Battery pack and battery pack assembling method

Abstract

The invention belongs to the technical field of battery packs, and discloses a battery pack and a battery pack assembling method. The battery pack specifically comprises a battery box body, battery modules and module pressing strips, the battery module is correspondingly arranged in the accommodating space of the battery box body, the battery module comprises at least two battery cell groups stacked along a first direction, each battery cell group comprises 2N + 1 single battery cells stacked along a second direction, and clamping grooves are formed in two ends of the top wall of each single battery cell along the first direction; the module pressing strips extend in the second direction, the module pressing strips are arranged at the tops of the single battery cells and located between the two battery cell sets, and the clamping grooves of every two adjacent single battery cells in the first direction are bonded and fixed to the module pressing strips; and the positive output electrode and the negative output electrode of the battery module are arranged at the same end of the battery module along the second direction. The battery pack is simple in structure, and the number of parts can be reduced, so that the utilization rate of the space in the battery pack is improved, the energy density is improved, and the production cost can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of battery packs, and in particular, to a battery pack and a method for assembling a battery pack. Background Art

[0003] Regarding the problem of how to improve the power of a battery pack, in addition to increasing the energy density of a single cell, increasing the grouping rate and space utilization rate of the battery pack are the main solutions for battery manufacturers. The traditional CTP (Cell to PACK) solution needs to use the structure of end plates and tie straps to integrate cells into a battery module, and then assemble multiple battery modules into the whole package box. Among them, copper bars are required to connect the output poles of each battery module, and wiring harnesses are needed to connect the low-voltage plugs of the battery modules to transmit the voltage and temperature acquisition signals of a single cell to the circuit board. This CTP solution is not conducive to the arrangement of single cells, and the copper bars and wiring harnesses occupy a large space in the whole package, resulting in low space utilization rate of the whole battery pack.

[0004] Therefore, there is an urgent need to provide a new type of battery pack and a method for assembling a battery pack to solve the above technical problems in the prior art. Summary of the Invention

[0005] An object of the present invention is to provide a battery pack, the structure of which is simple, can reduce the number of components, thereby improving the space utilization rate inside the battery pack, increasing the energy density, and also being able to reduce the production cost.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] The battery pack specifically includes a battery box body, at least one battery module, and a module pressing strip. The battery box body has at least one accommodating space; the battery module is correspondingly arranged in the accommodating space. The battery module includes at least two groups of cell groups stacked along a first direction. Each group of cell groups includes 2N + 1 single cells stacked along a second direction. Clamping grooves are respectively arranged at both ends of the top wall of the single cell along the first direction; the module pressing strip extends along the second direction, and the module pressing strip is arranged on the top of the single cell and between two groups of cell groups. The clamping grooves of two adjacent single cells along the first direction are adhesively fixed to the module pressing strip; the first direction is perpendicular to the second direction; where N is a positive integer, and the single cells of the battery module are connected in series, and the positive output pole and the negative output pole of the battery module are arranged at the same end of the battery module along the second direction.

[0008] Optionally, the above-mentioned clamping groove penetrates the above-mentioned single cell along the above-mentioned second direction, and the clamping grooves of two adjacent above-mentioned single cells along the above-mentioned first direction communicate with each other, so as to form a receiving groove for receiving the above-mentioned module pressing strip between two adjacent above-mentioned cell groups.

[0009] Optionally, a glue injection groove is provided on the inner bottom wall of the above-mentioned clamping groove, the glue injection grooves of two above-mentioned clamping grooves that communicate with each other along the above-mentioned first direction communicate with each other, and structural glue is provided in the above-mentioned glue injection groove.

[0010] Optionally, the size of the above-mentioned single cell along the above-mentioned first direction is h, the size of the above-mentioned single cell along the above-mentioned second direction is d, the size of the above-mentioned glue injection groove along the above-mentioned second direction is e, and e ≤ d - 6mm; the size of the above-mentioned glue injection groove along the above-mentioned first direction is g, and 0.02 ≤ g / h ≤ 0.09.

[0011] Optionally, an intermediate heat insulation plate is provided between two adjacent above-mentioned cell groups along the above-mentioned first direction, and the top wall of the above-mentioned intermediate heat insulation plate is not higher than the inner bottom wall of the above-mentioned glue injection groove, so that at least part of the above-mentioned structural glue is accommodated between two adjacent above-mentioned cell groups along the above-mentioned first direction.

[0012] Optionally, the above-mentioned cell group includes a first cell group and a second cell group, and any one of the above-mentioned first cell group and the above-mentioned second cell group is provided with an odd number of the above-mentioned single cells, and the other is provided with an even number of the above-mentioned single cells.

