that when the power battery operates within the range of 15°C to 35°C (or 15°C to 37°C), it can achieve optimal power input and output, maximum available energy, and the longest cycle life. Therefore, when the temperature of the battery returns from -20°C or lower to above -20°C, appropriate charging of the battery may be started.

[0063] According to the plot of the relationship between battery performance and temperature, after the battery is preheated and thawed to -20°C, as the temperature rises, the battery performance is gradually improved. Preferably, 5°C is taken as the median value of the temperature range from -20°C to 15°C, and the temperature range from -20°C to 15°C is divided into a second temperature range from -20°C to 5°C and a third temperature range from 5°C to 15°C, and the battery is charged within the second temperature range.

[0064] When the temperature enters the third temperature range, the user can appropriately select the usage state of the battery according to the usage environment of the battery pack. In order for the battery to be within the optimal temperature range and obtain the optimal battery performance and ensure the longest service life of the battery, within the second temperature range and the third temperature range, the thermal management of the battery management system continues to be controlled to send the heated heat exchange medium to the liquid cooling plate 3 and continue to supply heat to the battery pack 1.

[0065] Note that the temperature range is from -20°C to 15°C, but it is not limited to 5°C and may be 0°C or the like, as long as the temperature range from -20°C to 15°C is divided into two temperature ranges relatively evenly.

[0066] Preferably, the fourth temperature range may be set to 15°C to 37°C, that is, the first temperature range is within the optimal temperature range. At this time, it is not necessary for the battery to continuously supply heat, that is, the heating of the battery cell 11 is stopped, and only the heat generated in the battery cell 11 during use and the heat stored in the heat exchange medium inside the liquid cooling plate 3 are used to keep the battery in a relatively stable temperature range, that is, the battery can be kept at the optimal performance.

[0067] Furthermore, when the temperature of the battery exceeds 37°C, that is, when the fifth temperature range exceeds 37°C, the fifth temperature range is within a high-temperature range. At this time, the battery performance is gradually affected by the high temperature. That is, after the battery enters the fifth temperature range, as the temperature rises, the battery performance gradually decreases. Therefore, after the battery enters the fifth temperature range, it needs to be cooled during use. In order to control the heat management of the battery management system, the low-temperature heat exchange medium is sent to the liquid cooling plate 3, so that the heat of each battery cell 11 is transmitted to the heat exchange medium. Finally, with the discharge of the heat exchange medium from the battery pack, the liquid cooling plate 3 exerts an efficient heat dissipation effect on the battery.

[0068] In addition, the heat insulation member 2 can effectively avoid the heat outside the battery box 5 from being conducted to or not conducted to the assembled battery 1 inside the battery box 5. Thereby, the assembled battery 1 can be quickly returned to the optimal temperature range, and further, it is ensured that the battery pack maintains the optimal battery performance for a long time.

[0069] Furthermore, a first end temperature value is further set within the second temperature range. When the measured temperature value is higher than the first end temperature value, the first state ends. Preferably, the measured temperature value is set to -15°C or -10°C. Since the battery performance drops sharply at -10°C, when the measured temperature value returns above -10°C, the battery performance almost recovers and the first state ends.

[0070] Furthermore, a second end temperature value is further set within the third temperature range. When the measured temperature value is higher than the second end temperature value, the second state ends. Preferably, the measured temperature value is set to 10°C. A third end temperature value is further set within the fourth temperature range. When the measured temperature value is higher than the third end temperature value, the third state ends. Preferably, the measured temperature value is set to 20°C.

[0071] That is, in the thermal management of the battery management system, if the control continues to send the heated heat exchange medium to the liquid cooling plate 3 until the measured temperature value reaches 20°C, the temperature of the battery is within the fourth temperature range of 15°C to 37°C, ensuring that the battery is kept in a dynamic balance within the fourth temperature range. Thereby, by stopping the heat supply after the temperature of the battery reaches 15°C, the problem that the temperature of the battery drops below 15°C and the battery performance is not within the optimal performance range is avoided, effectively improving the stability of the battery pack.