[0013] Optionally, an intermediate cross beam extending along the above-mentioned first direction is provided inside the above-mentioned battery box body, and the above-mentioned intermediate cross beam is clamped between the above-mentioned first cell group and the above-mentioned second cell group; or, end heat insulation pads are provided at both ends of the above-mentioned first cell group and the second cell group along the above-mentioned second direction, and buffer pads are provided between two adjacent above-mentioned single cells of the above-mentioned first cell group and between two adjacent above-mentioned single cells of the above-mentioned second cell group along the above-mentioned second direction.

[0014] Optionally, the positive electrode post of one of two adjacent above-mentioned single cells along the above-mentioned first direction is arranged adjacent to the negative electrode post of the other above-mentioned single cell; the positive electrode post of one of two adjacent above-mentioned single cells along the above-mentioned second direction is arranged adjacent to the negative electrode post of the other above-mentioned single cell; the above-mentioned positive output electrode and the above-mentioned negative output electrode are correspondingly arranged at the positive electrode post and the negative electrode post with the farthest distance at both ends of the above-mentioned battery module along the above-mentioned first direction.

[0015] Optionally, the projection of the above-mentioned module pressing strip on the inner bottom wall of the above-mentioned clamping groove in the vertical direction has a dimension of a in the above-mentioned first direction, the dimension of the above-mentioned single cell in the above-mentioned first direction is h, and 0.02 ≤ a / h ≤ 0.10; the dimension of the above-mentioned module pressing strip in the above-mentioned first direction is b, and 0.04 ≤ b / h ≤ 0.20.

[0016] Another object of the present invention is to provide a battery pack assembly method, which is used to assemble the battery pack as described in any of the above solutions, including the steps of: S1. Assemble the battery cell group: Stack 2N + 1 of the above-mentioned single cells along the above-mentioned second direction; S2. Assemble the battery module: Stack at least two groups of the above-mentioned battery cell groups along the above-mentioned first direction and place them in the accommodation space of the above-mentioned battery box; S3. Connect the single cells in series: Place the bus bar assembly above the above-mentioned battery module, connect the bus bar assembly to the positive electrode posts and the negative electrode posts of the above-mentioned single cells, so that the single cells of the above-mentioned battery module are connected in series, and connect the above-mentioned positive output electrode and the above-mentioned negative output electrode to the same end of the above-mentioned battery module along the above-mentioned second direction; S4. Fix the battery module: Set the above-mentioned module pressing strip in the above-mentioned clamping groove between the above-mentioned single cells of two adjacent above-mentioned battery cell groups, and bond and fix the above-mentioned module pressing strip to the above-mentioned clamping groove.

[0017] Beneficial effects:

[0018] In the battery pack of the present invention, the accommodation space of the battery box is used to install the battery module. At the same time, the battery module is composed of at least two columns of battery cell groups stacked along the first direction. Each battery cell group includes a plurality of single cells stacked along the second direction. When fixing the battery module, a module pressing strip is used for bonding and fixing. Specifically, clamping grooves are provided at both ends of the single cell in the first direction, and the above-mentioned module pressing strip is bonded to the clamping groove. Since the module pressing strip is located between two adjacent battery cell groups, all the single cells of the adjacent battery cell groups can be bonded and fixed, thereby realizing the bonding and fixing of a battery module, and there is no need to use fixing parts such as fixing brackets or packing straps, which simplifies the structure of the battery pack; at the same time, the single cells in the battery module are connected in series, and the number of each battery cell group is set to 2N + 1, that is, an odd number. After the single cells are connected in series, the positive output electrode and the negative output electrode of the battery module can be set at the same end of the battery module along the second direction, so that the circuit output electrodes of the battery pack can all be set at the same end of the battery pack, reducing the layout space of copper bars and wire harnesses, and improving the space utilization rate of the battery pack. This battery pack can simplify the structure of the battery module, improve the integration degree of the battery module. At the same time, due to the reduction of the number of parts, the battery module can occupy a smaller space, thereby increasing the energy density of the battery pack, reducing the production cost of the battery pack, and the bonding and fixing method of the module pressing strip can improve the overall strength of the battery module and has higher use reliability. Description of the drawings

[0019] Figure 1 It is an axonometric view of the battery pack provided by the specific embodiment of the present invention;

[0020] Figure 2 It is an exploded view of a partial structure of the battery pack provided by the specific embodiment of the present invention;

[0021] Figure 3 It is a top view of the bus bar assembly provided by the specific embodiment of the present invention;

[0022] Figure 4 It is a top view of a partial structure of the battery pack provided by the specific embodiment of the present invention;

[0023] Figure 5 It is a longitudinal sectional view of the battery module along the first direction provided by the specific embodiment of the present invention;

[0024] Figure 6 is Figure 5 a partial enlarged view at A in

[0025] Figure 7 It is a top view of the single cell provided by the specific embodiment of the present invention.

[0026] In the figure:

[0027] 100, battery box; 101, accommodation space; 110, intermediate cross beam;

[0028] 200, battery module; 201, first core group; 202, second core group; 210, core cell group; 211, single cell; 2111, clamping groove; 2112, glue injection groove; 2113, positive electrode post; 2114, negative electrode post; 2115, cell top patch; 212, end heat insulation pad; 213, buffer pad; 214, intermediate heat insulation plate; 220, module interval heat insulation pad; 230, bus bar assembly; 231, bus bar bracket; 232, bus bar part; 233, circuit board; 234, low-voltage acquisition plug-in; 240, module upper cover; 250, output pole base; 251, positive output pole; 252, negative output pole;

[0029] 300, module pressing strip; 310, structural adhesive. Specific Embodiment

[0030] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. Additionally, it should be noted that for the convenience of description, only parts related to the present invention are shown in the drawings, rather than all structures.

[0031] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0032] In the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "over", and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "beneath", and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than that of the second feature.

[0033] In the description of this embodiment, the orientation or positional relationships such as "above", "below", "right", etc. are based on the orientation or positional relationship shown in the drawings. It is only for the convenience of description and simplifying the operation, 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. Therefore, it should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0034] The first direction described in this embodiment is Figure 2 the Y direction shown in Figure 2 i.e., the length direction of the single cell 211; the second direction is

[0035] as Figures 1 to 6As shown in the figure, the battery pack specifically includes a battery box body 100, at least one battery module 200 and a module pressing strip 300. The battery box body 100 has at least one accommodation space 101; the battery module 200 is correspondingly arranged in the accommodation space 101. The battery module 200 includes at least two groups of battery cell groups 210 stacked along a first direction. Each group of the battery cell groups 210 includes 2N + 1 single battery cells 211 stacked along a second direction. Clamping grooves 2111 are respectively arranged at both ends of the top wall of the single battery cell 211 along the first direction; the module pressing strip 300 extends along the second direction. The module pressing strip 300 is arranged on the top of the single battery cell 211 and is located between two groups of the battery cell groups 210. The clamping grooves 2111 of two adjacent single battery cells 211 along the first direction are adhesively fixed to the module pressing strip 300; the first direction is perpendicular to the second direction; wherein, N is a positive integer, and the single battery cells 211 of the battery module 200 are connected in series. The positive output pole 251 and the negative output pole 252 of the battery module 200 are arranged at the same end of the battery module 200 along the second direction.

[0036] In this embodiment, the battery pack uses the accommodation space 101 of the battery box 100 to install the battery module 200. At the same time, the battery module 200 is composed of at least two columns of battery cell groups 210 stacked along the first direction. Each battery cell group 210 includes a plurality of single battery cells 211 stacked along the second direction. When fixing the battery module 200, a module pressing strip 300 is used for bonding and fixing. Specifically, clamping grooves 2111 are provided at both ends of the single battery cell 211 along the first direction, and the above-mentioned module pressing strip 300 is bonded to the clamping grooves 2111. Since the module pressing strip 300 is located between two adjacent battery cell groups 210, all the single battery cells 211 of the adjacent battery cell groups 210 can be bonded and fixed. Thus, the bonding and fixing of a battery module 200 can be realized, and fixing components such as fixing brackets or packing straps do not need to be adopted, which simplifies the structure of the battery pack. At the same time, the single battery cells 211 in the battery module 200 are connected in series, and the number of each battery cell group 210 is set to 2N + 1, that is, an odd number. After the single battery cells 211 are connected in series, the positive output terminal 251 and the negative output terminal 252 of the battery module 200 can be arranged at the same end of the battery module 200 along the second direction, so that the circuit output terminals of the battery pack can all be arranged at the same end of the battery pack, reducing the layout space of copper bars and wire harnesses and improving the space utilization rate of the battery pack. This battery pack can simplify the structure of the battery module 200, improve the integration degree of the battery module 200. At the same time, due to the reduction of the number of components, the battery module 200 can occupy a smaller space, thereby improving the energy density of the battery pack, reducing the production cost of the battery pack. At the same time, the bonding and fixing method of the module pressing strip 300 can improve the overall strength of the battery module 200 and has higher use reliability.

[0037] Through specific measurement, the space utilization rate of the battery pack in this embodiment is increased by about 5% compared with the original structure.

[0038] As Figure 2 shown, both the positive output terminal 251 and the negative output terminal 252 are fixed on the battery box 100 through the output terminal base 250, and the fixing is more stable and the reliability is higher, which will not be elaborated here.

[0039] Furthermore, there are two columns of battery cell groups 210 in the battery module 200 in the first direction, that is, there are two columns of single battery cells 211 stacked along the second direction. An intermediate heat insulation plate 214 is provided between two adjacent battery cell groups 210 along the first direction. A buffer pad 213 is clamped between the single battery cells 211 stacked along the second direction, and end heat insulation pads 212 are provided at both ends of the battery module 200. After the battery module 200 is grouped, a certain force is applied in the second direction so that the battery module 200 is compressed by 2 mm to 6 mm, which is convenient for the battery module 200 to be put into the box.