[0072] Furthermore, a fourth end temperature value is further set within the fourth temperature range. When the measured temperature value is lower than the fourth end temperature value, the fifth state ends. Preferably, the fourth end temperature value is higher than the third end temperature value, and the measured temperature value is set to 33°C. That is, in the thermal management of the battery management system, if the control continues to send the cooled heat exchange medium to the liquid cooling plate 3 until the measured temperature value reaches 33°C, the temperature of the battery is within the fourth temperature range of 15°C to 37°C, ensuring that the battery is kept in a dynamic balance within the fourth temperature range. Thereby, by stopping the cooling after the temperature of the battery reaches 37°C, the problem that the temperature of the battery rises above 37°C and the battery performance is not within the optimal performance range is avoided, more effectively improving the stability of the battery pack.

[0073] To summarize the above, the above-mentioned temperatures are divided into multiple temperature ranges based on the optimal temperature value of the battery performance and the low-temperature sudden change value of the battery performance, making the controllable range of the temperature of the battery thermal management more reasonable, and effectively avoiding the problem of frequently turning on and off the thermal management of the battery management system due to the first end temperature value, the second end temperature, the third end temperature value, and the fourth end temperature value.

[0074] Most importantly, by combining the thermal management method with the heat preservation member 2 and the liquid cooling plate 3, the heat preservation performance and heat dissipation performance of the battery pack can be very effectively improved, and it can be ensured that the battery pack and the electrical device (for example, an electric vehicle, etc.) are in a balanced state of heat supply and heat dissipation and maintained in an optimal performance state, greatly improving the stability and reliability of the battery pack and the electrical device.

Description of Symbols

[0075] One set of batteries 11 Battery cells Two heat insulation members 21 Heat insulation layer 22 Air layer 23 Positioning opening 24 Heat insulation ring Three liquid cooling plates 31 First liquid cooling plate 32 Second liquid cooling plate Four pallets 41 Pressure release opening Five battery boxes 51 Outer frame 511 First stepped portion 512 Second stepped portion 513 Third stepped portion 52 Bottom protection plate 531 First pressure release chamber 532 Second pressure release chamber Six temperature control battery chambers

Claims

1. A heat-insulated battery pack, comprising: a battery module (1) including a plurality of rows of battery cells (11); a heat-insulating member (2) having two heat-insulating layers (21) installed therein, with all of the plurality of rows of the battery cells (11) being installed in one of the heat-insulating layers (21), the two heat-insulating layers (21) being installed opposite to each other, a hollow chamber being installed between the two heat-insulating layers (21), a gas being filled into the hollow chamber to form an air layer (22), and the heat-insulating member (2) suppressing heat conduction on both opposite sides of the air layer (22).

2. The heat-insulating member (2) further has a plurality of positioning openings (23) installed therein, wherein the shape and dimensions of each of the positioning openings (23) are adapted to the shape and dimensions of each of the battery cells (11), and each of the battery cells (11) is installed and fixed inside the positioning opening (23). The heat-insulated battery pack according to Claim 1, characterized in that.

3. A heat-insulating ring (24) is installed on the inner side wall of each of the positioning openings (23), and the heat-insulating ring (24) abuts against the end face of the corresponding battery cell (11). The heat-insulated battery pack according to Claim 2, characterized in that.

4. The heat-insulated battery pack further includes at least one liquid-cooling plate (3), wherein at least one of the liquid-cooling plates (3) is thermally connected to the battery module (1). The heat-insulated battery pack according to Claim 3, characterized in that.

5. All of the plurality of liquid-cooling plates (3) are vertically distributed in the heat-insulating member (2), each of the liquid-cooling plates (3) is installed between two adjacent rows of the battery cells (11), and the plurality of liquid-cooling plates (3) are connected in parallel by a liquid-cooling pipe. The heat-insulated battery pack according to Claim 4, characterized in that.

6. The battery cell (11) is a cylindrical cell, the plurality of rows of the battery cells (11) are alternately arranged and distributed, and each of the liquid-cooling plates (3) is installed in a wavy shape so that the circumferential side surface of each of the battery cells (11) is attached to the liquid-cooling plate (3). The heat-insulated battery pack according to Claim 5, characterized in that.

7. The heat-insulated battery pack further includes a pallet (4), wherein the heat-insulating member (2) is installed on the pallet (4). The heat-insulated battery pack according to Claim 4, characterized in that.