[0040] In this embodiment, a plurality of battery modules 200 are stacked in the battery box body 100 along the first direction, specifically 3 battery modules 200. A module spacer thermal pad 220 is clamped between the single cells 211 of two adjacent battery modules 200 to prevent thermal spread between adjacent battery modules 200, improving safety and reliability. Details are not elaborated here.

[0041] As Figure 3 shown, after the battery modules 200 are placed in the box, subsequent operations such as positioning, fixing, and welding of the busbar assembly 230 are carried out. According to the number of columns of the single cells 211, one busbar assembly 230 can be selected for every two columns of single cells 211 or one busbar assembly 230 for every three columns of single cells 211. In this embodiment, one busbar assembly 230 is used for every two columns of single cells 211, and there are 3 busbar assemblies 230 for 6 columns of single cells 211.

[0042] The busbar assembly 230 in this embodiment can connect two adjacent cell groups 210, thereby reducing the number of busbar assemblies 230 and the cost of molds and inspection tools. And if it connects three or more cell groups 210, it will cause difficulties in manufacturing the busbar assembly 230. Specifically, the busbar piece 232 and the busbar bracket 231 are fixed together by thermal riveting. The temperature sensor bracket is placed on the busbar bracket 231 and thermally riveted to the busbar. The temperature sensor bracket is partially grooved for placing an NTC (negative temperature coefficient thermistor). At the same time, the voltage is collected through the circuit board 233. The circuit board 233 in this embodiment is a flexible printed circuit board (FPC), a flexible flat cable (FFC), or a flexible die-cut circuit board (FDC). And a low-voltage acquisition plug 234 is used to transmit the voltage and temperature data of the single cell 211 to the battery management system of the battery pack. According to the overall space and electrical layout of the battery pack, the low-voltage acquisition plug 234 can be fixed on the cross beam of the battery box body 100 or directly plugged into the slave board. Details are not elaborated here.

[0043] Furthermore, the low-voltage acquisition plug 234, the positive output terminal 251, and the negative output terminal 252 are arranged at the same end. Details are not elaborated here.

[0044] In this embodiment, support protrusions are provided at both ends of the busbar piece 232 along its length direction. The support protrusions are used to support the module upper cover 240 of the battery module 200. Support protrusions are provided on both sides of the busbar piece 232 to support the top module cover, reducing the overall deformation of the module upper cover 240.

[0045] According to the requirements of thermal runaway, the upper cover 240 of the module can adopt ceramizable silicone rubber or a PC sheet. When using ceramizable silicone rubber, the thickness is 0.2 mm or 0.3 mm, and the back glue is pasted on the busbar part 232, and the back glue completely covers the busbar part 232 and the nickel sheet of the busbar assembly 230. When using a PC sheet, the thickness is 0.175 mm or 0.25 mm, and its back glue can cover the top wall of the entire battery module 200.

[0046] Optionally, the above-mentioned busbar part 232 further includes a support arch between the two above-mentioned support protrusions, and the top wall of the support arch is flush with the top wall of the support protrusion. In this embodiment, the arch height of the support arch is 1 mm to 5 mm, and the specific height is determined by the magnitude of the expansion force, so as to improve the buffering performance of the busbar part 232 when the battery module 200 expands, reduce the overall stiffness of the busbar part 232, and the higher the arch height of the support arch, the smaller the stiffness. The busbar part 232 is welded and fixed to the electrode post of the battery cell. This causes the movement of the electrode post due to the expansion of the single battery cell 211 during the charging and discharging process of the single battery cell 211 to stretch the busbar part 232. If the stiffness of the busbar part 232 is too large, the electrode post of the battery cell cannot withstand the tensile force, resulting in damage to the electrode post of the battery cell and seal failure.

[0047] That is, two adjacent busbar assemblies 230 are spliced through an inter-cell busbar part 232 along the first direction. This inter-cell busbar is fixed to one of the busbar assemblies 230, and a busbar placement groove is provided on the busbar support 231 of the corresponding other busbar assembly 230. When the busbar assembly 230 is assembled on the upper part of the single battery cell 211, each busbar assembly 230 is placed in sequence. The above-mentioned busbar support 231 is a PC plastic suction support, and the thickness of the PC plastic suction support is 0.5 mm.

[0048] As Figure 2 and Figure 4 shown, the above-mentioned battery cell group 210 includes a first cell group 201 and a second cell group 202. Any one of the first cell group 201 and the second cell group 202 is provided with an odd number of the above-mentioned single battery cells 211, and the other is provided with an even number of the above-mentioned single battery cells 211. By such a setting, the length of the entire battery module 200 along the second direction can be reduced, and its overall strength can be improved.

[0049] In this embodiment, an intermediate cross beam 110 extending along the first direction is provided inside the battery box 100, and the intermediate cross beam 110 is clamped between the first cell group 201 and the second cell group 202. The setting of the intermediate cross beam 110 can provide mechanical support for the middle part after the battery cell group 210 is divided into the first cell group 201 and the second cell group 202, and improve the mechanical strength of the battery module 200 and the battery pack.

[0050] As a preferred embodiment, end heat insulation pads 212 are provided at both ends of the first core group 201 along the second direction and both ends of the second core group 202 along the second direction. Moreover, buffer pads 213 are provided between two adjacent single cells 211 of the first core group 201 along the second direction and between two adjacent single cells 211 of the second core group 202 along the second direction. The end heat insulation pads 212 can ensure the overall heat preservation requirement of the battery module 200 after being placed in the battery pack, and the thermal conductivity of the material needs to be less than 0.1 W / (m*K); while the buffer pads 213 can enable the battery module 200 to withstand impacts, and undergo a certain amount of compression when the battery module 200 is installed in the shell, facilitating it to be placed into the box body of the battery pack and improving the installation convenience.

[0051] An intermediate heat insulation plate 214 is provided between the cells 211 of the first core group 201 or the second core group 202. The intermediate heat insulation plate 214 is made of a hard plate with relatively high strength. For ternary cells, an epoxy plate is recommended, and for lithium iron phosphate cells, a PC plate or an epoxy plate can be used. Structural adhesive is applied on both sides of the intermediate heat insulation plate 214 to bond the single cells 211 on both sides, and the pressure-bonding area requirement is > p%, where p is a value from 1 to 9 times of 10. The p value is determined according to the simulation of the expansion force to enhance the module's ability to resist the expansion force. The thickness range of the intermediate heat insulation plate is from 0.5 mm to 4 mm, and it is preferably from 1.5 mm to 2.0 mm.

[0052] The end heat insulation pad 212 adopts a composite structure of a hard plate + buffer foam. The thickness of the end heat insulation pad 212 ≤ 5 mm. The hard plate can be made of materials such as PP, PC, and epoxy plates. If the single cell 211 is a ternary cell, the hard plate is preferably an epoxy plate to play a role in thermal runaway protection. If the cell is a lithium iron phosphate cell, the hard plate can be a PP or PC plate. The thickness of the hard plate is from 0.5 mm to 2 mm. The buffer foam uses a material with low thermal conductivity, which can be MPP, PU foam, or silicone foam, to play a role in heat preservation of the end cells and providing expansion space. The thickness is determined according to the expansion space required by the single cell 211 and the compression rate of the foam.

[0053] To ensure the cyclic expansion space of the single cell 211 and the requirements for grouping and enclosing in the box, buffer pads 213, namely buffer foams, are provided between the large surfaces at both ends of the single cell 211 along the second direction. The gap between adjacent single cells 211 along the second direction is designed to be 1% - 10% of the thickness of the single cell 211, which is specifically determined according to the expansion force and cyclic requirements. The buffer pads 213 can adopt the structural form of a return-shaped frame or single-strip splicing, and the material can use MPP or silicon foam with better compressibility. If the single cell 211 is a ternary cell with relatively intense thermal runaway, heat-insulating materials are also required to be designed between the large surfaces, and aerogel felt is recommended. Aerogel felt has the characteristics of high temperature resistance, excellent heat insulation performance, and low density, meeting the thermal runaway requirements and reducing the weight of the whole package. The thickness is determined according to the thermal runaway requirements, the expansion space of the single cell 211, and the compression rate of the aerogel. Generally, aerogel with a thickness of more than 2 mm is used. And the aerogel felt can also be used in combination with buffer strips, and the buffer strips can be MPP, PU foam or silicon foam.

[0054] Between adjacent battery modules 200 along the first direction, there is also a module spacer thermal pad 220 with a single-sided adhesive tape pasted on it, and the thickness of the module spacer thermal pad 220 is more than 1 mm. If the single cell 211 is a lithium iron phosphate cell, the material of the module spacer thermal pad 220 is recommended to be MPP. A small piece of MPP can be pasted on each cell, or a whole piece of MPP can be pasted between two adjacent battery modules 200. If the single cell 211 is a ternary cell, a whole piece of aerogel felt or epoxy board is pasted on the side between adjacent battery modules 200 to prevent thermal spread between adjacent single cells 211 along the first direction. The height difference between the module spacer thermal pad 220 and the inner bottom wall of the clamping groove 2111 can be appropriately reduced according to the thermal runaway requirements.