8. The heat-insulated battery pack further includes a battery box (5), The battery pack (1), the heat insulation member (2), the pallet (4), and each of the liquid cooling plates (3) are all attached and fixed inside the battery box (5). The heat-insulated battery pack according to claim 7, characterized in that.

9. A plurality of pressure release openings (41) are provided in the pallet (4). Each battery cell (11) is installed corresponding to each pressure release opening (41). A pressure release passage is installed between the pallet (4) and the battery box (5). The inner hole of the heat insulation ring (24), the pressure release opening (41), and the pressure release passage are sequentially communicated to guide the hot gas flow generated in the battery cell (11) in a thermal runaway state to the outside of the battery box (5). The heat-insulated battery pack according to claim 8, characterized in that.

10. The battery box (5) includes a bottom protection plate (52) and a square-shaped outer frame (51). A first step portion (511), a second step portion (512), and a third step portion (513) are installed on the inner side wall of the outer frame (51). The first step portion (511), the second step portion (512), and the third step portion (513) are sequentially installed along the height direction of the outer frame (51) from the large surface of the outer frame (51). The bottom protection plate (52) is fixed to the first step portion (511). The pallet (4) is fixed to the third step portion (513). The heat-insulated battery pack according to claim 9, characterized in that.

11. The pressure release passage includes a first pressure release chamber (531) and a second pressure release chamber (532). The first pressure release chamber (531) is formed between the pallet (4), the bottom protection plate (42), and the inner side wall of the second step portion (512). The second pressure release chamber (532) is installed inside the outer frame (51). The first pressure release chamber (531) communicates with the second pressure release chamber (532). The heat-insulated battery pack according to claim 10, characterized in that.

12. A temperature-controlled battery chamber (6) is formed by the heat insulation member (2) and the inner side wall of the outer frame (51). The battery pack (1) is located inside the temperature-controlled battery chamber (6). The heat-insulated battery pack according to claim 10, characterized in that.

13. A thermal management method used for a battery pack, Comparing and evaluating the measured temperature value of the monitored battery with a preset temperature, and adjusting the usage state and heat exchange state of the battery, The preset temperature includes, from a low temperature to a high temperature, a first temperature range, a second temperature range, a third temperature range, a fourth temperature range, and a fifth temperature range, In the first state, when the measured temperature value is within the first temperature range, the usage state of the battery is set to a non-charging and non-discharging state, and the heat exchange state of the battery is set to a heating state, In the second state, when the measured temperature value is within the second temperature range, the usage state of the battery is set to a charging state, and the heat exchange state of the battery is set to a heating state, In the third state, when the measured temperature value is within the third temperature range, the usage state of the battery is set to a charging state or a discharging state, and the heat exchange state of the battery is set to a heating state, In the fourth state, when the measured temperature value is within the fourth temperature range, the usage state of the battery is set to a charging state or a discharging state, and the heat exchange state of the battery is set to a non-heating and non-cooling state, In the fifth state, when the measured temperature value is within the fifth temperature range, the usage state of the battery is set to a charging state or a discharging state, and the heat exchange state of the battery is set to a cooling state A heat management method characterized by the above.

14. The first temperature range is less than -20°C, The second temperature range is from -20°C to 5°C, The third temperature range is from 5°C to 15°C, The fourth temperature range is from 15°C to 37°C, The heat management method according to claim 13, characterized in that the fifth temperature range is greater than 37°C.

15. A first end temperature value is further set within the second temperature range, The heat management method according to claim 13 or claim 14, characterized in that when the measured temperature value is higher than the first end temperature value, the first state is terminated.

16. A second end temperature value is further set within the third temperature range, The heat management method according to claim 13 or claim 14, characterized in that when the measured temperature value is higher than the second end temperature value, the second state is terminated.

17. A third end temperature value is further set within the fourth temperature range, The heat management method according to claim 13 or claim 14, characterized in that when the measured temperature value is higher than the third end temperature value, the third state is terminated.

18. A fourth end temperature value is further set within the fourth temperature range, The heat management method according to claim 17, characterized in that when the measured temperature value is lower than the fourth end temperature value, the fifth state is terminated.

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