[0055] Optionally, the positive electrode post 2113 of one of the above-mentioned single cells 211 is arranged adjacent to the negative electrode post 2114 of another of the above-mentioned single cells 211 among two adjacent single cells 211 along the above-mentioned first direction; the positive electrode post 2113 of one of the above-mentioned single cells 211 is arranged adjacent to the negative electrode post 2114 of another of the above-mentioned single cells 211 among two adjacent single cells 211 along the above-mentioned second direction. Thus, the series high-voltage connection direction of the single cells 211 is spiral. The head or tail of each adjacent two columns of cell groups 210 is connected through an inter-cell busbar part 232 along the first direction, and there is no cross-connecting busbar between adjacent cell groups 210 or battery modules 200, reducing the number of bases and connecting copper bars, which is beneficial to cost reduction and improvement of module assembly efficiency.

[0056] In this embodiment, the positive output terminal 251 and the negative output terminal 252 are correspondingly arranged at the positive electrode post 2113 and the negative electrode post 2114 which are the farthest apart at both ends of the battery module 200 along the first direction. Such an arrangement can increase the distance between the positive output terminal 251 and the negative output terminal 252, reduce the voltage value between two adjacent rows of busbar assemblies 230, and is beneficial to improving the thermal runaway resistance and insulation performance of the entire battery pack. Specifically, when thermal runaway occurs, the distance between the positive output terminal 251 and the negative output terminal 252 is relatively far, and the voltage difference between adjacent battery modules 200 is about 100V to 200V, which is a relatively low voltage, greatly reducing the risk of arcing and short circuit. Moreover, there is a high-temperature fire-resistant insulating tape on the top of the module and the module upper cover 240 provides double protection, thus protecting the safety of users.

[0057] Please refer to Figures 4 to 7 , the clamping groove 2111 penetrates the single cell 211 along the second direction, and the clamping grooves 2111 of two adjacent single cells 211 along the first direction are communicated with each other, so as to form a receiving groove for receiving the module pressing strip 300 between two adjacent cell groups 210. Using the mutually communicated clamping grooves 2111 to receive the module pressing strip 300 can play a limiting role on the module pressing strip 300 and improve the reliability of fixation; it can also enable the receiving groove to receive part or all of the module pressing strip 300, reduce the space occupied by the module pressing strip 300, and further improve the energy density of the battery module 200.

[0058] The module pressing strip 300 is in a long strip shape, and its longitudinal section is rectangular. The material of the module pressing strip 300 is made of a high-strength material, such as epoxy board. The thickness c of the module pressing strip 300 is ≥3mm, and the upper surface of the module pressing strip 300 is not lower than the upper surface of the busbar part 232, which is used to prevent arcing between adjacent busbars during thermal runaway.

[0059] According to the expansion force condition of the battery module 200, the high-strength material used for the module pressing strip 300 should consider the tensile elastic modulus. For example, the tensile elastic modulus of a conventional epoxy board is ≥24GPa. When the shear force of the structural adhesive 310 at the bottom of the pressing strip is relatively large, an epoxy board with a reduced elastic modulus can be used, and the tensile elastic modulus of the epoxy board is ≤16GPa, and the tensile strength is ≥200MPa.

[0060] The module pressing strip 300 is made of a single material, such as an integral epoxy board. For lithium iron phosphate battery cells, the upper surface of the epoxy board should not exceed the upper surface of the bus bar. It is possible to choose to paste a material with lower strength on the upper part of the epoxy board, such as PC, PP, or a foam with higher temperature resistance and lower water absorption (such as silicone foam or silicone rubber, etc.). The module pressing strip 300 between adjacent battery cell groups 210 in the battery module 200 assembled by battery cell groups 210 without intervals in the middle is a whole strip. The module pressing strip 300 is positioned by the protrusion of the bus bar bracket 231. The width of the module pressing strip 300 is b, and the distance between the positioning protrusions is b + k, where k is the gap between adjacent bus bar parts 232, and its value ranges from 0.5 mm to 2 mm, preferably 0.7 mm. If the battery box 100 is provided with an intermediate cross beam 110, the module pressing strip 300 between adjacent battery modules 200 or the module pressing strip 300 between adjacent battery cell groups 210 is divided into two sections, and the two module pressing strips 300 are set to be disconnected above the intermediate cross beam 110, which is used to avoid the positioning deviation in the Y direction of the first cell group 201 and the second cell group 202 at both ends of the intermediate cross beam 110, and is beneficial to ensuring the coincidence bonding width a between the module pressing strip 300 and the inner bottom wall of the clamping groove 2111 of the single battery cell 211. Specifically, the module pressing strip 300 between adjacent battery modules 200 is positioned and assembled through a tooling.

[0061] In this embodiment, a glue injection groove 2112 is provided on the inner bottom wall of the above-mentioned clamping groove 2111. The glue injection grooves 2112 of two above-mentioned clamping grooves 2111 that communicate with each other along the above-mentioned first direction communicate with each other, and a structural adhesive 310 is provided in the glue injection groove 2112. Specifically, the structural adhesive 310 can firmly fix the module pressing strip 300 on the inner bottom wall of the clamping groove 2111, and the glue injection groove 2112 provides an accommodation space 101 for the injection of the structural adhesive 310, improving the stability of the structure.

[0062] As Figure 6 and Figure 7 shown, the top wall of the above-mentioned intermediate heat insulation board 214 or the module spacer heat pad 220 is not higher than the inner bottom wall of the above-mentioned glue injection groove 2112, so that at least part of the above-mentioned structural adhesive 310 is accommodated between two adjacent above-mentioned battery cell groups 210 along the above-mentioned first direction. Specifically, the height of the part of the structural adhesive 310 between two adjacent battery cell groups 210 is not less than 5 mm, and in this embodiment, it is 10 mm, which helps to improve the anti-expansion ability of the battery module 200 and further improves the use safety of the battery pack.

[0063] Further, the projection of the module pressing strip 300 on the latching groove 2111 along the first direction has a dimension a along the first direction, the dimension of the battery cell along the first direction is h, and 0.02 ≤ a / h ≤ 0.10; the dimension of the module pressing strip 300 along the first direction is b, b is 2 mm to 4 mm smaller than the distance between adjacent two rows of busbars, and 0.04 ≤ b / h ≤ 0.20.

[0064] The single battery cell 211 in this embodiment is a square shell battery cell. A battery cell top patch 2115 is attached to the top of the single battery cell 211. The dimension of the single battery cell 211 along the first direction is h, h is 100 mm to 300 mm, the dimension of the single battery cell 211 along the second direction is d, d is 20 mm to 100 mm, the dimension of the glue injection groove 2112 along the second direction is e, and e ≤ d - 6 mm; the distance between the positive electrode post 2113 or the negative electrode post 2114 of the single battery cell 211 and the end edge of the single battery cell 211 along the first direction is f, and 0.02 ≤ f / h ≤ 0.10; the dimension of the glue injection groove 2112 along the first direction is g, and 0.02 ≤ g / h ≤ 0.09

[0065] Another object of the present invention is to provide a battery pack assembly method, which is used to assemble the battery pack as described in any of the above solutions, including the steps of: S1. Assemble the battery cell group 210: Stack 2N + 1 of the above single battery cells 211 along the second direction; S2. Assemble the battery module 200: Stack at least two groups of the above battery cell groups 210 along the first direction and place them in the accommodation space 110 of the battery box 100; S3. Connect the single battery cells 211 in series: Place the busbar assembly 230 above the above battery module 100, connect the busbar assembly 230 to the positive electrode post 2113 of the above single battery cell 211 and the negative electrode post 2114 of the above single battery cell 211, so that the single battery cells 211 of the above battery module 200 are connected in series, and connect the above positive output pole 251 and the above negative output pole 252 to the same end of the above battery module 200 along the second direction; S4. Fix the battery module: Set the above module pressing strip 300 on the top wall between adjacent two groups of the above battery cell groups 210, and bond and fix the above module pressing strip 300 to the latching groove 2111 of the above single battery cell 211.

[0066] This battery pack assembly method is used to assemble the battery pack as described in any of the above solutions, and thus has all the beneficial effects of the battery pack as described in any of the above solutions, which will not be elaborated here.

[0067] Further, the battery module 200 is disposed in the accommodation space 101 formed by the cross beam and side beam of the battery box 100. The end of the battery module 200 is in close contact with the cross beam. The cross beam of the battery box 100 resists the expansion of the battery module 200. The bottom of the battery module 200, that is, the bottom of the single battery cell 211, is adhesively fixed to the liquid cooling plate at the bottom of the battery box 100 through a thermally conductive structural adhesive.

[0068] In the battery pack assembly method of this embodiment, during the process of assembling and forming the above-mentioned battery pack, a single module pressing strip 300 can be used to adhesively fix all the single battery cells 211 of the adjacent battery cell groups 210, thereby realizing the adhesive fixation of a battery module 200. Moreover, there is no need to use fixing components such as fixing brackets or tying straps, which simplifies the structure of the battery pack. At the same time, the single battery cells 211 in the battery module 200 are connected in series, and the number of single battery cells 211 in each battery cell group 210 is set to 2N + 1, that is, an odd number. After the single battery cells 211 are connected in series, the battery module 200 does not need to be provided with a jumper busbar. The positive output terminal 251 and negative output terminal 252 of the battery module 200 can be set at the same end of the battery module 200 along the second direction, so that the circuit output terminals of the battery pack can all be set at the same end of the battery pack, reducing the layout space of copper bars and wire harnesses and improving the space utilization rate of the battery pack. This battery pack assembly method can simplify the structure of the battery module 200, improve the integration degree of the battery module 200. At the same time, due to the reduction of the number of components, the battery module 200 can occupy a smaller space, thereby increasing the energy density of the battery pack, reducing the production cost of the battery pack, and the adhesive fixation method of the module pressing strip 300 can improve the overall strength of the battery module 200 and has higher use reliability.

[0069] This embodiment also provides an electrical device, which includes the battery pack described in any of the above solutions. The electrical device can specifically be an electric vehicle, a hybrid vehicle, an electric ship, an electric bicycle, an energy storage device, etc., as long as it uses the above battery pack for power supply or energy storage, and no specific limitation is made here.

[0070] Obviously, the above-mentioned embodiments of the present invention are merely examples for clearly explaining the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, various obvious changes, re-adjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A battery pack, characterized in that: include: A battery box, wherein the battery box has at least one accommodating space; At least one battery module, the battery module is correspondingly arranged in the accommodating space, the battery module comprises at least two groups of battery cell groups stacked along a first direction, each group of the battery cell groups comprises 2N+1 single battery cells stacked along a second direction, and the top walls of the single battery cells are respectively provided with clamping grooves at both ends along the first direction; A module pressure strip, the module pressure strip is extended along the second direction, the module pressure strip is arranged on the top of the single battery cell and is located between the two groups of the battery cell groups, and the clamping grooves of the two adjacent single battery cells along the first direction are both bonded and fixed to the module pressure strip; the first direction is perpendicular to the second direction; Wherein, N is a positive integer, and the single cells of the battery module are connected in series, and the positive output electrode of the battery module and the negative output electrode of the battery module are arranged at the same end of the battery module along the second direction.

2. The battery pack according to claim 1, characterized in that: The clamping groove is arranged to penetrate the single battery cell along the second direction, and the clamping grooves of two adjacent single battery cells along the first direction are connected to each other, so that an accommodating groove for accommodating the module pressure strip is formed between two adjacent battery cell groups.

3. The battery pack according to claim 2, characterized in that: The inner bottom wall of the clamping groove is provided with a glue injection groove, the glue injection grooves of two adjacent clamping grooves along the first direction are connected to each other, and structural glue is provided in the glue injection groove.

4. The battery pack according to claim 3, characterized in that: The size of the single battery cell along the first direction is h, the size of the single battery cell along the second direction is d, the size of the glue injection groove along the second direction is e, e≤d-6mm; the size of the glue injection groove along the first direction is g, 0.02≤g / h≤0.

09.

5. The battery pack according to claim 3, characterized in that: An intermediate heat insulating plate is arranged between two adjacent battery cell groups along the first direction, and the top wall of the intermediate heat insulating plate is not higher than the inner bottom wall of the glue injection groove, so that at least part of the structural glue is accommodated between the two adjacent battery cell groups along the first direction.

6. The battery pack according to claim 1, characterized in that: The battery cell group includes a first core group and a second core group. Either one of the first core group and the second core group is provided with an odd number of the single battery cells, and the other one of the first core group and the second core group is provided with an even number of the single battery cells.

7. The battery pack according to claim 6, characterized in that: An intermediate crossbeam extending along the first direction is arranged inside the battery case, and the intermediate crossbeam is sandwiched between the first core group and the second core group; or, end insulation pads are arranged at both ends of the first core group along the second direction and at both ends of the second core group along the second direction, and buffer pads are arranged between two adjacent single cells of the first core group along the second direction and between two adjacent single cells of the second core group along the second direction.

8. The battery pack according to any one of claims 1 to 7, characterized in that: The positive electrode column of one of the two single cells adjacent to each other along the first direction is arranged adjacent to the negative electrode column of the other single cell; the positive electrode column of one of the two single cells adjacent to each other along the second direction is arranged adjacent to the negative electrode column of the other single cell; the positive output electrode and the negative output electrode are correspondingly arranged at the positive electrode column and the negative electrode column that are farthest from each other at both ends of the battery module along the first direction.

9. The battery pack according to any one of claims 1 to 7, characterized in that: The projection of the module pressure strip along the vertical direction on the bottom wall inside the clamping groove has a dimension a along the first direction, the dimension of the single cell along the first direction is h, 0.02≤a / h≤0.10; the dimension of the module pressure strip along the first direction is b, 0.04≤b / h≤0.

20.

10. A battery pack assembly method, characterized in that: For assembling a battery pack as claimed in any one of claims 1 to 9, comprising the steps of: S1, assembling a battery cell group: stacking 2N+1 of the single battery cells along the second direction; S2, assembling a battery module: stacking at least two groups of the battery cell groups along the first direction and placing them into the accommodation space of the battery box; S3, connecting the single cells in series: placing a busbar assembly above the battery module, connecting the busbar assembly with the positive electrode column of the single cell and the negative electrode column of the single cell, so that the single cells of the battery module are connected in series, and connecting the positive output electrode and the negative output electrode to the same end of the battery module along the second direction; S4, fixing the battery module: providing the module pressure strip in the clamping groove between the single cells of two adjacent cell groups, and bonding and fixing the module pressure strip to the clamping groove.

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